老年人离体颈动脉管壁MRI表现与病理对照研究

Comparison of MRI manifestations and histopathologic findings of the elderly carotid arteries in ex vivo

目的通过与病理对照，探讨3．0T高分辨率MRI检测老年人离体颈动脉血管壁结构特征及对动脉粥样硬化病变形态学和定量分析的能力。方法对9对（18根）老年人的离体颈动脉标本，在3．0TMR仪上采用特制小孔径线圈行高分辨率T1WI、T2WI脂肪抑制扫描，测量血管截面的最大内膜厚度、管腔面积、内膜面积和中膜面积，并根据美国心脏病协会（AHA）动脉粥样斑块病理分型及MRI分型标准进行分型，进行病理与影像的Pearson和Spearman相关分析以及一致性Kappa检验。结果以T2WI脂肪抑制序列显示的颈动脉管腔面积、中膜面积和内膜面积的病理组织学相关性较高[T2WI与病理测量分别为（27．53±6．77）mm^2和（25．83±6．69）mm^2，r2=0．91，P2=0．024；（12．31±3．31）mm^2和（12．28±3．71）mm^2，r，=0．70，P2=0．020；中位数12．29mm^2（范围1．12—33．18mm^2）和11．62mm^2（范围0．89～32．84mm^2），r2=0．74，P2=0．016]；颈动脉粥样硬化MRI分型与AHA病理分型结果具有较好的一致性（Kappa值=0．74，95％可信区间为0．67～0．80）。结论3．0T高分辨率多序列MRI能清晰显示离体颈动脉血管壁的形态特征和细微结构并允许进行量化评估，尤其是T2WI脂肪抑制序列具有对动脉粥样硬化病变准确定位和分型的能力。

Objective To evaluate the ability of high resolution magnetic resonance （MR） imaging at 3.0 tesla to depict the characterization of human carotid arterial vessel wall and detect atherosclerotic lesions ex vivo in comparison to histopathologic results. Methods Eighteen carotid arteries obtained from 9 elderly donors underwent fat-suppressed T1- and T2-weighted MR imaging at 3.0 tesla MR system with a mouse coil. Corresponding histological sections were obtained for the comparison. Correlation between MR images and histopathologic slices was obtained by Pearson or Spearman correlation coefficient. Cohen K was computed to quantify the agreement between MRI and histopathologic findings. Results Lumen area, intima and media area measured on fat-suppressed T2-weighted images showed stronger correlation with the corresponding histopathologic slices [ MRI vs. histopathology： （ 27.53 ± 6.77 ） mm2 vs. （ 25.83± 6.69）mm2,r2 =0.91,P2=0.024,（12.31 ±3.31） mm2 vs. （12.28±3.71）mm2,r2 =0.70,P2 =0.020, Median 12. 29 mm2（Min 1.12 mm2, Max 33. 18 mm2） vs. Median 11.62 mm2（Min 0.89 mm2, Max 32. 84 mm2 ）, r2 = 0. 74, P2 = 0. 016, respectively ]. The Cohen K score between the MR imaging and American Heart Association classifications was 0. 74, which corresponds to a good agreement. Conclusions 3.0 T high-resolution multi-sequence MRI can clearly show the structure of ex vivo carotid artery wall and allow quantitative assessment. Fat-suppressed T2W imaging has a greater advantage in presenting athcrosclerotic lesions.