Faculty Bibliography

BACKGROUND: Dual-source computed tomography (DSCT) provides diagnostic quality images of the coronary arteries over a wide range of heart rates (HRs). Current dose reduction techniques, including electrocardiographic (ECG) dose modulation and prospective triggering, are optimized for use in patients with relatively slow (<70 beats/min) HRs by limiting radiation dose to the ideal phases of image acquisition. OBJECTIVE: We evaluated coronary vessel image quality (IQ) at different reconstruction phases in patients with fast HRs (>80 beats/min) to assess potential feasibility of prospective triggering techniques on DSCT. METHODS: Patients (n=101) underwent 64-slice DSCT with retrospective ECG-gating without beta-blocker premedication. Image reconstructions were performed at 10% R-R wave phase intervals (0%-90%). Patients were grouped by mean HR: group A, <60 beats/min (n=22); group B, 60-80 beats/min (n=57); group C, >80 beats/min (n=22). Coronary artery IQ was assessed by 2 readers in consensus on a 5-point scale. RESULTS: Optimal IQ occurred at 70% phase for all arteries in groups A and B. In group C, optimal IQ occurred at 30% and 40% phases. The 70% phase achieved diagnostic IQ in 97% of group A and 86% of group B. A widened reconstruction window (30%-50%) was necessary for diagnostic IQ in a similar high proportion (84%) of group C. CONCLUSION: Optimal IQ occurs during late-systolic phases for patients with fast HRs (>80 beats/min). Late-systolic phase prospective triggering is potentially feasible in these patients; however, given the widened reconstruction windows required, a higher radiation dose may be required compared with patients with slower HRs (<80 beats/min)

The multidetector coronary computed tomography angiogram findings of a rare variant crossed left circumflex and left anterior descending artery are presented. In this patient, multidetector coronary computed tomography angiogram enabled clear delineation of the aberrant coronary artery anatomy, including an estimation of patency during systole and diastole. To our knowledge, this is only the second reported case of this particular coronary artery anomaly in the world literature

OBJECTIVE: Dual-source CT improves temporal resolution, and theoretically improves the diagnostic image quality of coronary artery examinations without requiring preexamination beta-blockade. The purpose of our study was to show the improved diagnostic image quality of dual-source CT compared with single-source CT despite the absence of preexamination beta-blockade in the dual-source CT group. MATERIALS AND METHODS: We performed a retrospective analysis of consecutive patients who underwent coronary artery evaluation with either single-source CT or dual-source CT at our institution between February 2005 and October 2006. Examination reports were analyzed for the presence of image artifacts, and image quality was graded on a 3-point scale (no, mild, or severe artifact). Type of artifact (motion, calcium, quantum mottle) was also noted. RESULTS: Examinations (339 single-source CT and 126 dual-source CT) of 465 patients were analyzed. Artifact was reported in 39.8% of examinations using single-source CT and in 29.4% of examinations using dual-source CT (p < 0.05). The number of examinations with motion artifact was significantly higher with single-source CT than with dual-source CT (15.9% vs 4.8%; p < 0.001) despite significantly higher heart rates in the dual-source CT group (59.4 +/- 8.4 vs 68.6 +/- 14.6 beats per minute; p < 0.001). No patients in the dual-source CT group received preexamination beta-blockade compared with 81% of patients in the single-source CT group. The presence of severe (nondiagnostic) calcium artifact was also significantly reduced in the dual-source CT group (13.0% vs 3.2%; p < 0.001). CONCLUSION: Dual-source CT provides significantly better diagnostic image quality than single-source CT despite higher heart rates in the dual-source CT group. These findings support the use of dual-source CT for coronary artery imaging without the need for preexamination beta-blockade

OBJECTIVE: To evaluate the prevalence and characteristics of myocardial bridging in patients who underwent single- or dual-source multidetector cardiac computed tomographic angiography (MDCTA). METHODS: Retrospective review of the imaging characteristics of 57 myocardial bridges in 53 patients who underwent cardiac MDCTA examinations was performed. RESULTS: The prevalence of myocardial bridges was 10.4%, most of which were located in the mid-left anterior descending coronary artery. The average myocardial bridge length was 23.4 mm, and the average tunneled artery depth was 2.6 mm. CONCLUSIONS: Myocardial bridges are commonly found in patients who undergo cardiac multidetector computed tomographic angiograms on both single- and dual-source computed tomographic scanners and are most frequently located in the mid-left anterior descending coronary artery. Increasing utilization of cardiac MDCTA for noninvasive evaluation of coronary artery disease permits recognition, characterization, and functional assessment of this entity in a single examination

Continued improvements in multidetector computed tomographic (CT) scanners have made cardiac CT an important clinical tool that is revolutionizing cardiac imaging. Multidetector CT with submillimeter collimation and gantry rotation times under 0.5 seconds allows the acquisition of studies with high temporal resolution and isotropic voxels. The volumetric data set that is generated can be analyzed with a depth previously not possible, requiring a solid understanding of the cardiac anatomy and its appearance on CT scans and postprocessed images

OBJECTIVE: We describe the findings of contrast-enhanced gated cardiac CT in 15 patients with 23 incidentally noted cardiac ventricular diverticula. CONCLUSION: Cardiac diverticula most commonly occur in the left ventricle but have been reported to occur in all chambers of the heart. Despite reports of their rare occurrence, cardiac ventricular diverticula are fairly common findings in patients undergoing cardiac MDCT angiography.