Temporal Changes of the Apparent Diffusion Coefficients of Water and Metabolites in Rats With Hemispheric Infarction: Experimental Study of Transhemispheric Diaschisis in the Contralateral Hemisphere at 7 Tesla

Abstract

The purpose of the present study was to clarify the temporal changes of the apparent diffusion coefficients (ADCs) of cerebral metabolites during early focal ischemia using stimulated echo acquisition mode with short echo time at a 7 T magnet to assess the pathophysiology of the reduction in diffusion properties observed both in the ischemic cerebral hemisphere and in the contralateral hemisphere. The ADCs of metabolites in the infarcted hemisphere 1 hour and 3 hours after the onset of ischemia decreased with 25% and 29% for choline containing compounds (Cho), 16% and 26% for creatine and phosphocreatine (Cre), and 19% and 19% for N-acetylaspartate (NAA), respectively, compared with the ADC values 2 hours later in the contralateral hemisphere. There were decreases in the ADC of Cho, Cre, and NAA with 21%, 7%, and 18% 8 hours later, respectively, in the noninfarcted hemisphere, which suggested transhemispheric diaschisis in rats with focal cerebral ischemia. The present study proposed that the diffusion characteristics of the brain metabolites might offer new insights into circulatory and metabolic alteration in the cerebral intracellular circumstance.

Quantitative Imaging of Cerebral Blood Flow Velocity and Intracellular Motility using Dynamic Light Scattering–Optical Coherence Tomography

“…[36][37][38][39] For instance, our observation of a decrease in IM of organelles is closely related to the decrease in diffusion of metabolites during and immediately after ischemic stroke, as observed by diffusionweighted magnetic resonance imaging. [40][41] More detailed analysis of neuronal IM variation with ischemic stroke and its relation to tissue infarction using cellular-resolution DLS-OCT imaging will be the subject of subsequent studies.…”

Effect of osmotherapy with hypertonic saline on regional cerebral edema following experimental stroke: a study utilizing magnetic resonance imaging

“…Over the years, mechanisms such as impedance of cerebral venous return from cerebral swelling, intrahemispheric diaschisis [36], increased BBB permeability by inflammatory mediators [37], role of neurohormones such as arginine-vasopressin [34,38], induction of growth factors [39], have been shown to be important contributors to ischemia-evoked cerebral edema.…”

Apparent Diffusion Coefficients of Metabolites in Patients with MELAS Using Diffusion-Weighted MR Spectroscopy

“…As a result, there are few published studies and these focus mainly on healthy volunteers and patients with acute cerebral infarction. [10][11][12][13][14][15][16] According to the published research, the ADCs of NAA, Cr, and Cho reduce significantly in the acute phase of cerebral ischemia. 11,[14][15][16] These studies have indicated that DW-MR spectroscopy is a useful noninvasive technique in detecting pathologic changes in the intracellular environment.…”