Sensitivity and Accuracy of Doppler Ultrasound Compared to CT Angiography for the Diagnosis of Carotid Webs: Systematic Review

INTRODUCTION: Carotid webs (CaWs) are increasingly recognized as a cause of cryptogenic acute ischemic stroke (AIS). Due to the risk of recurrent ischemic stroke associated with CaW, it is important to identify them. Although several studies report digital subtraction angiography and computerized tomography angiography (CTA) to be better at diagnosing CaW than Doppler ultrasound (DUS), it remains to be defined which is the best radiological method to diagnose CaW. Our aim was to evaluate sensitivity and accuracy of DUS compared to CTA for CaW diagnosis. METHODS: We searched PUBMED and EMBASE databases from inception through August 2022. We included studies with patients with CaW diagnosed by DUS and/or CTA, in which both methods were used in each patient. Demographic characteristics, diagnostic reports of each method, and histology reports were collected. Descriptive analysis and sensitivity and accuracy estimates were made to evaluate DUS compared to CTA. RESULTS: We included 27 articles in the systematic review (121 patients with CaW). DUS identified 94 patients with CaW and CTA 116 patients. DUS missed diagnosis in 22.3% (27 patients) and CTA did not identify CaW detected by DUS in 4.13% (5 patients). Accuracy rate between DUS and CTA was 73.6% (95% CI: 64.8-81.2%). Sensitivity of DUS to diagnose CaW compared to CTA was 76.7% (95% CI: 68.0-84.1%). Most common misdiagnosis with DUS was normal exam (44.4%), atherosclerosis (22.2%), and dissection (22.2%). CONCLUSION: The sensitivity and accuracy of DUS to diagnosis of CaW were moderate. It might detect CaW in some cases in which it was not identified by CTA. Increased recognition of CaW and specific ultrasound protocols may enhance diagnosis of CaW by DUS.