Malignant and Benign Diffuse Pleural Disease : Utility Offdg PET in Differential Diagnosis and Comparison with CT 1

J Korean Radiol Soc 1997; 37 : 641 - 649

Malignant and Benign Diffuse Pleural Disease : Utility ofFDG PET in Differential Diagnosis and Comparison with CT 1

Kyung Soo Lee, M.D., Jung-Eun Cheon, M.D., Byung-Tae Kim, M.D.2 Yookyung Kim, M.D., Duk 、^J oo Ro, Ph.D., 0 Jung Kwon, M.D.3, ChongH. Rhee, M.D.3

Purpose : To assess the utility of 2-[18F] f1 uoro-2-deoxy-D-glucose (FDG) PET in differentiating malignant and benign diffuse pleural disease, and to compare it with CT. Materials and Methods : Both FDG PET and CT scans were performed in 20 con secutive patients with diffuse pleural disease(13 malignant and seven benign cases). In FDG PET, peak standardized uptake value (SUV) as well as visual assessment of abnor mally increased uptake in the pleura was evaluated. The results were compared with CT findings. Results : With only visual assessment of PET images, sensitivity, specificity, and accuracy for malignancy were 92 %, 43 %, and 75 %, respectively. With peak SUV of 4.8 or more, the corresponding figures were 100 %, 57 %, and 85 %, respectively, and on CT interpretation, were 100 %, 57 %, and 85 %, respectively. Tuberculous empyema simulated malignant pleural disease both on FDG PET (3/6 patients with peak SUV more than 4.8) and CT (3/6 patients) Conclusion : For the differentiation of malignant and benign diffuse pleural dis ease, FDG PET and CT are equally accurate. Combined visual and quantitative assessments of PET images enhance discriminatory ability. Tuberculous empyema simulates malignant pleural disease both on FDG PET and CT.

Index Words : Emission CT Fluorine Pleura, CT Pleura, diseases Pleura, neoplasms

Because diffuse pleural abnormalities usually in pleural disease is even more difficult because a specific volve various degrees of pleural thickening, calcifi diagnosis is often hard to make on the basis of clinical cation and effusion, there is an overlap of radiologic criteria, thoracentesis, and percutaneous pleural bi findings of different benign and malignant pleural dis opsy findings. eases(l). The differentiation ofmalignant from benign CT can play a major role in distinguishing malignant from benign pleural disease. Features that favor the 'Departments of Radiology. Samsung Medical Center. College of Medicine. former include circumferentiaL nodular and parietal SungKyunKwan University 2Departments of Nuclear Medicine. Samsung Medical Center. College of Medi pleural thickening of more than 1 cm, and mediastinal cine. SungKyunKwan University pleural involvement. Although specificity of the 'Departments of Pulmonary Medicine. Samsung Medical Center. College of findings was high(88 - 100 %), their sensitivity was Medicine. SungKyunKwan University This research was supported in part by Samsung lnstitutional Biomedical Re relatively low(36 - 56 %) (2). search grant C-95-028 It has been recognized that the increased rate of Received June 16. 1997; Accepted September 5. 1997 Address reprint requests to: Kyung Soo Lee. M.D .• Department of Radiology. glucose metabolism seen in human cancers may serve Samsung Medical Center 1 50. lrwon-Dong. Kangnam-Ku SeouI135-230. South as a useful target for positron emission tomographic Korea. Tel. 82-2-3410-251 1. 2518 FAX.82-2-341O-2559 (PET) metabolic imaging with radiolabeled glucose e-mail. [email protected]

- 641 - Kyung Soo Lee, et al : Malignant and Benign Diffuse Pleural Disease ana10gues such as 2-[18Fl fluoro-2-deoxy-D-g1ucose b100d glucose 1eve1 ranged from 70 to 113 (mean, 88) (FDG) . Severa1 recent studies have reported the diag mg/dL and image acquisition started just after injec nostic applicability of FDG PET to thoracic imaging for tion. A Hanning filter was used for image reconstruc the differentiation of ma1ignant from benign disease tion, resulting in a practica1 reso1ution of 9.0mm. Im (3 - 8) age processing and reconstruction were performed The aims of this study were to assess the utility of with an Apollo 735 computer system(Hew1ett Packard, FDG PET in differentiating between ma1ignant and be Rockville, Md이)ι). . Photon at야tem뻐 tion was corrected by nign diffuse p1eura1 diseases, and to compare it with the use of a transmission scan obtained with two CT. 68Gef'8Ga pin sources (10 mCi each) 20 mins before the injection ofFDG. On images obtained 40-60 minutes after injection, Materials and Methods we visually constructed over the 1esion a region of This study invo1ved 20 consecutive patients interest (ROI) showing the most active FDG uptake. diagnosed on chest CT as suffering from diffuse p1eura1 The size of an ROI varied from nine to 41 pixels; each disease. Ten were men and ten were women, and their pixe1 was 1. 95 mm in size, in 128 X 128 array. ages ranged from 18 to 74 years(mean + standard devi Standardized uptake va1ue(SUV), normalized for ation, 51. 8 ::t 15.6). These patients were consensually injected dose and body weight, was obtained in each se1ected by an experienced chest radio1ogist and a pixe1 using the previous1y described method(lO). The pu1mono1ogist aware of their name, age, sex, clinica1 maximum pixe1 va1ue of SUV in ROI was chosen as data, and radiographic findings but who did not take peakSUV(IL 12). part in image ana1ysis. On CT, p1eura1 thickening was PET scans were interpreted independent1y by two seen; this extended for 8cm craniocaudally and 5 cm qualified nuclear medicine physicians, who were 1aterally, and in the p1eura was over 3mm thick(9). blinded to patho1ogic results, but aware ofCT findings. P1eura1 effusion and/or calcification was a1so present. Because diffuse p1eura1 uptake was expected on PET, We excluded those patients with metastatic diffuse the pattern of abnormally increased uptake was p1eura1 disease originating from overt 1ung cancer, subclassified visually as smooth linear, nodu1ar, or in since cancer in these patients may easily be recognized terrupted. Increased uptake was considered to have byCTscans. occurred when the presumed 1esion showed more up All patho1ogic specimens were obtained by p1eura1 take than the mediastinum. Because spatia1 reso1ution biopsy(n= 10), open thoracotomy including decorti ofincreased uptake on PET was not satisfactory, the 10- cation(n=6), and video-assisted thoracoscopic sur cation of increased uptake (such as parietaL fissuraL or gery(n=4), and were reviewed by one patho1ogist. Ma mediastinaI) was not specified. When increased uptake 1ignant vs. benign disease was histo1ogically deter was detected in other areas including the 1ung, medias mined on the basis of standard architectura1 and tina1 node, chest waU, or extrathoracic area, the 10- cyto1ogic features. P1eura1 metastasis occurred in cation of the uptake was recorded. Initially, the PET eleven patients(from presumed 1ung carcinoma in four, scans were assessed visually, images were reviewed in and from unknown primary sites in seven); two were axiaL coronaL and sagitta1 p1anes, using an interactive suffering from malignant mesothelioma, and seven video disp1ay system. Inclusion criteria of 3 mm or from benign diffuse p1eura1 disease (tubercu1ous em more ofp1eura1 thickness, as seen on axia1 CT scans, did pyema, 6 cases; nontuberculous empyema, 1 case). not thus preclude interpretation of a PET scan of 9 mm in reso1ution. When FDG uptake of the p1eura11esion Image Acquisition and Interpretation of FDG was higher than that of the mediastinum, it was PET regarded as ma1ignant. In cases of a clash of opinion be All FDG PET scans were obtained with a GE tween the two observers, decisions on malignancy Advance™ PET scanner(GE Medica1 Systems, were reached by consensus. Interpretations were a1so Mi1waukee, Wis). This unit has 4.2건5-mrr따t based on an assessment of uptake semiquantitation, plane않s(18 direct p1anes and 17 cross p1anes), provides using peak SUV . full-width at ha1f maximum of 4.2mm both in direct and cross p1anes, and its 10ngitudina1 field of view is Image Acquisition and Interpretation of CT 15.2cm. Intravenous injection of 10 mCi (370 MBq) of All CT scanning was performed with a GE HiSpeed FDG was performed after an overnight fast of at 1east Advantage scanner(GE Medica1 Systems, Milwaukee, four hours. Just before FDG injection, the patients’ Wis). Helica1 scans(thickness, lOmm; tab1e feed, 10

- 642 - J Korean Radiol Soc 1997; 37 : 641 - 649 mm/sec) were obtained through the thorax after intra defined as p1eura1 thickening bordering the medias venous administration of 100 mL of Iopamiro(30 % of tinum, and a distinction between viscera1 and parieta1 Iopamid 이， Bracco, Mi1an, Ita1y). Additiona1 thin-sec p1eura1 thickening was made on1y in the presence of tion (l-mm collimation) CT scans were obtained p1eura1 effusion. The contour of p1eura1 thickening through the thorax at 20-mm interva1s. Image data was characterized as smooth, irregu1ar, or nodu1ar, and were reconstructed using bone a1gorithms. All scans parieta1 p1eura1 invo1vement was further characterized were photographed with both mediastina1 (window according to whether it was circumferentiaI(defined as width, 400 HU; window 1evel, 30 HU) and 1ung win invo1vement ofthe entire perimeter ofthe hemithorax, dow(window width, 1,500 HU; window 1evel, - 700 including the mediastinum, or p1eura1 rind), and on the HU) basis ofwidth ofthickening and 1ength of craniocauda1 CT scans were ana1yzed by two chest radio1ogists extension. Mediastina1 nodes were considered who did not participate in the se1ection ofpatients, and enlarged if they were greater than lOmm in short-axis decisions concerning CT findings were reached by diameter, and were recorded following the American consensus. The scans were assessed on the basis of 10- Thoracic Society 1ymph node mapping system(13) cation, type and extent of p1eura1 thickening, the pres After ana1yzing the CT findings of each patient, the ence of p1eura1 effusion, p1eura1 calcification, disease process ofthe p1eura was considered malignant extrap1eura1 invasion and mediastina1 adenopathy, if one or more of the following findings was present: and coexisting pu1monary parenchyma1 abnorma1ities, circumferential, nodu1ar or parieta1 p1eura1 thickening as recommended in a previous study(2). The 1ocation of greater than 1 cm, and/or mediastina1 p1eura1 invo1ve p1eura1 thickening was classified as parietaL visceraL ment. fissural, or mediastinal. Mediastina1 invo1vement was

Fig. 1. Metastatic adenocarcinoma of pleura presumably from lung carci noma (case 12) in a 41-year-old woman A. Enhanced lO-mm collimation CT scan obtained at ventricular level shows diffuse pleural thickening and mass with probable lung cancer in lingular segment of left upper lobe (arrows). Also note edematous thick ening (arrowheads) of extrapleural subcostal tissue posteriorly. B. FDG PET obtained at similar level to A shows nodular and interrupted uptake of FDG in pleura and lung B Peak SUV was 7.4. Ht : heart

Fig. 2. Malignant mesothelioma in a 42-year-old man(case 9) . A. Enhanced lO-mm collimation CT scan obtained at level of liver dome shows mild pleural thickening in par ietal pleura. Pleural effusion and smal- 1 cystic lesion in liver are associated Also note edematous swelling of chest wall. CT scan obtained at upper level (not shown here) also showed medias tinal pleural thickening. B. FDG PET pbtained at similar level to A reveals nodular and interrupted uptake of FDG (arrows) in parietal pleura. Peak SUV was 4.9. E: pleural A B effusion, Li : liver

- 643 - Kyung Soo Lee. et al : Malignant and Benign Diffuse Pleural Disease

%( 15 /20 patients). respectively. There was an overlap of peak SUV between malig Results nant and benign diffuse pleural diseases. The average FDG PET Findings peak SUV ofthese was 6.0 :t 1.27 (range. 4.8 - 9. 1) and Increased FDG uptake was nodular and interrupted 5.0 :t 2.02(range. 2.7 - 8 이. respectively; P=.60 in in 11 /13 patients(84 %)(Figs 1 and 2). nodular in 1/13 two-sample t test. In all patients with malignant pleural patients(8 %). and smooth linear in 1/13(8 %). Nodular disease. SUV was 4.8 or more. With peak SUV at this and interrupted uptake was seen in 3/7 patients (43 %) level. sensitivity. specificity. and accuracy for malig with benign diffuse pleural disease(Figs. 3 and 4) ; up nancy were 100 %(13 / 13 patients). 57 %(4/7 patients). take was smooth linear in 3 /7( 43 %) and nod ular in 1/7 and 85 %(17 /20 patients). respectively. Six of seven (1 4 %) (Table 1). Additional extrapleural areas of patients with benign pleural disease had tuberculous increased uptake were seen in six patients with malig empyema; their mean peak SUV was 5.5 :t 1. 9(range. nant pleural disease; these were the lung in four 3.0 - 8.0). and in three ofthe six. peak SUV was more patients. and the ipsilateral chest wall and contralateral than 4.8(Table 1) hilum in one each. On the basis of visual assessment only of PET images. sensitivity. specificity. and accu CTFindings racy in differentiating malignant from benign lesions Overall. CT correctly differentiated malignancy and were 92 %(12/13 patients). 43 %(3/7 patients). and 75 benignancy in 17 /20 patients(85 %) suffering from dif-

Fig. 3. Tuberculous empyema in a 53-year-old woman(case 14). A. Thin-section (l-mm collimation) CT scan obtained at level of liver dome shows thickening of parietal pleura (arrows) with accumulation of extrapleural fat(arrowheads). Also note areas of parenchymal nodule in right lower lobe. B. FDG PET obtained at similar level to A reveals interrupted nodular up take of FDG in pleura(arrows). Peak SUV of this patient was 4.1. L: lung. Li : liver

A B

Fig. 4. Tuberculous empyema mim icking malignant pleural disease both at CT and FDG PET in a 37-year-old man(case 19). A. Enhanced lO-mm collimation CT scan obtained at subcarinal level shows marked thickening of parietal (arrows) and mediastinal (arrowhead s) pleura. Also note thickening of in nermost intercostal muscle (open ar rows) and accumulation of extrapleur al fat. B. FDG PET obtained at similar level to A reveals nodular and circumfer ,,'5).. -'í").. ential increased uptake of FDG. Peak SUV of this patient was 8.0. M : med A 8 lastlnum -644 - J Korean Radiol Soc 1997; 37 : 641 - 649 fuse pleural disease; all 13(100 %) with malignant and in patients with malignant pleural disease, and in 4/13 4/7(57 %) with benign disease were correctly interpret such cases(31 %). ed(Table 2). Mediastinal pleural thickening was observed in Discussion 12/13 patients (92 %) with malignant pleural disease (Fig 1) and in 2/7 (29 %) with benign pleural disease(Fig Because FDG PET primarily ref1ects the metabolic 4). In 7/13 patients (54 %) with malignant pleural dis (biochemical) characteristics of a tissue, it provides a ease and in 1 /7( 14 %) with benign pleural disease, in physiologic approach for the evaluation of thoracic cluding one case of tuberculous empyema, the thick diseases and permits quantitative analysis of abnor ness of the parietal pleural was lOmm or more(Fig. 4); malities. By demonstrating increased glucose uptake in in malignant cases, the average was 11 mm. Nodular cancer tissues, FDG PET has been proven useful in thickening was observed in 7/13 patients(54 %) with differentiating between malignant and benign focal malignant pleural disease (Figs. 1 and 2) and in 3/7(43 lung lesion(3 - 5), between recurrent bronchogenic %) with benign pleural disease. Circumferential carcinoma and fibrosis after therapy(7), and even in the pleural thickening was observed in 5/13(38 %) and staging of lung cancer through the evaluation of 1/17(14%) with malignant and benign pleural disease, mediastinal nodes (6, 8). respectively(Fig. 4) (Table 2). Among six patients with Although SUV provides very sensitive measurement tuberculous empyema, circumferentiaL nodular and of malignant pleural disease(100 % in our study and parietal pleural thickening of over 1 cm, and medias more than 90 % in other studies(3 - 5)), its relatively tinal pleural thickening, were noted in one, three, one low specificity (43 % in our stud y and 67 - 100 % in and two, respectively. others (3 - 5)) is a problem. It has been reported that In 19/20 patients(95 %), there was associated pleural patients with active pulmonary tuberculosis and poor effusion. Mediastinal nodal enlargement was seen only ly marginated inf1ammatory infiltrates show increased

Table 1. FDG-PET Findings of 20 Patients with Diffuse Pleural Disease U ‘ 왜 . Dl ‘9 m Pt. Visual Type of Abnormal Uptake i ‘ No /Age/Sex pathology Assessment PSUV Smooth Nodular Interrupted Other areas DxMethod M -3 3 + 1/71 /F Mets Adenoca Contralat. hilar L/N Pleural Bx M A앙9 十 + 2/61 /F Mets Adenoca MassinRLL Pleural Bx B A% 8 + + 3/44/F Mets Adenoca PleuralBx M qJJ + + 4/7 1/M Mets Adenoca Pleural Bx M ζ 2 + + 5/50/F Malignant 」 VATS Mesothelioma M F30 十 + 6/74/F Mets Adenoca VATS M 7I 2 + + 7/36 /F Mets Adenoca MassinRUL Thoracotomy M rO 0 + + 8/64/F Mets Adenoca MassinRUL VATS M A 9 + + 9/42/M Malignant 앙 Pleuropneu Mesothelioma monectomy M + 1O/66 /F Mets Adenoca 6.0 Chest wall Pleural Biopsy M + + 1l/65 /M Mets Adenoca 6.6 Pleural Biopsy M + + + 12/41 /F Mets Adenoca 7.4 h ass inLUL VATS M + + ‘ 13 /51 /M Mets Adenoca 5.6 Thoracotomy B + + 14/53/F Tbcempyema 4.1 PleuralBx M 15 /41 /M Tbcempyema 5.8 Decortication B + 16/73 /M Empyema 2.7 PleuralBx B + + 17/18/M Tbcempyema 3.0 Decortication M + 18/40/M Tbcempyema 7.2 Pleural Bx M + + 19/37 /M Tbcempyema 8.0 Thoracotomy M + 20 /38/M Tbcempyema 4.7 + Pleural Bx Pt. : Patient, PSUV: peak standardized uptake value, Mets : Metastatic, Tbc : tuberculous, M: malignant, B: benign Bx : biopsy, L/N: lymph node, VATS : video-assisted thoracoscopic surgery, RUL: right upper lobe, RLL : right lower lobe

- 645 - Table 2. CT Findings of 20 Patients with Diffuse Pleural Disease Pleural Thickening Maximum Location Type Extent{cm) Pleural Effusion Mediastinal Others Pt. CT Thickness찌 No . Dx. Par Vis Fiss Med Smooth Irreg Nod Circum Length Width Small Moderate Large L/N

M 十 + + + + + 20 9 11 + 7 Pleural Ca + + Consolidation in RLL 2 M + + + + 11 0 3 + Atelectasis ofRLL 3 M + + + + + + 18 9 12 + Atelectasis ofRUL 4 M + + + 16 10 8 + Atelectasis ofRLL 5 M + + + 21 14 3 + 6 M + + + + + + + 18 8 14 + Conso이lidation 7 M + + + 15 9 8 + 4R, 1OR, 8 Suspicious mass in RUL 8 M + + + + + 15 9 9 + 4R,1OR Suspicious mass in RUL m 9 M 7 6 Single micronodule, RUL 1 + + + + f @A@ 10 M + + + + 20 8 11 + 2R Atelectasis ofRt lung 〈〈드그 Chest w all invasion P - ω 11 M + + + + 17 5 10 + 。。 S m α TL 「 12 17 6 35 때 “ 없 뻐 mm-ms A + + + + + + ‘ C 뼈 m이 따 m m 13 M + + 18 11 14 Noeffusion + + + + α~ 14 B 9 6 5 Subpleural nodule, RLL “ + + + + 르 15 24 13 9 Pleural Ca + + m:P h + + + + + ‘ 그 m Atelectasis ofLt lung 그야

α 16 B + + 18 9 4 + Atelectasis ofLt lung 그(나 17 B 18 8 4 Atelectasis ofRLL mm + + + 그·@그 18 B + + 14 8 4 + Subpleural nodules, BLL 므흑 19 M + + + + + 21 10 15 + Atelectasis ofRUL Emm 20 M + + + + + + 17 11 4 + 끄 Dx : diagnosis, Par : parietaL Vis: visceraL Fiss: fissuraL Med: mediastinaL Nod : nodular, Circum : circumferential mC 「@-。 RUL : right upper lobe, RLL : right lower lobe, LUL : left upper lobe, BLL: both lower lobes, Lt : left, M : malignant, B : benign Ca+ + : calcification RLL: right lower lobe, LUL: left upper lobe, BLL: both lower lobes, Lt : left, M : malignant, B: benign, .mmmmm Ca + + : calcification J Korean Radiol Soc 1997; 37 : 641 - 649 uptake during FDG PET(4). In our study, six of seven distinguish benign and malignant diseases was not dif patients with benign p1eura1 disease had tubercu10us ferent from that of average SUV in our previous study empyema, and their mean peak SUV was 5.5 =t 1.9 (1 6). In our hospitaL a diffuse p1eura1 disease showing (range, 3.0 - 8.0) which was higher than our cut-off an SUV peak higher than 4.8 is regarded as probab1y va1ue of peak SUV (4.8) for malignant p1eura1 disease. malignant. Furthermore, three of six patients showed a nodu1ar CT can p1ay an important ro1e in differentiating be and interrupted pattern of increased uptake(Fig 4) tween malignant and benign p1eura1 disease(l, 2). In These resuIts suggest that tubercu10us empyema with one study, its overall diagnostic accuracy in this re increased uptake of FDG may mimic malignant p1eura1 spect was about 77 %, while its sensitivity was 72 % disease. (28 /39 malignant diffuse p1eura1 diseases were cor We expected that an ana1ysis of the pattern of rectly diagnosed) and its specificity, 83 % (29β5 benign increased uptake wou1d he1p differentiate between diseases correctly diagnosed)(2). This overall resu1t is malignant and benign p1eura1 disease ; there were, comparab1e to ours. In our study, 17 of 20 (85 %) 1esions however, overlaps in this pattern between malignancy were correctly differentiated ; sensitivity was very and benignancy, and so this ana1ysis was not helpfu1 high (13 /13 ma1ignant 1esions, 100 %) whi1e specificity (Tab1e 1) was unusually 10w(4/7 benign 1esions, 57 %). A1though FDG PET is high1y sensitive in the detec CT features that arehe1pfu1 in differentiating malig tion ofmalignant diffuse p1eura1 disease, the prob1em is nant from benign p1eura1 disease include circumfer its 10w spatia1 reso1ution. In cases of diffuse p1eura1 up entiaL nodu1ar and parieta1 p1eura1 thickening ofmore take, differentiation ofFDG uptake between the p1eura than 1 cm, and mediastina1 p1eura1 thickening(2). The and the 1ung parenchyma, 1ymph nodes, or even the 10w specificity (4/7, 57 %) of CT in our study was pri chest wall is difficu1t, though not impossib1e. This can marily due to the relatively high incidence of cases of be substantiated in our cases 1, 7, 8, and 10(Tab1e 2) tubercu10us empyema among benign p1eura1 diseases. A1though CT demonstrated en1arged mediastina1 Malignant p1eura1 disease tends to invo1ve the entire 1ymph nodes, FDG PET cou1d not differentiate be p1eura1 surface, while that which is benign does not tween uptake in the p1eura and mediastina1 nodes. Im usually affect the mediastinal pleura(l, 2). The main age fusion may be the solution for this 10w spatia1 reso1- exception to this rule is tuberculous empyema. In ad ution(6), but is a time-consuming procedure. dition, tuberculous empyema may show circumfer For the detection of distant metastasis, FDG PET is ential and/or nodu1ar thickening, sometimes greater superior to CT, and is a1so more sensitive and specific than lOmm in thickness. Among six patients with tu for the detection of mediastina1 noda1 metastasis(6, 8) berculous empyema, circumferentiaL nodu1ar, and With CT, the detection rate of distant metastasis in parieta1 p1eura1 thickening of over 1 cm, and medias asymptomatic patients is 10w(14, 15), but FDG PET tinal p1eural thickening were noted in one, three, one permits the detection of metastatic disease by showing and two patients, respective1y. the difference in glucose uptake between metastatic Due to the small number of cases and a 1ack of diver disease and norma1 tissue ; CT, on the other hand, sity of diseases, our study suffers certain limitations, visualizes the difference in attenuation va1ue between and in addition, se1ection bias cannot be disregarded. metastatic focus and norma1 tissue. In our study, AIthough we tried to include consecutive patients increased extrap1eura1 uptake was detected by FDG with diffuse p1eural disease, severe forms ofthe disease PET in 6/20 patients, thus assisting in the differen with marked pleura1 thickening may have been tiation ofthe diseases. se1ectively included. This may be reflected by the fact In this study, we calcu1ated peak SUV(ll, 12), which that CT, with a reported sensitivity of 70 % (2) is per is somewhat different from average SUV. To determine fectly sensitive in the detection of malignant pleural this peak, the uptake va1ue is calcu1ated by choosing disease. In addition, this study was performed in an the highest SUV in the ROI. According to our experi area in which p1eura1 tubercu10sis is endemic. Tu ence, this method of measuring peak SUV was easier bercu10us empyema, showing increased uptake on than that for average SUV, which is widely used. FDG PET and CT features of malignant p1 Drawing an ROI exactly, in order to assess average SUV, is somewhat difficuIt, and, moreover, becau

- 647 - Kyung Soo Lee. et al : Malignant and Benign Diffuse Pleural Disease variety and greater number of cases of diffuse p1eura1 5. Hubner KF, Buonocore E, Singh SK, Gould HR, Cotten DW. disease are therefore needed. Characterization of chest masses by FDG positron emission tom ography. Clin Nuc/ Med 1995; 293-298 Compared with CT, FDG PET is expensive, but de 6. Wahl RL , Quint LE, Greenough RL, et al. Staging of medias spite this extra cost, its accuracy in differentiating be tinal non-smalJ celJ lung cancer with FDG PET, CT, and fusion tween malignant and benign diffuse p1eura1 diseases images: preliminary prospective evaluation. Radiology 1994; 191 was not greater than that of CT. The use of FDG PET as 371-377 a routine diagnostic too1 for the eva1uation of diffuse 7. Patz EF, Lowe VJ, Hoffman JM, Paine SS, Harris LK, Goodman p1eura1 disease cannot therefore be justified. Further Pc. Persistent or recurrent bronchogenic carcinoma : detection with PET and 2-[F-18]-2-deoxy-D-glucose. Radiology 1994; 191 more, as our resu1ts indicated, FDG PET is not usually 379-382 necessary. In this particu1ar disease it may be used for , 8. Valk PE, Pounds TR, Hopkins DM, et al. Staging non-smalJ cell determining an optima1 biopsy site, and may be helpfu1 lung cancer by whole-body positron emission tomographic in the eva1uation of tissue characterization in foca1 imaging. Ann Thorac Surg 1995;60: 1573-1582 p1eura1 disease, prior to 산tthor야raco야tomηψ} 9. Lynch DA, Gamsu G, Aberle DR. Conventional and high-resol ution computed tomography in the diagnosis of asbestosis-re t디icαu1ar disease, negative uptake can preclude thora lated disease. RadioGraphics 1989; 9: 523-551 cotomy. 10. Strauss LG, Conti PS. The applications of PET in clinical on In summary, after ana1 yzing the usefu1ness of FDG cology. J Nuc/ Med 1991; 32: 623-648 PET for differentiating between malignant and benign 11. Inoue T, Kim EE, Wong FCL, et al. Comparison of diffuse p1eura1 diseases and comparing it with CT, we fluorine-18-florodeoxyglucose and carbon-ll-methionine PET found that the two modalities are equally accurate. On in detection of malignant tumors. J Nuc/ Med 1996; 37 : 1472-1476 FDG PET, quantitative ana1ysis ofFDG uptake, such as 12. Jones DN, McCowage GB, Sostman HD, et al. Monitoring of measurement ofpeak SUV-which in cases ofmalignant neoadjuvant therapy response of soft-tissue and p1eura1 disease is high1y sensitive-is diagnostically musculoskeletal sarcoma using fluorine-18-FDG PET. J Nuc/ more accurate than simp1e visua1 assessment. Tubercu- Med 1996; 37: 1438-1444 10us empyema simu1ates malignant p1eura1 disease on 13. Tisi GM, Friedman PH, Peters RM , et al. American Thoracic both FDG PET and CT scans. Society : clinical staging of primary lung cancer. Am Rev Respir Dis 1983; 127 : 659-664 14. Lewis RJ, Caccavale RJ, Sisler GE. Imaged thoracoscopic lung biopsy. Chest 1992; 102: 60-62 References 15. Grant D, Edward D, Goldstraw P. Computed tomography of the 1. MulJer NL. Imaging of the pleura. Radiology 1993; 186: 297-309 brain, chest and abdomen in the pre-operative assessment of 2. Leung AN, MulJer NL, Miller RR . CT in differential diagnosis non-small-celJ lung cancer. Thorax 1988; 43: 883-886 of diffuse pleural disease. AJR 1990; 154: 487-492 16. Yoon SB, Choi JY, Kim SJ, et al. Usefulness of positron 3. Gupta NC, Frank AR, Dewan NA, et al. Solitary pulmonary emission tomography in solitary pulmonary nodules. Kor J Nuc/ nodules: detection of malignancy with PET with 2-[F-18] Med 1996; 30: 192 (abstract in Korean) -fluoro-2-deoxy-D-glucose. Radiology 1992; 184:441-444 17. Bury T, Paulus p, Dowlati A, Corhay JL, Rigo P, Radermecker 4. Patz EF, Lowe VJ , Hoffman JM, et al. Focal p비 monary abnor MF. Evaluation of pleural diseases with FDG-PET imaging: pre malities: evaluation with F-18 fluorodeoxyglucose PET scan liminary repoπ . Thorax 1997; 52: 187-189 ning. Radiology 1993; 188: 487-490

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/ J Korean Radiol Soc 1997; 37 : 641 - 649

[H 한밤사선의학회지 1997; 37: 641-649

악성 및 양성 미만성 늑막 질환:두 절환 감별에서 양전자방출 단층촬영기의 유용성 및 전산화단층촬영기와의 비교 l

1 성균관대학교 의과대학 삼성서울병원 진단방사선과 2 성균관대학교 의과대학 삼성서울병원 핵의학과 3 성균관대학교 의과대학 삼성서울병원 호흡기내과

이정수 · 천정은 · 김병태 2 • 김유경 · 노덕우 · 권오정 3 • 이종헌 3

목 적 . 양성 및 악성 미만성 늑막 질환의 감별에 있어 2-[ 18F] fluoro-2 깅eoxy-D-glucose (FDG) 양전자 방출 단층촬영기 (Positron emission tomography : PET) 의 유용성을 알아 보고 전산화단층촬영기 (CT) 와 비교해 보기 위함이다. 대상 및 방법 : 만성 미만성 늑막 질환(악성 질환 13명， 양성 질환 7명)을 가진 일련의 20명의 환자에서 FDG PET와 CT 검사를 시행하였다. FDG PET에서는， 최대 표준섭취값 (peak standardized uptake value : peak SUB) 의 측정 뿐아니라늑막에 FDG 의 섭취 정도를목측으로평가하였다.이 결과를 CT 소견과비교하였다. 결 과 :PET 영상을 목측으로 평가한 경우， 악성 질환에 대 한 민감도， 특이도 및 정 확도는 92% ， 43% ， 75% 였 다. Peak SUV 4.8 이상을 악성으로 예측한 경우， 민감도， 특이도， 정확도는 각각 100%, 57% 그리고 85% 였다. CT 판독의 경우 악성 질환에 대한 민감도， 특이도， 정확도는 각각 100%, 57%, 85% 였다. 결핵성 농흉의 경우 FDG PET (3/6 환자가 peak SUV 4.8 이상) CT (3/6 환자) 모두에서 악성 질환을 흉내내였다. 결 론: FDG PET와 CT는악성 및 양성 미만성 늑막질환감별에 거의 같은정확도를보인다.목측과정량적 분석을 함께 하는 경우 FDG PET의 변별 능력을 증가시 키며 결핵 성 농흉은 FDG PET, CT 모두에서 악성 미 만성 질환을흉내낼수있다.

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