Clinical outcomes of brain metastases treated with Gamma Knife radiosurgery with 3.0 T versus 1.5 T MRI-based treatment planning: Have we finally optimised detection of occult brain metastases?

Introduction The goal of this study was to determine if clinically relevant endpoints were changed by improved MRI resolution during radiosurgical treatment planning. Methods and Materials Between 2003 and 2008, 200 consecutive patients with brain metastases treated with Gamma Knife radiosurgery (GKRS) using either 1.5 T or 3.0 T MRI for radiosurgical treatment planning were retrospectively analysed. The number of previously undetected metastases at time of radiosurgery, distant brain failures, time delay to whole brain radiotherapy (WBRT), overall survival and likelihood of neurological death were determined. Results Additional metastases were detected in 31.3% and 24.5% of patients at time of radiosurgery with 3.0 T and 1.5 T MRI, respectively (P = 0.27). Patients with multiple metastases at diagnostic scan were more likely to have additional metastases detected by 3.0 T MRI (P