Noninvasive coronary angiography by retrospectively ECG-gated multislice spiral CT

Background-We investigated the applicability and image quality of contrast- enhanced coronary artery visualization by multislice spiral CT using retros pective ECG gating. Methods and Results-Twenty-five patients in sinus rhythm (significant coron ary artery stenoses ruled out by invasive angiography) were studied with a multislice, spiral CT (Siemens SOMATOM Volume Zoom). In inspiration (mean b reathhold, 37 seconds), a volume data set of the heart was acquired (intrav enous contrast agent; 4X1-mm slice thickness; 500-ms rotation; table feed, 1.5 mm/360 degrees). Simultaneous recording of the ECG permitted retrospect ive reconstruction of contiguous cross sections in intervals of 1 mm at any desired interval of the cardiac cycle. The mean duration of the image reco nstruction window was 185 ms. Next to 3-dimensional reconstructions of the heart and coronary arteries, multiplanar reconstructions were rendered to d etermine the visualized length of the coronary arteries, the contrast-to-no ise ratio, and the correlation of coronary artery diameters to quantitative coronary angiography. Conclusions-The coronary arteries could be visualized over long segments (l eft main, 9+/-4 mm; left anterior descending, 112+/-34 mm; left circumflex, 80+/-29 mm; right coronary artery, 116+/-33 mm). On average, 78+/-16% of t hese distances were visualized free of motion artifacts. The mean contrast- to-noise ratio was 9.3+/-3.3. Coronary artery diameters in multislice spira l CT showed close correlation to quantitative coronary angiography (CT, 3.3 +/-1.0 mm; angiography, 3.2+/-0.9 mm; mean difference, 0.38 mm; r=0.86). Co ntrast-enhanced multislice spiral CT permits visualization of the coronary artery lumen. Further studies are necessary to determine whether image qual ity is sufficient to reliably detect coronary artery stenoses.