Quantitative Regional Cerebral Blood Flow Measurement Techniques Improve Noninvasive Detection of Cerebrovascular Vasospasm after Aneurysmal Subarachnoid Hemorrhage

Abstract

Adequate therapy of vasospasm (VS) in patients suffering from aneurysmal subarachnoid hemorrhage critically depends upon early and reliable diagnosis of cerebral hypoperfusion. The objective of the present study was to evaluate the usefulness of quantitative regional blood flow (rCBF) analysis as an adjunct in noninvasive prediction of VS. Therefore, 33 transcranial Doppler sonography (TCD) studies assuming cerebrovascular VS (TCD flow velocity >120 cm/s) were followed by ^sXe/CT and cerebral panangiography (PA). TCD plus ^sXe/CT significantly increased the predictability of VS from 34 to 91%, proving that a combination of TCD and rCBF studies improves the noninvasive detection of VS and might help to prevent unnecessary angiographic examinations.

Effects of positive end-expiratory pressure on regional cerebral blood flow, intracranial pressure, and brain tissue oxygenation*

“…Correct probe position was confirmed by a computed tomography (CT) scan. In the same setting, a stable xenon CT (sXe-CT) was performed to validate the TD-rCBF measurements (6,9).…”

“…The diagnostic work-up for vasospasm was further complemented by an sXe-CT study on the day of angiography. In the presence of a mean cerebral blood flow of Ͻ32 mL/100g/ min, hemodynamically relevant cerebral vasospasm was assumed (8,9,11).…”

Regional cerebral blood flow monitoring in the diagnosis of delayed ischemia following aneurysmal subarachnoid hemorrhage

“…7,27 For determination of sXe-rCBF values, a 4.5-min wash-in protocol was applied. Patients received a mixture of medical-grade 30% sXe, 60% O 2 , and balanced air, while a three-level investigation (slice thickness 10 mm) was performed.…”

Visual Grading System for Vasospasm Based on Perfusion CT Imaging: Comparisons with Conventional Angiography and Quantitative Perfusion CT

“…An advantage of PCT over other screening tests such as transcranial Doppler includes its ability to calculate blood flow throughout the entire territory perfused by a cerebral artery, whereas transcranial Doppler is limited to the evaluation of proximal, large vessels only [7, 10]. Also, increases in blood flow velocities measured by transcranial Doppler do not always correlate with brain perfusion values and do not reliably determine the severity of the patient’s vasospasm [11, 12]. In contrast, different studies have reported PCT thresholds to diagnose and characterize the severity of vasospasm and thus stratify treatment [7,13,14,15].…”