Kirstie S. Opstad1, Simon P. Robinson2,
Franklyn A. Howe1
1Division of Cardiac & Vascular
Sciences, St. George's, University of London, London, United Kingdom; 2Cancer
Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer
Research, Sutton, United Kingdom
Vascular
disrupting agents (VDAs) reduce tumour blood flow and non-invasive methods of
monitoring are essential for brain tumours. Vessel size index (VSI) MRI was
used to determine effects of the Tumour-VDA ASA404 (vadimezan, formerly
AS1404, 5,6-dimethylxanthenone-4-acetic acid, DMXAA) on fractional blood
volume (fBV) and blood vessel size (Rv) in orthotopic C6 gliomas. We show a
post-treatment histogram shift towards reduced fBV and significant increase
in fBV<0.4%, consistent with vascular collapse; and large post-ASA404
reductions in fBV and Rv indicate development of necrosis. In conclusion, VSI
MRI appears effective in monitoring treatment effects of the Tumour-VDA
ASA404 on brain tumour vasculature.