β Scribed by James E. Olson; Abi Katz-Stein; Nicholas V. Reo; Ferenc A. Jolesz
No coin nor oath required. For personal study only.
We developed a quantitative magnetic resonance imaging method to permit a rapid assessment of brain water content during osmotic brain edema produced by intraperitoneal (ip) injection of distilled water. Fifteen minutes after water injection, the normalized mean image intensity (MI~n~) from a spinβecho pulse sequence (TE = 80 ms, TR = 1085 ms) was the same as that measured from control animals not injected with water. Sixty minutes after the water injection, the mean Β± SEM brain image MI~n~ had increased by 10.8 Β± 2.4% compared to 3.4 Β± 0.7% in control animals (P < 0.05). Blood plasma osmolality decreased by 6β10% during this time interval. A subsequent ip injection of hypertonic NaCl solution (100 gm/liter) caused the blood plasma osmolality and brain image MI~n~ to return toward their initial values. MI~n~ of cerebral gray matter correlated with tissue water content measured in parallel studies. Animals pretreated with 0.25 mg/(kg day) dexamethasone had cerebral gray matter MI~n~ values during osmotic edema which were lower than those of untreated animals. Β© 1992 Academic Press, Inc.
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