MRI evaluation of the effects of whole brain radiotherapy on breast cancer brain metastasis.

摘要: PURPOSE To assess early changes in brain metastasis response to whole radiotherapy (WBRT) by longitudinal Magnetic Resonance Imaging (MRI). MATERIALS AND METHODS Using a 7T system, MRI examinations of metastases breast cancer MDA-MD231-Br mouse model were conducted before and 24 hours after 3 daily fractionations 4 Gy WBRT. Besides anatomic MRI, diffusion-weighted (DW) dynamic contrast-enhanced (DCE) applied study cytotoxic effect blood-tumor-barrier (BTB) permeability change, respectively. RESULTS Before treatment, high-resolution T2-weighted images revealed hyperintense multifocal lesions, many which (∼50%) not enhanced on T1-weighted contrast images, indicating intact BTB the metastases. While no difference number new lesions was observed, WBRT-treated tumors significantly smaller than sham controls (p < .05). DW detected significant increase apparent diffusion coefficient (ADC) WBRT (p < .05), correlated with elevated caspase staining apoptotic cells. Many remained non-enhanced post However, quantitative DCE analysis showed higher parameter, Ktrans, group despite marked spatial heterogeneity. CONCLUSIONS allowed non-invasive assessments induced permeability, may provide useful information for potential combination treatment.