中文摘要：

目的 探讨建立腹主动脉粥样硬化斑块模型的方法及超高场强磁共振成像（MRI）在活体监测及量化小鼠腹主动脉粥样硬化斑块中的应用价值.方法 高脂饮食法小鼠腹主动脉粥样硬化斑块模型的建立及磁共振检测（高脂饮食组）：选择3批10～12月龄apoE-/-小鼠13只、WT鼠3只高脂饮食喂养,分别于喂养前、喂养3个月、喂养6个月3个时期进行小鼠腹主动脉7.0 T磁共振活体扫描.血管紧张素Ⅱ（AngⅡ）灌注法小鼠腹主动脉粥样硬化斑块模型的建立及磁共振检测（AngⅡ灌注组）：选用10只6月龄apoE-/-小鼠,分为AngⅡ1000 ng·kg^-1·min^-1组3只、AngⅡ500 ng·kg^-1·min^-1组3只（以上两组均在背部埋置AngⅡ缓释泵14 d）和对照组为4只（埋置生理盐水缓释泵）,分别于灌注前后行磁共振扫描,选用FLASH T1WI黑血及MSME-T2WI-PDWI双回波序列.高脂饮食组依次在各时期扫描后分别处死3、5、5只小鼠,AngⅡ灌注组于装泵后14 d行磁共振扫描,然后处死本组小鼠,取处死小鼠的肾动脉段腹主动脉制作病理切片,进行苏木素-伊红（HE）染色、Masson胶原纤维（CME）染色.每只小鼠选5～7层肾动脉段腹主动脉病理图像及多对比MRI图像,分别测量外腔面积（VOA）、内腔面积（LA）,计算管肇面积（VWA）并进行MRI与病理测量结果的相关性分析.结果 两种方法建立的小鼠模型,其腹主动脉MRI与病理切片均可见不稳定斑块形成.高脂饮食组随着高脂饮食时间的延长,斑块进展,VWA不断增加,3个时期VWA方差分析F=29.94（P〈0.05）,斑块信号于PDWI、T2WI逐渐增加,且不均匀.高脂饮食组MRI测量的斑块面积与病理测量的斑块面积有较高的-致性（高脂喂养前、喂养3和6个月3个时期r值分别为0.84、0.95、0.90）.病理切片中斑块成分与磁共振显示信号一致,均表现为脂质成分增加,纤维成分减少.AngⅡ1000 ng·kg^-1·min^-1组AngⅡ灌注后斑块面积与?

英文摘要：

Objective To explore the value of in vivo dynamic monitoring of abdominal aortic atherosclerosis （AS） by high field magnetic resonance （MR） imaging （MRI） in apoE - / - mice fed a high fat diet or infused with angiotensin. Methods High fat diet or angiotensin Ⅱ infusion was applied to apoE-/- mice for establishment of abdominal aortic atherosclerosis model. Abdominal aorta MRI was performed at 3 time points （baseline, 3 and 6 months） in 13 high fat diet fed apoE -/- mice aged 10 -12months and 3 wild-type control mice; 10 apoE -/- mice aged 6 months were infused with angiotensin Ⅱaortic artery MRI was performed at baseline and 14 d after infusion. Black blood sequences of FLASH T1 weighted images and Proton density weighted -T2 weighted dual echo images were obtained. At each observation time post MRI, mice （n =3, 5 and 5 for high fat diet group and n =5 and 5 for angiotensin Ⅱinfusion group） were sacrificed for pathological examination of the abdominal artery. Results （ 1 ） The abdominal aorta atherosclerosis was identified in both high fat diet and angiotensin Ⅱ treated apoE -/-mice but in WT controls. Lesion progression was documented in high fat diet fed apoE -/- mice characterized by significantly increased vessel wall（ a marker of atherosclerotic burden, F = 29. 94, P 〈 0. 05 ）and gradually increased plaque signal in PDW and T2W images. Results derived from MRI corresponded histopathology findings in high fat diet fed apoE -/- mice （ correlative coefficient = 0. 84, 0. 95, 0. 90,P 〈 0. 05, respectively）. Both MRI and histology showed increased lipid composition and decreased fibrotic composition in these mice. （2） The vessel wall area increased significantly [（1.21 ±0.21） mm^2 vs.（2. 65 ±0. 48 ）mm^2 ,P 〈0. 05] and the abdominal aortic dissection aneurysms was identified in apoE-/-mice infused with high angiotensin Ⅱ. The vessel wall area also increased [（0.85 ±0. 11） mm^2 vs. （ 1.01 -0. 17） mm^2, P 〈0. 05] in low angiotensin Ⅱ infused