Can Carotid Plaque Volume be Measured by 3d Tomographic Ultrasound?

Abstract

Introduction - Carotid Plaque Volume (CPV) correlates more closely than severity of stenosis with symptoms of cerebral ischemia in patients with carotid disease [1]. If we could measure CPV by a minimally-invasive technique, it may replace severity of stenosis as the principle indication for carotid endarterectomy (CEA) and may even be used for population screening in the future. Methods - Standard Duplex and 3D tomographic ultrasound (tUS) imaging of the carotid bifurcations were undertaken on the day of CEA in 50 patients. CPV of the endarterectomy specimen was measured using a validated modified Archimedes suspension technique. CPV by tUS was calculated by dedicated software using the intima-plaque and plaque-blood boundaries in 1mm slices through the tUS image, corrected for the plaque length. Results - The mean endarterectomy specimen CPV was 0.92±0.51cm3 and the tUS CPV was 1.08±0.61cm3 with the mean difference between the endarterectomy specimen and tUS CPV’s being only -0.16±0.24cm3 (95% LOA -0.63-0.32). There was an excellent correlation (Figure) between CPV measured by tUS and the endarterectomy specimen with r = 0.92 (95%CI 0.87 – 0.96 cm3) p<0.0001. There was no correlation between CPV and the severity of stenosis measured by peak systolic velocity; (r = 0.0052, p=0.97). Conclusion - tUS measurement of CPV strongly correlated with CPV of the endarterectomy specimen and is an accurate technique for calculating atherosclerotic burden or CPV. This technique may lead to a new indication for CEA and possibly even to population screening for carotid disease associated with enhanced stroke risk.