Diffusional kurtosis imaging in evaluating progression of subacute stroke

GUO Yuelin; ZHANG Zhongping; ZHANG Guishan; KONG Lingmei; RAO Haibing; CHEN Wei; CHEN Xuan; SHEN Zhiwei; ZHENG Wenbin; WU Renhua

doi:10.19300/j.2017.L5739zt

Abstract：Objective This study aimed to identify the responsible lesions that may lead to progression in subacute ischemic stroke patients using diffusional kurtosis imaging (DKI) and the National Institutes of Health Stroke Scale (NIHSS)score,as well as to analyze the association between imaging findings and clinical features.Methods Seventy-nine patients with subacute cerebral infarction were divided into 4 groups according to neurological deterioration and lesion number:single infarction neurological deterioration negative group,single infarction neurological deterioration positive group,multiple infarction neurological deterioration negative group,and multiple infarction neurological deterioration positive group.For multiple infarction subjects,two independent ischemic lesions were selected in the same blood supplying areas on the same brain slice of the MD and MK maps,and the ROIs were outlined within the core region (ROI 1) and the surrounding region (ROI 2)respectively.All patients underwent cranial DKI and conventional MRI scan,then maps of diffusion (MD) and mean kurtosis (MK) were calculated.The MD,MK,and areas of lesions on parameter maps were measured and compared with Wilcoxon Signed Ranks Test.Scatter plots were used to describe the time-signal evolution.Result 1.lesion areas:The MD lesions were significantly larger than the MK deficits in the neurological deterioration positive group (P＜0.05),But no significant difference in the neurological deterioration negative group (P＞0.05).The proportion of MD/MK mismatch in the subacute ischemic stroke patients with neurological deterioration was 9.7％;however,this rate was only 0.2％ in the patients without neurological deterioration.2.Time-signal scatter plots:a.The single infarction group:The MD in the ischemic lesions was significantly decreased compared to the contralateral normal region,whereas the MK was significantly increased.The recovery trends in the neurological deterioration positive group were substantially slower than the negative one.The MD and MKvalues changed more in the neurological deterioration positive group than in the neurological deterioration negative group,and the magnitude of MK changed more than that of MD in both two groups,b.The multiple infarction group:The time-signal scatter plots of the MD and MK lesions in ROI 1 and ROI 2 of the multiple infarction neurological deterioration negative group were similar to the single infarction group;the trends of the time-signal scatter plots in ROI 1 and ROI 2 had good consistency.In the multiple infarction neurological deterioration positive group,the trends of time-signal scatter plots of the MDand MK lesion in ROI 1 were similar to the single infarction one;However,the time-signal scatter plots of the MD and MK lesion in ROI 2 exhibited non-homogeneous.Conclusion Significant MD/MK mismatch and heterogeneity of multiple ischemic lesions on MK in subacute ischemic stroke may relate to progression.