Detection of an unkown peak at 1.2 ppm in proton magnetic resonance spectra of cats with cerebral ischemic necrosis.

Objective: To confirm an unknown peak (Pu) in proton magnetic resonance spectra ((1)H-MRS) in cats with permanent focal cerebral ischemia, and surmise its potential value of application.

Methods: After focal cerebral ischemia, diffusion-weighted imaging (DWI) was used to identify regions of ischemia for (1)H-MRS voxel localization with the assistance of stereotaxic atlas of cat brain. (1)H-MRS was used to monitor the progression of focal cerebral ischemia in 6 cats over a period of 7 d following middle cerebral artery occlusion (MCAO). The changes in lactate, N-acetyl-aspartate (NAA), choline, creatine, and Pu were observed.

Results: In the involved regions, lactate was elevated almost immediately after the onset of cerebral ischemia, and NAA declined within several hours of acute infarction. The Pu at 1.2 ppm was persistently detected in the affected cerebral areas 2 to 7 d after MCAO.

Conclusion: Pu has a close relationship with cerebral ischemia necrosis and may be a intrinsic production of the necrotic tissue, which can be utilized as a specific marker and therefore has important clinical diagnostic value.