NMR imaging and spectroscopy of experimental brain edema

A canine model of experimental brain edema utilizing the classic cold lesion technique was used to identify the optimal nuclear magnetic resonance (NMR) spin-echo imaging parameters needed to detect cerebral edema with maximum sensitivity. Each animal was studied with four separate spin-echo sequences, utilizing pulse intervals ranging from 0.5 to 2.0 seconds. The echo delays following each pulse interval were 28 and 56 msec. Cerebral edema was best identified with the longest pulse interval (2.0 seconds), and the second echo delay (56 msec). T1 and T2 relaxation values were obtained from in vitro spectroscopy. The relaxation times were prolonged in the edematous white matter; however, absolute T1 and T2 values proved of little use in comparing different animals.