Dynamic Changes Of Intramural Hematoma In Head And Neck Artery Dissection Based On High Resolution Magnetic Resonance Imaging

Objective: To explore the dynamic changes of lumen and wall in intracranial and extracranial arterial dissection by applying high resolution magnetic resonance imaging(HRMRI).The purpose is to provide imaging evidence for the degree of repairing of the arterial dissection and the duration of the drug treatment.Methods and materials: We prospectively investigated 13 patients with acute stroke caused by intracranial and extracranial arterial dissection which diagnosed and followed by HRMRI in the First Affiliated Hospital of Fujian Medical University from January2015 to February 2019.Follow-up time is 90-730 days.Clinical features,initial imaging features and dynamic changes in HR-MRI including signal intensity of intramural hematoma,maximal wall thickness,intramural hematoma absorption residual and influencing factors were assessed.Results :(1).Baseline clinical and imaging features: 13 patients(12 males and 1 female),15 cerebral artery dissection segments(10 internal carotid arteries,4 vertebral arteries,1 basilar artery),The most common clinical presentation were unilateral limb weakness in 8 cases(61.5%).Intramural hematoma was the most common direct sign of the dissection,and all hematomas were high-signal,12-segment lumen(80%)showed positive remodeling,all lumen have different degrees of stenosis,mainly severe stenosis.(2)Dynamic changes of HRMRI follow-up: The signal changes of intramural hematoma were most obvious in the T1 WI sequence.(1)Hematoma signal:The signal intensity of the intramural hematoma was gradually attenuated by hyper-,iso-and hypointense.(2)Intramural hematoma absorption: All hematomas were absorbed at different degrees after the follow-up,The residual degree was ?1 grade(n=8,53.3%)of which 0(13.3%)were completely absorbed and 1(40%)were basic absorbed,residual degree was =2(n=7,46.6%).Good absorption rate of intramural hematoma was 26.6% at 3 month,46.6% at 6 months,and 55.5% at12,18and24 months.(3)Influencing factors of hematoma absorption:According to the absorption of intramural hematoma at 6 months of follow-up,it was divided into 2 groups(well-absorbed group,residual degree was ?1 grade,n=7;bad-absorbed group,residual degree was =2,n=8).There were no significant differences in age,gender,vascular risk factors and clinical presentation between the two groups(P>0.05).The initial maximum wall thickness of the well-absorbed group was is thinner than the bad group(P<0.05).The thicker the wall,the slower the absorption.Conclusion: HRMRI can demonstrate the dynamic changes of lumen and wall in dissection therefore provides a more accurate examination for the diagnosis of cerebral artery dissection.intracranial and extracranial arterial dissection can be spontaneously repaired,mainly in 1 year,most commonly within 6 months.The absorption rate of intramural hematoma is affected by the initial maximum wall thickness.The thicker the wall,the slower the absorption.The follow-up of the arterial dissection using HRMRI can determine the degree of repair of the arterial dissection and guide the duration of subsequent drug use.