AUTHOR=Shi Liwei , Yu Bo , Chen Qiuyan , Zheng Tianxiu , Xing Peiqiu , Wei Dingtai 

TITLE=Heterogeneity evaluation of multi-high b-value apparent diffusion coefficient on cerebral ischemia in MCAO rat

JOURNAL=Frontiers in Neuroscience

VOLUME=16

YEAR=2022

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2022.1048429

DOI=10.3389/fnins.2022.1048429

ISSN=1662-453X

ABSTRACT=<sec><title>Purpose</title><p>To assess brain damage in a rat model of cerebral ischemia based on apparent diffusion coefficient (ADC) data obtained from multi-high <italic>b</italic>-values and evaluate the relationship between Aquaporin 4 (AQP4) expression and ADC.</p></sec><sec><title>Methods</title><p>Thirty eight male Sprague–Dawley rats were randomized into two groups: (1) sham controls (<italic>n</italic> = 6) and (2) cerebral ischemia (successful model, <italic>n</italic> = 19). All rats underwent diffusion-weighted imaging (DWI) with both standard <italic>b</italic>-values and multi-high <italic>b</italic>-values (2,500–4,500 s/mm<sup>2</sup>) using a 3.0-T device. Standard ADC (ADC<sub>st</sub>) maps and multi-high <italic>b</italic>-value ADCs (ADC<sub>mh</sub>) were calculated, respectively. Aquaporin 4 expression was quantified using Western blot. Relative values of ADC<sub>st</sub> and ADC<sub>mh</sub>, AQP4 expression were compared between the sham group and the ischemia group. Correlations between ADC values and AQP4 expression were evaluated.</p></sec><sec><title>Results</title><p>At 0.5 h after suture insertion, the value of ADC<sub>mh</sub> on the lesion was obviously decreased, and there was no difference in lesion volume when compared with ADC<sub>st</sub>. After reperfusion, besides similar regions where ADC<sub>st</sub> values decreased, we also found additional large values on ADC<sub>mh</sub> within the cortex of the ipsilateral side or surrounding the lesion. The lesion evolution of the large value on ADC<sub>mh</sub> was quite different from other indicators. But the total ADC<sub>mh</sub> values were still significantly associated with ADC<sub>st</sub>. The AQP4 protein expression level was appreciably increased after middle cerebral artery occlusion (MCAO), but there was no correlation between AQP4 expression either with ADC<sub>mh</sub> or ADC<sub>st</sub>.</p></sec><sec><title>Conclusion</title><p>We found the large values on ADC<sub>mh</sub> during the progression of cerebral infarction is varied, but there was no correlation between ADC<sub>mh</sub> values and AQP4 expression. ADC<sub>mh</sub> may indicate the heterogeneity of ischemia lesions, but the underlying pathological basis should be further explored.</p></sec>