Application Of 256-Slice Computed Tomography In Coronary Venous Imaging

BackgroundInvestigations of the coronary venous system are overshadowed by numerous studies of the coronary arteries. In contrast to that for coronary arteries, the literature for coronary veins is scarce. The clinical importance of the coronary venous system, nevertheless, should not be underestimated. The coronary venous system is being used increasingly for various electrophysiological purposes, such as cardiac resynchronization therapy (CRT), percutaneous mitral annuloplasty (PMA), radiofrequency catheter ablation (RFA), and so on. A thorough knowledge of the coronary venous anatomy prior to the procedure will not only ease the intervention process but also increase the success rate. There are several imaging methods to assess coronary venous system. Retrograde cardiac venography is the current gold standard for defining the coronary venous anatomy. However, such a procedure is invasive, technically challenging, and unable to outline the coronary arteriovenous relationship. Multi-slice spiral computed tomography (MSCT) has become an important tool for noninvasive visualization of the coronary venous system. It is less invasive than conventional angiography and has fewer complications. Up to now, a number of previous studies have used 4-,16-,64-, and128-slice MSCT to describe the coronary venous tree. Compared with the older generation MSCT, the 256-slice MSCT with the reduction of scanning time, breath-holding duration, motion artifacts, contrast medium and radiation dose can provide superior noninvasive visualization of coronary artery and venous anatomy. However, to our best knowledge, there are no published papers regarding coronary venous system depiction using the latest generation 256-slice CT.ObjectiveTo investigate the coronary venous system and its relation to adjacent structures using 256-slice computed tomography (CT), which can provide guidance for the patients who need cardiac electrophysiology interventional therapy.MethodsThe study consisted of 125 patients who underwent coronary CT angiography (CTA) using 256-slice CT.1. For each patient, the coronary venous system and its relation to adjacent structures were evaluated.2. Anatomic variation was recorded.3. The appropriate locations and diameters of the posterior interventricular vein (PIV), posterior vein of the left ventricle (PVLV) and the left marginal vein (LMV) were detected.4. The paired student’s t test was used to evaluate the difference between the diameter of the coronary sinus (CS) ostium in anteroposterior direction and that in superoinferior direction.5. The effective dose (ED) was recorded for each patient.Results1. Three kinds of anatomic variation (5 cases) were recorded, which were excluded for analysis.2. The CS, great cardiac vein (GCV), PIV, and anterior interventricular vein (AIV) were visualized in all cases (100%); the PVLV was visualized in 94 cases (78.3%), there were 2 PVLVs in 14 cases (14.9%); the LMV was visualized in 77 cases (64.2%), there were 2 or 3 LMVs in 9 cases (11.7%); the small cardiac vein (SCV) was observed as a very small vein in 32 cases (26.7%), and 50% of which directly drained into PIV; the Marshall vein was present in 9 cases (7.5%).3. The diameter of the CS ostium in superoinferior direction (11.6 ±2.3mm) was larger than that in anteroposterior direction (8.8±2.1 mm) (P<0.05).4. It was possible to evaluate at least one main vein with adequate caliber and regular course for cardiac resynchronization therapy (CRT) in 115 cases (95.8%).5. For majority of the cases (91.7%), the CS-GCV was located above the level of the mitral valve annulus (MVA), while the left circumflex coronary artery (LCX) was coursed between the CS-GCV and the MVA in 83 cases (69.2%). LMV had more intersection with the circumflex or circumflex marginal than PVLV.6. The effective dose (ED) was 7.8±0.8mSv (6.0-9.8mSv).Conclusions1. In addition to be as a useful diagnostic imaging modality for the noninvasive assessment of coronary artery disease, 256-slice CCTA can provide superior noninvasive evaluation of the coronary venous system and its relation to adjacent structures, which has important clinical implications and can provide guidance for the patients who need cardiac electrophysiology interventional therapy.2. 256-slice CCTA can provide superior noninvasive evaluation of the coronary venous system with the benefit of a low radiation dose.BackgroundCoronary computed tomography angiography (CCTA) has emerged as a reliable and accurate modality for the noninvasive assessment of coronary artery and venous. However, high radiation dose with conventional retrospective (electrocardiogram) ECG-gating draw much attention. Within the past few years, a variety of strategies have been proposed to reduce exposure to ionizing radiation including the prospectively ECG-gated axial scan mode. A lot of studies have support that high diagnostic accuracy is achieved with both retrospective and prospective ECG-gated CCTA for detecting CAD. However, to our best knowledge, there are no studies to evaluate the coronary venous system using prospective ECG-gated CCTA.ObjectiveTo investigate the feasibility in evaluation of the coronary venous system with prospective electrocardiography(ECG)-gated CCTA using a 256-slice Scanner.Methods120 patients (68 males,52 females) with suspected coronary artery disease (CAD) underwent CCTA using 256-slice CT. The Prospectively gated transverse (PGT) patients were enrolled prospectively between October 2014 and December 2014. For each PGT patient, we selected the paired ones in retrospective gated helical (RGH) patient’s database and built up the RGH group. Image quality for all tributaries of the coronary venous system was assessed and compared between the two groups using a 3-point scale(3-good, 2-moderate and 1-poor) in a blinded fashion. Quantitative measurements of signal intensity, image noise, Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and radiation dose were obtained in each group. Comparisons between the PGT and RGH techniques were performed by two-sample t-test for continuous covariates and by Chi-square test for categorical variables. A level of P<0.05 was considered statistically significant.ResultsThere were no significant difference in assessable coronary venous segments between the two groups (PGT:90%, RGH:91.7%, X2=0.237, P=0.888). There were no significant differences in signal intensity and SNR measurements between the two scan groups (P=0.197, P=0.145, respectively). The image noise and CNR measurements of the PGT group are better than those of the RGH group (P=0.000, P=0.003, respectively). The effective dose (ED) of the PGT group was 3.2■0.3 mSv, representing reduction of 58% compared to that of the RGH group (7.6±0.7mSv) (P< 0.05).ConclusionsProspective ECG-gated 256-slice CCTA can provide superior noninvasive evaluation of the coronary venous system with the benefit of a low radiation dose.