Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights. ORIGINAL RESEARCH Diagnostic Performance of Myocardial Perfusion MR at 3 T Ⅲ in Patients with Coronary Artery CARDIAC IMAGING Disease1 Rolf Gebker, MD Purpose: To prospectively determine the diagnostic performance of Cosima Jahnke, MD myocardial perfusion magnetic resonance (MR) imaging at Ingo Paetsch, MD 3 T for helping depict clinically relevant coronary artery Sebastian Kelle, MD stenosis (Ն50% diameter) in patients with suspected or Bernhard Schnackenburg, PhD known coronary artery disease (CAD), with coronary an- Eckart Fleck, MD giography as the reference standard. Eike Nagel, MD Materials and The study was approved by the local ethics committee; Methods: written informed consent was obtained. Vasodilator stress perfusion imaging by using a turbo field-echo sequence was obtained in 101 patients (71 men, 30 women; mean age, 62 years Ϯ 7.7 [standard deviation]) scheduled for coro- nary angiography. Myocardial ischemia was defined as stress-inducible perfusion deficit in arterial territories without delayed enhancement (DE) or additional stress- inducible perfusion deficit in territories with nontransmu- ral DE. Images were evaluated in consensus by two blinded readers. Diagnostic performance was determined on per- patient and per–coronary artery territory bases. The num- ber of dark rim artifacts in patients without DE was deter- mined in a second read. Interobserver variability was as- sessed in 40 randomly selected patients. Results: One hundred one patients underwent MR examinations. Coronary angiography depicted relevant stenosis in 70 (69%) patients. Patient-based sensitivity and specificity were 90% and 71%, respectively. Sensitivity, specificity, and diagnostic accuracy for the detection of coronary ste- nosis in a specific territory were 76%, 89%, and 86%, respectively. In 24% of patients without DE, dark rim artifacts were detected, mostly in the left anterior de- scending artery territory (56%). Among 40 randomly se- lected patients, there was agreement in the determination of myocardial perfusion deficits in 37 (93%, ␬ϭ0.79) patients. Conclusion: Myocardial perfusion MR imaging by using saturation-re- covery spoiled gradient-echo imaging at3Thasanaccu- racy of 84% for depicting hemodynamically relevant coro- nary artery stenosis in patients with suspected and known 1 From the Department of Internal Medicine/Cardiology, CAD. German Heart Institute Berlin, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353 Berlin, Germany (R.G., C.J., I.P., S.K., E.F., E.N.); and Clinical Science, ௠ RSNA, 2008 Philips Medical Systems, Hamburg, Germany (B.S.). Re- ceived March 31, 2007; revision requested May 31; revi- sion received July 30; accepted August 20; final version accepted September 24. Address correspondence to R.G. (e-mail: [email protected] ). ஽ RSNA, 2008 Radiology: Volume 247: Number 1—April 2008 57 CARDIAC IMAGING: Diagnostic Performance of Myocardial Perfusion MR at 3 T Gebker et al iven the pathophysiologic events We hypothesized that by using a nosine-related side effects (n ϭ 2) and during the ischemic cascade, the combined MR imaging approach with (b) poor-quality MR images (n ϭ 1) Gassessment of myocardial perfu- stress-rest first-pass perfusion imaging, (Fig 1). Of the patients with adverse sion appears to be the most promising followed by delayed-enhancement (DE) side effects, one developed severe dys- concept for a noninvasive test to help imaging at 3 T, it is possible to detect pnea and requested termination of the detect hemodynamically relevant coro- relevant coronary stenosis in patients examination; the dyspnea resolved after nary artery disease (CAD) (1). Myocar- with clinically suspected or known 30 seconds without the administration dial perfusion assessment is frequently CAD. Thus, the purpose of our study of theophylline (Bronchoparat; Astellas performed by using stress and rest sin- was to prospectively determine the di- Pharma, Munich, Germany). The other gle photon emission computed tomogra- agnostic performance of myocardial patient developed bradycardia of 30 phy (SPECT) or positron emission to- perfusion MR imaging at 3 T for depict- beats per minute, with atrioventricular mography (PET). However, both mo- ing clinically relevant coronary artery node block being the most likely cause; dalities expose patients to radiation, stenosis (Ն50% diameter stenosis) in 15 seconds after the termination of the SPECT is limited by attenuation arti- patients with suspected or known CAD, adenosine infusion, heart rate returned facts and reduced spatial resolution, with coronary angiography as the refer- to normal. Thus, a total of 101 patients and PET is limited by its reduced avail- ence standard. were evaluated in our study (Table 1). ability. Myocardial perfusion magnetic res- MR Examination onance (MR) imaging has been devel- Materials and Methods MR sequence design.—All patients oped extensively over the past decade. were examined in the supine position by So far, clinical trials have mostly been Patients using a 3-T whole-body imager (Achieva performed with 1.5-T scanners and The study was approved by the Charite´ 3T; Philips, Best, the Netherlands) have shown that MR perfusion yields and Virchow-Klinikum Ethics Commit- equipped with a dual gradient system diagnostic results for the detection of tee. Written informed consent was given (Quasar; Philips) by using gradient CAD comparable to those of clinically by all patients. One hundred four pa- strength of 80 mT/m and slew rate of established nuclear techniques such as tients (72 men, 32 women; mean age, 200 T/m/sec. A six-element cardiac syn- SPECT or PET (2–4). When using coro- 62 years Ϯ 7.7 [standard deviation]) ergy coil was used for signal detection. nary angiography as the reference stan- scheduled for clinically indicated coro- Cardiac synchronization was performed dard (5–9), MR perfusion imaging is as- nary angiography were examined be- by using a four-electrode vector electro- sociated with good diagnostic accuracy tween August 2005 and July 2006. cardiogram, and image acquisitions (sensitivity, 88%–93%; specificity, 75%– Patients with contraindications to were triggered on the R wave (11). 90%). Recently, MR imaging at3Thas either MR imaging (noncompatible bio- For cine imaging, a balanced steady- become available and potentially pro- metallic implants or claustrophobia) or state free precession sequence was used vides a substantial improvement of tis- adenosine-related side effects (atrio- (repetition time msec/echo time msec, sue contrast in T1-weighted imaging ventricular node block grade Ͼ I, acute 3/1.5; flip angle, 40°). A saturation pre- techniques relying on gadolinium-based coronary syndrome, severe hyperten- contrast material enhancement. Yet, sion, asthma) and patients with ar- 3-T systems in general are known to be rhythmia were not considered for study Published online before print prone to imaging artifacts (eg, suscepti- inclusion. All patients were instructed 10.1148/radiol.2471070596 bility artifacts) (10). to refrain from any beverages or foods Radiology 2008; 247:57–63 containing caffeine within 24 hours be- fore the MR study. The pertinent medi- Abbreviations: Advances in Knowledge cal history of the patients was recorded CAD ϭ coronary artery disease ϭ Ⅲ Myocardial stress perfusion imag- at the time of the examination by one of DE delayed enhancement LAD ϭ left anterior descending artery ing at 3 T has an accuracy of three authors (R.G., C.J., or I.P.). LCX ϭ left circumflex artery 84%–86% to detect relevant cor- Three of 104 patients could not be RCA ϭ right coronary artery onary artery stenoses. evaluated owing to (a) adverse ade- Ⅲ Dark rim artifacts represented by Author contributions: Guarantors of integrity of entire study, R.G., E.N.; study matched perfusion defects be- Implication for Patient Care concepts/study design or data acquisition or data analy- tween stress and rest imaging oc- sis/interpretation, all authors; manuscript drafting or cur in almost one-fourth of pa- Ⅲ Myocardial perfusion MR imaging manuscript revision for important intellectual content, all tients without evidence of delayed at3Tisanoption for patients authors; approval of final version of submitted manu- enhancement. with suspected or known coro- script, all authors; literature research, R.G., I.P., B.S., Ⅲ There is high interobserver agree- nary artery disease to help depict E.F., E.N.; clinical studies, R.G., C.J., I.P., S.K.; statistical analysis, R.G.; and manuscript editing, all authors ment (␬ϭ0.79) for the detection hemodynamically relevant coro- of perfusion deficits. nary stenosis in patients. Authors stated no financial relationship to disclose. 58 Radiology: Volume 247: Number 1—April 2008 CARDIAC IMAGING: Diagnostic Performance of Myocardial Perfusion MR at 3 T Gebker et al pared (prepulse delay, 95 msec) single- their breath as long as possible during defects were determined qualitatively shot spoiled gradient-echo sequence imaging and to continue breathing shal- by using subjective visualization. Ische- was used for perfusion imaging. The ac- lowly when they could no longer hold mia was defined as (a) territories with- quisition parameters were as follows: their breath. out DE that showed a perfusion deficit 2.8/0.9; flip angle, 18°; field of view, 5. Rest perfusion imaging by using 380 ϫ 380 mm; turbo factor, 59; and geometry identical to the short-axis cine Figure 1 matrix, 128 ϫ 128. For 60 consecutive views and giving a bolus of contrast cardiac cycles, three short-axis sections agent identical to that given during with a spatial resolution of 2.9 ϫ 2.9 ϫ stress imaging after 15 minutes to allow 8 mm recorded every heartbeat up to for myocardial washout. a heart rate of 110 beats per minute. 6. An additional bolus of 0.15 DE imaging was performed by using mmol/kg gadopentetate dimeglumine an inversion-prepared three-dimen- immediately after the rest perfusion sional spoiled gradient-echo sequence scan and standard DE gadolinium-based (1.5 ϫ 1.7 ϫ 5 mm).