| PartⅠ Characterization of Intracranial Atherosclerotic Unstable Plaque by High Resolution Magnetic ResonanceObjective: To study the vessel wall imaging features of middle cerebral arterial atherosclerotic plaque stability using high-resolution magnetic resonance(HR-MRI).The aim of this study was to explore the value of HR-MRI in the diagnosis of intracranial arterial atherosclerotic disease.Methods: Consecutive patients with cerebral atherosclerotic stenosis undergoing HR-MRI examination during the hospitalization in Changhai Hospital were collected during January 2015 and December 2016.The patients were divided into symptomatic and asymptomatic group according to acute cerebral infarction or TIA in the ipsilateral middle cerebral arterial territory.3D-TOF MRA,and vessel wall imaging of T1 WI,T2WI,STIR and T1 WI enhanced sequence in 3T MRI were performed in all patients.The extent of the stenosis and the imaging features,morphology and enhancement of the plaques were analyzed.Results: 116 consecutive patients were included in this study,of which 80 cases in symptomatic group and 36 cases in asymptomatic group.3D TOF MRA showed that the rate of severe stenosis and occlusion of the middle cerebral artery in the symptomatic group was significantly higher than those in the asymptomatic group(65%vs36.11%,P=0.009).Thirty-one(37.85%)patients had annular plaque and forty-nine(61.25%)arcuate plaque in symptomatic group.Thirty(83.33%)patients had arcuate plaque and six(16.7%)annular plaque in asymptomatic group.The ratio of annular plaques in symptomatic group was significantly higher than that in asymptomatic group(P=0.019).The plaques were obviously enhanced in 58 cases(72.5%),mild enhanced in 15(18.75%)and not enhanced in 7(8.75%)in symptomatic group and obviously enhanced in one case(2.78%),mild enhanced in 20(55.56%)and not enhanced in 15(41.56%)respectively in asymptomatic group.The plaque enhancement was significantly more common in symptomatic group than that in asymptomatic groups,(P < 0.001),while the rate of no enhancement or mild enhancement in the asymptomatic group were significantly higher than that in the symptomatic group(all P<0.001).However,there were no significant differences in the plaques signal types on T1 WI,T2WI,and STIR sequences between the symptomatic and asymptomatic groups(all P>00.5).Conclusion: HR-MRI can clearly display MCA atherosclerotic plaque.Plaques in symptomatic MCA stenosis are usual annular and obvious enhancement and those in asymptomatic MCA stenosis arcuate and mild or without enhancement.PartⅡ High Resolution Magnetic Resonance Imaging Study of Basilar Arteries in Isolated Pontine InfarctionObjective: Atherosclerotic plaques in basilar arteries of isolated pontine infarction were investigated by high-resolution magnetic resonance imaging(HR-MRI).Methods: Patients suffered from isolated pontine infarction who were underwent high resolution magnetic resonance imaging of basilar arteries in our stroke center during January 2014 and January 2017 were analyzed.To examine the BA basilar artery wall,3.0T HR-MRI sequences including T2 weighted imaging(T2WI),T1 weighted imaging(T1WI)and T1 enhancement scanning were performed.The plaque and its characteristics of basilar artery at the maximal stenosis between PPI(paramedian pontine infarction)and SDPI(small deep pontine infarction),were analyzed and compared.Results: Included in this study were 55 patients with acute isolated pontine infarction,37 with PPI and 18 with SDPI.The rates of basilar arterial atherosclerotic stenosis(≥50%)were 58.8% and 38.9%,respectively.There was no significant difference between PPI and SDPI(P=0.214).HR-MRI detected underlying atheromatous plaques without basilar arterial stenosis(branch atheromatous disease,BAD)in 14 of 16 patients(87.5%)with PPI,which was more common than that of patients with SDPI and without basilar arterial stenosis(16.7%,P=0.001).Compared with patients with SDPI,plaque enhancement in BAD was more frequently observed in PPI(35.1% vs 5.6%,P=0.018).Conclusion: Basilar arterial atherosclerosis is a common cause of both PPI and SDPI.BAD with plaque enhancement is frequently detected in PPI,but few in SDPI. |
