Accuracy and criteria for localizing arterial occlusion with transcranial Doppler

The authors determined transcranial Doppler (TCD) accuracy for the proximal internal carotid artery (ICA), distal ICA, proximal middle cerebral artery (MCA), distal MCA, anterior cerebral artery (ACA), posterior cerebral arte ry (PCA), terminal vertebral artery (tVA), and basilar artery (BA) occlusio n in cerebral ischemia patients. Detailed diagnostic criteria were prospect ively applied for TCD interpretation independent of angiographic findings. Of 320 consecutive patients referred to the neurosonology service with symp toms of cerebral ischemia, 190 (59%) patients also underwent angiography (M RA or DSA). 48 of those 190 patients had angiographic occlusion and 12 of t hose 48 patients had involvement of multiple vessels. Median time from TCD until angiography was performed was 1 hour (41 patients had angiography bef ore TCD). TCD showed 40 true positive, 8 false negative, 8 false positive,a nd 134 true negative studies with sensitivity 83.0%, specificity 94.4%, pos itive predictive value 83.0%, negative predictive value 94.4%, and accuracy 91.6% to determine all sites of occlusion. Sensitivity for each individual occlusion site was: proximal ICA 94%, distal ICA 81%, MCA 93%, WA 56%, BA 60%. Specificity ranged from 96% to 98%. TCD is sensitive and specific in d etermining the site of the arterial occlusion using detailed diagnostic cri teria, including proximal ICA and distal MCA lesions. TCD has the highest a ccuracy for ICA and MCA occlusions. If the results of TCD are normal, there is at least a 94% chance that angiographic studies will be negative.