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Background: Isolated middle cerebral artery dissection(MCAD)is an important but increasingly less rare cause of stroke in the young.Although several cases of dissections in the MCA have been reported,findings of high resolution magnetic resonance imaging(HRMRI)has less been evaluated alone.HRMRI at 3T is a valuable tool to evaluate the intracranial arterial wall and lumen using 3D-VISTA sequence which works as black blood imaging,due to its strong flow void effect.Besides,HR-MRI may therefore be helpful in further firming radiologists` confidences in diagnosis of MCAD.Purpose: To demonstrate initial radiologic characteristics of MCAD by HRMRI with symptomatic isolated MCAD.And to explore the additional benefits far from the basic DSA diagnosis of MCAD.Materials and methods: The respective institutional review boards approved this retrospective study and waived the need for informed consent because of the retrospective review of data.Patients all enrolled underwent digital subtraction angiography(DSA)within 2 weeks of symptom onset between June 2013 and May 2016.Angiographically and clinically confirmed,37 MCADs patients,who suffered acute/subacute infarction or transient ischemic attack(TIA)due to MCA M1 occlusion were recruited and underwent HR-MRI.A receiveroperating characteristic(ROC)analysis was conducted with a continuous rating scale from 1 to 100 to compare observer performance in MCAD detection.Five readers participated to analyze and assess patients` radiologic resource.Their performances with DSA were compared with that of using DSA and HRMRI images.these images of DSA and HRMRI were randomly analyzed.These readers were qualified ones with 10-15 years of radiologic experience in cerebrovascular diseases.Meanwhile,readers were blinded to the patients identities,clinical histories and radiologic diagnosis.Results: There were 19 men in the MCAD cohort with ages ranging from 21 to 56 years(median,45 years).HRMRI delineated intramural hematoma and double lumen in 25 and 14 patients,respectively,and intimal flap in 14,while gadolinium enhanced T1-weighted images(WI)visualized mural linear or intramural crescentic enhancement in all the patients.The observers found that the mean areas under the best-fit ROC curve for DSA images alone and fused DSA and HRMRI images were 0.63±0.05 and 0.91±0.14,which were significantly different(P<0.01).CONCLUDISION: HRMRI appears to delineate more features of MCAD clearly and then provides incremental information to the diagnosis of MCADs.The fusion images provided to further firm radiologists` confidences in diagnosis of MCAD.