Faculty Bibliography

Cardiac computed tomographic angiography algorithms emphasize radiation reduction while maintaining diagnostic image quality (IQ). The aim of this study was to evaluate IQ and interreader variability using prospective electrocardiographically triggered high-pitch spiral cardiac computed tomographic angiography (FLASH-CT) compared to retrospective electrocardiographic gating (RETRO-CT) for coronary artery disease evaluation in a patient population including overweight and obese individuals. MATERIALS AND METHODS: Seventy patients (24 women; mean age, 60 years) matched for gender, age, body mass index (27.4 ± 5.5 kg/m(2)), and calcium score (184 ± 328) underwent cardiac computed tomographic angiography, 35 with FLASH-CT (Definition Flash) and 35 with RETRO-CT (Somatom Definition). Images were reconstructed using standard protocols and least motion phase for RETRO-CT acquisitions. Two independent, blinded readers evaluated the coronary arteries using an 18-segment model, grading IQ on a 5-point, Likert-type scale and coronary stenosis on a 5-point semiquantitative and binary scale. RESULTS: Effective radiation dose (1.50 vs 17.3 mSv, P < .0001) and mean heart rate (58 vs 62 beats/min, P < .05) were significantly lower for FLASH-CT compared to RETRO-CT. Seven hundred forty segments (> 1.5 mm) were evaluated. There was no significant difference between FLASH-CT and RETRO-CT scans in overall per-segment IQ (3.11 ± 0.75 vs 3.10 ± 0.82, P = .94). FLASH-CT had noninferior IQ relative to RETRO-CT (95% confidence interval, -0.25 to 0.26). There was no significant difference in interreader variability in diagnosis between FLASH-CT and RETRO-CT for all coronary segments (77.5% vs 78.2%, P = .83). CONCLUSIONS: FLASH-CT is an acceptable coronary computed tomographic angiographic method for reducing radiation dose without compromising IQ for a patient population including overweight and obese individuals.

OBJECTIVES: This study examined short-term cardiac catheterization rates and medication changes after cardiac imaging. BACKGROUND: Noninvasive cardiac imaging is widely used in coronary artery disease, but its effects on subsequent patient management are unclear. METHODS: We assessed the 90-day post-test rates of catheterization and medication changes in a prospective registry of 1,703 patients without a documented history of coronary artery disease and an intermediate to high likelihood of coronary artery disease undergoing cardiac single-photon emission computed tomography, positron emission tomography, or 64-slice coronary computed tomography angiography. RESULTS: Baseline medication use was relatively infrequent. At 90 days, 9.6% of patients underwent catheterization. The rates of catheterization and medication changes increased in proportion to test abnormality findings. Among patients with the most severe test result findings, 38% to 61% were not referred to catheterization, 20% to 30% were not receiving aspirin, 35% to 44% were not receiving a beta-blocker, and 20% to 25% were not receiving a lipid-lowering agent at 90 days after the index test. Risk-adjusted analyses revealed that compared with stress single-photon emission computed tomography or positron emission tomography, changes in aspirin and lipid-lowering agent use was greater after computed tomography angiography, as was the 90-day catheterization referral rate in the setting of normal/nonobstructive and mildly abnormal test results. CONCLUSIONS: Overall, noninvasive testing had only a modest impact on clinical management of patients referred for clinical testing. Although post-imaging use of cardiac catheterization and medical therapy increased in proportion to the degree of abnormality findings, the frequency of catheterization and medication change suggests possible undertreatment of higher risk patients. Patients were more likely to undergo cardiac catheterization after computed tomography angiography than after single-photon emission computed tomography or positron emission tomography after normal/nonobstructive and mildly abnormal study findings. (Study of Perfusion and Anatomy's Role in Coronary Artery [CAD] [SPARC]; NCT00321399).

Introduction: Patients receiving radiofrequency ablation (RFA) for the treatment of atrial fibrillation frequently undergo pre-procedural cardiac CT for evaluation of the left atrium and pulmonary veins. Left atrial outpouchings (LAO), including diverticula and accessory appendages, can be mistaken for an ostium of a pulmonary vein, which are important to identify as there is a potential risk of complications during RFA. The prevalence of these outpouchings has been described to be as high as 27 percent in the population of patients undergoing routine cardiac CT.1 The purpose of this study is to describe the prevalence, morphology, and size of LAO in patients undergoing RFA for treatment of atrial fibrillation. Methods: Fifty consecutive patients referred for RFA were identified from our registry of patients undergoing gated cardiac CT. Data was independently analyzed by two blinded readers for LAO. Images were evaluated using multiplanar reformatted and 3D reconstruction. The presence of LAO was defined as any abnormality that had a discernable ostium stemming from the left atrial wall. The number and size of LAO were recorded. Comparison of prevalence was evaluated using the Fisher's exact test. Results: There were a total of 29 LAO found in 24 of the 50 patients for a calculated prevalence of 48% (95% CI: 33.6 to 62.6). The prevalence in our population was significantly higher than reported in the general cohort of patients undergoing routine cardiac CT (p=0.003). The average size (length, width, and depth) of the LAO were 0.54 +/- 0.28 by 0.39 +/- 0.20 by 0.56 +/- 0.26 cm. Conclusions: Patients undergoing RFA for atrial fibrillation have a high prevalence of L

Introduction: Patients receiving radiofrequency ablation (RFA) for treatment of atrial fibrillation typically undergo pre-procedural cardiac computed tomography angiography (CCTA) to delineate pulmonary venous anatomy and transesophageal echocardiogram (TEE) to exclude left atrial and/or left atrial appendage thrombus (LAT). The addition of a late phase acquisition is theorized to aid CCTA identification and discrimination of LAT from slow left atrial appendage filling. The purpose of this study is to evaluate the diagnostic accuracy of dual-phase, ECG-gated dual-source CCTA (64-slice Definition, Siemens) compared to TEE for identification of thrombus and to assess the added value of a late phase CCTA acquisition. Methods: Fifty-three consecutive patients (37 men; mean age 63) had both dual-phase CCTA and TEE prior to RFA. Mean time between CCTA and TEE was 9 days (range 1-22). Mean early phase and late phase scan acquisition delay times were 29 sec and 30 sec, respectively. Presence of LAT was independently graded on both early phase and combined early and late phase (CP) CCTA acquisitions using a 5-point Likert scale by 2 readers blinded to the TEE results. Diagnostic accuracy for LAT was assessed for early phase and CP CCTA acquisitions using TEE results as truth. Results: CCTA identified LAT in 2 out of 3 patients with thrombi on TEE (67%). Relative to TEE, early phase and CP CCTA acquisitions demonstrated: 47% and 67% sensitivity, 84% and 100% specificity, 54% and 100% PPV, 80% and 98% NPV, respectively. Overall diagnostic accuracy was significantly improved for CP compared to early phase acquisition (98% and 77%, respectively, p<0.001). Conclusions: CCTA has excellent specificity (100%) but only modest sensitivity (66.7%) for identification of LAT in patients undergoing RFA. Addition of a late phase CCTA acquisition significantly improves overall diagnostic accuracy

OBJECTIVE: Published cardiac CT angiography (CTA) reference measurements for the cardiac chambers, aorta, and pulmonary artery (PA) are incomplete and compromised by study population, coronary artery disease (CAD), or its risk factors. The purpose of our study was to establish sex-specific normalized ranges of cardiac chamber size, wall thickness, ejection fraction (EF), and aorta and PA diameter on cardiac CTA in a population without CAD or its risk factors. MATERIALS AND METHODS: Seventy-six patients (38 men and 38 women) without known diabetes; hypertension; smoking history; or evidence of structural heart, vascular, or coronary artery diseases underwent 64-MDCTA. Obtained left atrial (LA) size, left ventricular (LV) volumes, LV wall thickness, thoracic aorta, and PA diameter measurements were normalized to body surface area (BSA). RESULTS: There were statistically significant differences noted between men and women for all measured left-sided heart and great vessel measurements. After normalization to BSA, only chamber dimensions and ascending aorta and left PA sizes remained significantly different. Selected normalized measurements for men versus women, respectively, include LA area, 10.6 +/- 2.1 versus 12.3 +/- 2.1 cm(2)/m(2); LV end-diastolic size, 72.4 +/- 15.1 versus 60.9 +/- 13.3 mL/m(2); EF, 67% +/- 7% versus 72% +/- 8%; aortic sinus, 1.6 +/- 0.2 versus 1.7 +/- 0.2 cm/m(2); ascending aorta, 1.4 +/- 0.2 versus 1.6 +/- 0.2 cm/m(2); descending aorta, 1.1 +/- 0.1 versus 1.2 +/- 0.1 cm/m2; main PA, 1.3 +/- 0.1 versus 1.4 +/- 0.1 cm/m(2); right PA, 1.1 +/- 0.1 versus 1.1 +/- 0.2 cm/m(2); and left PA, 1.0 +/- 0.1 versus 1.1 +/- 0.1 cm/m(2). CONCLUSION: Cardiac CTA measurements of the left cardiac chambers, thoracic aorta, and pulmonary arteries were established for a population without CAD or its risk factors

Accurate interpretation of cardiac computed tomography requires fundamental knowledge of the normal cardiac anatomy and its common variations. This article reviews the normal anatomy of the coronary arteries, cardiac chambers, and cardiac valves

Cardiac computed tomographic angiography (CTA) using multidetector computed tomographic scanners has proven to be a reliable technique to image the coronary vessels. CTA also provides excellent visualization of the mitral and aortic valves, and yields useful information regarding valve anatomy and function. Accordingly, an assessment of the valves should be performed whenever possible during CTA interpretation. In this paper, we highlight the imaging features of common functional and structural left-sided valvular disorders that can be seen on CTA examinations