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Following treatment for aneurysmal subarachnoid hemorrhage, increased cerebral perfusion heterogeneity is an independent predictor of poor clinical outcome, Finnish researchers report.

Following treatment for aneurysmal subarachnoid hemorrhage (SAH), increased cerebral perfusion heterogeneity is an independent predictor of poor clinical outcome, Finnish researchers report in the October issue of the Journal of Neurology, Neurosurgery and Psychiatry.

"Very interestingly," lead investigator Dr. Esko Vanninen told Reuters Health, "measurement of cerebral perfusion heterogeneity seems to add significant prognostic information beyond the routinely used clinical classification, and it is associated with long-term ischemic MRI findings."

Dr. Vanninen of Kuopio University Hospital and colleagues note that SAH may be associated with an acute global and regional decrease in cerebral perfusion. Cerebral vasospasm may also lead to delayed ischemic deficits.

The team also observes that in earlier work, they determined that relative dispersion as measured by single-photon emission tomography (SPET), an indicator of the spatial heterogeneity of regional perfusion, was markedly greater in SAH patients than in healthy controls.

In the current study, the team sought to determine whether the heterogeneity of perfusion before and 1 week after treatment of the ruptured aneurysm was of value in predicting outcome.

The investigators used SPET to examine 384 brain regions of interest in each of 55 patients.

High perfusion heterogeneity following treatment was an independent predictor of poor to moderate clinical outcome (odds ratio, 1.96). These findings also correlated with those of several neuropsychological tests after a year.

Moreover, patients who had focal lesions as determined by MRI at 12 months had a higher degree of heterogeneity in both SPET studies than did other patients.

"These findings," Dr. Vanninen concluded, "potentially make it possible to define a group of high-risk patients who need more intensive therapeutic interventions. The methodology might be also applicable to other acute cerebrovascular incidents such as stroke."

J Neurol Neurosurg Psychiatry 2008;79:1128-1133