Evaluation of 3D blood flow patterns and wall shear stress in the normal and dilated thoracic aorta using flow-sensitive 4D CMR.
Evaluation of 3D blood flow patterns and wall shear stress in the normal and dilated thoracic aorta using flow-sensitive 4D CMR.
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DOI：
10.1186/1532-429x-14-84
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发表时间：
2012-12-13
期刊：
影响因子：
--
通讯作者：
Markl M
中科院分区：
文献类型：
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作者：
Bürk J;Blanke P;Stankovic Z;Barker A;Russe M;Geiger J;Frydrychowicz A;Langer M;Markl M
本研究的目的是研究升主动脉扩张患者、年龄匹配的受试者和健康志愿者的三维血流模式和管壁参数。对33例升主动脉扩张症患者(直径≥40 mm，年龄=60±16岁)、15例年龄匹配的正常对照组(直径≤直径37 mm，年龄=68±7.50岁)和15例健康志愿者(直径≤直径30 mm，年龄=23±2岁)进行了三维速度编码胸腔时间分辨三维相位对比成像。三维血流被可视化，并使用半定量3点分级标准对存在超生理螺旋和涡流的血流模式进行分级。测量血流速度、局部壁切应力(WSS)和振荡切变指数(OSI)。升主动脉扩张组(16/33和31/33，分级0.9±1.0和1.5±0.6)明显高于对照组(2/15和7/15，分级0.2±0.6和0.6±0.7，P<0.05)和正常对照组(1/15和0/15，分级0.1±0.3，P<0.05)。更强的升主动脉螺旋和涡流与AAO直径的显著差异有关(P<；0.05)。AAO扩张组升主动脉和主动脉弓的收缩峰值WSS显著降低(P<；.0157~.0488)。AAO内径与收缩末期血流速度呈正相关(r=0.30~0.53，P<0.05)，与OSI呈正相关(r=0.33~0.49，P<0.02)，与收缩期峰值WSS呈负相关(r=0.32~0.40，P<0.05)。右、外弯AAO和近端弓内AAO动脉瘤的收缩峰值WSS显著降低(P<；.01~.05)。AAO直径的增大与AAO内超生理性螺旋和涡旋的存在和强度显著相关，与收缩时WSS的减少和OSI的增加显著相关。
The purpose of this study was to investigate 3D flow patterns and vessel wall parameters in patients with dilated ascending aorta, age-matched subjects, and healthy volunteers. Thoracic time-resolved 3D phase contrast CMR with 3-directional velocity encoding was applied to 33 patients with dilated ascending aorta (diameter ≥40 mm, age=60±16 years), 15 age-matched normal controls (diameter ≤37 mm, age=68±7.5 years) and 15 young healthy volunteers (diameter ≤30 mm, age=23±2 years). 3D blood flow was visualized and flow patterns were graded regarding presence of supra-physiologic-helix and vortex flow using a semi-quantitative 3-point grading scale. Blood flow velocities, regional wall shear stress (WSS), and oscillatory shear index (OSI) were quantified. Incidence and strength of supra-physiologic-helix and vortex flow in the ascending aorta (AAo) was significantly higher in patients with dilated AAo (16/33 and 31/33, grade 0.9±1.0 and 1.5±0.6) than in controls (2/15 and 7/15, grade 0.2 ± 0.6 and 0.6 ± 0.7, P<.05) or healthy volunteers (1/15 and 0/15, grade 0.1 ± 0.3 P<.05). Greater strength of the ascending aortic helix and vortex flow were associated with significant differences in AAo diameters (P<.05). Peak systolic WSS in the ascending aorta and aortic arch was significantly lower in patients with dilated AAo (P<.0157-.0488). AAo diameter positively correlated to time to peak systolic velocities (r=0.30-0.53, P<.04), OSI (r=0.33-0.49, P<0.02) and inversely correlated to peak systolic WSS (r=0.32-0.40, P<.03). Peak systolic WSS was significantly lower in AAo aneurysms at the right and outer curvature within the AAo and proximal arch (P<.01-.05). Increase in AAo diameter is significantly correlated with the presence and strength of supra-physiologic-helix and vortex formation in the AAo, as well with decrease in systolic WSS and increase in OSI.