Perfusion-weighted magnetic resonance imaging in patients with vasospasm: a useful new tool in the management of patients with subarachnoid hemorrhage.

OBJECTIVE: Cerebral vasospasm (VSP) is one of the most important risk factors for the development of a delayed neurological deficit after subarachnoid hemorrhage (SAH). Perfusion-weighted magnetic resonance imaging (pwMRI) provides the possibility of detecting tissue at risk for infarction. The objective of our study was to evaluate the feasibility and impact of pwMRI in the management of SAH patients. METHODS: From a consecutive series of 180 patients experiencing SAH and treated at our institution over a 3-year period, we identified 20 who underwent pwMRI during their acute illness. For these 20 patients, the results of pwMRI were compared with the results of diffusion-weighted MRI, transcranial Doppler sonography, and neurological examinations performed at the same time and with repeated pwMRI examinations of the same patient at different times. RESULTS: Nineteen of 20 patients showed perfusion changes predominantly in the time maps. Fifteen of 19 patients with changes in pwMRI had a neurological deficit at the same time. In 7 of 15 patients with neurological deterioration, transcranial Doppler sonography showed signs of VSP, whereas all 15 patients showed alterations in pwMRI. The areas of perfusion changes in pwMRI correlated well with the neurological deficits of the patients and were larger than the areas of changed diffusion in diffusion-weighted MRI performed at the same time. There were no clinical complications with regard to the pwMRI examinations. CONCLUSION: pwMRI is safe and helpful in the management of patients with VSP after SAH. The sensitivity of pwMRI is higher than that of transcranial Doppler sonography in the detection of decreased perfusion as a result of VSP. pwMRI can detect tissue at risk before definitive infarction occurs and therefore may lead to a change of therapy in those patients.