Non Tumor Perfusion Changes Following Stereotactic Radiosurgery to Brain Metastases

Raphael Jakubovic; Arjun Sahgal; Mark Ruschin; Ana Pejović-Milić; Rachael Milwid; Richard I Aviv

doi:10.1177/1533034614600279

Non Tumor Perfusion Changes Following Stereotactic Radiosurgery to Brain Metastases

Technol Cancer Res Treat. 2015 Aug;14(4):497-503. doi: 10.1177/1533034614600279.

Authors

Raphael Jakubovic¹, Arjun Sahgal², Mark Ruschin², Ana Pejović-Milić³, Rachael Milwid⁴, Richard I Aviv⁵

Affiliations

¹ Department of Medical Imaging, Division of Neuroradiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada Department of Biomedical Physics, Ryerson University, Toronto, Ontario, Canada.
² Department of Radiation Oncology, Odette Cancer Centre of the Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
³ Department of Biomedical Physics, Ryerson University, Toronto, Ontario, Canada.
⁴ Department of Medical Imaging, Division of Neuroradiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
⁵ Department of Medical Imaging, Division of Neuroradiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada richard.aviv@sunnybrook.ca.

Abstract

Purpose: To evaluate early perfusion changes in normal tissue following stereotactic radiosurgery (SRS).

Methods: Nineteen patients harboring twenty-two brain metastases treated with SRS were imaged with dynamic susceptibility magnetic resonance imaging (DSC MRI) at baseline, 1 week and 1 month post SRS. Relative cerebral blood volume and flow (rCBV and rCBF) ratios were evaluated outside of tumor within a combined region of interest (ROI) and separately within gray matter (GM) and white matter (WM) ROIs. Three-dimensional dose distribution from each SRS plan was divided into six regions: (1) <2 Gy; (2) 2-5 Gy; (3) 5-10 Gy; (4) 10-12 Gy; (5) 12-16 Gy; and (6) >16 Gy. rCBV and rCBF ratio differences between baseline, 1 week and 1 month were compared. Best linear fit plots quantified normal tissue dose-dependency.

Results: Significant rCBV ratio increases were present between baseline and 1 month for all ROIs and dose ranges except for WM ROI receiving <2 Gy. rCBV ratio for all ROIs was maximally increased from baseline to 1 month with the greatest changes occurring within the 5-10 Gy dose range (53.1%). rCBF ratio was maximally increased from baseline to 1 month for all ROIs within the 5-10 Gy dose range (33.9-45.0%). Both rCBV and rCBF ratios were most elevated within GM ROIs. A weak, positive but not significant association between dose, rCBV and rCBF ratio was demonstrated. Progressive rCBV and rCBF ratio increased with dose up to 10 Gy at 1 month.

Conclusion: Normal tissue response following SRS can be characterized by dose, tissue, and time specific increases in rCBV and rCBF ratio.

Keywords: Brain; Cancer; Dynamic susceptibility; Imaging; MR perfusion; Metastases; Normal tissue response.

MeSH terms

Brain Neoplasms / blood supply*
Brain Neoplasms / diagnosis
Brain Neoplasms / secondary
Brain Neoplasms / surgery*
Cerebrovascular Circulation*
Female
Humans
Magnetic Resonance Imaging
Male
Radiometry / methods
Radiosurgery* / methods
Radiotherapy Dosage