高分辨MRI检测兔小管径动脉粥样斑块的可靠性

目的 探讨高分辨MRI(HRMRI)技术评价大白兔模型小管径动脉粥样斑块的价值。方法 通过高脂饮食和球囊损伤新西兰大白兔(12只)腹主动脉内膜制作模拟小管径动脉的粥样硬化模型,行高分辨FSE T2WI成像和病理分析。病理切片严格与MRI匹配,分析包括HE染色、Masson及免疫组化染色。以病理分析结果为标准,评价MRI在显示动脉斑块形态、成分以及定量测量方面的价值。结果 模型腹主动脉可见以脂质沉积和纤维增生为特征的斑块。不同组织成分的斑块表现为不同的T2WI信号特点,有大量炎性细胞浸润的疏松纤维帽表现为近管腔的高信号带,脂质聚集区多表现为高信号带下的低信号区,致密和薄的纤维帽不能显示。T2WI测量管腔面积和管壁面积与组织学测量值有较高的相关性(管腔r=0.7503,管壁r=0.8666,P均<0.05)。结论 高分辨MR T2WI可准确显示小管径动脉粥样斑块的形态学特征,提供斑块负荷和主要组织成分的信息。

Feasibility of high-resolution MR imaging in the evaluation of small diameter artery atherosclerosis: An animal study

Objective To study the value of high-resolution MR imaging (HRMRI) in detection of atherosclerosis of small diameter arteries with rabbit models. Methods Abodominal aortic atherosclerosis was induced through endothelial denudation and high-cholesterol diet in 12 New Zealand white (NZW) rabbits. HRMRI was performed with fast spin echo T2-weighted (T2W) imaging on a 1.5T clinical scanner. HE, Masson stain and imunohistochemical stain were performed after HRMRI. MRI performance and histological findings of atherosclerosis lesions were compared slice by slice. Results Atherosclerotic plaques characterized by lipid deposition and fibrosis were induced in the abdominal aorta. HRMRI clearly showed the lesions, and a good match was observed between MRI and histological findings. There was significant correlation for both lumen area and wall area measurements between MRI and histology (lumen area: r=0.7503, wall area: r=0.8666, both P<0.05). On T2WI, the luminal high signal band corresponded to the thick fibrous cap with extensive inflammatory cell infiltration, while underlying low signal areas corresponded to lipid core. Thin and dense fibrous cap was not displayed on T2WI due to resolution limitation. Conclusion HRMRI is reliable to show the morphologic structure of atherosclerotic lesions of small diameter arteries. It can provide information about lesions burden and main compositions.