Background and Purpose Transcranial Doppler sonography is of established value in the detection and monitoring of middle cerebral artery vasospasm. Little information exists on the utility of transcranial Doppler for detection of posterior circulation vasospasm.Methods Cerebral angiography and conventional handheld transcranial Doppler sonography were compared to determine sensitivity and specificity of transcranial Doppler for detection of vertebral and basilar artery vasospasm.Results Of 59 consecutive subarachnoid hemorrhage patients with transcranial Doppler angiogram correlations, 42 underwent posterior circulation angiography to evaluate 64 vertebral arteries and 42 basilar arteries during the period of risk for vasospasm and had technically adequate transcranial Doppler examinations within 24 hours of the angiogram. A mean flow velocity of 60 cm/s and above was indicative of both vertebral and basilar artery vasospasm. For the vertebral artery, there were 7 true-positive test results, 42 true-negatives, 6 false-positives (unknown cause in 3, increased collateral flow in 1, adjacent vessel vasospasm in 1, hyperperfusion V asospasm is a common occurrence after aneurysmal subarachnoid hemorrhage (SAH); it is detectable angiographically in 21% to 70% of patients with this disorder.
"4 Angiographic vasospasm tends to occur between days 2 and 17 after SAH, with its maximal severity between days 7 and 12.' 3 Rarely, vasospasm may last for 3 to 4 weeks or even longer. The overall rate of focal neurological deficits in the 2-week period after initial SAH is 30%, with the etiologic fraction attributable to vasospasm ("clinical vasospasm") being 80%, yielding a cumulative rate of 24% by 14 days. 56 Recent data confirm that vasospasm is the leading cause of mortality (7.2%) and morbidity (6.3%) in survivors of aneurysmal SAH.7 -8 Transcranial Doppler sonography (TCD) has demonstrated value in the detection of middle cerebral artery vasospasm, 919 with an overall sensitivity of 68% to 94%, specificity of Received January 27,1994; final revision received Jury 28, 1994; accepted Jury 28, 1994. © 1994 American Heart Association, Inc.in 1), and 9 false-negatives (anatomic in 7, operator error in 2). Sensitivity was 44% and specificity was 87.5%. For the basilar artery, there were 10 true-positives, 23 true-negatives, 6 falsepositives (unknown cause in 4, hyperemia/hyperperfusion in 1, increased collateral flow in 1), and 3 false-negatives (operator error in 2, tortuous vessel course in 1). Sensitivity was 76.9% and specificity was 79.3%. When the diagnostic criterion was changed to ^80 cm/s (vertebral artery) and £95 cm/s (basilar artery), all false-positive results were eliminated (specificity and positive predictive value, 100%). Conclusions Our data suggest that transcranial Doppler has good specificity for the detection of vertebral artery vasospasm and good sensitivity and specificity for the detection of basilar artery vasospasm. Transcranial Doppler is highly specific (100%) for vertebra] and basilar artery vas...