LITERATURE HIGHLIGHTS: Diagnostic Accuracy of 64 Multidetector CTA Studied

January 1, 2010—In Catheterization and Cardiovascular Interventions, Shahrzad Shareghi, MD, et al have published findings from a study on the diagnostic accuracy of 64 multidetector computed tomographic (MDCT) angiography in peripheral vascular disease (2010;75:23–31).

According to the investigators, previous studies of MDCT of the lower extremities for the detection of peripheral vascular disease showed high diagnostic accuracy but were performed with older-generation systems. 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).

In the study, 28 consecutive patients with symptomatic lower extremity intermittent claudication and an abnormal ankle-brachial index (< 0.9) were evaluated by both 64 MDCT and DSA. Axial images were acquired with a 64 multidetector LightSpeed VCT scanner (GE Healthcare, Wauwatosa, WI). Images were analyzed using a GE Advantage workstation (AW 4.3) capable of advanced image processing and manipulation. The aortoiliac and lower extremity arteries were divided into 15 segments per limb (30 segments per patient).

The investigators reported that physicians with level III CT certification analyzed 840 segments in a blinded fashion. Segments were classified as grade I (< 10% stenosis), grade II (10%–49%), grade III (50%–99%), and grade IV (occlusion). 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 aortoiliac segments, the diagnostic accuracy was 98%, with a sensitivity of 100% and a specificity of 99%. For the femoropopliteal segments, the overall accuracy was 98%, with a sensitivity of 100% and a specificity of 99%. For the infrapopliteal 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.

The investigators concluded that 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, the investigators advised.

In their conclusions, the investigators stated that considerable variation exists in the number and size of embolic particles generated during carotid artery stenting. Embolic potential is positively correlated with lesion grayscale median and the combination of lesion echogenicity, heterogenicity, and irregularity. Restenosis after prior carotid endarterectomy is associated with minimal embolic particulate generation, suggesting that embolic protection may not be necessary for carotid artery stenting of restenotic lesions.