The accuracy of transcranial Doppler in the diagnosis of stenosis or occlusion of the terminal internal carotid artery

Background and Purpose. Transcranial Doppler (TCD) can detect intracranial stenoses and occlusions that can help in the diagnosis and management of ischemic stroke. The accuracy parameters for lesions located in the terminal internal carotid artery (TICA) are less known, unlike other basal cerebral vessels. Patients and Methods. The authors studied consecutive patients referred for TCD who underwent contrast angiography or magnetic resonance angiography. They calculated the sensitivity, specificity, positive and negative predictive values (PPV and NPV), and likelihood ratios. Results. Forty-three patients had TCD and angiography: mean age was 57 ± 20 years, and 65% were men. Twenty-two patients were diagnosed with TICA stenosis or occlusion on TCD underwent angiography. Four patients had abnormal TCD findings that were not confirmed by angiography. Two of 21 patients with normal TCD showed moderate (< 50%) stenosis of the TICA and cavernous segment of the internal carotid artery at angiography. Accuracy parameters for TCD were as follows: sensitivity = 90% (confidence interval [CI], 63%-96%), specificity = 83% (CI, 61%-94%), PPV = 82%, NPV = 86%, positive likelihood ratio = 5, and negative likelihood ratio = 0.17. Conclusions. TCD is a sensitive screening tool for the lesions in the TICA. Specificity is likely affected by a wide spectrum of the stenosis severity shown at angiography and time lags between the studies.