Comparison of visibility and diagnostic capability of noninvasive coronary angiography by eight-slice multidetector-row computed tomography versus conventional coronary angiography

The usefulness of multidetector-row computed tomography (MDCT) for visualization of coronary arteries has been reported; however, little is known about the diagnostic capability of noninvasive coronary angiography (CA) using 8-detector row CT. We investigated the visualization and diagnostic values of 8-slice MDCT-CA. Twenty-five consecutive patients who underwent conventional CA were investigated. The entire heart was scanned for approximately 20 seconds. Images were created using different reconstruction methods (half-scan and multisectors) followed by image creation during different time windows of the cardiac cycle. The data set containing the fewest artifacts was selected, then reformatted images were created and evaluated. In 348 segments in 25 subjects as determined by conventional CA, 258 segments (74.1%) were judged visible by MDCT-CA. Lower visibility was observed in segments with smaller diameters. Visibility in segments with diameters of ≥2.0 mm was 85.8% (212 of 247 segments). Patients with higher mean heart rates and a larger range of heart rate alteration during the breath-holding scan time had lower visibility. The most frequent cause for invisibility was “adjacent structure” (47%), followed by “small diameter” (33%), and “motion artifact” (16%), suggesting that motion artifacts were reduced by multisector reconstruction and search for the best-optimized time window. MDCT-CA detected 27 of 37 significant stenotic lesions (73%) that had a diameter reduction of >50% and correctly judged 226 of 311 segments (72.7%) as normal. Sensitivity, specificity, and accuracy of the visualized segments by MDCT-CA was 90% (27 of 30 segments), 99.1% (226 of 228 segments), and 98.1% (253 of 258 segments), respectively. Low visibilities in the left circumflex artery and distal and small segments are limitations of 8-slice MDCT-CA because of limited spatial resolution.