Forty-two intracranial internal carotid arteries were visualized by both arteriography and 2 MHz pulse ultrasonic Doppler examinations. The intracranial internal carotid artery Doppler signals were studied at 5-7 cm depth behind the eyelid using frequency spectral analysis. Stenosis criteria were developed and methods of avoiding confusion with collateral effects devised. Among 33 intracranial ICAs visualized on the arteriograms, 22 were normal without stenosis and 11 displayed some degree of

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... enosis ranging from 20 to 75 percent. An additional 7 were totally occluded. Doppler criteria of stenosis representing elevated frequencies and symmetrical prominent low frequencies (SPLF) were utilized and separated from collateral effects to provide an overall accuracy of the technique of 88 percent with a 95 percent specificity and a 73 percent sensitivity. The technique appears sufficiently promising to justify further development and utilization.