The temporal evolution of diffusional kurtosis imaging in an experimental middle cerebral artery occlusion (MCAO) model

Purpose: Diffusional kurtosis imaging (DKI), as a non-Gaussian diffusion model, has been applied in human and animal studies of ischemic stroke. This study aimed to intensively characterize the temporal evolution of DKI-derived variables in an experimental middle cerebral artery occlusion (MCAO) model, and to explore its potential application in ischemic stroke.

Materials and methods: Eleven MCAO rats and ten control rats underwent DKI and diffusion weighted imaging (DWI) scans, at different time points of 0.5, 2, 6, 12, 24 and 72h after operation respectively. The infarct area in DKI- and DWI-derived variables was compared among different time points, and between different groups [INFARCTION, MIRROR, CONTROL-R (right side of the control group, the same side as in the infarction group), CONTROL-L (left side of the control group)] using repeated measures analysis of variance (ANOVA). The percent changes from normal to that in ischemic tissues and histology were also evaluated.

Results: In the infarct region, from 0.5 to 72h, MK, K∥, K⊥ demonstrated irregular high signal, whereas relative homogeneous low signals were revealed by MD, D∥, D⊥ and ADC. Compared with the MIRROR and CONTROL-R group, MK, K∥, K⊥ in the infarcted area increased aggressively which peaked at 12h and gradually decreased; MD, D∥, D⊥ and ADC decreased gradually until 12h and then began to increase gradually; FA decreased rapidly from 0.5 to 72h. MD, D∥ and ADC were significantly different between Mirror and CONTROL-L group (P<0.05).

Conclusion: DKI can provide more detailed information to describe ischemic lesion, and has great potential application in ischemic stroke.