Posterior interatrial muscular connection between the coronary sinus and left atrium: anatomic and functional study of the coronary sinus with multidetector CT.

PURPOSE: To demonstrate coronary sinus-left atrium connections and evaluate coronary sinus function and anatomy in detail by using multidetector computed tomography (CT). MATERIALS AND METHODS: In this institutional review board-approved retrospective study, the authors evaluated coronary CT angiograms obtained in 65 patients with normal sinus rhythm (normal group) and seven with atrial fibrillation at CT (atrial fibrillation group). Coronary sinus-right atrium muscle continuity was indirectly evaluated by measuring the length of the coronary sinus contraction during atrial systole. The length, number, and extent of coronary sinus-left atrium connections were recorded. The accuracy of CT was validated by comparing microscopic images of autopsied hearts with corresponding CT images. Comparisons were performed by using Student t tests for continuous variables. P ≤ .05 was considered indicative of a statistically significant difference. RESULTS: In the normal group, coronary sinus contraction was seen in 60 of the 65 patients (92%, mean length ± standard deviation, 25.7 mm ± 8.0). The coronary sinus narrowed 26% from middiastole to atrial systole (P < .0001). Coronary sinus-left atrium muscle connections were seen in 58 of the 65 patients (89%). A single connection was seen in 43 of the 65 patients (66%), with a mean length of 21.0 mm ± 14.0 within 12.0 mm ± 11.0 of the coronary sinus ostium. In 10 of the 43 patients (26%) with single connections, the connection extended to the coronary sinus ostium. In 10 of the 65 patients (15%), the entire coronary sinus was attached to the left atrial wall. Fifteen patients (23%) had two connections; distal connections measured 9 mm ± 2.4 in length within 2.2 mm ± 3.8 of the coronary sinus ostium, and proximal connections measured 15.4 mm ± 10.0 in length within 24.0 mm ± 8.0 of the coronary sinus ostium. In seven patients (11%), no coronary sinus-left atrium connection was seen; however, all showed a coronary sinus constriction during atrial systole, indicating that coronary sinus-right atrium muscle continuity is likely the primary cause for coronary sinus contractions. In the atrial fibrillation group, no coronary sinus contraction was seen. All images in the atrial fibrillation group showed a coronary sinus-left atrium connection, which was single in five patients and double in two. The area of the coronary sinus during diastole was larger in the atrial fibrillation group than in the normal group (114 mm(2) ± 37 vs 77 mm(2) ± 40, respectively; P = .02). CONCLUSION: CT can provide excellent information about coronary sinus function and coronary sinus-left atrium muscle connections.

Quantification of epicardial adipose tissue: correlation of surface area and volume measurements.

OBJECTIVES: Epicardial adipose tissue (EAT) is an important structure both as an active secretor of hormones and cytokines that play a role in the development of atherosclerosis, as well as its potential as a cardiac risk marker. The purpose of this article was to determine an easy but accurate quantification of EAT for routine clinical use. METHODS AND RESULTS: We randomly selected coronary computed tomography angiographies of 60 patients (20 lean, 20 overweight, and 20 obese) derived from a larger study. Systolic and diastolic surface areas (SAs) were measured at two axial levels: a) fat pocket (FP) between right atrium and right ventricular outflow tract at origin of right coronary artery (RCA-FP) and b) FP anterior to right ventricular free wall (RVFW-FP) at coronary sinus ostium level. Maximum RVFW-FP thickness and total diastolic EAT volume were measured. EAT SA and thickness measurements were correlated to EAT volume and compared. Both interobserver and intraobserver reliability were assessed for SA and thickness with the intraclass correlation coefficient (ICC) as well as mean relative difference ± standard deviation (SD). Differences between systolic and diastolic SA measurements were also evaluated. Diastolic RCA-FP showed the highest SA correlation with volume (ρ = 0.92) and compared to the correlation of EAT thickness with volume (ρ=0.59) demonstrated the largest difference in correlation (+ 0.33, P < .0001). Systolic RCA-FP, systolic RVFW-FP, and diastolic RVFW-FP correlations to volume were less than diastolic RCA-FP (ρ = 0.84, ρ = 0.82, ρ = 0.86 respectively), but all correlations were statistically significantly higher than EAT thickness with volume. Values of systolic SA were mildly higher than diastolic SA for the RCA-FP (relative difference ± SD = 1.8 ± 21%, P = .8), but significantly higher for the RVFW-FP (relative difference ± SD = 17 ± 35%, P < .0001). Both systolic and diastolic SA measurements showed excellent reproducibility (ICC >0.95). However, for EAT thickness, the inter-observer reliability was comparatively low (ICC = 0.66). CONCLUSION: Diastolic RCA-FP SA is a quick, reproducible estimate of total EAT and compared to EAT thickness demonstrates a significantly better correlation with EAT volume.

Coronary venous aneurysm in patients without cardiac arrhythmia as detected by MDCT: an anatomic variant or a pathologic entity.

OBJECTIVES: The aim of this study was to determine the prevalence of coronary venous aneurysm in patients with no history of cardiac arrhythmia using 64-slice multidetector computed tomography. BACKGROUND: Coronary vein aneurysm frequently has been reported in association with cardiac arrhythmias such as ventricular pre-excitation. METHODS: Coronary computed tomography angiograms of 187 patients (108 men, 79 women; mean age +/- SD, 60 +/- 12 years) were analyzed retrospectively for the presence of a focal coronary venous aneurysm. Fusiform aneurysm was defined as a focal dilatation of twice the normal vein. However, any size of diverticular aneurysms was included. Cross-sectional diameters of normal and aneurysmal segments of the posterior interventricular vein, great cardiac vein, and coronary sinus (CS) were measured at mid-diastole, late systole, and atrial systole. The Student t test was used for continuous variables and contingency tables were used for categorical variables. RESULTS: A single aneurysm was found in 19 (10%) patients (fusiform, n =16; diverticular, n = 3). The most common anatomic location was the posterior interventricular vein near the confluence with the CS (n = 14), followed by the great cardiac vein near the junction with the CS (n = 3), and the CS (n = 2). The mean diameter of the aneurysms was 9.3 +/- 1.2 mm (range, 8.1 to 11.4 mm) at mid-diastole and 10.4 +/- 1.4 mm (range, 8.5 to 12.7 mm) at late systole. However, the difference was not statistically significant. All normal CSs and 1 aneurysm arising from the CS showed contraction during atrial systole, which may suggest atrial myocardial coverage of these structures. Patients with a venous aneurysm were significantly older than patients without an aneurysm (67.6 +/- 11 vs. 59 +/- 12 years, respectively; p = 0.006). CONCLUSIONS: Coronary vein aneurysms (especially the fusiform type) were seen in up to 10% of patients with no history of cardiac arrhythmia and can be well visualized on computed tomography angiograms.