Prognostic impact of magnetic resonance perfusional study in cerebral metastases treated with radiosurgery

Radiosurgery arrests metastatic growth by means of vascular thrombosis that causes tumor necrosis. We therefore evaluated whether tumor hypervascularization (studied with perfusional magnetic resonance sequences) is a positive prognostic factor predicting radiosurgery outcome. Twenty-four metastases were studied before radiosurgery with perfusional MR and then post therapy clinical and morphological status was evaluated. The group of lesions responsive to radiosurgery had the highest mean rCBV value (23.3) in comparison to the non responding lesions (14.7) with a statistically significant difference (p<0.005). High vascularization for radio-treated metastases was a positive prognostic factor because the radiosurgery thrombosis effect was more effective. Pre-treatment MR rCBv evaluation is a useful tool to establish metastatic response to radiosurgery.