Is myo-inositol a measure of glial swelling after stroke? A magnetic resonance study.

OBJECTIVE

To determine whether the hypothesis that the phenomenon of persistent cytotoxic edema in the subacute stage of ischemic stroke is in fact associated with the glial population. This is done by assessing the evolution of both the apparent diffusion coefficient (ADC) and the glial-specific marker myo-inositol (Ins) in a group of patients, and by comparing the results with the total cellular density by means of the creatine (Cre) level.

METHODS

Twenty-two patients with stroke in the territory of the middle cerebral artery were each examined once only at a time ranging from eight hours to six days following the onset of symptoms. Lesion-to-contralateral values of ADC were obtained based on diffusion-weighted echo-planar imaging. Short TE single-voxel proton magnetic resonance ((1)H MR) spectroscopy was used for quantification of cerebral metabolites in infarcted regions. Their levels were also compared with those in homotopic contralateral regions.

RESULTS

In the stroke lesion, there was a significant correlation between ADC and the Ins level, albeit less pronounced than that for Cre. During different pathophysiological stages between 12 hours and three days, the Ins-to-Cre ratio increased by a factor of two and returned to apparently normal thereafter.

CONCLUSIONS

Our study provides the first demonstration of a relationship between persistent cytotoxic edema and the glial population in the context of cell swelling due to osmotic imbalance in stroke patients.