Clinical Research, Non-invasive Coronary Angiography

PartⅠVolume Targeted and Whole Heart Coronary MRA Using Intravascular Contrast EnhancementPurpose: To compare volume-targeted and whole heart coronary MR angiography after the administration of an intravascular contrast agent.Materials and Methods: Six healthy adult subjects underwent a navigator gated and corrected (NAV) free breathing volume-targeted cardiac-triggered inversion recovery (IR) 3D steady-state free precession (SSFP) coronary MRA sequence (t-CMRA) (spatial resolution = 1×1×1.5mm3 ) and IR 3D SSFP whole heart coronary MRA (WH-CMRA) (spatial resolution = 1×1×1mm3 ) after the administration of an intravascular contrast agent B-22956. Subjective and objective image quality parameters including maximal visible vessel length, vessel sharpness and visibility of coronary side branches were evaluated for both t-CMRA and WH-CMRA.Results: No significant differences (P = NS) in image quality were observed between contrast enhanced t-CMRA and WH-CMRA. However, using an intravascular contrast agent, significantly longer vessel segments were measured on WH-CMRA vs. t-CMRA (right coronary artery (RCA) (13.5±0.7cm vs. 12.5±0.2cm; P < 0.05) and left circumflex coronary artery (LCX) (11.9±2.1mm vs. 69.1±0.2mm; P <0.05)). Significantly more side branches (13.3±1.2 vs. 8.7±1.2; P < 0.05) were visible for the left anterior descending coronary artery (LAD) on WH-CMRA vs. t-CMRA. Scanning time and navigator efficiency were similar for both techniques (t-CMRA: 6.05min; 49% vs. WH-CMRA: 5.51min; 54%, both p=NS).Conclusion: Both WH-CMRA and t-CMRA using SSFP are useful techniques for coronary magnetic resonance angiography after the injection of an intravascular blood-pool agent. However, WH-CMRA shows both more distal coronary segments and smaller-diameter coronary side branches. PartⅡComparison of Dual-Source CT Coronary Angiography and Conventional Coronary Angiography for the Detection of Coronary Artery DiseaseObjective: To evaluate the diagnostic accuracy of dual-source CT coronary angiography for the detection of coronary artery stenosis.Materials and Methods: From February 2008 to January 2009, dual-source CT coronary CT angiography (DSCT-CCTA) and conventional coronary angiography (CAG) were performed in 84 patients with either clinical symptoms or high risks of coronary artery disease. The diagnostic accuracy of DSCT-CCTA was evaluated by comparison with CAG, which was regarded as the gold standard for diagnosis.Results: Occlusion or stenosis of various degrees was revealed by DSCT-CCTA in 244 segments of 84 patients. Compared to CAG, the sensitivity, specificity, positive predictive value and negative predictive value of DSCT-CCTA were 97.40%, 97.80%, 92.21% and 100% respectively. The diagnostic accuracy of DSCT-CCTA for the detection of coronary artery stenosis was 96.50%. The pairedχ2 test revealed no significant difference between DS-CCTA and CAG for diagnosis of coronary artery disease (p=0.076).Conclusion: The diagnostic performance of DS-CCTA is generally as accurate as CAG. Thus it is a reliable non-invasive method for the detection of coronary artery stenosis.PartⅢContrast-Enhanced Whole-Heart Coronary Magnetic Resonance Angiography at 3.0-T: An Initial Comparative Study With X-Ray Coronary Angiography and DSCT Coronary CT AngiographyObjectives: The purpose of this study was to prospectively evaluate the diagnostic performance of contrast-enhanced whole-heart coronary magnetic resonance angiography (WH-CMRA) at 3.0T MR system in detecting significant stenosis among patients with suspected coronary artery disease (CAD).Material and Methods: The 3.0-T contrast-enhanced whole-heart CMRA was performed in 26 patients. An electrocardiography-triggered, navigator-gated, inversion-recovery prepared, segmented gradient-echo sequence was used to acquire isotropic whole-heart CMRA with slow infusion of 0.2 mmol/kg gadobenate dimeglumine or gadopentetic acid dimeglumine. Delay-enhanced images were also acquired in 10 to 15 minutes after the administration of contrast agent with a phase-sensitive inversion recovery sequence. The MR image quality with both contrast agents was graded on a 4-point scale and compared subjectively. Some patients got X-ray coronary artery angiography (CAG) and DSCT coronary CT angiogram (DSCT-CCTA) studies before or after CMRA. The diagnostic accuracy of whole-heart CMRA in detecting significant stenoses (≥50%) was evaluated using X-ray coronary artery angiography (CAG) as the reference. CMRA and CCTA images were compared to evaluate the characteristics of these two modalities.Results: Twenty patients completed the CMRA examinations successfully. Among them, 4 patients just performed CMRA studies, 13 got CMRA and CAG studies, 10 got DSCT-CCTA and CMRA studies, 7 got all these three studies. Acquisition time of whole-heart CMRA procedure was 536±183ms. There was no significant difference between CMRA Image quality with gadobenate dimeglumine and gadopentetic acid dimeglumine (2.86±0.92 vs. 2.74±1.20, p=0.44>0.05). The sensitivity, specificity, and accuracy of whole-heart CMRA for detecting significant stenoses were 85.2%(23/27),71.8%(74/103) and 74.6%(97/130), respectively, on a per-segment basis. These values were 100%(10/10),33.3%(1/3)和84.6%(11/13), respectively, on a per-patient basis. The abnormal origin of coronary artery, myocardial bridge and CAD could be shown on both DSCT-CCTA and CMRA images. But the lumen of coronary artery could be depicted more clearly with CMRA when there were plaques of heavy nodular calcification. And stenosis caused by non-calcified plaque could be evaluated more precisely with DSCT-CCTA.Conclusions: Contrast-enhanced whole-heart CMRA at 3.0-T allows for the accurate detection of coronary artery stenosis with high sensitivity and moderate specificity. CMRA is a supplement to CCTA when there is a plaque of heavy nodular calcification. Delay-enhanced study can be performed with CMRA simultaneously to evaluate patients of suspected CAD comprehensively.