Correlations between cerebral arterial velocities, blood flow, and delayed ischemia after subarachnoid hemorrhage.

Abstract

Background and Purpose: Elevated middle cerebral erythrocyte velocities and tissue hypoperfusion have been correlated with delayed ischemia after subarachnoid hemorrhage, but few studies have compared serial arterial velocities with cerebral blood flow and neurological deficits.Methods: Serial measurements of middle cerebral velocities, using transcranial Doppler ultrasonography, were performed in 34 patients after subarachnoid hemorrhage and correlated with cerebral blood flow, measured in 20 of the 34 using single-photon emission computed tomography with technetium-99m hexamethylpropylene amine oxime and neurological evidence of delayed ischemia.Results: In 16 patients without delayed ischemia, eight had evidence of vasospasm (>120 cm/sec), but only one of seven had hypoperfusion, suggesting that vasospasm might be more common than hypoperfusion in this group (p=0.1). In 10 patients with delayed ischemia and a lateralizing deficit, both asymmetrical middle cerebral vasospasm (eight of nine with vasospasm) and hypoperfusion (six of six studied) were concordant with the clinically ischemic hemisphere (p<0.05). Vasospasm occurred with nonlateralized delayed ischemia in seven of eight patients and with hypoperfusion in five of six, affecting the anterior cerebral territory in three.Conclusions: Concordant vasospasm and hypoperfusion were most often present in patients with delayed ischemia and lateralizing neurological deficits. Discordant results reflect inherent limitations and the different levels of the circulation monitored by the two techniques. (Stroke 1992;23:492-497) KEY WORDS • blood flow velocity • cerebral blood flow • subarachnoid hemorrhage

Guidelines and Recommendations for Perfusion Imaging in Cerebral Ischemia

“…86 SPECT can provide the early evidence of vasospasm-induced hypoperfusion and may help to differentiate this hypoperfusion from other causes of neurological deterioration, such as edema, hydrocephalus, elevated intracranial pressure, and metabolic etiologies. SPECT combined with transcranial Doppler may prove to be sensitive enough for the early detection of vasospasm and delayed ischemic deficits to obviate other more invasive techniques 87 (class IV).…”

Basilar Artery Vasospasm and Delayed Posterior Circulation Ischemia After Aneurysmal Subarachnoid Hemorrhage

“…[1][2][3] Although TCD measurements do not provide information on cerebral blood flow (CBF) and cerebral tissue perfusion, 1,4,5 significant arterial narrowing resulting from VS is associated with perfusion impairment, and many studies have demonstrated that cerebral VS in the anterior circulation is associated with reduced cerebral perfusion in the affected territories. 5,6 Unlike anterior circulation VS, little is known about VS in the vertebrobasilar system, [7][8][9][10] and with an absence of data regarding CBF disturbances in the posterior circulation brain territories after aneurysmal SAH, many clinicians may not be well guided in the monitoring and treatment of vertebrobasilar VS. 10,11 In the present study, we used 99m Tc ethyl cysteinate dimer single-photon emission computed tomography (ECD-SPECT) imaging to determine the incidence of delayed brain stem (BS) ischemia and posterior circulation territory ischemia that may be related to VS after aneurysmal SAH.…”

Vertebrobasilar Vasospasm after Aneurysmal Subarachnoid Hemorrhage: Review

“…Indeed, subsequent research on the hemodynamics of BA-VS designed to explore that very thesis provides the basis for current knowledge on the neuroanatomic determinants of clinical outcomes associated with spasm in the VB system. In similar fashion to previous efforts that shed light on the correlation between regional hypoperfusion and DCI in the anterior circulation [39]. Sviri et al [40,41] ascertained a causal link between basilar artery vasospasm and hypoperfusion to the brainstem and other areas supplied by the posterior circulation.…”