Sensitivity and specificity of transcranial Doppler ultrasonography in the detection of high-grade carotid stenosis.

We evaluated the ability of transcranial Doppler ultrasonography (TCD) of the middle cerebral artery to detect internal carotid artery luminal area stenosis of 70% or greater by comparing TCD with cerebral angiography in 79 subjects, including 22 with normal cerebral arteriograms and 57 with 30% to 100% internal carotid artery stenosis on at least one side. Of six TCD measurements assessed, the flow acceleration provided the greatest sensitivity (82%) and specificity (73%) in distinguishing 70% to 100% carotid stenosis from lesser degrees of stenosis. The overall accuracy of the flow acceleration was 78%, and the positive predictive value was 79%. A flow acceleration of 351.6 cm/sec2 or less was useful for detecting high-grade stenosis, but there was difficulty in distinguishing unilateral from bilateral high-grade stenosis. TCD measurement of the flow acceleration allows for fairly reliable detection of high-grade stenosis and can thus serve as a useful indirect component of a carotid noninvasive battery.

Evaluation of internal carotid artery stenosis by transcranial Doppler ultrasonography and oculopneumoplethysmography.

We compared the results of cerebral angiography, transcranial Doppler ultrasonography of the middle cerebral artery and oculopneumoplethysmography in 35 subjects. The subjects included eight with normal cerebral arteriograms and 27 with varying degrees of internal carotid stenosis. We found a statistically significant (P = .0001) decreasing linear trend in the middle cerebral artery flow acceleration as a function of the degree of internal carotid artery stenosis. We also observed a decreasing trend in oculopneumoplethysmography (P = .0004) as a function of the degree of internal carotid stenosis. This latter relationship was enhanced with the addition of a quadratic term in the regression model (P = .02). We also found that there was a statistically significant reduction in the flow acceleration, on average, when comparing carotid stenosis of 75 to 100% to lesser degrees of stenosis (P = .0001). This was also the case for oculopneumoplethysmography (P less than .02). The flow acceleration and oculopneumoplethysmography appear to be relatively sensitive indicators of the distal hemodynamic effect of internal carotid artery stenosis.

Transcranial Doppler ultrasonography of the middle cerebral artery in the hemodynamic assessment of internal carotid artery stenosis.

We performed transcranial Doppler ultrasonography of the middle cerebral arteries in 43 patients who underwent cerebral angiography. Twelve patients had normal arteriograms, 18 had internal carotid artery stenosis, and 13 had complete occlusion. Parameters measured included: flow velocity (mean, maximum, and peak systolic), flow acceleration, systolic-to-diastolic ratio, and pulsatility index. Patients with 75% to 100% stenosis had lower average ipsilateral flow acceleration and mean velocity than did normal subjects. Correlation analysis revealed an inverse relationship between degree of stenosis and ipsilateral flow acceleration, as well as ipsilateral mean velocity. These correlations were no longer significant when we excluded normals, however. There was a linear relationship between right and left velocity values for both normal subjects and patients with occlusion but not for patients with stenosis. This technique has potential for the reliable assessment of the hemodynamic effect of carotid stenosis on intracranial circulation.