Division Oncological Diagnostics and Therapy (E0100 / E010) Head: Prof

Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

Division Oncological Diagnostics and Therapy (E0100 / E010) Head: Prof. Dr. Gerhard van Kaick (- 9/02), Priv.-Doz. Dr. Stefan Delorme (acting, 10 - 12/02)*) Scientists Most of our clinical projects evaluate technical improve- Priv.-Doz. Dr. Stefan Delorme ments in the field of Magnetic Resonance Imaging which Dr. Ljubica Dukic (1/02 -) are developed in close cooperation with the Division of Priv.-Doz. Dr. Marco Essig Biophysics (E0200). New methods are mainly related to Dr. Christian Fink functional imaging, e.g, of perfusion, diffusion, or metabo- Dr. Stefan Heckl (- 5/02) lism in tumors. We intend to obtain more information on Dr. Fabian Kießling the biological behavior of tumors, particularly their aggres- Dr. Martin Krix siveness and their response to radiotherapy, chemother- Dr. Matthias Lichy apy, or novel approaches, such as antiangiogenic treat- Dr. Dagmar Liebermann (½) ment. Together with E0200, we are evaluating new devel- Dr. Michael Puderbach (7/02 -) opments in interventional MRI, i.e., MR-guided treatment Dr. Cornelia Rehm using intravascular catheters or percutaneous probes for Priv.-Doz. Dr. Heinz-Peter Schlemmer (-5/02) local drug delivery or, e.g., thermal ablation. Priv.-Doz. Dr. Stefan Schönberg (-10/01) Besides MRI, multiphasic, contrast-enhanced spiral CT Dr. Bram Stieltjes (6/02 -) and new-developed ultrasound techniques are capable of Dr. Klaus Wasser (-6/02) assessing tissue perfusion. They are being evaluated in Dr. Marc-André Weber (-7/01) experimental and clinical settings for assessing therapeuti- cally induced changes in tumor perfusion, and are corre- Guest Scientists lated with reference measurements using MRI. Dr. Jutta Debus (5/02 -) Dr. Holger Hof (1-12/02) Since recently, we have opened a cooperation with the Di- Dr. Lin Jiang (China, Shanghai, -02/02) vision Differentiation and Carcinogenesis (B0600) where Dr. Maria-Katherina Ganten tumors in small animals (mice and rats) are examined non-invasively, using ultrasound or MRI. For anyone in- Technicians volved in studies with experimental tumors in animals, Peter Bontzol Adelheid Fuxa such functional examinations constitute a major gain, Jürgen Heiss Martina Jochim since until recently, an assessment of changes in a tumor Kathleen Knauer Barbara Rimmler (- 2/02) was only possible either with caliper size measurements, 221 Heike Streib-Retzbach (½) Susanne Wetzel or histologic preparation of the excised tumor. Marie Zuna (½) Besides numerous journal publications, four habilitation theses have been concluded in 2001 and 2002. With the retirement of Prof. Dr. Manfred Volm in January *) The founder and head of the Division Oncological Diag- 2000, his working group was closed. Publications of his nostics and Therapy, Prof. G. van Kaick, retired in Septem- group which have been published or accepted within the ber 2002. Priv.-Doz. S. Delorme acted temporarily as report period are listed separately below. Since January head. Since January 2003 Prof. Hans-Ulrich Kauczor is 2002, the working group Positron Emission Tomography head of the Division. (headed by Prof. Strauss) belongs to the Clinical Coopera- tion Unit Nuclear Medicine (E0600), headed by Prof. Haberkorn. This group’s publications that refer to its activities until end of 2001 and are meanwhile published or in press are also listed separately. Their activities, however, are reported in detail by E0600.

Publications by the groups of Prof. Strauss and Prof. Volm (* = external co-author) [1] Dimitrakopoulou-Strauss A; Strauss LG; Burger C*: Quantita- tive PET-studies in pretreated melanoma patients: a comparison of F-18-DOPA to F-18-FDG and O-15-water using compartment and non-compartment analysis. Journal of Nuclear Medicine, 42 (2001) 248-256. [2] Dimitrakopoulou-Strauss A; Strauss LG; Burger C*; Mikolajczyk K*; Lehnert T*; Bernd L*; Ewerbeck V*: Fractal di- mension based on box counting: A new parameter for the quantification of dynamic PET studies. Journal of Nuclear Medicine, in press.

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

[3] Dimitrakopoulou-Strauss A; Strauss LG; Schwarzbach M*; [20] Volm M; Koomägi R; Rittgen W: Cellular predictive factors of Burger C*; Heichel T*; Willeke F*; Mechtersheimer G*; Lehnert drug resistance in non-small cell lung carcinomas. In: Method in T*: Dynamic PET 18F-FDG studies in patients with primary and Molecular Medicine. Lung Cancer Vol. 2. Diagnostic and Thera- recurrent soft tissue sarcomas: impact on diagnosis and correla- peutic Methods and Reviews. Driscoll B (Ed.) Totowa NJ: tion with grading. Journal of Nuclear Medicine, 42 (2001) 713- Humana Press (2003) in press 720. [21] Volm M; Sauerbrey A*; Zintl F*; Koomägi R; Efferth T*: Pro- [4] Efferth T*; Koomägi R; Mattern J; Volm M: Expression profiles tein expression profile in newly diagnosed acute lymphoblastic of proteins involved in the xenotransplantability of non-small cell leukemia of children developing relapses. Oncology Reports lung cancer. International Journal of Oncology, 20 (2002) 391-395 (2003) in press. [5] Haberkorn U; Bellemann ME; Gerlach L; Morr I; Trojan H; Brix [22] Wu H; Dimitrakopoulou-Strauss A; Heichel TO*; Lehner B*; G; Doll J; Wießler M; van Kaick G: Positron emission tomography Bernd L*; Ewerbeck V*; Burger C*; Strauss LG: Quantitative of 2-fluror-2-deoxyglucose uptake in rat prostate adenocarcinoma evaluation of skeletal tumours with dynamic FDG PET: SUV in during chemotherapy with glucosylifosfamide. Nuclear Medicine comparison to patlak analysis. European Journal of Nuclear Medi- and Biology (2003) in press. cine, 28 (2001) 704-710. [6] Koomägi R; Zintl F*; Sauerbrey A*; Volm M: Vascular endothe- [23] Zhou X*; Frohlich ED*; Clorius JH; Haufe S: Functional and lial growth factor in newly diagnosed and recurrent childhood structural involvement of afferent and efferent glomerular arteri- acute lymphoblastic leukemia as measured by real-time quantita- oles in hypertension. Americal Journal of Kidney, 37 (2001) 1092- tive polymerase chain reaction. Clinical Cancer Research 7 1097. (2001) 3381-3384 [7] Masanek U*; Stammler G*; Volm M: Modulation of multidrug resistance in human ovarian cancer cell lines by inhibition of P- glycoprotein 170 and PKC isoenzymes with antisense oligonucle- otides. Journal of Experimental Therapeutics and Oncology 2 (2002) 37-41 [8] Mattern J, Koomägi, R, Volm M: Characteristics of long-term survivors of untreated lung cancer. Lung cancer 36 (2002) 277- 282. [9] Mattern J: Role of angiogenesis in drug resistance. Anticancer Research, 21 (2001) 4265-4270 [10] Mattern J; Koomägi R; Volm M: Characteristics of long-term survivors of untreated lung cancer. In: Lung Cancer. Pontifex G (Ed.) Amsterdam: Excerpta Medica (2003) in press. [11] Mattern J; Koomägi R; Volm M: Expression of drug resistance gene products during progression of lung carcinomas. Anti- 222 cancer Research (2003) in press. [12] Mattern J; Volm M: Clinical estimation of the rate of lung cancer. Anticancer Research, 21 (2001) 4067-4070. [13] Schwarzbach M*; Dimitrakopoulou-Strauss A; Mechtersheimer G*; Hinz U*; Willeke F*; Cardona S*; Attigah N*; Strauss LG; Herfarth C; Lehnert T: Assesment of soft tissue lesions suspicious for liposarcoma by F18- deoxyglucose (FDG) positron emission tomography (PET). Anticancer Research, 21 (2001) 3609-3614. [14] Strauss LG; Dimitrakopoulou-Strauss A: Positronenemissionstomographie (PET) in der onkologischen Diagnostik und Therapieplanung. In: Onkologie: Grundlagen, Diagnostik, Therapie, Enrwicklung 1995, Vol. 1. Zeller WJ, zur Hausen H (Eds.) München-Landsberg: Ecomed (2001) Chapter III-5 [15] Strauss LG; Kontaxakis G; Dimitrakopoulou-Strauss A: Per- formance characteristics of iterative image reconstruction for routine use in positron emission tomography. Alasbimn 3 (13) Octo- ber 2001, www.alasbimnjournals.cl/revistas/13/strauss.html. [16] Volm M and Koomägi R: Case revies: Prognostic relevance of angiogenic, proliferative and apotpotic factors in lung carcinomas. In: Methods in Molecular Medicine. Lung Cancer Vol. 1: Mo- lecular Pathology methods and Reviews. Driscoll B (Ed.) Totowa NJ: Humana Press (2002) 271-284 [17] Volm M; Koomägi R; Mattern J; Efferth T*: Expression profile of genes in non-small cell lung carcinomas from long-term surviv- ing patients. Clinical Cancer Research (2003) in press. [18] Volm M; Koomägi R; Mattern J; Efferth T*: Expression profiles involved in drug resistance of non-small cell lung cancer. Britisch Journal of Cancer (2003) in press. [19] Volm M; Koomägi R; Mattern J; Efferth T*: Protein expression profile of primary squamous cell lung carcinomas indicative for the incidence of metastases. Clinical and Experimental Metasta- sis (2003) in press.

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

Magnetic Resonance Imaging in Oncology the Division Differentiation and Carcinogenesis (B0600), (E0101) where we non-invasively monitor tumor growth and angiogenesis and evaluate the effects of anti-angiogenic sub- S. Delorme, M. Essig, C. Fink, F. Kießling, M. Krix, stances. M. Lichy, C. Rehm, H.-P. Schlemmer, B. Stieltjes, K. Wasser, M.-A. Weber Dynamic MR imaging For dynamic MRI, images or image stacks are rapidly ac- Magnetic resonance imaging (MRI) has become an in- quired after intravenous contrast agent injection, and ana- dispensible method in oncology, allowing a rapid and cor- lyzed for the change of signal intensity over time on a rect diagnosis in numerous conditions. The main topic of pixel-by-pixel basis. Pharmacokinetic models help to pa- our work is functional tumor diagnostics for characterizing rametrize and also color-code the contrast behavior of tis- the biological behaviour of a tumor, for estimating its prog- sue. The parameters used to express the contrast behav- nosis, assisting therapy planning, or assessing treatment ior were the amplitude “A” (which is the relative signal in- response. We use MR angiography for assessing macro- crease after contrast agent injection), and the exchange circulation, dynamic MRI for mircrocirculation, blood-oxy- rate constant “kep” (which according to the calculation de- gen-level-dependent (BOLD) imaging for neurofunctinal scribes the return of contrast agent from the interstitium studies, and MR spectroscopy for tumor metabolism. into the intravascular space). A is mainly influenced by the Novel methods in the field of MRI are developed, evalu- amount of blood delivered to the tissue, and thereby also ated and refined in close cooperation with the Division reflects vessel density. kep is a compound parameter which Biophysics and Medical Radiation Physics (E0200) and is determined by blood flow into the tumor, vessel density, the Clinical Cooperation Unit for Radiooncology (E0500) capillary exchange surface, as well as transendothelial [9,50]. A major part of our activities is dedicated to plan- permeability [32]. Dynamic MRI has been extensively ning, evaluation and follow-up of precision radiotherapy evaluated for breast cancer [3,4,6,15,16,24,25,30,47], tu- using stereotactic photon treatment or heavy ion therapy. mors of the brain and base of skull, pelvis, bone marrow, In current studies, we examine tumors, e.g., of the brain, as well as for experimental murine tumors. base of skull, axis skeleton, hematopoietic and lymphatic system, breast, lung, liver, kidney, and female pelvis. In Dynamic MRI for monitoring neoadjuvant additional projects related to, e.g., neurofunctional issues chemotherapy of breast cancer. or diagnostics of large vessels, we evaluate novel tech- Neoadjuvant chemotherapy is given prior to operation for niques which have the potential of being used for tumor breast cancer in order to induce shrinkage of the tumor. diagnostics in future. Since recently, we are performing This may enable breast-conserving surgery in large tu- studies in experimental murine tumors, in cooperation with mors which would initially warrant breast ablation, but ad- 223 ditionally provides important information on possible che- moresistance of the tumor. However, a reduction in tumor size not only occurs late during chemotherapy but is also difficult to assess using x-ray mammography or ultrasound alone. Therefore, we used dynamic MRI to better assess the tumor’s size and also determine whether the change in tumor vascularization, as reflected by the pharmacokinetic parameters derived from dynamic studies, would help to judge upon the tumor’s response. For dynamic MRI of the breast (“MR mammography”, MRM), 32 stacks of 15 images each are acquired during 12 minutes, resulting in 22.5 secs per stack. Each stack covers the entire, or almost entire glandular tissue of the breast. Since 1993, more than 3000 MR mammographic examinations have been performed in our Division. Comparison between x-ray mammography, ultrasonography, and MR mammography for the assessment of chemotherapeutically treated breast cancer: MRM studies from 24 patients treated with neoadjuvant chemotherapy for invasive breast cancer between 1995 and 1999 were retrospectively analyzed. The patients had received repeated MRM examinations accompanying four cycles of Epirubicin with Paclicaxel or Cyclophosphamide. Figure 1: Color-mapped dynamic MRI of a ductal invasive carci- The size measurements in calibrated, color-coded MRM noma before (a, b) and after (c,d) neoadjuvant treatment. The images (Figure 1) were compared with those made on x- largest tumor diameter as well as the largest diameter orthogonal to it were measured (a, c). The region of interest (ROI) for the ray mammographies and ultrasound scans, and correlated evaluation of the dynamic contrast enhancement was drawn over with the histopathologically determined tumor diameter as the whole assumed tumor area (b, d). In the follow-ups each re- well as the size estimated by palpation alone. maining contrast enhancement inside the original tumor site was considered as residual tumor (c, d).

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

On the final scans, aquired no longer than two weeks before operation, the correlation with histology (pearson correlation coefficient) was 0.58 for palpation, 0.47 for ultrasound, 0.37 for x-ray mammography, and 0.77 for MR mammography. We also found that including the tumor periphery, which showed a stronger enhancement than the apparently unaffected ipsi- or contralateral breast parenchyma, but according to the enhancement curve still ap- peared ambiguous, more precisely matched the true tumor size than measuring only the tumor core [29]. We also found that a tumor response (size reduction by at least 25 %) would not be anticipated earlier if the tumor volume (calculated by adding the areas in single slices oc- Figure 2: Percentual change of the contrast enhancement param- cupied by tumor, and multiplying by the slice thickness) eter kep in responders (>25% reduction of tumor area, n=10, top).

were measured instead of only the largest cross-secion A clear decrease of the parameter kep is already noticed in the area (as is standard according to WHO) [48]. first follow-up (p<0.008). Regressive changes after neoadjuvant chemotherapy Dynamic MRI in multiple myeloma for breast cancer affect the accuracy of preoperative Multiple myeloma is a low-malignant non-Hodgkin lympho- MRI measurements of tumor size: ma. Its hallmark is a clonal proliferation of plasma cells in- The pathological specimens from thirty-one patients with filtrating the bone marrow in a diffuse or multinodular fash- breast cancer who underwent MRI before and after neo- ion, and producing immunoglobulin-derived paraproteins adjuvant treatment were classified to show a regression as well as mediators which stimulate bone resorption score 0 (no regression), 1 or 2 (reduction of invasive tu- (most commonly Interleukin-1 and Tumor Necrosis Fac- mor, with cytopathic effects,and additional resorptive tor). Along with bone marrow infiltration goes neoangio- changes), 3 (only in-situ components left), and 4 (com- genesis, stimulated by production of the Vascular Endot- plete histological response). Considering the conventional helial Growth Factor (VEGF) by myeloma cells. At the De- MR images, tumor diameters were measured on the color partment of Hematology / Oncology (Medizinische Klinik maps and compared with histological tumor size. The cor- und Poliklinik V) at the Heidelberg University Hospital, relation between tumor sizes measured by MRI and histo- anti-angiogenic substances are evaluated for the treat- 224 pathology was 0.83 (p<0.0007) in 12 tumors without re- ment of multiple myeloma [31]. Presently, thalidomide is gressive changes (score 0), and 0.48 (p<0.051) in 17 tu- given alone or in combination with a CED (Cyclophospha- mors with regressive changes scored 1 or 2, without any tendency for systematic over- or underestimation. In two cases without residual tumor (score 4), MRI likewise showed no signs of persistent tumor. The decrease of the

contrast enhancement parameters A and kep was significantly more marked in tumors with signs of histological regression than in those without. Histological regression of breast tumors after neoadjuvant chemotherapy is therefore associated with inaccuracies in MRI measurement of tumor size. We assume that therapy-induced reduction of contrast enhancement, decreased tumor continuity, and additional contrast enhancement in non-cancerous reac- tive changes can make it difficult to exactly define tumor residues [49]. For 21 patients one pre- and one post-treatment study as well as at least one study performed after the first through third cycle were available. In these, a reduction of tumor size after chemotherapy of more than 25% was associated with a decrease of both analyzed contrast enhancement

parameters (kep:p<0.002; amplitude: p<0.006), where kep began to drop already after the first cycle of chemotherapy (p<0.008) (Figure 2). A clear reduction of tumor size was Figure 3 Colour mapped dMRI of a lumbar spine in a patient with only noted after the third cycle (p<0.008). However, we multiple myeloma and diffuse bone marrow infiltration. Prior to found that in patients without macroscopic tumor regres- and following thalidomide therapy the parameters Amplitude and

sion there was also a trend towards an early reduction of kep are analysed in three selected vertebral bodies. The region of contrast enhancement, as reflected by k . It must there- interest (ROI) completely coveres each vertebral body. Six ep months after therapy changes of color-mapping are observed in fore be considered that chemotherapy has an effect on tu- each vertebral body. As shown in the 3rd vertebral body this is mor vascularity, detectable by dynamic MRI, which is inde- coming along with a flattening of the time-intensity curves and a pendent on the tumor cells themselves [48]. decrease of the parameters Amplitude and kep.

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy mide, Etoposide, Dexamethasone) protocol, depending on pies are commonly performed with tumor heterotrans- the tumor stage and previous relapses. In a close coop- plants in nude mice. To monitor therapeutic effects, im- eration with the Department of Hematology / Oncology, we proved noninvasive analyses of functional data are re- are examining whether anti-angiogenic treatment is asso- quired, in addition to the assessment of tumor volume and ciated with characteristic changes of bone marrow micro- histology. Here, we report on sequential monitoring of vas- circulation, as measured with a dynamic MRI protocol cularization of human squamous cell carcinomas growing similar to that used for breast tumors. We have found that as heterotransplants in nude mice, using MRI. Using a in patients with multiple myeloma, A and kep are signifi- custom-developed animal coil in a conventional whole- cantly higher than in the bone marrow of healthy subjects. body 1.5 T MRI scanner, dynamic T1w sequences were Changes were only observed in patients in whom thalido- recorded after i.v. injection of Gd-DTPA, in tumors grown mide was combined with an established chemotherapeutic for 17, 21, 25, 29 and 33 days. Amplitude and the ex- regimen. The reduction in contrast enhancement was par- change rate constant (kep) were calculated according to a ticularly marked where it had been markedly increased be- 2-compartment model, discriminating intravascular and in- fore treatment (Figure 3). With focal involvement and the terstitial spaces, and correlated with tumor size and histology. High-resolution imaging of small heterotransplants presence of compact tumor nodules, we saw a drop in kep in therapy responders, similar to our observations in from 100 to 1,000 mm³ was achieved, clearly discriminat- breast cancer (see above). Our current efforts are directed at developing a measurement protocol together with E0200 (Division of Biophysics and Medical Radiation Physics) which will more reliably depict subtle contrast enhancement, as present in diffuse bone marrow involvement. Magnetic resonance imaging of nude mice with heterotransplanted highgrade squamous cell carcinomas (SCC): Use of a low loaded, covalently bound Gd-HSA conjugate as contrast agent with high tumor affinity Malignant tumors often show an increased uptake and metabolism of plasma proteins, especially albumin. We investigated whether a low loaded Gd-DTPA albumin conjugate accumulates in heterotransplanted SCC of nude mice and 225 thus improves tumor visualisation. This approach may help to select tumors for a therapy with cytostatica-loaded albumins, and to monitor therapeutic effects. Figure 4: A Color coded map presenting amplitudes of a HaCaT- ras-tumor (A) is shown together with a corresponding histologic Twelve nude mice with heterotransplanted squamous cell section in double immunofluorescence preparation (B). An anti carcinomas were studied. The signal intensity of tumor, PECAM-1 antibody was used for labeling of endothelial cells blood, liver, kidney and muscle tissue was studied in MR (red). Tumor cells were visualized with an anti pan keratin anti- images after application of Gd-albumin during a period of body (green). Higher magnifications of a solid tumor region (framed in B) are shown as HE-stained (C) and double immunof- 144 hours with standard high-resolution T1- and T2-weigh- luorescence images (D). ted pulse sequences, using 1 mm slice thickness for T1- A and B: bar = 1 cm, C and D: bar = 1 mm. weighted, and 2 mm for T2-weighted images, and a dynamic protocol. MRI results were histologically correlated ing vital and necrotic areas (Figure 4). Preceding the de- after simultaneous injection of Gd- and fluorescein-labeled velopment of necroses, which were hyperintense in T2w albumins in 9 nude mice. images and confirmed with histology, a local decrease of Although liver and kidney had a maximum increase in sig- amplitude and kep values was observed. Significantly nal intensity within 30 minutes, tumors showed a delayed higher amplitudes were found in tumor periphery than in 51% increase in the 24 hours after application. Histologic central parts, correlating well with the vascular pattern ob- and fluorescence evaluation demonstrated albumin local- tained by immunocytochemistry. Tumor size correlated ization in tumors predominantly in stroma and necroses. negatively with amplitude, probably as a result of increas- Our results suggest that the use of a low-loaded albumin ing necrotic areas, whereas the reason for the observed conjugate that accumulates in tumor tissues may improve increase of kep value with tumor size remains unclear. the detection and delineation of malignant tumors with These data demonstrate that dynamic MRI is an excellent high metabolic activity. This may lead to clinical applica- method for noninvasive assessment of tumor vasculariza- tions helping to identify tumors with high metabolism for tion in small animals, using a clinical whole-body scanner possible treatment with chemotherapeutics coupled to al- with little technical modifications. This technique provides bumin [27]. functional data characterizing essential features of tumor biology and is thus appropriate for monitoring Dynamic T1-weighted monitoring of vascularization in antiangiogenic therapies [28]. human carcinoma heterotransplants by magnetic resonance imaging Studies on tumor angiogenesis and antiangiogenic thera-

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

Effect of anti VEGF-receptor II antibody (DC101) 1,8 on vascularisation of human squamous cell 1,6 carcinomas in nude mice monitored with 1,4 treated untreated dynamic magnetic resonance imaging 1,2 We monitored vascularisation of subcutaneously grown 1 human squamous cell carcinomas in nude mice treated 0,8 total by an VEGF-receptor II antibody, using dynamic magnetic amplitude 0,6 resonance imaging (MRI) at 1.5T. 0,4 0,2 12 nude mice with subcutaneously grown HaCaT-ras RT3 0 tumors were examined longitudinally. 6 mice were treated 0 5 10 15 with 800 mg anti VEGF-receptor antibodies subutaneously days after start of antibody treatment every second day, 6 were controls. All animals were examined at 1, 2, 4, 7 and 14 days after starting the antiangio- Figure 5: Amplitude in treated and untreated tumors measured in genic treatment, using dynamic T1w sequences. Intensity- ROI´s drawn around the entire tumor cross-section during follow time curves were calculated, as well as the parameters up examinations. Data is given as mean ± standard deviation. “amplitude” and “k ”. In a separate setting with 10 nude ep hancing and nonenhancing tumor parts. Fast FLAIR was mice, MR results were compared with vessel staining superior in the delineation of cortically located and small (CD31) on immunofluorescence images. lesions but was limited in lesions adjacent to the ven- Two weeks after antibody treatment the mean volumes of tricles. treated (56±85 mm3) tumors was significantly lower Fast FLAIR provided a significantly better tumor-to-CSF (p>0.001) than of untreated ones (1208±750 mm3). contrast and tumor-to-CSF contrast-to-noise (p< .001). Amplitudes of treated tumors decreased more than in un- Based on these observation the technique was integrated treated tumors already after a single antibody application. into the planning process of stereotactic radiotherapy. The The most evident difference between treated and un- concurrent presentation of enhancing and non enhancing treated tumors was observed 4 days after starting the anti- tumor tissue on contrast enhanced fast FLAIR imaging en- body treatment (p<0.05). After one week of treatment am- ables to use a single imaging sequence in the treatment plitudes of treated tumors increased again and showed protocol. This enables to load a reduced image amount higher values than in the control group 14 days after start- into the radiotherapy planning software, is therefore time ing the therapy (Figure 5). Microvessel density changed in saving and reduces potential errors. 226 line with the amplitudes. kep was unchanged longitudinally in both groups. In two technical reports the optimization of the used sequence was described and the limitations discussed [10]. Dynamic MRI is valuable to detect early effects of anti-an- After surgical resection of a brain tumor or infection of the giogenic therapy. The increase of amplitudes after 1 week cerebrospinal fluid (CSF), elevated levels of blood by- of treatment can be explained by the decreasing tumor cell products or protein contaminations are seen in the mass but persistence of large vessels at the tumor border. patient’s liquor spaces. In fast fluid-attenuated inversion- Therefore, for appraisal of dynamic data of tumor vascu- recovery (FLAIR) imaging CSF signal is nulled by an ap- larisation, alterations of tumor size and the ratio of tumor propriate choice of the inversion recovery time TI to im- cells to vessels have to be taken in account. prove the contrast between tissue structures adjacent to Brain liquor-filled volumes and CSF. With contaminated CSF Morphologic MR imaging in the assessment of however the longitudinal relaxation time T1 of liquor may intraaxial brain tumors change significantly, which results in an incomplete sup- The detection and delineation of brain pathologies in MR pression in the FLAIR images, if standard inversion times imaging requires a high lesion contrast which depends on are used. In this work, a fast single-voxel T1 measurement the signal of the lesion in relation to the surrounding tis- pulse sequence with integrated T1 calculation is intro- sue. In several previous studies it has been shown that the duced, that allows to determine the optimal TI value in 15 use of modern morpholigic MRI techniques incresed the seconds. The method is tested in 5 patients after surgical lesion contrast. resection of a brain tumor, where FLAIR MRI with and In several clinical studies the diagnostic potential of a fast without contrast agent is performed to identify remaining FLAIR (fluid-attenuated inversion-recovery) and a HIRE tumor fragments at the margin of the resection cavity. (high intensitiy reduction) technique for the assessment of To assess the diagnostic potential of a new dark fluid se- primary intraaxial brain tumors and cerebral metastases quence HIRE (High Intensity REduction) in the diagnostic were evaluated [9,10,12]. work-up we examined 15 patients with histologically con- In an initial study on 21 patients the use of FLAIR in pri- firmed cerebral gliomas [9]. The HIRE sequence utilize the mary intraaxial brain tumors was first described by our very long T2 value of CSF to suppress its high signal con- group. tribution in T2-weighted imaging by a image subtraction technique. In a qualitative evaluation, all readers found the fast FLAIR to be superior to fast spin-echo in the exact delineation of HIRE achieved a significant reduction of the CSF signal intraaxial brain tumors (p< .001) and the delineation of en- without loosing the high gray-to-white matter contrast of T2

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

Several functional MR imaging methods were implemented and clinically used in the assessment of CNS neo- plasms. The major clinical studies are subsequently described [7,9,13,14]. The contrast-enhanced perfusion MRI methods have been applied in the diagnostic work-up of low-grade astrocytomas since there is minimal blood brain barrier breakdown and thus no contrast enhancement. The differential diagnosis can be ischemic infarcts. Due to tumor-induced angiogenesis, most of these low grade astrocytomas present an increased blood volume compared to the surrounding Figure 6: Mean regional cerebral blood volume of gray matter, white matter (Figure 6). white matter, low grade astrocytoma and anaplastic high grade astrocytoma. Following radiotherapy, there is a reduction in intratumoral blood volume. Patients with high pretherapeutic intratu- weighted sequences. In the quantitative analysis the con- moural rCBV values have a worse outcome after radio- trast ratios of the HIRE were lower compared to the FLAIR therapy indicating more aggressive tumor growth corre- images due to a relative high background and CSF signal. lated to a higher tumor-induced angiogenesis. This DSC After the application of contrast media HIRE images technique may also allow a non-invasive functional as- present a significant signal increase in enhancing lesions sessment of delayed radiation injury, which is based on fi- which subsequently increased the contrast and contrast- brosis and occlusion of small vessels. Patients who have to-noise ratios. had whole-brain radiotherapy reveal a significantly decreased rCBV in normal brain tissue. In contrast, patients The presented T2 based HIRE sequence is an alternative with grade II astrocytoma after conformal radiotherapy to the T1 based FLAIR sequence with the advantage of a better gray to white matter contrast and shorter measure- have only a relatively moderate decrease in rCBV of nor- ment time. mal tissue after therapy. The data demonstrate a measur- able sparing of normal tissues with advanced radiotherapy Functional MR imaging in the assessment of techniques with regard to blood volume. intraaxial brain tumors In a multicenter trial the method was used for differentia- One of the most frequent uses of MRI since its introduction of different astrocytoma grades. A total of 100 patients tion has been in the assessment of the CNS for neoplasm. was examined in three european centers (University of 227 While MRI initially focused on the superb contrast and Munich, University of London and DKFZ). Perfusion MRI spatial resolution in the brain to enable detailed morpho- proved to able to differentiate between low grade tumors logical analysis, recent developments have focused on and anaplastic tumors (Figure 7). evaluating these in conjunction with additional functional assessments. Functional information can reflect macro- Based on the data of the multicentric trial, the effect of vasculature, the breakdown of the blood brain barrier contrast media extravasation on dynamic susceptibility- (BBB) with resulting permeability for the contrast agent, contrast enhanced Echo-Planar Imaging of cerebral glio- and tissue perfusion. Neurofunctional magnetic resonance mas was examined. imaging (nfMRI) is a recently established technique which Another recent study using pre-therapeutic measurements increases our diagnostic potential in neurosciences, while of rCBF and rCBV has shown that the method can be MR-spectroscopic techniques such as chemical shift imag- used to predict the response of brain metastases to radia- ing (CSI) allow a metabolic analysis. tion therapy. In 18 patients with solitary cerebral metastases dynamic susceptibility-contrast-enhanced (DS) MRI was used to assess whether pre-radiation regional cerebral blood volume (rCBV) measurements can predict treatment outcome in patients with cerebral metastases and to evaluate rCBV changes in tumor and normal tissue after radiosurgery. The pretherapeutic rCBV was not able to predict a treatment outcome (p<0.05), however, the method proved to be highly sensitive and specific for a treatment outcome prediction at the 6 weeks follow-up.A decrease of the rCBV value predicted the treatment outcome with a sensitivity of more than 90%. The tumor volume change alone had only a sensitivity of 64%.The measured rCBV values of normal brain tissue and their ratio were comparable to Figure 7: T1-weighted contrast enhanced SE (a) and rCBV-map physiologic data and remained unchanged after therapy. (b) of a patients with recurrent low grade astrocytoma. The con- Our results suggest that dynamic susceptibilty contrast- ventional T1 weighted sequence showed a non-enhancing lesion whereaes the rCBV map revealed a high perfused lesion suspi- enhanced MRI is a useful method for the assessment of cious of an anaplastic tumor, which was later verified by histology. radiosurgically treated brain metastases. The implemented

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

technique with determination of the arterial input function MR-venography in patients with cerebral AVMs enables an absolute quantification of the rCBV and predic- The purpose of this study was to evaluate the diagnostic tion of tumor response. potential of a high resolution MR venography technique in patients with cerebral arteriovenous malformations Magnetic resonance imaging and magnetic (AVMs). A high-resolution, 3D, gradient echo sequence resonance angiography in the assessment of was used with a long echo time TE to obtain venous infor- cerebral arteriovenous malformations (AVMs) mation down to sub-pixel sized vessel diameters of sev- FLAIR MR imaging in the assessment of gliotic eral hundred microns. The method is based on the para- changes magnetic property of deoxy-hemoglobin and the resulting 45 patients with cerebral AVMs were examined with FLAIR developing phase difference between veins and brain pa- and conventional T1- and T2-weighted MR imaging using renchyma at long echo times which leads to signal cancel- identical slice parameters. lation. The reconstructed venograms were compared with Images were assessed in a two-reader study for detection TOF-MRA using qualitative and quantitative criteria with and delineation of gliotic and ischemic tissue. Additionally, the conventional DSA serving as the reference gold stan- the extent of the flow void phenomenon and image arti- dard. facts were evaluated. In 17 patients with angiographically proven cerebral AVMs FLAIR MRI was rated superior to the conventional T2- the method indicates its potential in clinical applications. weighted FSE imaging in the assessment of intra- and Venography was able to detect all AVMs whereas TOF- perilesional gliosis. The superior delineation was a result MRA failed in three patients. of the suppression of CSF, mild T1-weighting and the In the delineation of venous drainage patterns MR venog- more pronounced flow void phenomenon. There was no raphy was superior to TOF-MRA. significant correlation between the extent of gliosis and the Due to susceptibility artifacts at air/tissue boundaries and clinical symptoms. However, larger AVMs presented with interference with paramagnetic hemosiderin, venography more extensive signal changes. was limited with respect to the delineation of the exact ni- FLAIR was found to be a valuable MRI technique to as- dus sizes and shapes in ten patients with AVMs located sess gliotic and ischemic changes within or close to cere- close to the skull base or having suffered from previous bral AVMs. As gliotic and ischemic changes are frequent bleeding. findings and are known to be associated with epilepsy, the use of FLAIR in the assessment of these patients is clini- MR spectroscopy MR spectroscopy (MRS) offers the possibility to acquire 228 cally useful and may guide the treatment decision and treatment planning, e.g. extent of surgical resection of the non-invasive and in-vivo pathobiochemical properties of potential epileptogenic focus. tumors [46]. Clinical studies demonstrated that changes of tumour metabolism during and after therapy occur be- Ultrafast 3D MR-DSA of cerebral AVMs fore changes of tumour morphology. The purpose of this study was to evaluate the usefulness Proton MRS (1H MRS) is successfully applied to neuro-on- of a new ultrashort contrast-enhanced (CE) MR angiogra- cological problems. Reasons are the important role of raphy (MRA) for the morphologic evaluation of cerebral arte- diotherapy in case of unresectable brain tumours. Based riovenous malformations (AVMs). The method was com- on earlier studies with single-voxel 1H MRS (SVS), spec- pared with conventional x-ray DSA and time-of-flight troscopic imaging (SI) was applied to patients with irradi- (TOF-) MRA in 22 patients to assess the angioarchitecture ated brain tumours to improve differentiation between tu- of the malformations which is essential for treatment plan- mour recurrence and radiation injury. Correlation between ning and follow-up [7]. FDG-uptake and choline levels in 1H MRS / SI could be CE-MRA was able to detect all AVMs seen on DSA, while observed. IMT-SPECT was superior to FDG-PET and SI in the TOF-MRA failed in one patient with a very small AVM. the detection of tumour progression in irradiated gliomas. In the assessment of the different vessel components of SI was more capable than FDG-PET to differentiate be- the AVM there was no difference for the detection and de- tween tumour progression and non-neoplastic changes lineation of feeding arteries and the AVM. The venous [5]. Choline levels detected by SI may indicate proliferative drainage patterns could always be clearly delineated in the tumour activity, but may also be increased in case of in- CE-MRA whereas TOF-MRA could demonstrate the exact flammation or demyelisation in radionecrosis. venous drainage in only 9 patients. To predict clinical value of 1H SI multireader analysis was CE MRA was found to be superior to conventional TOF performed in a group of 25 patients with irradiated glio- MRA in the assessment of the angioarchitecture of cere- mas. In this trial, 1H SI could improve diagnostic accuracy bral AVMs especially regarding the assessment of the significantly for each reader and in consensus. The appli- venous drainage patterns. cation of 1H SI could improve sensitivity and specificity sig- The major limitations of this new technique consist of a nificantly for intra- and inter-reader agreement. 1H SI has low spatial resolution at the used time resolution which therefore the potential to improve correct classification and can be improved by further sequence modifications. should be regarded as integral part of routine MR follow- CE MRA is thus an important additional imaging technique up [35,36,37]. for treatment planning and follow up of AVMs.

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1H MRS and SI was also used to assist diagnosis of treat- (PC) and glycerophosphorylcholine (GPC) in patients with ment failure in irradiated brain metastases. In 62 patients, ALD. The increase of hepatic PE/PC and GPE/GPC inten- which were examined primary to evaluate changes of per- sity ratios in patients with cirrhosis indicates alterations in fusion in irradiated brain metastases with arterial spin-la- phospholipid metabolism, which may be associated with beling techniques (ASL), a subgroup of 10 patients re- the chronic alcohol consumption. Inhibition of phosphati- ceived in addition 1H MRS and SI to evaluate metabolic dyl-ethanolamine-N-methyltransferase (PEMT) in chronic parameters. Progression was indicated by a highly el- alcohol consumption has been described, hence the al- evated choline peak and lack of NAA. ASL MR perfusion tered metabolite levels could be explained by decreased imaging and 1H MR spectroscopy was able to permit differ- production of choline and choline-containing compounds. entiation of radiation effects from tumour progression in Polyunsaturated phosphatidylcholine may protect against brain metastasis. the development of alcohol-induced liver cirrhosis. Another focus of clinical applications of 1H MRS was the Magnetic resonance angiography of thoracic detection of prostate cancer and its differentiation from be- vessels nign prostate hyperplasia. In this ongoing work morpho- Major experience in magnetic resonance angiography logic, dynamic and metabolic parameters are acquired and (MRA) and phase contrast flow measurements could be compared to histological findings. gained using the renal arteries and kidney perfusion as a To improve the understanding of findings under pathologic well-evaluated model [1,2,22,23,33,34,40-45]. Recent im- conditions, for selected disease patterns several studies provements of the gradient hardware and pulse sequence were performed during the last years not only with 1H MRS design have substantially improved the temporal and spa- but also using rare nuclei like 31P. Chronic alcohol con- tial resolution of gadolinium-enhanced 3D MRA [19]. This sumption leads to various forms of liver disease (ALD). has especially improved the potential for a non-invasive The mechanism of alcohol-associated liver injury includes assessment of the thorax, particularly the pulmonary vas- changes in hepatic redox-state, free radical production cular system [20,21,38,39]. and membrane damage due to severe alterations of phos- In cooperation with the Thoraxklinik and Department of pholipid metabolism. In 40 patients with ALD proton- Cardiology of the universities children’s hospital several 31 1 31 decoupled P MR spectroscopic imaging ({ H}- P SI) was studies on patients with lung cancer or congenital heart used for measuring relative concentrations of hepatic disease have been performed: phosphoethanolamine (PE), In a study on patients with lung cancer the influence of glycerophosphorylethanolamine (GPE), phosphocholine higher concentrated MR contrast agents (1.0 M gadobutrol) on the contrast characteristics and image quality of 229 pulmonary MR angiograms was investigated. In total, six healthy volunteers and 31 patients were examined with a time-resolved pulmonary MRA (FLASH 3D, TR/TE=2.2/ 1.0ms, a=25º, BW=1220Hz/Pixel, TA=5.6s). All subjects were examined with a standardized injection protocol (flow rate 5ml/s, 30 ml saline flush). Volunteers were examined with both 0.2 mmol/kg body weight (b.w.) of 1.0 M gadobutrol and 0.5 M Gd-DTPA. Patients were randomized to receive either 0.1 mmol/kg b.w. and 0.2 mmol/kg b.w of 1.0 M gadobutrol or standard 0.2 mmol/kg b.w 0.5M Gd- DTPA. The image analysis included a quantitative analysis of the signal-to-noise ratio (SNR) and contrast-to-noise ra-

Figure 8: 35-year old female volunteer. Maximum intensity projec- Figure 9: 7-year old girl with sequestration of the right lower lobe. tions (MIP) of time-resolved 3D MRA data sets acquired in the A,B: Maximin intensity projections of the time-resolved 3D MRA. pulmonary arterial phase (A,C) and mixed arteriovenous phase A: In the early arterial phase no blood vessels can be observed in (B,D) after injection of 0.2 mmol/kg b.w. of gadobutrol (A,B) and the right lower lobe. B: During the venous phase two systemic ar- Gd-DTPA (C,D). No relevant differences with respect to the vas- teries feeding the sequestration can be observed. C: Conven- cular contrast can be observed between both contrast agents. tional angiogram adds no further relevant information.

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In a study in children with suspected anomalies of the pulmonary vascular system the feasibility of time-resolved, multiphasic 3D MR angiography was evaluated. For this, 10 children aged 6 to 15 years (mean age 10 years) were examined with a time-resolved, multiphasic 3D MRA after injection of 0.2 mmol/kg of GD-DTPA. With the use of an ultrafast gradient echo pulse sequence with asymmetric k- space filling and very short echo- and repetition times a nominal spatial resolution of 1.4x1.4x2.0 mm3 could be achieved within a scan time of 5.6 and 6.2 s. The data analysis was performed by two radiologists blinded to the clinical diagnosis and included the assessment of the image contrast and artefacts as well as a quantitative analysis of the signal-to-noise and contrast-to-noise ratios (SNR and CNR) for central and peripheral lung vessel seg- ments. All exams were tolerated by the children without any side effects. The clinical diagnosis which was based on echocardiography, catheter angiography and surgery was confirmed by MRA in all cases (Figure 9). The image contrast was rated at least satisfactory in all but one case (19 of 20) and no artefacts were observed. These findings Figure 10: High-resolution MRA of the pulmonary vessels ac- were also confirmed by the quantitative analysis of the quired with parallel MRI SNR and CNR which showed a high contrast throughout the entire pulmonary circulation. From this results it can be tio (CNR) in lung arteries and veins as well as a reader concluded that time-resolved, multiphasic 3D-MRA allows analysis of the image quality. a non-invasive diagnostic evaluation of the pulmonary cir- Despite a narrower bolus profile, no relevant advantages culation in children. Based on the excellent image quality of 1.0 M gadobutrol could be observed for time-resolved MRA may replace conventional diagnostic catheter an- pulmonary MRA in this study (Figure 8). In detail, the giography in the near future [8,18]. quantitative analysis of the SNR and CNR values in lung With the use of partially parallel imaging techniques (e.g. 230 arteries and veins showed slightly lower mean SNR and SMASH) the temporal resolution of MRI can be further im- CNR values for single-dose compared to double-dose of proved by exploiting the spatial information inherent in the 1.0 M gadobutrol. 0.2 mmol/kg b.w. of Gd-DTPA achieved geometry of surface coil arrays. In practice, using parallel a substantially higher (41%-114%) mean SNR and CNR MRI either the temporal and/or spatial resolution can be than with all doses of 1.0 M gadobutrol. The image quality improved by the factor 2-3. This can be used to acquire of the MRA data sets was rated equal for gadobutrol and high-resolution MR-angiograms of the pulmonary vessels Gd-DTPA. Potential explanations for these results are T2/ (Figure 10) or assess to the passage of a contrast bolus T2*-effects caused by the high intravascular concentration during the first pass through the pulmonary circulation and in combination with non-optimized pulse sequence param- lung parenchyma. From the latter it is possible to calculate eters. Future work is needed for refining pulse sequence perfusion-weighted 3D data sets of the lungs (Figure 11). and injection parameters for time-resolved pulmonary MR- angiography to fully benefit from highly concentrated con- In a pilot study the feasibility of partially parallel MRI for trast agents like 1.0 M gadobutrol. the assessment of lung perfusion was assessed in two healthy volunteers and 14 patients. All subjects were ex-

Figure 11: 3D perfusion weighted MRI acquired with parallel imaging techniques: A. Conventional radionuclide perfusion scintigraphy showing perfusion defect of right lower lobe. B. Perfusion weighted MRI shows a much sharper delineation of perfusion defect. C. T2- w-HASTE MRI shows central lung cancer

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

Figure 12: Maximum intensity in kidneys, liver, muscle, and blood. Regional lymphatic projection of a T1-weighted vessels, the thoracic duct, as well as popliteal, inguinal, 3D gradient echo data set aorto-iliac, and axillary lymph node groups could be visual- obtained 5 minutes after interstitial injection of 0.5 mL ized with the high-resolution 3D MRI (Figure 12). From the gadobutrol into left hind paw data it can be concluded that gadobutrol is suitable for in- (left lower margin; open ar- terstitial MR lymphography, as it rapidly appears in the row). Strong enhancement of lymphatic system. Based on estimates of local tissue con- the lymphatic system includ- centrations future studies have to assess the optimal con- ing regional lymphatic vessels, thoracic duct (curved trast agent dosage. Furthermore the investigation of meta- open arrow) and various static lymph nodes is required in order to evaluate the fur- lymph node groups (arrows; ther potential of gadobutrol for interstitial MR lymphogra- from top to bottom: axillary, phy [17]. aorto-iliac, inguinal, and popliteal lymph nodes) Publications (* = external co-author) [1] Amann M; Bock M; Floemer F*; Schoenberg S; Schad LR: amined with a contrast-en- Three-Dimensional Spiral MR Imaging: Application to Renal hanced 3D GRE pulse se- Multiphase Contrast Enhanced Angiography. Magnetic Reso- nance in Medicine (2003) in press. quence with partially paral- [2] Aumann S; Schoenberg S; Just A*; Briley-Saebo K*; Bjornerud lel image acquisitions (TE/ A*; Bock M; Brix G*: Quantification of Renal Perfusion Using an TR/a: 0.8/1.9 ms/40º; voxel Intravascular Contrast Agent (Part I): Results in a Canine Model. size 3.6x2.0x5.0 mm3, TA: Magnetic Resonance in Medicine (2003) in press. 1.5 s) after injection of 0.1 [3] Brix G*; Henze M; Knopp M; Lucht R*; Doll J; Junkermann H*; mmol/kg b.w. Gd-DTPA. Hawighorst H; Haberkorn U: Comparison of pharmacokinetic MRI The image analysis included an analysis of the signal-to- and 18F fluorodeoxyglucose PET in the diagnosis of breast can- noise ratio (SNR) in the lungs in areas with normal and im- cer: initial experience. European Radiology, 11 (2001) 2058-2070. paired perfusion. 3D perfusion-weighted image data sets [4] Brix G, Lucht REA, and Delorme S: Neural network-based seg- mentation of dynamic MR mammographic images. J Magn Reson were analyzed for perfusion defects and compared to con- Imaging, 20 (2002) 147-154. ventional radionuclide (RN) perfusion scans. The analysis [5] Chan YL; Schlemmer HP; Yeung DKW; Wilhelm T; Bachert P: of the 3D perfusion-weighted data allowed a clear differen- Comparison of magnetic resonance spectroscopic imaging and tiation of perfusion abnormalities: MRI showed a normal single voxel magnetic resonance spectroscopy for suspected re- lung perfusion in 9 of 16 cases, whereas perfusion abnor- current brain tumour or radiation necrosis. Journal of the Hong 231 malities were observed in 7 cases. When compared to the Kong College of Radiology, 4 (2001) 259-263. RN perfusion scans a good inter-modality agreement was [6] Delorme S, Schulz-Wendtland R*, and Sinn HP*: Mamma- shown (κ=0.74). When compared to normally perfused karzinom. In: Radiologische Diagnostik in der Onkologie. Layer G and van Kaick G (Eds.) Heidelberg: Springer (2003) in press lung a significantly lower SNR was observed in hypoperfused lung (7 vs. 17) (p=0.02). From the data it [7] Duran M, Schoenberg SO, Yuh WTC, Knopp MV, van Kaick G, Essig M: Cerebral arteriovenous malformations: morphologic can be concluded that partially parallel MRI might be used evaluation by ultrashort 3D gadolinium-enhanced MR angiogra- for the assessment of lung perfusion. Future studies are phy. Europ Radiol (2003) in press. required to further evaluate the diagnostic impact of this [8] Eichhorn J*; Fink C; Bock M; Delorme S; Brockmeier K*; technique. Ulmer HE*: Time-Resolved Three-Dimensional Magnetic Reso- nance Angiography in the Assessment of a Pulmonary Artery MR lymphography in a rat model Sling in a Pediatric Patient. Circulation, 106 (2002) 61e-62e, DOI: New concepts in MRI are based on the use Gd-chelates 10.1161/01.CIR.0000033488.00403.96 for the assessment of the lymphatic system in cancer. [9] Essig M: Morphologische und funktionelle Magnetresonanz- However, most studies have used non-approved, experi- tomographie zur individualisierten Strahlentherapieplanung von mental contrast agents with an unknown safety profile. In Pathologien des Gehirns. Habil Schr Med Fak Univ Heidelberg an animal study we assessed the potential of a conven- (2002) tional extracellular MR contrast agent (1.0 M gadobutrol) [10] Essig M; Metzner R; Bonsanto MM*; Hawighorst H; Debus J; Tronnier V*; Knopp MV; van Kaick G: Postoperative fluid-attenu- for the use in interstitial MR-lymphography. In eleven rats ated inversion-recovery (FLAIR) MR imaging of cerebral gliomas; 0.5 mL undiluted gadobutrol was injected subcutaneously initial results. European Radiology, 11 (2001) 2004-2010. into the hind paw. Contrast kinetics were measured in [11] Essig M; Reichenbach JR*; Schad L; Debus J; Kaiser WA*: lymph nodes, kidney, liver, muscle, and blood of six ani- Hochaufgelöste MR-Venographie zerebraler arteriovenöser mals using a time-resolved 2D GRE sequence. Addition- Malformartionen. Radiologe, 41 (2001) 288-295. ally, high-resolution 3D T1-weighted data sets were ob- [12] Essig M; Schlemmer H; Tronnier V*; Hawighorst H; Wirtz R*; tained in five animals. Immediately after injection, a pro- van Kaick G: Fluid-attenuated inversion-recovery MR imaging of nounced signal intensity loss was observed in popliteal, gliomatosis cerebri. European Radiology, 11 (2001) i303-308. inguinal and aorto-iliac lymph nodes, followed by a con- [13] Essig M; Waschkies M; Wenz F; Debus J; Hentrich HR*; Knopp MV: Assessment of brain metastases by means of dy- tinuous signal intensity increase. From the data peak con- namic susceptibility (DSC) contrast enhanced MRI. Radiology centrations of up to 78 mmol/L were estimated for selected (2003) in press. lymph nodes. A contrast enhancement was also observed

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[14] Essig M; Wenz F; Scholdei R*; Brüning C*; Berchtenheimer [31] Moehler T*; Hawighorst H; Neben K*; Egerer G*; Hillengass M*; Meurer M*; Knopp MV: Effect of Contrast Media Extravasa- J*; Max R*; Benner A*; Ho AD*; Kaick van G; Goldschmidt H*: tion on Dynamic Susceptibility-Contrast Enhanced Echo-Planar Bone Marrow Microcirculation Analysis in Multiple Myeloma by Imaging of Cerebral Gliomas. Acta Radiologica 43 (2002) 354- Contrast-Enhanced Dynamic Magnetic Resonance Imaging. Inter- 359. national Journal of Cancer, 93 (2001) 862-868. [15] Fink C, Lüdemann H, Wasser K, and Delorme S: Incidental [32] Port RE; Knopp MV; Brix G: Dynamic contrast-enhanced MRI finding of a mucinous carcinoma of the breast by dynamic MRI in using Gd-DTPA: interindividual variability of the arterial input func- a patient with a history of breast trauma (horse bite). Clin Imag- tion and consequences for the assessment of kinetics in tumors. ing, 26 (2002) 254-257. Magnetic Resonance in Medicine 45 (2001) 1030-1038. [16] Fink C, Wasser K, Aufderstraße D, Lüdemann H, and [33] Prince MR*; Dong Q*; Schoenberg SO: Magnetic resonance Delorme S: Irreführende Kontrastmittelanreicherung in der angiographic diagnosis of renovascular disease. In: Current dynamischen MR-Mammographie. Radiologe (2003) in press. Therapy in Vascular Surgery. Ernst CB, Stanley JC (Eds.) Mosby, [17] Fink C; Bock M; Kießling F; Delorme S: Interstitial MR Lym- Philadelphia (2000) 723-728. phography with Gadobutrol in Rats: Evaluation of Contrast Kinet- [34] Rohrschneider WK*; Hoffend J*; Becker K*; Darge K*; ics. Investigative Radiology, 37 (2002) 655-662 Wunsch R*; Clorius JH; Kooijman H*; Tröger J*: Statisch- [18] Fink C; Eichhorn J*; Bock M: Pulmonary arteriovenous mal- dynamische MR-Urographie. Vergleich mit Ausscheidungs- formation and aortopulmonary collateral imaged by time resolved urographie und Szintigraphie bei experimentell induzierter contrast enhanced magnetic resonance angiography. Heart, 88 Harntransportstörung (HTS). Radiologe, 41 (2001) 154-167. (2002) 292. [35] Schlemmer HP: Klinische Magnetresonanzspektroskopie in [19] Grau AJ, Schönberg SO, Lichy C, Buggle F, Bock M, and der Radioonkologie. Habil Schr Med Fak Univ Heidelberg (2002) Hacke W: Lack of evidence for pulmonary venous thrombosis in [36] Schlemmer HP; Bachert P; Henze M; Buslei R; Herfarth K; cryptogenic stroke: a magnetic resonance angiography study. Debus J; van Kaick G: Differentiation of radiation necrosis from Stroke, 33 (2002) 1416-1419 tumor progression using proton magnetic resonance spectros- [20] Haberkorn U and Schönberg SO: Imaging of lung cancer with copy. Neuroradiol, 44 (2002) 216-222. CT, MRT and PET. Lung Cancer, 34 Suppl 3 (2001) S13-S23 [37] Schlemmer HP; Bachert P; Herfarth KK; Zuna I; Debus J; [21] Haberkorn U; Schönberg S: Imaging of lung cancer with CT, van Kaick G: Proton MR spectroskopic evaluation of suspicious MRT and PET. In: Lung Cancer. Pontifex G (Ed.) Amsterdam: brain lesions after stereotactic radiotherapy. American Journal of Excerpta Medica (2001) 13-23. Neuroradiology, 22 (2001) 1316-1324. [22] Hallscheidt P*; Schoenberg SO; Schenk JP*; Zuna I; [38] Schoenberg SO: Bildgebende Darstellung des Petirsch O*; Riedasch G*: Multi-Slice CT in der Planung der Bronchialkarzinoms mit der Magnetresonanztomographie. In: organerhaltenden Operation des Nierenzellkarzinoms. Fortschritte Management des Lungenkarzinoms. Drings P, Dienemann H, auf dem Gebiet der Röntgenstrahlen und der Nuklearmedizin Wannenmacher M (Eds.) Springer, Heidelberg (2003) in press (2003) in press [39] Schoenberg SO: Bildgebung des Bronchialkarzinoms mit radiologischen und nuklearmedizinischen Verfahren. In: 232 [23] Hallscheidt P*; Weber MA; Schenk JP*; Riedasch G*: MRT der xanthogranulomatösen Pyelonephritis: Epidemiologie, Manegold Ch. (Eds.) Therapieoptionen beim nicht-kleinzelligen Pathogenese und Erscheinungsbild in der Magnetresonanz- Bronchialkarzinom. Bremen: Uni-Med (2002) 50-62. Tomographie. Urologe A (2003) in press [40] Schoenberg SO: Morphologische und funktionelle [24] Hellwig G*; Brix G*; Griebel J*; Lucht R*; Delorme S, Siebert Evaluierung des renovaskulären Systems mit der Manetreso- M*; Englmeier KH*:: Dynamic MR mammography: 3D real-time nanztomographie. Habil Schr Med Fak Univ Heidelberg (2002) visualization of contrast enhancement in virtual reality. Acad [41] Schoenberg SO; Aumann S; Just A*, Bock M; Knopp MV; Radiol, 9 (2002) 1255-1263 Johansson LO*; Ahlstrom H*. Quantification of renal perfusion ab- [25] Hellwig G*; Englmeier K-H*; Griebel J*; Lucht R*; Delorme S; normalities using an intravascular contrast agent (Part 2): results Siebert M; Brix G*: Dynamic MR Mammography: Multidimen- in animals and patients with renal artery stenosis. Magn Reson sional Visualization of Contrast Enhancement in Virtual Reality. Med (2002), in press In: Medical Imaging 2002. San Diego, SPIE, (2002) 54-61 [42] Schönberg SO, Essig M, Hallscheidt P, Sharafuddin MJ, [26] Jauss M*; Herholz K*; Kracht L*; Pantel J*; Hartmann T*; Stolpen AH, Knopp MV, and Yuh WT: Multiphase magnetic reso- Jensen M*; Essig M, Schröder J*: Frontotemporal dementia: clini- nance angiography of the abdominal and pelvic arteries: results of cal, neuroimaging, and molecular biological findings in 6 patients. a bicenter multireader analysis. Invest Radiol, 37 (2002) 20-28 Eur Arch Psychiatry Clin Neurosci 251 (2001) 225-231. [43] Schönberg SO, Knopp MV, Londy F, Krishnan S, Zuna I, [27] Kiessling F, Fink C, Hansen M, Bock M, Sinn H, Schrenk HH, Lang N, Essig M, Hawighorst H, Maki JH, Stafford-Johnson D, Krix M, Egelhof T*, Fusenig N, and Delorme S: Magnetic reso- Kallinowski F, Chenevert TL, and Prince MR: Morphologic and nance imaging of nude mice with heterotransplanted highgrade functional magnetic resonance imaging of renal artery stenosis: a squamous cell carcinomas (scc): use of a low loaded, covalently multireader tricenter study. J Am Soc Nephrol, 13 (2002) 158-169 bound Gd-HSA conjugate as contrast agent with high tumor affin- [44] Schönberg SO; Bock M; Just A*: Experimentelle Fluss-und ity. Invest Radiol 37 (2002) 193-198. Perfusionsmessungen im Tiermodell mit der Magnetresonanz- [28] Kiessling F, Heilmann M, Vosseler S, Lichy M, Krix M, tomographie. Der Radiologe, 41(2) (2001) 146-153. Kiessling I, Steinbauer H, Schad L, Fusenig N, Delorme S. Dy- [45] Schönberg SO; Londy FJ*; Licato P*; Williams DM*; namic T1-weighted monitoring of vascularization in human carci- Wakefield T*; Chenevert TL*: Multiphase-Multistep Gadolinium- noma heterotransplants by magnetic resonance imaging. Int J Enhanced MR Angiography of the Abdominal Aorta and Runoff Cancer 2003;104:113-120 Vessels. Investigative Radiology, 36 (2001) 283-291. [29] Klein SK: Größenänderung von Mammakarzinomen während [46] Semmler W, Bachert P, Schlemmer HP. Klinische MR- präoperativer Chemotherapie: Beurteilung durch Palpation, Spektroskopie. In: Magnetresonanztomographie, 3rd edition. Röntgenmammographie, Sonographie und Magnetresonanztomo- Reiser M, Semmler W (Eds.) Berlin, Heidelberg, New York: graphie. Diss Schr Med Fak Univ Heidelberg (2002) Springer (2002) 1001-1045. [30] Lucht R*; Delorme S; Brix *: Neural network-based segmen- [47] Wasser K, Delorme S, and van Kaick G: Radiologische tation of dynamic MR mammographic images. Magnetic Reso- Diagnostik kleinster Gefäße - die nicht-invasive Untersuchung der nance Imaging, 20 (2002) 147-154 Mikrozirkulation von neoplastischen Erkrankungen. Onkologe 7 (2001) 1134-1144

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[48] Wasser K; Klein SK; Fink C; Junkermann H*; Sinn HP*; Zuna tumors, and clinical trials, use as monitoring criteria for I; Knopp MV; Delorme S: Evaluation of neoadjuvant chemothera- therapeutic efficacy only end points such as tumor size. In peutic response of breast cancer using dynamic MRi with hight order to assess early and specific vasculature-related temporal resolution. European Radiology, 13 (2002) 80-87, DOI: 10.1007/s00330-002-1654-1. therapeutic criteria, improved methods for non-invasive [49] Wasser K; Sinn HP*; Fink C; Junkermann H*; Lüdemann monitoring of blood flow and tissue perfusion are desir- HP*; Zuna I; Delorme S: Histological Regression of Breast Tu- able. mors after Neoadjuvan Chemotherapy: Influence on the Preop- Ultrasound provides promising methods to evaluate tumor erative MRI Measurement of Tumor Size. European Radiology vascularization. With Doppler US, blood flow is detectable (2003) in press in larger vessels and can be quantified using computer- [50] Weber MA; Lichy MP; Thilmann C; Günther M; Bachert P; Maudsley AA*; Delorme S; Schad LR; Debus J; Schlemmer HP: ized tools. Recently, it has been shown that a reduction of Verlaufsbeobachtung bestrahlter Hirnmetastasen mittels MR- such tumor vessels during anti-vascular or gene therapy Perfusionsbildgebung und 1-H-MR-Spektroskopie. Radiologe can be detected with Doppler sonography. (2003) in press However, measuring perfusion (i.e., the blood flow per tissue unit), requires the detection of capillary blood flow. Ultrasound in Oncology This is a difficult task considering the slow velocity and irregular nature of vessels particular in tumor vasculature. S. Delorme, M. Krix, M. Essig, H.-P. Schlemmer Conventional power Doppler US is not capable of visualiz- Owing to its broad availability and non-invasiveness, ultra- ing capillary blood flow. sonography (US) is frequently the first diagnostic modality Quantification of tumor perfusion in small to be used for various benign conditions [4,6,9,12,14], and animals with intermittent, bolus-contrast particularly in patients with suspected cancer [3,7,13]. Ul- sonography. trasonography has undergone significant improvement in Intermittent sonography is an approach which is appropri- the past years, and enables a rapid assessment in symp- ate to assess perfusion indirectly using replenishment ki- tomatic patients and a well-focused planning of ensuing netics of microbubbles. Therefore, parameters like blood diagnostic procedures. Our group has performed basic volume, flow, perfusion, and mean blood velocity can be work in the field of quantitative sonography. Current stud- measured with this new US method. We have adapted the ies are related to the assessment of tumor vascularization, model, which was based on continuous infusion of a con- until recently mainly using color Doppler ultrasonography trast medium, to a single bolus injection (Figure 2). This is [1,5,8]. Our present efforts are directed at developing mod- a prerequisite for quantitative examinations with intermit- els for quantifying vascularity with contrast harmonic ultra- tent sonography on small animals, where reliable continu- 233 sound, and at evaluating contrast-enhanced techniques ous infusions of the required small volumes and flows of for oncological diagnostics. contrast agent are hardly ever feasible. This is why quanti- Dynamic data on tissue vascularization are valuable in tative evaluation of such tumors with intermittent imaging various clinical problems. In malignant tumors, vascular- has not been performed yet. However, fundamental and ization correlates with their invasive potential, and the pharmaceutical research on angiogenesis is mainly per- mean vessel density is a prognostic factor in several tumor formed on tumor models of small animals. Furthermore, a types. As a con- direct comparison of parameters derived by intermittent sequence, differ- imaging and by conventional, quantitative power Doppler ent attempts to US, which analyses the signal-intensity-time curve after modulate tumor bolus injection of contrast agent, is not possible without vascularization by

antiangiogenic colour pixel density strategies are 0,4 subject of current research. Both 0,3 experimental approaches with heterotransplanted 0,2

Figure 1: Power 0,1 Doppler ultrasound

pictures (main 0 frame rate 1.33 s-1) -10 40 90 140 190 240 290 340 390 440 of murine tumours time after injection [s] prior injection of 100 µl Levovist® (A/C), Figure 2: US Signal intensity-time curve after bolus injection of and at the maximal contrast agent. Colour pixel density (power Doppler) is plotted enhancement (B/D). over time t. Multiple ”flashs” (short increases of the US signal in- Perfusion calculated tensity) are visible (circles) in the late phase decrease due to the with intermittent im- replenishment effect during the intermittent phase, caused by aging was lower in lower power Doppler frame rates (the Doppler mode was manu- larger tumours ally switched off)

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Figure 3: Ultrasound picture of a treated tumor (murine, HaCaT- ras) at start of therapy (A) and a control (C), both three weeks old, and one week later (3 x 800 mg of an antibody to VEGF receptor 2; DC101) (B) in comparison to the time matched control (D). Pictures visualize maximal enhancement (power Doppler) after bolus injection of contrast agent (Levovist® 100µl). Figure 4: Comparison of microvessel staining (composed picture) and snap shots of US signals at the time of maximal enhance- using intermittent sonography with a contrast-agent bolus ment of a treated tumor, three weeks after start of therapy instead of a continuous infusion. (DC101) (B/D), and of a control (A/C). Vessels were stained with A re-formulation of the imaging protocol and the derivation an CD31 antibody (red), tumor cells were visualized with Hoechst of perfusion parameters was necessary, taking into ac- detergent (blue) (A/B). count the time-dependence of the systemic microbubble microvessel density was quantified morphometrically in tu- concentration after single bolus injection. Using this new mor sections at different time points. method tumor vascularization was evaluated in 13 experi- Our results revealed that quantitative US analysis was mental murine tumors. Furthermore, parameters calcu- possible in all examined tumors (Figure 3). The calculated lated with intermittent imaging after bolus injection of relative blood volume was significantly correlated with the 100µl Levovist® were compared with parameters from the microvessel density (k=0.84, p<0.01; Figure 4). DC101 signal intensity-time curve. The results showed that quanti- treatment resulted in a significant decrease in tumor blood 234 fying tumor perfusion, blood volume and flow, as well as flow (p<0.05) and volume (p<0.05) compared to untreated the assessment of the mean blood velocity (in mm/s) is controls (Figure 5). Perfusion (blood flow per tissue unit) possible in tumors with a volume of more than 0.1ml. In was only reduced in central parts of treated tumors, but larger tumors a lower perfusion was calculated than in this parameter and the initial blood flow could predict the smaller ones (k=-0.88; p<0.001; Figure 1). Only limited correlations were found between conventional power Dop- blood flow 10.28 A) 6 pler US quantities and parameters of intermittent sono- [n.a.u.] graphy: Perfusion correlated with the maximum signal intensity (k=0.61, p<0.05) and the gradient to maximum 4 (k=0.82, p<0.01), full width-half maximum was associated control with blood volume (k=0.62, p<0.05). 2 In conclusion, intermittent, bolus-contrast sonography al- treated lows the quantification of tumor perfusion even in small 0 before1234 therapy 132 animals with perfusion parameters showing a higher sig- time after start of therapy [weeks] nificance than conventional power Doppler US [11]. The feasibility to monitor antiangiogenic therapies with this new 1.29 B) tumor volume US modality was evaluated in the following study. [ml] 0,8 Monitoring antiangiogenic therapy with control intermittent sonography

Non-invasive quantitative monitoring of antiangiogenic 0,4 therapy was performed with intermittent, bolus-contrast sonography. Subcutaneous heterotransplants of human treated squamous cell carcinoma cells (HaCaT-ras) in 10 nude 0 before therapy 12 3 1234 mice were examined weekly, repeatedly over one month, time after start of therapy [weeks] by intermittent, bolus-contrast sonography using power ® Doppler US after a single bolus injection of Levovist Figure 5: Time dependence of calculated tumor blood flow with 100µl i.v. For antiangiogenic therapy 5 mice were treated intermittent sonography (A) and tumor volume (B) during the ob- with a blocking antibody to VEGF receptor 2 (DC101) in- servation period (3 weeks). A significant reduction of tumor blood jected i.p. every second day. Immuno-fluorescence stain- flow (A) and volume (B) of treated tumors (black circle) is visible ing (CD31 antibody) of blood vessels was performed, and versus an increase in untreated tumors (rhombus). Hatched lines indicate the remove of tumors at the last examination time.

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cal application of intermittent sonography. In conclusion, a more valid, detailed and accurate calculation of perfusion parameters especially of tumors can be accomplished with the new hyperbolic model of intermittent sonography. Homogenous arterial enhancement of liver metastases using intermittent, low-energy sonography with Sonovue®. In this clinical study the feasibility to visualize the arterial perfusion in liver metastases was assessed using intermittent sonography with Sonovue® and low mechanical-index (MI) imaging. Examinations of untreated liver metastases (different primaries) in 25 patients were performed using a triggered (frame rate 4/s) pulse inversion techniques (CCI, Sequoia, Siemens-Acuson) in low MI imaging after bolus injection of Figure 6: Dynamics of the arterial vascularization of a liver me- 2.4 ml Sonovue® i.v.. The maximal relative enhancement tastases (colon carcinoma) visualized with intermittent songraphy in low MI-imaging after bolus injection of 2.4 ml sonovue®. (gray scale level), and the time to maximum of the liver lesions, respectively of the normal liver tissue were quanti- subsequent, treatment-dependent changes in tumor size fied. In addition, the arterial enhancement in ultrasound (k=0.69, p<0.05). was compared with contemporary performed contrast-en- In conclusion, intermittent sonography is a valuable, non- hanced, dual-phase spiral CT of 15 patients according to a invasive method to provide a comprehensive functional pattern-based classification scheme. status of tumor perfusion and to quantitatively monitor All metastases, even of ´hypovascularized´ primaries like anti- or pro-angiogenic therapies. In contrast to conven- colon carcinomas, showed an early enhancement in the tional, contrast enhanced US, microvessel density corre- arterial phase using intermittent imaging, which was pre- lated with the derived blood volume. Using DC101 regres- dominantly homogenous and clearly visible (on average 2 sion of functional vessel parameters could be observed times higher signal level than liver tissue; Figure 6). CT did early and a prospective evaluation of therapy effects may not show any comparable early enhancements (t-test of be possible. gray scale levels, p < 0.001). 235 A new hyperbolic model describing It can be concluded that extravasal contrast agents as replenishment kinetics of ultrasound contrast used in CT may not be able to visualize short lasting but agent for quantification of tissue perfusion. large differences of the arterial perfusion of liver me- To improve intermittent sonography as a quantitative tech- tastases compared to normal liver tissue. Thus, low-MI nique to calculate tissue perfusion a new model describing sonography using intermittent imaging non-invasively pro- replenishment kinetics of microbubbles was developed vides a completely new, information about perfusion in and compared with an established, phenomenologically liver lesions. The detection of its changes can monitor tu- derived kinetic model. mor therapy and may allow early assessment of tumor response or relapse. The new model consistently describes the refilling process of microbubbles after destruction by US with high energy Publications (* = external co-author) and takes into account the variability of blood velocities [1] Beissert M, Delorme S, Mutze S, Lees WR, Bahner ML, found in vivo, especially in tumors. Based upon this Filimonow S, Gillams AR, Zuna I, Bauer A, and Jenett M: Com- model, blood volume, blood velocity, blood flow, and perfu- parison of Diagnoses made upon Liver Lesions by B-mode and Unenhanced Color and Power Doppler US, Contrast-enhanced sion in 17 experimental tumors were calculated, and com- Doppler US as well as Spiral CT: Results of a Multicenter Study. pared with the results obtained with the existing model. Ultraschall Med, 23 (2002) 245-250 In contrast to the established model, our approach de- [2] Delorme S, Haberkorn U, Kinscherf R, Zuna I, Bahner ML, and scribes tissue vascularization more physiologically and al- van Kaick G: Changes in tumor vascularity during gene therapy lows to derive a consistent new hyperbolic model for quan- monitored with color Doppler US. Ultrasound Med Biol, 27 (2001) 1595-1603 tification of intermittent sonography. Nevertheless, the experimental results revealed that blood volume and mean [3] Delorme S, Hoffner S. Diagnostik der Schilddrüse. Teil 2: Schilddrüsenknoten, Diagnostik und Therapie des Schilddrüsen- blood velocity did significantly correlate between both, the karzinoms. Radiologe (2003) in press new and the established model (k=0.99; k=0.94, both [4] Delorme S, Hoffner S. Diagnostik des Hyperparathyreoidis- p<0.001). However, mean tumor blood velocity was under- mus. Radiologe (2003) in press estimated (-19%, p<0.01) with the established model com- [5] Delorme S: Beurteilung der Tumorvaskularisation mit der pared to the newly developed model. In addition, the Dopplersonographie. In: Farbkodierte Duplexsonographie. Kubale range and distribution of blood flow velocities found in vivo R and Stiegler H (Eds.) Stuttgart: Thieme (2002) 498-508 can be estimated with the new model. Furthermore, it uses [6] Delorme S: Diagnostik der Schilddrüse. Teil 1: Diffuse simpler mathematical fitting routines and allows an easier Erkrankungen, Epithelkörperchen. Radiologe, 42 (2002) 309-327 data acquisition, which may allow a more practicable clini-

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[7] Delorme S: Mammasonographie und Magnetresonanz- The number of examinations for radiotherapy planning has Mammographie als ergänzde Methoden im Mammographie- increased from 376 (in 1997) to 567 in 2001 and well screening. Radiologe, 41 (2001) 371-378. above 600 in 2002 (precise figure not available as of yet). [8] Delorme S; Peschke P; Zuna I; Kaick G.van: Darstellbarkeit While most examinations are carried out for fractionated kleinster Tumorgefäße mit Hilfe der Farbdopplersonographie. Der Radiologe, 41 (2001) 168-172. or single-fraction radiotherapy (mainly for arteriovenous malformations or metastases to the brain, lung, or liver) [9] Grau T, Leipold RW, Delorme S, Martin E, and Motsch J: Ultra- sound imaging of the epidural space. Reg Anesth Pain Med, 27 planning intensity-modified radiotherapy (IMRT) or heavy (2002) 200-206 ion radiation therapy is becoming more frequent. [10] Huber S; Vesely M*; Zuna I; Delorme S; Czembirek H: Fi- Examinations are carried out in appropriate fixation of the broadenomas: Computer-Assisted Quantitative Evalution of Con- target area with protocols as similar as possible to those trast-Enhanced Power Doppler Features and Correlation with His- used for diagnostic purposes [4]. In most tumors MRI topathology. Ultrasound in Medicine and Biology, 27 (2001) 3-11. scans are required for correlation while radiotherapy plan- [11] Krix M, Kiessling F, Vosseler S, Kiessling I, Le-Huu M, Fusenig N, Delorme S. Comparison of intermittent, bolus-contrast ning for cerebral arteriovenous malformations, pulmonary, imaging with conventional power Doppler sonography: Quantifica- hepatic or prostatic tumors relies solely on CT scans. tion of tumour perfusion in small animals. Ultrasound Med Biol For abdominal large field planning a new method with digi- (2003) in press tally reconstructed radiograms of spiral CT angiography [12] Lorenz A; Delorme S: Sonographie - Physikalische und data was developed to facilitate radiotherapy planning. Ab- technische Grundlagen. In: Handbuch der Radiologie. Vogl TJ, Freyschmidt J, Schmitt Th (Eds.) Berlin, Heidelberg: Springer dominal extended field radiotherapy requires exact field (2002). shaping to spare critical non - target structures such as the [13] Weber MA and Delorme S: Routine-Nachsorge 16 Jahre kidneys and to fully cover the abdominal lymphnodes and nach Adrenalektomie links aufgrund eines Nebennierenrinden- the spleen. Conventional treatment planning is difficult to karzinoms. Radiologe, 42 (2002) 331-334 adapt to individual vessel anatomy, whereas 3D-planning [14] Weber MA, Wasser K, Schwenger V*, Hallscheidt P, Nahm is time consuming for routine use [7]. AM* and Delorme S: Palpable Resistenz unterhalb des rechten Rippenbogens. Radiologe, 42 (2002) 46-50 Three patients were imaged using a non breath-hold biphasic contrast enhanced spiral CT-angiography sequence. The image data were edited on the CT console Computed Tomography in Cancer Research with manual removal of all bony structures and digitally re- S. Delorme, L. Dukic, M. Essig, C. Fink, S. Heckl, constructed. F. Kießling, M. Krix, M. Lichy, M. Puderbach, Edited and original CT images are then calculated in cen- 236 C. Rehm, H.-P. Schlemmer, S.O. Schönberg tral beam projection using a maximum intensity projection algorithm. The two MIP-DRR images are then fused (Fig- The main tasks of the computed tomography group are ure 1). The resulting image has an identical geometry to a support activities for other working groups. CT serves the standard simulation film, showing all bony landmarks as following purposes: Radiotherapy planning; reference for PET and MRI studies; screening for patients with a history of Thorotrast exposure; diagnostic studies for patients re- ferred from different clinics within the ‘Tumorzentrum Heidelberg/Mannheim’ (cancer center) and radiology resi- dent training. CT continues to be the ”working horse” in oncologic imaging outside the brain. Approx. 2.400 clinical exams are performed annually. Additionally approx. 1.100 ultrasound exams are done by the members of the CT group. The gained revenue from these activities helps financing other working groups within the department [1-8]. The main research projects between 2001 and 2002 were radiotherapy planning improving contrast for radiotherapy planning by scanning at reduced tube voltage, 3D CT in oncology and dynamic functional CT (e.g. elasticity measurement in aortic aneurysms, temperature monitoring and dynamic contrast-enhanced CT). Computed tomorgraphy for radiotherapy planning In the radiotherapy planning projects CT was used to pro- Figure 1: Digitally reconstructed radiogram in central beam provide reference images for stereotactic radiotherapy plan- jection using the described spiral CT protocol for planning of large ning. Despite the potential of MRI for a precise delineation abdominal fields. The reconstruction geometry is identical to the of tumors, CT remains indispensable for radiotherapy radiotherapy simulator and the linear accelerator thus enabling planning, since it is free of distortion and provides the nec- direct planning on these images. All major structures (spleen, essary data for calculating radiation absorption. splenic vessels, kidneys, major vessels, and bony landmarks) are shown.

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy well as the major vessels and organs allowing direct plan- tween the treated target volume and MRA volume were not ning of the optimal field covering the target structures significantly different when comparing all AVM together. while sparing critical organs at the same time. This was identical for larger AVM with volumes >4.9 cc. The absolute differences between volumes derived from Computed tomography angiography using low CTA and MRA in smaller AVM (volumes <4.9 cc) were sta- voltage techniques tistically different (p<0.006), as were the relative differ- CT angiography of the intracranial vessels is just evolving. ences to the treated target (p<0.007). In this study we report on our experience using CTA for 3D treatment planning of stereotactic radiosurgery of intracra- In a second study the improved vascular opacification in nial AVM. Furthermore we retrospectively compared CTA CTA with 80 kV was examined. The k - edge of iodine as to the established 3D TOF MRA in these patients. Re- the contrast-giving component in contrast dye is 33.17 cently, Debus and coworkers introduced a method using a keV. CT - angiography is usually performed at generator linear accelerator and a micro-multi-leaf collimator en- settings of 120 kV, sometimes even at 140 kV, resulting in abling stereotactic radiosurgery with irregular fields for mean effective energies in the range of 65 to 70 keV or treatment of AVM. With this is a three dimensional confor- above in the body. mal shaping of the treatment volume according to the The free selection of generator settings, as usually pos- shape of the target is possible. An imaging assessment by sible in conventional x - ray diagnostics, is not feasible in 3D volume scanning is essential for this method of treat- computed tomography. There are commonly three tube ment. Conventional i.a. angiography is the gold standard voltages available on modern CT equipment: one setting for diagnosis of an AVM. Until now magnetic resonance in the range of 80 kV, one around 120 kV, and a third one angiography (MRA) is the procedure of choice for 3D plan- around 140 kV. ning of radiosurgery of AVM, a 3D times of flight (TOF) Reducing the tube voltage results in a reduction of dose. technique is established. This can partially be accounted for by increase in tube cur- With the introduction of slip ring technology spiral CT was rent. Nevertheless, tube voltage affects dose approxi- made possible. In CT angiography (CTA) a fast volumetric mately by x3, while the tube current has a linear relation- data acquisition is combined with an intravenous bolus in- ship to dose. Thus, an equivalent effective dose is usually jection of contrast material leading to an almost exclusive beyond the scope of modern CT hardware when changing enhancement of vessel structures during the early phase. from 120 kV to 80 kV generator settings. Reconstruction with an overlapping increment achieves CT for preoperative staging of advanced lung angiography like views using maximum intensity projec- cancer tions (MIP) with acceptable z-axis resolution. 30 consecu- 237 To improve non-invasive assessment of tracheal infiltration tive patients with 32 angiographically proven intracranial and contralateral lymph node spread using multiplanar re- AVM were included into this study. The skull of the patients constructions of high-resolution MS-CT data sets. was immobilized for stereotactic treatment planning as well as for stereotactic radiosurgery. Digital subtraction an- Thin-slice CT data sets were acquired with a 4-detector- giography was available in all patients. All patients were multislice CT (slice collimation 1mm). To optimize imaging treated with stereotactic radiosurgery using 6 MeV pho- of thoracic vessels, contrast media arrival in the ascending tons of a linear accelerator (Siemens Mevatron Experi- aorta was detected by a software tool controlling the mental, Siemens AG, Erlangen, Germany) with established power-injector assisted contrast infusion. techniques. All CT procedures were performed on a clini- In a preliminary study, 11 patients with suspected medias- cal CT scanner with spiral option (Siemens SOMATOM tinal invasion of lung cancer and questionable tracheal in- Plus 4, Siemens AG, Erlangen, Germany) with standard- vasion were examined. The data sets were reformatted in ized scanner settings, standard adult head kernel and ma- the axial, coronal and sagittal plane. Suggested metastatic trix. MRA was performed in 24 of the 30 patients, showing contralateral lymph nodes or tracheal invasion were com- 26/32 AVM (1,5 T Magnetom, Siemens AG, Erlangen, Ger- pared to the results of mediastinoscopy and surgery. many). The 3D TOF MRA was performed based on a 3D CT-findings for tracheal infiltration included indenting of velocity compensated fast imaging with steady-state pre- the tracheal wall by the tumor, while growth of the tumor cession (FISP) sequence with variable flip angle (TONE) along the course of the trachea with a preserved fat plane and magnetization transfer contrast. All source images (Figure 2) was not considered suggestive of infiltration. Of from CTA and MRA as well as MIP projections from CT the eleven cases, MS-CT was able to correctly identify tra- data were evaluated by two radiologists in a blinded fash- cheal infiltration in both two cases, while in all nine nega- ion. tive cases infiltration could be ruled out. The performance CTA proved to be superior (χ2: p = 0.001, Mantel-Haenszel for contralateral nodal spread was substantially worse. χ2: p = 0.001, validated by Fisher’s exact test) comparing MS-CT detected enlarged contralateral nodes in all cases, the image quality of axial CTA and of axial 3D TOF MRA. however, these were only found to be malignant in a single In no case 3D TOF MRA was superior to CTA. case during surgery. The absolute differences of calculated volumes between In conclusion, preliminary results show that MS-CT ac- CTA and MRA were significantly different (p<0.0001), while quires data sets resolving anatomic structures in multiple the relative differences between the treated target volume orientations with a better delineation of tumor extent. and CTA volume compared to the relative differences be-

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the vessel specimens measured at two locations (distance: 90 mm) using two line-CCD cameras (DALSA, Wa- terloo, Ontario, Canada) with a 0.1 mm pixel spacing and a temporal resolution of 0.1 ms. The results of the phantom measurements showed an excellent correlation of the MSCT data with the optical method. In detail, a mean compliance of (2.7 ± 0.9)×10-5 Pa-1 was found with the CT method, while the compliance was (2.8 ± 1.0)×10-5 Pa-1 with the optical method. It is possible to calculate aortic wall elasticity dividing the Figure 2: Multislice-CT (effective slice thickness 1mm, 100 ml of relative change in vessel area by the systolic/diastolic iodinated, non-ionic contrast at a rate of 3ml/s) of a 59-year-old pressure change. patient with non-small-cell lung cancer. Coronal reformats demonstrate mediastinal invasion (stage T4), however no signs of tra- In an ongoing feasibility study we develop image acquisi- cheal invasion. On these thin-slice reformats, a small fat plane tion and reconstruction algorithms which allow to deter- (arrow) is appreciated between the tumor and the left atrium, thus mine changing of vessel area in patients aorta. In a follow- excluding tumor infiltration. up study we will correlate annual aneurysm growth with elasticity. Since surgical proof can be rarely obtained in patients with In summary, measurement of aortic compliance using CT advanced lung cancer, data collection is still ongoing. with ECG-gating is feasible and easily fits into clinical rou- Computed tomography for aortic vessel wall tine scanning protocols. This will make it worthwhile to in- assessment vestigate in further patient studies if compliance is helpful To evaluate feasibility of aortic wall ealsticity determination in the diagnosis of aortic diseases. in ECG-gated MSCT and to evaluate the predictive value Dynamic computed tomography of the lung of aortic wall elasticity for the risk of rupture of abdominal Computed tomography continues being the gold standard aortic aneurysms we developed a method that allows to for the radiological investigation of pulmonary and medias- determine aortic compliance from MSCT data. It is based tinal tumors and for monitoring therapy of malignant dis- on ECG-gated data acquisition during CT angiography. eases of the chest. The tumor staging, which is crucial for We provide experimental validation of this method in a the applied therapy, has to assume the extend of the tu- phantom set-up, and show preliminary results of its appli- mor exactly and infiltration into the neighbored tissue 238 cation to patient data. should be detected. Also the response to a therapy should All experiments were performed using a multi-slice spiral early be detected in order to change treatment as early as CT scanner (SOMATOM Volume Zoom; Siemens Medical possible if this is necessary. Aim of this study was the Solutions, Erlangen, Germany). The basic idea of the evaluation of dynamic data using computed tomography, method is to add retrospective ECG-gating to an otherwise which reflect tumor vascularisation and perfusion. The standard CT angiography protocol. The acquired raw data prognostic value of this appoach for early detection of che- set is used to obtain two image sets: First, standard an- motherapy response will be evaluated. In a second study giography images without ECG-synchronization are calcu- dynamic CT is applied to examine patients with irradiated lated on the scanner console. Second, time-resolved im- lung tumors. It will be investigated if this methods can help ages are calculated with the present ECG-gated algorithm. to distinguish radiation effects (like fibrosis) and tumor. To this end, the raw projection data from the CT scanner The patients are examined with dynamic CT additionally to were transferred to a standard PC via a local network. On their routine staging CT examinations using a multislice this PC, retrospective ECG-gating and image reconstruc- CT scanner (Somatom Plus 4 Volume Zoom, Siemens, tion was performed using programs developed using Erlangen Deutschland) and a voltage of 80kV and a power Matlab (The MathWorks, Natick, MA, USA) and Visual of 100 mAs. Following an unenhanced scan of the chest C++ (Microsoft, Redmond, WA, USA). An algorithm was with 5/5 mm collimation to localize the tumor, the dynamic developed that uses data from several heart beats for im- examination is applied in a representative area with four age reconstruction. By selection of data belonging to a slices of 5 mm each. During the infusion of 50 ml contrast certain heart phase, it allows to improve temporal resolu- agent (5 ml/sec) first 25 scans (1 scan/sec) are recorded. tion at the expense of spatial resolution. Temporal resolu- Than 3 scans follow in a distance of 20 sec. Finally 5 tion depends on the relation between heart rate and scan- scans are performed over the next 5 minutes (1 scan/min). ner rotation time. For an interpolation range of 4 rotations, After the dynamic examination the routine staging CT scan which was used is this study, temporal resolution ranges is applied, examining the whole chest after second appli- between 90 and 250 ms. With a heart rate of 70 beats per cation of contrast agent (7 ml, 3 ml/sec) during arterial en- minute, a temporal resolution of 140 ms is obtained. To hancement. Tumor perfusion was calculated using the provide some oversampling, 20 time frames are calculated maximum slope method of Miles et al.. In addition, blood which results in smooth area -over-time-curves. volume and blood flow were determined using a pharma- In order to test the accuracy of the method, phantom mea- cokinetic two-compartment model. After calculation of the surements were performed using porcine aortic speci- dynamic parameters, these were color-coded and mens. These data were correlated to the cross-section of overlayed to the morphologic CT images to reveal dy-

DKFZ 2003: Research Report 2001/2002 Research Program E Division E0100 Radiological Diagnostics and Therapy Oncological Diagnostics and Therapy

German Thorotrast Study (E0107) G. van Kaick, D. Liebermann, H. Wesch*) *) E0200, DKFZ The aim of this clincal, epidemiologigal study is to evaluate late effects of chronic alpha irradiation due to the x-ray contrast agent Thorotrast, and to assess the radiation-related tumor risk. Thorotrast was used for angiography world-wide between 1930 and 1950, and consisted of a Figure 3: CT image of a bronchial carcinoma prior cytostatic colloidal solution of thorium dioxide. Thorium, as a primor- therapy (left) and the according color coded parameter map of the dial radionuclide, has a physical half-life of 1010 years. Fol- tumor perfusion (right). lowing injection, it is permanently stored in the reticuloen- dothelial system, mainly in the liver, lymph nodes, and namic parameter maps (Figure 3). These improve obser- spleen. vation of regionary changes of vascularisation and perfusion of the tumors. In the past years, the epidemiological data have become stable for several thorotrast-induced diseases, particularly Up to now about 50 patients with primary lung cancer trea- for liver tumors, liver cirrhosis, and leukemia (Table 1). Un- ted with cytostatic therapy and 15 patients with irradiated til now, only 25 of all persons exposed to Thorotrast have lung tumors were examined repeatedly. Blood volume, survived, whereas 200 from the control group are still perfusion and maximum slope were calculated reliably in a alive. In an ongoing project, the causes of death in the clinically practicable form. Initial results indicate an early control group are being compared with those in the gen- decrease of tumor vascularity under cytostatic therapy. eral population (in cooperation with N. Becker, DKFZ). The prognostic value of this measurement procedure will be elucidated during the process of the study. In a clinical study, we examined the late effects of para- vascular Thorotrast deposits. The long-term alpha irradia- Publications (* = external co-author) tion mainly caused a scarry destruction of the involved soft [1] Bahner ML: Methodische Entwicklungen zur Cardio-Computer- tissue, in rare cases followed by vascular rupture and le- tomographie. Habil Schr Med Fak Univ Heidelberg (2002) thal bleeding. The incidence of soft tissue sarcomas, how- [2] Delorme S and Goldschmidt H*: Lymphknotenmetastasen und ever, remained far below what had been expected. maligne Lymphome. In: Radiologische Diagnostik in der Onkologie. Layer G and van Kaick G (Eds.) Heidelberg: Springer Table 1: Neoplastic diseases (T/C>2) in Thorotrast patiens. T/K: (2003) in press Relation of the percentages of tumors in Thorotrast (T) anc in 239 [3] Delorme S: Tumorcharakterisierung mit radiologischen control patients (C) Methoden: Leber, Nieren, Pankreas. Ultraschall Med, 22 (2001) Diagnosis Thorotrast Controls T/C M110-M113 n = 2326 n = 1890 [4] Herfarth KK; Debus J; Lohr F; Bahner ML; Rhein B; Fritz P*; Primary liver tumor 454 3 122,9 Höss A; Schlegel W; Wannenmacher M*: Stereotactic single-dose radiation therapy of liver tumors: results of a phase I/II trial. Jour- Carcinoma of extrahepatic 42 7 4,9 nal of Clinical Oncology, 19 (2001) 164-170. bile ducts or the gall bladder [5] Kiessling F; Seitz KH*; Schlemmer HP: Rezidivierende Malignant mesothelioma 9 0 Oberbauchschmerzen mit Gewichtsverlust und Inappetenz. Pancreatic carcinoma 18 6 2,4 Radiologe 41 (2001) 783-785. Non-lymphatic leukämia and 70 11 5,2 [6] Oh J*; Wunsch R*; Turzer M*; Bahner ML; Raggi P*; Querfeld myelodysplastic syndrome U*; Mehls O* and Schaefer F*. Advanced coronary and carotid Non-Hodgkin lymphoma 15 5 2,4 arteriopathy in young adults with childhood-onset chronic renal failure. Circulation, 106 (2002) 100 - 105 Multiple myeloma 10 2 4,1 [7] Plathow C*; Thilmann C; Delorme S; Stippich C*; Osteosarcoma 4 1 3,2 Wannenmacher M*; Debus J: Bestrahlungsplanung rückenmarks- naher Tumoren unter Zuhilfenahme der CT-Myelographie. Strahlentherapie und Onkologie 177 (2001) 307-312. [8] Wasser K, Hofmann WJ*, Singer R*, Essig M, and Delorme S: Rätselhafter Leberbefund: Peliosis hepatis. Radiologe, 41 (2001) 95-98

DKFZ 2003: Research Report 2001/2002