Application Study Of Noninvasive Coronary Angiography Using 64-slice Spiral Computed Tomography

PART I :TITLE: Noninvasive coronary angiography with 64-slice MSCT: Effect of Heart RatePurpose: To evaluate the effect of heart rate on the quality of coronary angiography performed by 64-slice computed tomography (CT). Material and Methods: 260 consecutive patients underwent CT coronary angiography (heart rate range, 46-113 beats per minute, mean 72.10±12.54 ). Five groups were designed according to the heart beat (<60, 60-69, 70-79, 80-89 and >90 beats per minute). Image quality of each segment was graded with a four-point scale from one (worst image quality) to four (best image quality). Images scored between two and four were considered valuable for coronary artery assessment;those with a score of 3 or 4 were excellent images. The heart rate, image quality and reconstruction phase were evaluated. Pearson's analysis and correlation was performed and p<0.05 was considered as significant difference. Result: 2581 segments diagnostic images were available from 2600 coronary segments(99.26%), while 2306 (88.69%)of them were excellent images. A significant negative correlation was observed between heart rate and image quality(r=-0.92). Significant differences of excellent images were shown betweenheart rate lower and higher than 70 beats per minute( x =44.68, p = 0.00).Reconstruction phase at mid-diastolic (50%-75%) and end-systolic phase (25%-45%) yielded the best images when heart rates were lower and higher than80 beats per minute, respectively( x~2 = 98.8826, p = 0.000). Conclusion:Diagnostic coronary artery images can be obtained at high heart rates with 64-slice CT scanners, but image quality was negatively correlated with heart rate,and excellent image can be achieved as heart rates less than 70 beats per minute.PART II:TITLE: Diagnostic accuracy on coronary atherosclerosis by applying noninvasive coronary angiography 64-slice spiral computed tomographyPurpose: To evaluate the diagnostic accuracy of 64 multi-slice computed tomography (MSCT) coronary angiography on the coronary atherosclerosis. Material and Methods: 61 (52 male,9 female, age 58±llyears) patients underwent invasive coronary angiography and computed tomography angiography for suspected coronary disease between 5 and 20 days. Image quality was assessed with scores from 1 to 4 (image quality score 1: poor;2: good ";3: good+, and 4: excellent) on RCA, LM, LAD and LCX respectively. All lesions on these four coronary arteries were divided into 2 grades by over 50% and under 50% luminal narrowing. Sensitivity, specificity, negative predictive value were analyzed respectively. Result: Mean score of the image quality on RCA, LM, LAD and LCX was 3.57 + 0.18 with heart beats 50—104 bpm (mean 70+11 bpm ). Sensitivity for stenosis over 50% and under 50% were 95%, 84%respectively, specificity to detect coronary artery lesions was 93% and negative predictive value for coronary artery lesions was 96%. Conclusion: 64 MSCT provided a high diagnostic accuracy in assessing coronary artery stenosis compared to invasive coronary angiography.