The Clinical And Imaging Characteristics Of Different Types Of Internal Watershed Infarction

Objective:Through Internal Watershed Infarction(IWI)in patients with retrospective study,the analysis of risk factors of patients with different types of IWI,etiology,pathogenesis and clinical features,and discusses the relationship between IWI and collateral circulation for the occurrence and development of different types of IWI and corresponding theoretical foundation for clinical individualized,accurate treatment,so as to further improve the success rate of diagnosis and treatment of IWI.Methods:We collected 86 cases of IWI patients who were hospitalized in our hospital during January 2014 to June 2017.According to the imaging features of diffusion weighted magnetic resonance imaging function,the 86 cases were divided into three groups,including partial internal watershed infarction(PIWI)group,confluent internal watershed infarction(CIWI)group and beaded internal watershed infarction(BIWI)group.We recorded their clinical and imaging dates carefully.The correlative vessels were evaluated by magnetic resonance angiography、CT angiography or digital subtraction angiography.And we retrospectively analyzed the clinical and imaging characteristics including the general data,risk factors,etiology,pathogenesis and the relationships between IWI and collateral circulation.Results:(1)In 86 cases,there are 37(43.02%)cases PIWI,30(34.88%)cases CIWI and19(22.09%)BIWI.The clinical manifestation of IWI in 86 cases included hemiplegic paralysis accounts for 47,hemidysesthesia 18,aphasia 13,hemianopsia 3,cognitive disorder3,dysarthria 3,There were not significant difference among the three groups(P>0.05).And the gender,hypertension,diabetes mellitus,hyperlipidemia,history of smoking and previous stroke/TIA.There were not significant difference among the three groups(P>0.05).(2)Among the three groups,there are 66 cases(76.74%)with vascular stenosis or occlusion of the internal carotid artery system in the focus.Internal carotid artery(ICA)accounts for 21(24.41%),middle cerebral artery(MCA)27(31.39%),both ICA and MCA with stenosis or occlusion 18(20.93%).In PIWI group,there are 25 cases(67.58%)with vascular stenosis or occlusion of the internal carotid artery system in the focus.In CIWI group,there are 26 cases(86.67%)with vascular stenosis or occlusion of the internal carotid artery system in the focus and there are 15 cases(78.95%)with vascular stenosis or occlusion of the internal carotid artery system in the focus in the BIWI group.There were higher incidences of the stenosis or occlusion of the MCA in CIWI group(c~2=10.321,P=0.006).But in BIWI group,there were higher incidences of the stenosis or occlusion of the MC A and IC A(c~2=6.707,P=0.035).(3)In 86 cases,the proportions of light,medium and severe stenosis of the internal carotid artery system in the focus were 18 cases(20.93%),25 cases(29.07%)and 23cases(26.74%).In PIWI group,the proportions of light,medium and severe stenosis of the internal carotid artery system in the focus were 4 cases,11 cases and 10 cases.In CIWI group,the proportions of light,medium and severe stenosis of the internal carotid artery system in the focus were 12 cases,8 cases and 6 cases.In BIWI group,the proportions of light,medium and severe stenosis of the internal carotid artery system in the focus were 2cases,6 cases and 7 cases.There were higher incidences of the light stenosis in CIWI group(c~2=10.124,P=0.006)and there were higher incidences of the medium and severe senosis in both PIWI group and BIWI group(c~2=5.382,P=0.020,c~2=4.557,P=0.033).(4)In 86 cases,there are 58 cases(67.74%)with atherosclerotic plaque of the internal carotid artery in the focus.There are 20 cases(23.25%)with stable atherosclerotic plaque and 38 cases(44.19%)with unstable atherosclerotic plaque.Among the three groups,there are 18 cases(48.65%)with atherosclerotic plaque in the PIWI group,26cases(86.67%)in the CIWI group and 14 cases(73.68%)in the BIWI group.The differences among the three groups has statistical significance(c~2=11.338,P=0.003).Meanwhile,there are 8 cases(21.62%)with stable atherosclerotic plaque in the PIWI group,7 cases(23.33%)in the CIWI group and 5 cases(26.32%)in the BIWI group.The differences with stable atherosclerotic plaque among the three groups has no statistical significance(c~2=0.254,P=0.881).But there were 10 cases(27.02%)with stable atherosclerotic plaque in the PIWI group,19 cases(63.33%)in the CIWI group and 9cases(47.34%)in the BIWI group.The differences with unstable atherosclerotic plaque in the three groups has statistical significance(c~2=8.955,P=0.011).(5)In 86 cases,there were 80 cases(93.02%)with poor collateral circulation,including 41 cases(47.67%)anterior communicating artery(ACOA)were not open,28cases(32.56%)posterior communicating artery(PCOA)were not open and 11 cases(12.79%)both ACOA and PCOA were not open.In PIWI group,the proportions of unopen ACOA,PCOA,both ACOA and PCOA were 16 cases,14 cases and 2 cases.In CIWI group,the proportions of unopen ACOA,PCOA,both ACOA and PCOA were 18 cases,8cases and 3 cases.In BIWI group,the proportions of unopen ACOA,PCOA,both ACO A and PCOA were 7 cases,6 cases and 6 cases.Among the three groups,the differences with unopen both ACOA and PCOA has statistical significance(c~2=8.031,P=0.018).Conclusion:The clinical manifestations of patients with different types of IWI were comp licated.There were higher incidences of the CIWI with the stenosis or occlusion of the MC A and with the unstable atherosclerotic plaque of the internal carotid artery system in the focus.The occurrence of the CIWI may be closely related to the microembolus.There were higher incidences of the PIWI and BIWI with the medium and severe senosis of the internal carotid artery system and the occurrence of the PIWI and BIWI may be closely related to the hypoperfusion.There were higher incidences of the BIWI with the stenosis or occlusion of both the MCA and ICA.There were poor collateral circulation in patients with different types of IWI.