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

William Crowe, Lulu Wang, Zhongwei Zhang, Jasmina Varagic, J. Daniel Bourland, Michael D. Chan, Amyn A. Habib, Dawen Zhao

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


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

Original languageEnglish
Pages (from-to)338-346
Number of pages9
JournalInternational Journal of Radiation Biology
Issue number3
StatePublished - Dec 6 2018


  • Brain metastasis
  • blood-tumor-barrier (BTB)
  • diffusion-weighted (DW) MRI
  • dynamic contrast-enhanced (DCE) MRI
  • volume transfer coefficient Ktrans
  • whole brain radiotherapy (WBRT)


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