Experimental Study Of Carotid Atherosclerosis Plague In Metabolic Syndrome By MRI

PartⅠMulti-contrast MRI Imaging Characterize the Carotid artery in RabbitsPurpose:Our aim was to explore the feasibility and accuracy of multi-contrast MRI imaging((TOF,T1WI,T2WI,PDWI) to show the carotid artery of rabbits.Material and Methods:20 New Zealand rabbits underwent multi-contrast MRI scan and DSA respectively.The images of the same slice were compared and the diameter of the ipsilateral carotid artery was measured.At the same time,the source images of T1WI,T2WI and TOF were reconstructed by the means of MIP and MPR.Results:The mean of diameter is 2.42±0.15mm measured by MRI and 2.15±0.08mm by DSA.The two measurements were highly correlated,with a correlation coefficient of 0.749(P＜0.01) The reconstructed imagings is excellent.Conclusions:Multi-contrast MRI is an noninvasive technology which can evaluate the diameter and characterize the wall signal of carotid artery accurately.Combined with vascular reconstruction technology,the new multi-contrast MRI is going to take the place of DSA to diagnose atherosclerosis.In the conclusion,the new and promising technology will facilitate build an atherosclerotic animal model.And future MRI studies may improve our understanding of the pathophysiology of atherosclerosis and its relationship with cerebral ischemia in human. PartⅡEstablishing experimental atherosclerosis and evaluated by serial MRIPurpose:Establishing the experimental carotid atherosclerosis of New Zealand rabbits is to explore the feasibility of this method and evaluated it by phased array coil according to histology,which is helpful to study the relationship between carotid atherosclerosis and cerebral ischemia diseasse.Material and Methods:After the initiation of a high cholesterol diet for 8 weeks,20 rabbits underwent balioon injury of common carotid artery.The trauma of vascular was examined by MRI seven days later after the surgery.We continued to feed the rabbits with a high cholesterol diet for 2 month and examined the carotid artery by MRI every 2 weeks.At the end of the study,the rabbits were killed by an intravenous overdose of fluanizone and phentany.Tissue samples from each carotid artery were compared with the imagings of the rabbits.Results:There are three rabbits died in the feeding and four died after balloon injury,ln the summary,achievement ratio of this experimental model is 75%(12/16).We can see high signal density in the wall of trauma vascular in the first MRI(7 days after surgery).In the second to sixth MRI,intimal thickeness can be seen.The accumulation of foam cells results in the formation of fatty streaks,Smooth muscle cells immigrate from the medial layer into the subendothelial space where they may proliferate,ingest modified lipoproteins and contribute to lesion development,which is similar to the lesion in human vessel.Conclusions:It is feasible to establish experimental atherosclerosis combinating a high cholesterol diet with balloon injury.MRI is a good tool to examine the trauma vessel and carotid atherosclerosis. PartⅢCarotid MRI technique:Comparative Research of QIRPURPOSE:In order to eliminate motion and flow artifacts,reduce scan time,and improve spatial resolution,we apply QIR-FSE and FSE only with flow saturation in comparative research.MATERIALS AND METHODS:There are three patients went through this researsh.We used both QIR-T1WI FSE and TIWI FSE only with flow saturation in each patient.We accquired 18 images in total.Three attending doctors devide these images into five qualities according to having artifacts or not.Five score -no artifact;four score-flow artifact in only one side,but no motion artifact;three artifact - flow artifact in both sides,but no motion artifact,two score-flow artifact and motion artifact in only one side;one score-flow artifact and motion artifact in both sides.We used non-parametric test to analyse results.RESULTS:The means of QIR—FSE T1WI is 4.6 and FSE T1WI 2.6.P＜0.05.There is significant difference in statistical analysis.CONCLUSION:In conclusion,the qualitity of image with QIR-FSE T1WI is better than images with T1WI FSE.In-flow signal were eliminate effectively with QIR-FSE T1WI,which make the images more clearer.,especially in enhance MRI scan.PartⅣCharacteristics of Carotid Plague MRI in Metabolic SyndromePURPOSE:To clarify the relationship between metabolic syndrome and carotid atherosclerosis plague,we design a comparative research to test this relationship.MATERIALS AND METHODS:Sixty patients were chosen in the research according to WHO defination on Metabolic Syndrome.They all took MRI on both carotid artery and head.We apply Student's t tests and Fisher's exact test in analyzing the data.RESULTS:The mean age of patients with atherosclerosis plague is 70.0±9.7,whereas patients without atherosclerosis plague is 69.7±7.6.There are 54.2%patients with carotid atherosclerosis plague,which are male.There are 58.3%patients without carotid atherosclerosis plague,which are male.There are 41.7%patients smoking with carotid atherosclerosis plague.There are 41.7%patients smoking without carotid atherosclerosis plague.Among the patients with atherosclerosis plague,there are 75.0%patients with metabolic syndrome.Among the patients without atherosclerosis plague,there are 41.7% patients with metabolic syndrome.P=0.026.Among the patients with atherosclerosis plague,there are 37.5%patients having family history.Among the patients without atherosclerosis plague,there are 36.7%patients with metabolic syndrome having family history.There are 46 patients with carotid atherosclerosis plague,which have thick and intact fiber cap. There are 2 patients with carotid atherosclerosis plague,which have thin and rupture fiber cap.There are one patient with carotid atherosclerosis plague,which have haemorrhage in plague.There are 36 patients with carotid atherosclerosis plague,which have calcification in the plague.CONCLUSION:In this research,patients with metabolic syndrome have the tendency to suffer from carotid atherosclerosis plague.And the characteristic of the plague are stable in most with intact fiber cap and calcification in the center of the plague.Most plague located in the bifurcation of carotid artery.Our conclusion need to be tested in large sample through prospective research in the future.