Efficacy of computer aided analysis in detection of significant coronary artery stenosis in cardiac using dual source computed tomography.

OBJECTIVE: To analyze the diagnostic efficacy of computer aided analysis of relevant coronary artery stenosis using dual source computed tomography (DSCT). METHODS: In a larger scale study patients scheduled for conventional coronary angiography (CA) were additionally examined with DSCT. Based on a 13-segment model 30 CT scans of this study population were analyzed for significant stenosis using conventional 3D charts (3D) as well as a specialized cardiac analysis tool (CAT). Diagnostic accuracy and time to diagnosis was recorded for each vessel separately as well as the three readers' confidence. RESULTS: With severe coronary artery calcifications, 53 false interpretations of segments were found for the total of 390 coronary segments analyzed. 3D and CAT analysis showed a Sensitivity, Specificity, PPV and NPV of 0.59, 0.91, 0.57, 0.92 and 0.57, 0.92, 0.56, 0.92, respectively. No significant differences in diagnostic accuracy could be found between 3D and CAT (P = 0.1667). 3D took a mean of 5.2 min (3-10 min). With CAT a mean time of 8.2 min (4-12 min) was needed. No significant inter-reader time differences (P = 0.4954) and no significant confidence level differences were found between readers and analyzes. CONCLUSION: CAT of the coronary tree shows comparable accuracy to manual 3D analysis but needs improvements concerning coronary tree segmentation times.

Dual-source computed tomography: advances of improved temporal resolution in coronary plaque imaging.

OBJECTIVES: The aim of this study was to quantify image quality gains of a moving coronary plaque phantom using dual-source computed tomography (DSCT) providing 83 milliseconds temporal resolution in direct comparison to 64 slice single-source multidetector CT (MDCT) with a temporal resolution of 165 milliseconds. MATERIALS AND METHODS: Three cardiac vessel phantoms with fixed 50% stenosis and changing plaque configurations were mounted on a moving device simulating cardiac motion. Scans were performed at a simulated heart frequency of 60 to 120 bpm. Image quality assessment was performed in different anatomic orientations inside a thoracic phantom. RESULTS: A significant improvement of image quality using the DSCT could be found (P=0.0002). Relevant factors influencing image quality aside from frequency (P=0.0002) are plaque composition (P<0.0001), as well as orientation (P<0.0001). CONCLUSION: Scanning with 83 milliseconds temporal resolution improved image quality of coronary plaque at higher heart frequencies.

Global left ventricular function in cardiac CT. Evaluation of an automated 3D region-growing segmentation algorithm.

The purpose was to evaluate a new semi-automated 3D region-growing segmentation algorithm for functional analysis of the left ventricle in multislice CT (MSCT) of the heart. Twenty patients underwent contrast-enhanced MSCT of the heart (collimation 16 x 0.75 mm; 120 kV; 550 mAseff). Multiphase image reconstructions with 1-mm axial slices and 8-mm short-axis slices were performed. Left ventricular volume measurements (end-diastolic volume, end-systolic volume, ejection fraction and stroke volume) from manually drawn endocardial contours in the short axis slices were compared to semi-automated region-growing segmentation of the left ventricle from the 1-mm axial slices. The post-processing-time for both methods was recorded. Applying the new region-growing algorithm in 13/20 patients (65%), proper segmentation of the left ventricle was feasible. In these patients, the signal-to-noise ratio was higher than in the remaining patients (3.2+/-1.0 vs. 2.6+/-0.6). Volume measurements of both segmentation algorithms showed an excellent correlation (all P

New vessel analysis tool for morphometric quantification and visualization of vessels in CT and MR imaging data sets.

Image processing algorithms and a prototypical research software tool have been developed for visualization and quantitative analysis of vessels in data sets from computed tomography and magnetic resonance imaging. The software is based on a sequence of processing steps, which are as follows: (a) vessel segmentation based on a region growing algorithm, (b) interactive "premasking" to optionally exclude interfering structures close to the vessels of interest, (c) distance transform-based skeletonization, (d) multiplanar reformation orthogonal to the vessel path, (e) identification of the lumen boundary on the orthogonal cross-section images, and (f) morphometric measurements. The development of the algorithmic components and the application user interface has been carried out in close cooperation with clinical users to achieve a high degree of usability and flexible support of work flow. The software has been successfully applied to the intracranial arteries, carotid arteries, and abdominal and thoracic aorta, as well as the renal, coronary, and peripheral arteries.