Coronary CT Angiography

Clinical evaluation of new automatic coronary-specific best cardiac phase selection algorithm for single-beat coronary CT angiography

The aim of this study was to evaluate the workflow efficiency of a new automatic coronary-specific reconstruction technique (Smart Phase, GE Healthcare—SP) for selection of the best cardiac phase with least coronary motion when compared with expert manual selection (MS) of best phase in patients with high heart rate. A total of 46 patients with heart rates above 75 bpm who underwent single beat coronary computed tomography angiography (CCTA) were enrolled in this study. CCTA of all subjects were performed on a 256-detector row CT scanner (Revolution CT, GE Healthcare, Waukesha, Wisconsin, US). With the SP technique, the acquired phase range was automatically searched in 2% phase intervals during the reconstruction process to determine the optimal phase for coronary assessment, while for routine expert MS, reconstructions were performed at 5% intervals and a best phase was manually determined. The reconstruction and review times were recorded to measure the workflow efficiency for each method. Two reviewers subjectively assessed image quality for each coronary artery in the MS and SP reconstruction volumes using a 4-point grading scale. The average HR of the enrolled patients was 91.1±19.0bpm. A total of 204 vessels were assessed. The subjective image quality using SP was comparable to that of the MS, 1.45±0.85 vs 1.43±0.81 respectively (p = 0.88). The average time was 246 seconds for the manual best phase selection, and 98 seconds for the SP selection, resulting in average time saving of 148 seconds (60%) with use of the SP algorithm. The coronary specific automatic cardiac best phase selection technique (Smart Phase) improves clinical workflow in high heart rate patients and provides image quality comparable with manual cardiac best phase selection. Reconstruction of single-beat CCTA exams with SP can benefit the users with less experienced in CCTA image interpretation.

Diagnostic accuracy of 64 multidetector computed tomographic angiography in peripheral vascular disease

BACKGROUND

Previous studies of multidetector CT (MDCT) of the lower extremities for the detection of peripheral vascular disease showed high diagnostic accuracy but were performed with older generation systems.

OBJECTIVE

The purpose of this study was to evaluate the diagnostic accuracy of 64 MDCT for the detection of hemodynamically significant disease within the lower extremity peripheral vasculature as compared to digital subtraction angiography (DSA).

METHODS

Twenty-eight consecutive patients with symptomatic lower extremity intermittent claudication and an abnormal ankle-brachial index (ABI; less than 0.9) were evaluated by both 64 MDCT and DSA. Axial images were acquired with a 64 multidetector general electric light speed VCT scanner. Images were analyzed using a GE Advantage workstation (AW 4.3) capable of advanced image processing and manipulation. The aorto-iliac and lower extremity arteries were divided into 15 segments per limb (30 segments per patient). Eight hundred forty segments were analyzed in a blinded fashion by physicians with level III CT certification. Segments were classified as grade I (<10% stenosis), grade II (10-49%), grade III (50-99%), and grade IV (occlusion).

RESULTS

For all segments evaluated, the overall diagnostic accuracy for detecting grade III and IV lesions was 98% with a sensitivity of 99% and a specificity of 98%. For the aorto-iliac segments, the diagnostic accuracy was 98% with a sensitivity of 100% and a specificity of 99%. For the femoro-popliteal segments, the overall accuracy was 98% with a sensitivity of 100% and a specificity of 99%. For the infra-popliteal segments, the overall accuracy was 98% with a sensitivity of 97% and a specificity of 99%. One segment could not be visualized by MDCT compared to 49 segments that could not be visualized by DSA.

CONCLUSIONS

This study demonstrates excellent diagnostic accuracy of 64 MDCT in the detection of hemodynamically significant disease of the lower extremities. More segments are visualized using 64 MDCT than DSA, allowing more complete visualization of the vascular tree. CT angiography should be considered in the diagnostic evaluation of symptomatic patients with peripheral vascular disease.