多层螺旋CT定量评估腹主动脉瘤弹性的可重复性及风险因素

摘要

目的 探讨多层螺旋CT定量评价腹主动脉瘤弹性的可重复性与风险因素.资料与方法 前瞻性研究54例肾下型腹主动脉瘤患者的腹主动脉CT血管成像资料.所有受检者均采用64排螺旋CT、回顾性心电门控技术和分段数据采集方式扫描.在肾动脉水平和肾动脉下采用半自动分割软件计算主动脉弹性D值和脉搏波波速,比较不同水平腹主动脉弹性的差异,并进行一致性检验.结果 腹主动脉瘤D肾动脉水州值和D 肾动脉下值分别为(1.05±0.22) ×l0-5/pa、(0.49±0.18)×10-5/Pa,对应的脉搏波波速分别为(9.68±1.09) m/s、(14.96±4.01) m/s.肾动脉水平主动脉弹性观察者内及观察者间组内相关系数分别为0.92、0.89,肾动脉下水平主动脉弹性观察者内及观察者间组内相关系数分别为0.85、0.79.Bland-Altman图显示绝大部分点位于95％一致性界限内,2个位置测量的观察者间差异分别为0.017× 10-5/Pa、0.010×105/pa,观察者内差异分别为0.013×10-、/Pa、0.018×1 0-5/Pa.多元分析显示,瘤体的弹性与体重指数、脉压、舒张压和腹主动脉瘤直径具有独立相关性(R2=0.68).结论 多层螺旋CT定量评价腹生动脉瘤弹性值具有较高的稳定性.研究不同危险因素与腹主动脉瘤发生的相关性,有助于临床选择合适的治疗方式.%Purpose To investigate the reproducibility and risk factors of aortic distensibility quantification in patients with abdominal aortic aneurysm using multi-slice spiral CT.Materials and Methods The abdominal aortic computed tomography angiography data of 54 patients with infrarenal abdominal aortic aneurysm were prospectively studied.64-muti detector spiral CT,retrospective ECG-gating and segment data collecting scanning were all carried out.The aortic distensibility,D value,and pulse wave velocity at renal artery level and infrarenal artery level were calculated using semiautomatic segmentation software.The difference of aortic distensibility at different levels was compared,and consistency test was performed.Results The D value at renal artery level and infrarenal artery level of abdominal aortic aneurysm was (1.05 ±0.22)×10-5/Pa and (0.49± 0.18)× 10-5/Pa,respectively;and the corresponding pulse wave velocity was (9.68± 1.09) m/s and (14.96 ±4.01) m/s,respectively.The intraclass correlation coefficient of intra-and interobserver at renal level was 0.92 and 0.79,while it was 0.85 and 0.79 at inffa level.The Bland-Altman graph showed that the vast majority of points were within the 95％ CI,the difference of intraobserver between the two positions was 0.017×105/pa and 0.010×10-5/Pa,and the difference of interobserver was 0.013×105/Pa and 0.018×10-5/Pa.Multivariate analysis of all these variables showed aortic distensibility to be independently correlated to body mass index,pulse pressure,diastolic pressure and abdominal aortic aneurysm diameter (R2=0.68).Conclusion The quantification of aortic distensibility using multi-slice spiral in patients with abdominal aortic aneurysm shows high stability.Taking into consideration of the relationship between different risk factors and the incidence of abdominal aortic aneurysm can lead to a better clinical approach.