Early Accumulation of 1H MRS Detected Lipids and Lactate in Rat 9L Glioma to Anti-Angiogenic Treatment

Enrico C. Lallana¹, Kyle A. Brong², Khan Hekmatyar¹, Neil Jerome¹, Martin Wilson³, Camilo E. Fadul¹, Risto A. Kauppinen⁴

A rodent anti-VEGF-antibody, B20-4.1.1, was used to treat orthotopic 9L glioma bearing rats. During the first week of treatment kinetics of T1-weighted signal enhancement following rapid Magnevist iv-bolus slowed down greatly, reflecting reduced vascular leakiness and perfusion. At the same time, 1H MRS showed large increase both in relative lactate and 1.3ppm and 0.9ppm lipids, while water diffusion in treated gliomas was unchanged. These results indicate that 1H MRS provides endogenous imaging biomarkers for tumour cell responses during anti-angiogenic therapy, that are not obtained by contrast enhanced MRI or diffusion.