ABSTRACT
Ten patients who underwent conventional coronary angiography (CA) were examined with both 8- and 16-slice multidetector-row computed tomography (MDCT) angiography within 6 months, and visibility and image quality of 16-slice MDCT-CA were compared with those of 8-slice MDCT-CA directly. In 136 segments determined by conventional CA, 101 (74.3%) and 126 (92.6%) segments were judged assessable by 8- and 16-slice MDCT-CA, respectively. Segment visibility in the right coronary and left circumflex arteries, as well as distal segments and small segments with diameters of <3.0 mm, was higher using 16-slice MDCT-CA than that of 8-slice MDCT-CA. As causes for invisibility in segments considered to be invisible, adjacent structures, as well as small diameters, were reduced by 16-slice MDCT-CA, suggesting that high spatial resolution contributes to higher visibility; however, nonassessable segments due to extensive calcium by 8-slice MDCT-CA were also judged nonassessable by 16-slice MDCT-CA.
Subject(s)
Coronary Angiography , Tomography, X-Ray Computed/methods , HumansABSTRACT
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 > or =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.
