UCLA

The purpose of the current study was to quantify the reduction in T2 signal abnormality accompanying administration of the anti-angiogenic drug bevacizumab in recurrent glioblastoma (GBM) patients using a voxel-wise differential quantitative T2 (DQT2) mapping technique. Twenty-six patients with recurrent GBM treated with bevacizumab were scanned before and 4-6 weeks after treatment on a 1.5T clinical MR scanner. Quantitative T2 maps were created from proton density and T2-weighted images acquired using a standard multi-echo fast-spin echo sequence. T2 maps after treatment were co-registered with T2 maps prior to treatment in the same patient, and then voxel-wise subtraction was performed to create DQT2 maps for each patient. Results suggest DQT2 maps allow visualization and quantification of voxel-wise T2 changes resulting from anti-VEGF therapy. Results demonstrated a significant decrease in T2 within pre-treatment T2 abnormal regions (mean reduction = 49.4 ms at 1.5T) following anti-VEGF treatment (Wilcoxon signed rank test, P < 0.0001). An elevated residual, post-treatment, median T2 was predictive of both progression-free (Log-rank, P = 0.0074) and overall survival (Log-rank, P = 0.0393).