Qualitative Perfusion-Computed Tomography and Vasospasm-Related Infarction after Subarachnoid Hemorrhage

Abstract

To prospectively assess if alterations in cerebral perfusion as seen by perfusion-computed tomography (PCT) color-maps are associated with vasospasm-related infarction after subarachnoid hemorrhage (SAH). Ten consecutive patients were assigned to regularly scheduled PCT screening exams during two weeks posthemorrhage (total of 36 studies). Radiographic outcomes were defined for each vascular territory as either presence of vasospasm- related cerebral infarction or absence of delayed infarction on non-enhanced CT. Cerebral perfusion encoded by PCT color maps was compared between groups by means of χ2-statistics. Qualitative assessments were obtained from two blinded investigators. Of ten patients, three developed vasospasm-related delayed cerebral infarctions. Prior to the CT-diagnosis of vasospasm-related cerebral infarction, affected vascular territories showed a delay in the time-to-peak (TTP) parameter of PCT more frequently than unaffected territories (50% vs. 17.5%, p = 0.02); no difference was observed for cerebral blood flow (CBF) and cerebral blood volume (CBV). By the time of diagnosis of infarction on non-enhanced CT, findings for qualitative perfusion data were as expected in irreversible cerebral ischemia (i. e. decreased CBF and prolonged TTP). PCT color-maps may be useful for the evaluation of patients in the course of subarachnoid hemorrhage because a delay of TTP seems to be associated with vasospasm and subsequent infarction.