MR Images Study In The Middle Cerebral Artery Plaque

The patients with a symptomatic atherosclerosis of middle cerebral artery (MCA) are inhigh risk of future ischemic stroke. For those patients with a symptomatic plaque ofMCA,especially with a vunerable plaque,if we can detecte the plaque, decide its stabilityearlierly, evaluate whether the cerebral blood flow in the lesion areas supplied by the lesionside of MCA stenosis is low or not,and then select the reasonable therapy,the disability rateand death rate of this disease will be redused obviously.These problems must be solvedquickly by radiologists.High-Resolution Magnetic Resonance has been gradually used toevaluate middle cerebral artery atherosclerosis plaque with the merit of noninvasive,safe,good repeatable,good sensitivity and specificity. It can display the size and the internalcomponent of middle cerebral artery atherosclerosis plaque and reveal the relation betweenthis character of plaque and acute ischemic stroke. we use the capblity of multiple sequenceand multiple parameters imaging with3.0T MR scanner to analyse the components andclassification of middle cerebral arterry plaque, to evaluate the relationship between themiddle cerebral artery plaque burden and ischemic cerebrovascular events,and to comparethe cerebral perfusion of the lesion areas between the stable and vulnerable plaque. Thisstudy collected a total of40cases of TIA patients with unilateral cerebral middle arterysclerosis conformed by ultrasound,all patients were performed by Siemens Trio Tim3.0Tsuperconductive magnetic resonance imaging systems. We also have6health person ascontrol group. Compare the imagings and AHA~recommended classification,analyse thecomposition,classification and stability of the cerebral middle artery plaque;The total vesselarea (TVA), lumen area (LA), wall area (WA) and normalized wall index (NWI) weremeasured on T1WI,study the relationship between middle cerebral artery plaque burden andischemic cerebrovascular events;On the maps of MTT,TTP,CBF and CBV, the region ofinterest (ROI) was placed on anterior cortical watershed and posterior cortical watershed.The rMTT, rTTP,rCBF and rCBV ratio of the patients were calculated as stenotic sideagainst contralateral side.we divided patients with middle cerebral artery plaque into twogroups acoording to the imagings of plaque:stable plaque group and vunerable plaquegroup.The cerebral PWI of these two groups were evaluated.Through the statistics and analysis to get the following the results:(1)147sections and45middle artery sclerosis were detected by3.0T MR from former study,the number ofvunerable plaque (typeⅣ-Ⅴ a nd Ⅵ) were110(61.80%),stable plaque(typeⅠ~Ⅱ、 Ⅲand Ⅴc) were68个（38.20%), there was no significant bias between the two type of plaque indistribution (p=0.872)；(2)TVA and WA between Ischemia group and non-Ischemia groupwere significant difference(p＜0.05);TVA,WA and NWI between Ischemia group and controlgroup,non-Ischemia group and control group were significant discrepancy(p＜0.05);(3)TheMTT ratios of the anterior cortical watershed and posterior cortical watershed wereprolonged significantly in vulnerable paque group compared with stablegroup(t=0.43,P=0.017and t=0.046, P=0.006).3.0T MR scanner is capable of detecting the componenets of the middle cerebral arteryplaque through multiple sequence and multiple parameters. Total plaques were classifieddifferent groups according to AHA~recommended classification;there was relationshipbetween the middle cerebral artery plaque burdenand and ischemic cerebrovascularevents.we can use the total vessel area (TVA) and wall area (WA)evaluate the plaqueburdenand.For the patients with cerebra middle artery stenosis ranging above50%,Thestability of the middle cerebral artery plaque has close relationship with the perfusion ofrelativecortical watershed region, and MTT is the most sensitive parameter to detect theunilateral hypoperfusion.So MRI combined with PWI play an important role in clinicaldiagnosis and treatment.