The Ratio of T2* and T1 Relaxivities in Experimental Cerebral Tumor and Normal Brain
Bagher-Ebadian H, Paudyal R, Ewing J
Henry Ford Health Systems
Five male Fischer rats with implanted cerebral tumors were studied at 7 Tesla using a Look-Locker inversion-recovery imaging sequence (TOMROP). ?2, the ratio of T2* to T1 relaxivities after injection of the contrast agent (Gadomer), was calculated. In the leaky tumor vascular bed, ?2 was a factor of 5.6 smaller than it was in the contralateral normal side. Thus, in vascular beds permeable to the contrast agent, this observation impacts all attempts to use T2* contrast as a measure of contrast agent concentration in estimating such physiological variables as blood flow, blood volume, and vascular permeability.