| Objective: To study the use of MR imaging in diagnosis animal's atherosclerotic plaque and to evaluate the characterization of atherosclerotic plaque.Methods: Ten adult New Zealand rabbit were divided into three groups .Control group was 2 ; practice No.(1) was 6; practice No. (2) was 2. All the practical animal's was done with by aortic balloon endothelial injury .The animals were anesthetized , whose four limbs were fixed . Balloon-induced arterial wall injury of the aorta was performed with a 3.5F fogarty catheter introduced through a right femoral artery cutdown. The balloon was then inflated with 0.5 ml saline, and the catheter was gently retracted to the iliofemoral artery.Animals were fed a high cholesterol diet (1.5g) incorporated into the rabbit chow (made in navy research ) immediately after balloon injury and continuing for 10 weeks. The control group was fed basic food .Practical NO.2 was injected Vit D on11week, 12week.The control group and the practical group was examined by MR CT and ultrasound after 13weeks .The atherosclerotic plaque was located and analyzed .MR CT and ultrasound was be compared and analyzedAfter the examination was done ,animal was killed The aorta was separated and fixed for pathological study .Comparing with the examination imaging ,characterization of atherosclerotic plaque components was observed including narrow of the aorta.Software SPSS 8.0 was taken for the analysis ,after counting all the pathology of plaque or not. x~2 was measured for the ration's differenceResult:1. Confirming injuryAfter balloon injured ,one animal was killed and the aorta was made for 50 pathology. 37 was found that endepidermis was injured .The injured ratio was 74%.2. cholesterol in blood changeAt 2 , 5 , 10weeks during high cholesterol diet, blood was get and analysis (P < 0.01) . Cholesterol' s increasing with the weeks fling out was proved.3.the ratio of ASAfter all the examination was over the pathology was made .Fat plaque and fibrous plaque was measured respectively . The Fat plaque' s ratio was 9.64% and the fibrous plaque' s ratio was 1.56%.Traverse pathology was made and the number was 109. x analysis was taken and x~2 =17.1468, (P < 0.0001) showed that the control' s groups and practical' s groups has the predominant difference.4. Characterization of ASAtherosclerotic plaque was found in all the practical animal and calcification was found in the practical NO. (2) The control group's aortal wall was soft The typical atherosclerotic plaque was observed in all the experimental animal. White swell and stiff was the atherosclerotic plaque's characterize .After the red oil tinct the atherosclerotic plaque was observed as red swell. The experimental group endodermis cell was obviously hyperplasia. In the fibrin cap we can see a lot of foam cell get together and stick to blood vessel that was the typical vulnerable plaque .5.AS' characterization on imaging5.1 MRI The normal blood vessel was shown concatenation and smooth in MRI and media of wall was clear. All plaque was showed deflect in high intensity of vessel lumen on TOF sequence. The thickness of plaque was about 0.5-2mm. Fat plaque was high intensity on T1WK T2WK PDWI sequence. Because of it's component was cholesterol,the plaque's signal was different of the signal of fat. it's signal was lower than fat around the vessel. Fibrin cap was medial intensity on T1WI -, PDWI sequence and was high intensity on T2WI sequence . Calcification was low intensity on T1WI ^ T2WI x PDWI. Media of wall was medial intensity on T1WI > PDWI. sequence and was high intensity on T2WI sequence. The signal of it was overlap with plaque.5.2 Ultrasound ultrasound show that the normal blood vessel was smooth ; blood vessel was high series line ; while plaque was observed that... |
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