AJR:169, July 1997 93 Evaluation of Electron Beam CT Coronary Angiography in Healthy Subjects Daniel M. Chernoff1’2 Cameron J. Ritchie3 Charles B. Higgins1 OBJECTIVE. This study evaluated the performance characteristics of electrocardio- graphically triggered, contrast-enhanced electron beam CT (EBCT) in defining the coro- nary artery lumen in healthy subjects. SUBJECTS AND METHODS. The coronary arteries of II healthy young men (mean age, 24 years old) were evaluated by contrast-enhanced EBCT. Measured parame- ters included degree of luminal enhancement, intravascular contrast-to-noise ratio, appar- ent luminal diameter, and length of continuously visualized lumen ( 1(X)-H threshold for diameter and length measurements). RESULTS. Aortic blood pool attenuation was 44 ± 5 H (mean ± SD) before and 27) ± 35 H after IV injection of contrast material. Contrast-to-noise ratios ranged from a high of 10.0 ± 2.6 in the proximal right coronary artery to a low of 3.2 ± 2.7 in the distal left circumflex artery. decreasing from proximal to distal within each vessel. Apparent luminal diameters were as follows: left main coronary artery, 4.5 ± 0.6 mm: left anterior descending artery. 3.7 ± 0.5 mmli: left circumflex artery, 2.9 ± 0.6 mm; and right coronary artery, 3.5 ± 0.5 ii ni. The mean lengths of visualized lumina were as follows: left main coronary artery, 10±4 mm: left anterior descending artery, 65 ± 26 mm; left circumflex artery. 45 ± 20 mm: and right coro- nary artery. 58 ± 24 mm. CONCLUSION. EBCT angiography can reveal the lumen of long segments of the major coronary arteries. Received September 3, 1996; accepted after revision January 8, 1997. 1 Department of Radiology, University of California, 505 Parnassus Ave., San Francisco, CA 94143-0628. 2Present address: Saint Mary’s Hospital, 427 Guy Park Ave., Amsterdam, NY 12010. Address correspondence to D.M.Chernoff. 3lmatron, Inc., 389 Oyster Point Blvd., South San Francisco, CA 94080. AJR 1997;169:93-99 0361-803X/97/1 691-93 © American Roentgen Ray Society E lectron beam CT (EBCT) with ECG triggering is a noninva- sive method for volumetric imaging of the heart and great vessels with few motion artifacts from cardiac pulsa- tions I 1 J. EBCT has become established as a method of detecting and quantifying cor- onary artery calcifications, which are mdi- rect markers of coronary atherosclerosis [2-5]. Recent studies have suggested that EBCT-derived calcium scores have prog- nostic significance in asymptomatic adults who have other risk factors for coronary artery disease [6. 71. Although coronary calcium scores cor- relate well with the total atherosclerotic burden [3-5], the amount of calcification does not correlate well with the severity of stenosis of a given lesion. For grading of coronary artery stenosis. selective catheter angiography [8, 9] remains the only widely accepted technique. Although selective angiography has excellent spatial and tem- poral resolution, it is invasive and expensive and therefore is best suited for symptomatic patients. MR angiography has shown promise as a noninvasive alternative to selective cathe- ter angiography ( l()- 14) hut remains a techni- cally challenging technique that has yet to enter routine clinical use. Luminal visualization, using X-ray contrast material to increase the attenuation of blood, is a natural extension of EBCT coronary artery evaluation. Recent studies have used con- trast-enhanced EBCT for detecting and grading coronary artery stenoses, using selective angiography as the standard of reference [15, 16]. These studies used three- dimensional surface rendering and maximum- intensity-projection techniques to visualize stenoses in patients with known or suspected coronary artery disease. Comparing the effectiveness of EBCT coronary angiogra- phy with MR angiography without specific measures of image quality is difficult. For example. the extent of the coronary artery Downloaded from www.ajronline.org by 52.73.204.196 on 05/17/22 from IP address 52.73.204.196. Copyright ARRS. For personal use only; all rights reserved