Histologically Verified Carotid Plaque Characteristics by Ultrasound: A Diagnostic Accuracy Systematic Review

Ultrasound (US) has been considered the first-line diagnostic technique for evaluating carotid atherosclerosis, where plaque composition plays a key role in stroke risk. We aimed to analyze the diagnostic accuracy of carotid plaque characteristics using US techniques compared to histology in patients with symptomatic/asymptomatic carotid plaques. After prospective study registration in PROSPERO, we searched Medline Ovid, Embase.com, Cochrane Library, and Web of Science without any search limitation for the diagnostic accuracy of US in detecting carotid plaque features based on histology. From 8168 studies, 63 were included evaluating 13 histologically verified plaque characteristics by 14 different US techniques. Diagnostic accuracies for all plaque characteristics usually varied between 35% and 100% without a trend towards increasing accuracy over the last 40 y but were affected by large heterogeneity. In characteristics with >5 diagnostic accuracy comparisons, the highest diagnostic performance was found for detection of calcification (mean sensitivity 65.7%/mean specificity 84.7%), fibrous tissue (61.2%/84.9%), vulnerable/unstable plaque (76.3%/70.3%), and stable plaque (63.2%/82.7%). However, several advanced techniques investigated showed high diagnostic accuracy, promising interesting diagnostic options for the future. Carotid US allows for widely available and reliable evaluation of atherosclerotic plaque morphology by conventional and advanced techniques. Registration: PROSPERO ID CRD42022329690 (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=329690).