Multi-b Value Diffusion Weighted Imaging Combined With 3D-ASL In The Clinical Application Of Ischemic Cerebrovascular Disease

Objective:Through the use of more than b value of DWI technology combined with 3D-ASL technology,can the infarcts in patients with ischemic stroke and ischemi c half dark stripe for qualitative evaluation,explore the value of DWI b?b=1200s/mm²?1400 s/mm²?1600 s/mm²?1800 s/mm²?2000 s/mm²?than clinical commonl y used standard b value of DWI?b=1000 s/mm²?can,in better diagnostic value in ac ute ischemic stroke,and select the optimal value of b.Methods:Choose April 2018-September 2018 of 70 patients who was diagnosed of acute ischemic stroke for routine MRI scan,b value of DWI and 3D-ASL can scan,observation,the conventional MRI image of b value of DWI,3D-ASL can data and image processing,statistical analysis under different b values observed on the number of lesions and lesions of SNR,contrast to noise ratio,ADC values,lesions of side mirror area ADC values,the values of CBF and lesions of the contralateral CBF value image area.Results:When b=1800,2000 s/mm²,the number of lesions detected is slightly higher than when b=1000,1200,1400,1600 s/mm².When b=1000,1200,1400,1600 s/mm²,the number of lesions was similar,With the increase of b value,the signal-to-noise ratio and the contrast noise ratio of lesions on DWI showed a decreasing trend,both higher than that on T₂WI,and the differences were statistically significant;The SNR and CNR of DWI and T₂WI lesions were compared in pairs with different b values.When the b value was 1000 s/mm²,there was no statistical significance between the SNR and the b value of 1200 s/mm²?P<0.05?,and there was statistical significance between the SNR and the CNR with the b value of 1400,1600,1800 and 2000 s/mm²?P<0.05?;When b value is 1200 s/mm²,there is no statistical significance between b value and 1400 s/mm²?P<0.05?,and there is statistical significance between b value and 1600,1800 and 2000 s/mm²?P<0.05?.When b value is1400 s/mm²,there is no statistical significance between b value and 1600,1800 and2000s/mm²?P?29?0.05?.The ADC value in the infarct area was less than that in the contralateral mirror area under the condition of b value?P<0.05?,and the difference was statistically significant;The value of ADC in the ischemic penumbra region was less than that in the contralateral mirror region under the conditions of b value?P<0.05?,indicating a statistically significant difference;Under the conditions of b value and infarct area ADC value is less than that of ischemic penumbra area ADC value?P<0.05?,the difference has statistical significance.There was no significant difference between the selected b values in the ADC value of infarct area and the ADC value of contralateral mirror area?P?29?0.05?.There was no significant difference in the ADC values of ischemic penumbra band and contralateral mirror region between the selected b values?P?29?0.05?;The CBF value of the central infarct area was different from that of the mirror area on the opposite side,and the difference was statistically significant?P<0.05?.The value of CBF in the ischemic penumbra was compared with that in the contralateral mirror area?P<0.05?,and the difference was statistically significant.There was also a difference between the central infarct CBF value and the ischemic penumbra CBF value?P<0.05?,and the difference was statistically significant.Conclusion:Among the b values of 1000,1200,1400,1600,1800 and 2000 s/mm²,when the b value is 1400 s/mm²,the display and resolution of ischemic stroke lesions in DWI images can reach a relative equilibrium point,which can make the DWI image have the best display and resolution ability of ischemic stroke lesions.Therefore,the selected b value of1400 s/mm² in this study is better than the commonly used b value?1000 s/mm²?in displaying and resolving ischemic stroke lesions.When the b value is 1400 s/mm²,if the microscopic lesions cannot be observed and the clinical symptoms and signs of the patients are very obvious,the b value can be appropriately increased.Mb-DWI combined with 3D-ASL and the measurement of ADC value can objectively reflect the blood perfusion status of the acute cerebral infarction area,judge the presence of ischemic penumbra and define the range?...