Diffusion-perfusion mismatch in symptomatic vasospasm after subarachnoid hemorrhage

Diffusion-weighted and perfusion-weighted magnetic resonance (MR) imaging were investigated as a method to detect diffusion-perfusion mismatch in the early stages of vasospasm in 17 patients with acute subarachnoid hemorrhage after aneurysm clipping. Single photon emission computed tomography (SPECT) with N-isopropyl-p-[(123)I]iodoamphetamine was also performed. Diffusion-perfusion mismatch was clearly identified in the 3 patients who manifested clinical deterioration. Perfusion-weighted imaging showed increased mean transit time, normal cerebral blood flow, and increased or normal cerebral blood volume. SPECT revealed no earlier signs of vasospasm. Diffusion-perfusion mismatch was clearly demonstrated in the early stages of vasospasm, so may be useful for early identification of ischemia in vasospasm and initiating appropriate treatment.