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 journalArticle

3 Scopus citations

Abstract

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, Ktrans, 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 (US)
JournalInternational Journal of Radiation Biology
DOIs
StateAccepted/In press - Jan 1 2018

Keywords

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

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

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