Detection of coronary artery stenoses using multi-detector CT with 16x0.75 collimation and 375 ms rotation

Aims Insufficient spatial and temporal resolutions have limitedimage quality and accuracy of multi-detector CT (MDCT) for coronaryartery visualization and detection of stenoses. We assessedthe accuracy of a new 16-slice scanner with 370 ms rotationand 0.75 mm collimation for detection of coronary stenosesusing an analysis approach based on coronary artery segments. Methods and results Fifty consecutive patients scheduled fordiagnostic coronary angiography in stable clinical conditionand sinus rhythm were enrolled. All patients with a heart rate>60 b.p.m. received 100 mg atenolol p.o. and upto four doses of 5 mg metoprolol i.v. before the scan.MDCT was performed using 16x0.75 mm collimation, 120 kV,and ECG-gated tube current modulation. Ninety millilitres ofcontrast agent was injected intravenously. MDCT images werevisually analysed using the 16-segment coronary artery modelof the American Heart Association and compared with invasive,quantitative coronary angiography in a blinded fashion. A significantstenosis was assumed if the diameter reduction was 50%. Meanheart rate was 58 b.p.m. during MDCT. After exclusion oftwo patients with not fully evaluable data sets, MDCT correctlyidentified at least one coronary stenosis in all 25 patientswith significant coronary lesions in angiography and correctlydemonstrated the absence of stenoses in 19/23 patients (sensitivity100%, specificity 83%). Sensitivity and specificity for all50 patients were 93 and 83%, respectively. On a per-segmentbasis, nine coronary segments distal of total occlusions and128 coronary segments with a reference diameter <1.5 mmwere excluded from the analysis. Twenty-eight of the included663 segments (4%) were unevaluable due to calcification or motionartefact. In the remaining 635 segments, 50/53 stenoses weredetected by MDCT (sensitivity 94%, specificity 96%, negativepredictive value 99%, positive predictive value 69%). Conclusion Increasing temporal and spatial resolutions of MDCTlead to improved evaluation and diagnostic accuracy for detectionof coronary stenoses.