Repetitive Computed Tomography Perfusion for Detection of Cerebral Vasospasm-Related Hypoperfusion in Aneurysmal Subarachnoid Hemorrhage.

Background: Delayed cerebral infarction after aneurysmal subarachnoid hemorrhage (aSAH) still remains the leading cause of disability in patients that survive the initial ictus. It has been shown that computed tomography perfusion (CTP) imaging can detect hypoperfused brain areas. The aim of this study was to evaluate if a single acute CTP examination at time of neurologic deterioration is sufficient or if an additional baseline CTP increases diagnostic accuracy.

Methods: Retrospective analysis of acute and baseline (within 24 hours after aneurysm treatment) CTP examinations of patients with neurologic deterioration because of vasospasm-related hypoperfusion. Patients without clinical deterioration during the vasospasm period served as control subjects. The following CTP parameters were analyzed for predefined brain regions: time to drain (TTD), mean transit time, time to peak, cerebral blood flow, and volume.

Results: Thirty-three patients with and 23 without neurologic deterioration were included. Baseline CTP examination did not ameliorate diagnostic accuracy of the acute CTP examination in symptomatic patients. The same was true for interhemispheric comparison of perfusion parameters of the acute examination. The CTP parameter with the highest diagnostic yield was TTD of the symptomatic brain region (threshold value, 4.7 seconds; sensitivity, 97%; specificity, 96%).

Conclusions: Acute CTP examination in case of suspected vasospasm-induced neurologic deterioration after aSAH has the highest diagnostic accuracy to detect misery perfusion. Additional baseline CTP is not needed. The most sensitive parameter to detect critically perfused brain areas is TTD.