Kimberly R. Pechman1,2, Deborah L. Donohoe2,3,
Devyani Bedekar2,3, Kathleen M. Schmainda2,4
1Neurosurgery, Medical
College of Wisconsin, Milwaukee, WI, United States; 2Translational
Brain Tumor Research Program, Medical College of Wisconsin, Milwaukee, WI, United
States; 3Radiology, Medical College of Wisconsin, Milwaukee, WI,
United States; 4Radiology & Biophysics, Medical College of
Wisconsin, Milwaukee, WI, United States
Few systematic studies examined the influence of timing on efficacy of anti-angiogenic therapy for brain tumors. MRI measures of enhancing tumor volume are unreliable indicators of response since anti-angiogenic drugs decrease contrast enhancement. The purpose of this study was to evaluate rCBV, derived from DSC imaging, and ADC to determine whether the treatment effect is altered when given in later stages of tumor growth. The studies, performed in the U87 xenograft brain tumor model, demonstrate treating tumors earlier provides greater tumor inhibition but treating later maximally decreases rCBV. Each marker is sensitive to different or complementary aspects of tumor response.