Cardiac Dual-source CT Research Articles

Quantification of left ventricular function and mass in cardiac Dual-Source CT (DSCT) exams: comparison of manual and semiautomatic segmentation algorithms

The purpose of our study was to evaluate reliability of left ventricular (LV) function and mass quantification in cardiac DSCT exams comparing manual contour tracing and a region-growing-based semiautomatic segmentation analysis software. Thirty-three consecutive patients who underwent cardiac DSCT exams were included. Axial 1-mm slices were used for the semiautomated technique, and short-axis 8-mm slice thickness multiphase image reconstructions were the basis for manual contour tracing. Left ventricular volumes, ejection fraction and myocardial mass were assessed by both segmentation methods. Length of time needed for both techniques was also recorded. Left ventricular functional parameters derived from semiautomatic contour detection algorithm were not statistically different from manual tracing and showed an excellent correlation (p<0.001). The semiautomatic contour detection algorithm overestimated LV mass (180.30+/-44.74 g) compared with manual contour tracing (156.07+/-46.29 g) (p<0.001). This software allowed a significant reduction of the time needed for global LV assessment (mean 174.16+/-71.53 s, p<0.001). Objective quantification of LV function using the evaluated region-growing-based semiautomatic segmentation analysis software is feasible, accurate, reliable and time-effective. However, further improvements are needed to equal results achieved by manual contour tracing, especially with regard to LV mass quantification.

New applications for noninvasive cardiac imaging: dual-source computed tomography

Coronary catheter angiography is considered to be the standard of reference for the diagnosis of coronary artery disease (CAD) and the grading of coronary artery stenoses. Even with the established generation of 16- and 64-multislice CT (MSCT) systems, with remarkable results reported for diagnostic accuracy, a substantial number of limitations remain, hindering full acceptance of the method as a standard technique in the clinical cascade for CAD patients. Recently, dual-source CT (DSCT) with improved temporal resolution has been introduced into clinical routine, raising the hope that some of the earlier problems might be overcome. MSCTA with 64-slice CT scanners has successfully been validated for the evaluation of clinically relevant lumen reduction of the coronary arteries with high negative predictive values and for the simultaneous assessment of pulmonary embolism, coronary artery stenoses, and aortic dissection and aneurysm in patients with chest pain ("triple rule out"). However, certain limitations continue to exist including partial volume effects due to heavy calcium deposits in the coronary artery wall, impaired assessability of coronary artery branches smaller than 2 mm in diameter, and impaired assessability of patients with a high heart rate and/or arrhythmia. While MSCT has mainly been tested to detect obstructive CAD, an accurate assessment of regional and global ventricular function, as well as of the aortic and mitral valves, might be feasible using DSCT, since image reconstruction is possible in virtually any phase of the cardiac cycle with a sufficiently high temporal resolution. DSCT is a robust method for the evaluation of patients with higher heart rates and arrhythmias and, in most cases, obviates the need for beta-blocker premedication. While the evaluation of coronary artery stenoses will remain the primary clinical indication for cardiac DSCT, a simultaneous and sufficiently accurate assessment of global left ventricular functional parameters, regional wall motion, and valve assessment becomes feasible with a single scan.