Preliminary Study On Clinical Application Of Diffusion Kurtosis Magnetic Resonance Imaging In Early Ischemic Stroke

Part1 The repeatability of diffuse kurtosis imaging on the brain tissue in healthy adultsObjective:To study the repeatability of DKI on the brain tissue healthy adults.Materials and methods: Twenty-six healthy volunteers aged from 23 to 60 years were enrolled into this present study.All enrolled subjects were scanned with the DKI on their head and b values of 0,1000 and 2000 s/mm2 were applied.And the The gradient direction is 30.After two radiologists measured MD?MK?RK?AK images obtained by the post-processing of DKE software at different periods,SPSS 24.0software was used for statistical analysis to observe the consistency within and among physicians.Results:The consistency analysis of MD?MK?RK and AK values obtained by the two physicians in the measurement of the knee of the corpus callosum,the compression of the corpus callosum,the forelimb of the internal capsule,the hind limb of the internal capsule and the thalamus at different time periods showed no statistically significant difference in the measurement values of the same physician at different time periods(P > 0.05).There was no statistically significant difference between the measured values seen by different physicians(P>0.05).Conclusions:Diffuse kurtosis imaging of adult brain tissue has good repeatability,and brain DKI has reliable application value in clinical diagnosis.Part 2 Magnetic resonance diffusion kurtosis imaging in early acute ischemic strokeObjective: in this study,DKI was used in patients with early acute ischemic stroke to observe the changes of DKI parameters with time;to explore RESOLVE to evaluate the core infarct area;to explore the value of DKI in the diagnosis and prognosis of patients with early acute ischemic stroke.Materials and methods: A total of 38 patients with early acute ischemic stroke in our hospital from September 2018 to February 2020 were collected,including 23 males and 15 females.All patients were examined for cranial MRI within 3 days of onset,and were divided into three groups according to the time of onset: the hyperacute group,the acute group,and the subacute early group.Among them,13 patients in the acute stage(within 24 hours of onset)were reexamined for routine and DKI sequences of cranial MRI 30 days after onset,and the same level as the first scan was maintained when reexamined.Data measurement and statistics: Image J software was used to analyze the parametric graph data and record the measurements.SPSS 24.0 software package was used for statistical analysis,and the measurement data obtained after numerical analysis conformed to normal distribution.Follow-up of FLAIR final infarct volume and first MK,RESOLVE-DWI map lesion volume correlation analysis,using Spearman correlation analysis for testing.The above statistical results were statistically different when P < 0.05.Results: 1.Early acute ischemic stroke lesions showed heterogeneous hyperintensity in MK,and the corresponding lesions showed relatively uniform hypointense on MD,AD,RD,RESOLVE-ADC maps;the contours and internal signal homogeneity of acute ischemic lesions in corpus callosum,white matter of brain,subcortical gray matter showed the best on MK maps.2.The change trend of MK,RK and AK values in the lesion area was basically the same.After ischemia,the value was higher than that in the mirror side,and the increase was the largest in the acute phase.The change trend of MD,RD and AD values in the lesion area was basically the same.After ischemia,the value was lower than that in the mirror side,and the decrease was the largest in the acute phase.P <0.05 for lesion side and mirror side in each period.The percentage change rate of diffusion kurtosis parameters(MK,AK,RK)on the side of infarct lesion in each period was higher than that of traditional diffusion tensor parameters(MD,AD,RD),and the change rate of axial kurtosis diffusion parameter AK was the largest.3.The volume of abnormal areas in follow-up FLAIR was positively correlated with that in acute phase MK and RESOLVE-DWI,and the volume of lesions in acute phase DKI was better correlated with that in follow-up reexamination FLAIR than that in RESOLVE-DWI(r=0.929,0.868,P<0.01,respectively).Conclusion: DKI can provide more information than traditional diffusion imaging.In DKI,the parameters of hyperacute,acute and subacute ischemic stroke have a characteristic time-dependent evolution pattern,and the parameters of the acute stage change most significantly.DKI can provide more diffusion information related to pathological evolution.DKI is easier to detect signal changes in early ischemic stroke lesions than traditional diffusion imaging.The abnormal signal area of MK map is helpful to predict the final infarct area,and DKI has great potential in the application of ischemic stroke.