Sigovan Monica, Dyverfeldt Petter, Wrenn Jarrett, Tseng Elaine E, Saloner David, Hope Michael D
Department of Radiology and Biomedical Imaging, UCSF, CA, USA; Université de Lyon, CREATIS; CNRS UMR5220; Inserm U1044; INSA-Lyon; Université Lyon 1; Hospices Civils de Lyon, France.
Department of Radiology and Biomedical Imaging, UCSF, CA, USA; Linkoping University, Linkoping, Sweden.
Magn Reson Imaging. 2015 Jun;33(5):695-700. doi: 10.1016/j.mri.2015.02.020. Epub 2015 Feb 23.
Flow displacement quantifies eccentric flow, a potential risk factor for aneurysms in the ascending aorta, but only at a single anatomic location. The aim of this study is to extend flow displacement analysis to 3D in patients with aortic and aortic valve pathologies.
43 individuals were studied with 4DFlow MRI in 6 groups: healthy, tricuspid aortic valve (TAV) with aortic stenosis (AS) but no dilatation, TAV with dilatation but no AS, and TAV with both AS and dilatation, BAV without AS or dilatation, BAV without AS but with dilation. The protocol was approved by our institutional review board, and informed consent was obtained. Flow displacement was calculated for multiple planes along the ascending aorta, and 2D and 3D analyses were compared.
Good correlation was found between 2D flow displacement and both maximum and average 3D values (r>0.8). Healthy controls had significantly lower flow displacement values with all approaches (p<0.05). The highest flow displacement was seen with stenotic TAV and aortic dilation (0.24±0.02 with maximum flow displacement). The 2D approach underestimated the maximum flow displacement by more than 20% in 13 out of 36 patients (36%).
The extended 3D flow displacement analysis offers a more comprehensive quantitative evaluation of abnormal systolic flow in the ascending aorta than 2D analysis. Differences between patient subgroups are better demonstrated, and maximum flow displacement is more reliably assessed.
血流位移可量化偏心血流，这是升主动脉瘤的一个潜在风险因素，但仅在单一解剖位置进行评估。本研究的目的是将血流位移分析扩展至患有主动脉及主动脉瓣病变的患者的三维情况。
对43名个体进行了4D血流磁共振成像研究，分为6组：健康组、患有主动脉狭窄（AS）但无扩张的三尖瓣主动脉瓣（TAV）组、有扩张但无AS的TAV组、既有AS又有扩张的TAV组、无AS或扩张的二叶式主动脉瓣（BAV）组、无AS但有扩张的BAV组。该方案经我们机构审查委员会批准，并获得了知情同意。计算升主动脉多个平面的血流位移，并比较二维和三维分析结果。
二维血流位移与三维最大值和平均值之间均存在良好的相关性（r>0.8）。所有方法测得的健康对照组血流位移值均显著较低（p<0.05）。狭窄的TAV和主动脉扩张时血流位移最高（最大血流位移为0.24±0.02）。在36例患者中的13例（36%）中，二维方法低估最大血流位移超过20%。
扩展的三维血流位移分析比二维分析能更全面地定量评估升主动脉异常收缩期血流。患者亚组之间的差异得到了更好的体现，并且最大血流位移得到了更可靠的评估。
