MRI contrast enhancement by MnTPPS of experimental brain tumours in rats.

In the experimental F98 rat glioma model the nuclear magnetic resonance contrast agent MnTPPS was used to increase the contrast between tumour and peritumourous brain tissue. By evaluating pre- and postcontrast CPMG echo trains after different dose and circulation times of MnTPPS, the transverse relaxation time T2, the magnetization extrapolated to the time zero M (0), and the contrast ratio Rc of the magnetizations in neoplastic and normal tissues were determined. According to these data a maximum contrast is obtained a few hours after injection of 0.25 mmol MnTPPS/kg bw, using spin echo pulse sequences with short repetition times TR (1,100 ms), and short spin echo time TE (25 ms).