Detection of moderate to severe middle cerebral artery atherosclerotic stenosis in stroke patients: Transcranial color-coded duplex sonography versus computed tomography angiography

Background: Intracranial atherosclerotic stenosis is a common cause of ischemic cerebrovascular events and is associated with a high risk of stroke recurrence. This study aimed to assess the diagnostic accuracy of transcranial color-coded duplex sonography for moderate-to-severe middle cerebral artery stenosis in stroke patients.Methods: A retrospective analysis was carried out, including 31 patients aged =18 years hospitalized for ischemic cerebrovascular event in whom middle cerebral artery stenosis =30% was identified on computed tomography angiography. Transcranial color-coded duplex sonography findings were compared to the degree of stenosis blindly identified on the computed tomography angiography used as the reference method.Results: Overall, 27 patients had M1 stenosis and the other 4 had M2 stenosis. To detect M2 stenosis = 50% and = 70%, stenotic to pre-stenotic ratio = 2 and = 3 had a sensitivity of 100%, respectively. To detect M1 stenosis = 70%, peak systolic velocity = 300 cm/s had a sensitivity of 53.8% and specificity of 85.7% with area under the receiver-operating characteristic curve of 0.753 (95% confidence interval: 0.568-0.938; p = 0.026), and stenotic to pre-stenotic ratio = 3 had a sensitivity of 84.6% and a specificity of 78.6% (area under the curve = 0.854; 95% confidence interval: 0.707-1; p = 0.002). Middle cerebral artery/anterior cerebral artery velocity ratio < 0.7 had a sensitivity of 57.1% and specificity of 90% to detect dampened pre-stenotic flow in middle cerebral artery secondary to downstream M1 stenosis = 70% (area under the curve = 0.800; 95% confidence interval: 0.584-1; p = 0.040).Conclusion: This study showed that stenotic to pre-stenotic ratio = 3 was more sensitive than peak systolic velocity = 300 cm/s to screen M1 stenosis = 70%. Middle cerebral artery/anterior cerebral artery ratio < 0.7 was a good indirect sign to detect dampened pre-stenotic flow due to M1 stenosis = 70%.