Abstract #2919

Ansiaux R, Crokart N, DeWever J, Feron O, Gallez B, Baudelet C, Cron G

Acute tumor hypoxia (~blood flow instabilities) can be investigated using signal fluctuations in dynamic T2*w gradient echo MRI. We compared histological measures of vascular density (CD31), tumor vessel immaturity (alpha-Smooth Muscle Actin immunoreactivity), and vessel functionality (Hoechst 33242) with 4.7T MRI measures of similar characteristics (MRI during air, 5% CO2, and carbogen breathing, respectively). The results show that adequate vessel functionality and advanced vessel maturation are not crucial factors involved in spontaneous T2*w GRE signal fluctuations, since a large fraction of fluctuations were observed to occur in non-perfused and/or immature vessels.