The effect of resolution on viscous dissipation measured with 4D flow MRI in patients with Fontan circulation: Evaluation using computational fluid dynamics.
The effect of resolution on viscous dissipation measured with 4D flow MRI in patients with Fontan circulation: Evaluation using computational fluid dynamics.
复制标题
DOI：
10.1016/j.jbiomech.2015.07.039
复制
发表时间：
2015-09-18
影响因子：
2.4
通讯作者：
Wentzel JJ
中科院分区：
文献类型：
--
作者：
Cibis M;Jarvis K;Markl M;Rose M;Rigsby C;Barker AJ;Wentzel JJ
Fontan循环内的粘性耗散是与Fontan患者的运动不耐受相关的参数，可以从计算流体动力学（CFD）或4D流动MRI速度中导出。然而，空间分辨率和测量噪声对粘性耗散估计的影响尚不清楚。我们的目的是评估这些参数对粘性耗散计算的影响。6例Fontan患者接受了全心脏4D flow MRI。进行了特定主题的CFD模拟。将CFD速度下采样至0.5 mm、1 mm、2 mm的各向同性空间分辨率和MRI分辨率。比较了（1）高分辨率CFD速度、（2）下采样至MRI分辨率的CFD速度、（3）下采样至MRI模拟噪声水平的CFD速度和（4）体内4D血流MRI速度之间的粘性耗散。还计算了受试者之间的相对粘性耗散。尽管与CFD速度（13.8±4.7 cm/s，p=0.16）、下采样CFD速度（12.3±4.4 cm/s，p = 0.06）和有噪声的下采样CFD速度（13.2 ± 4.2 cm/s，p = 0.06）无显著差异，但4D血流MRI速度（15.6±3.8 cm/s）较高。基于CFD的粘性耗散（0.81±0.55 mW）显著高于基于下采样CFD（0.25±0.19 mW，p=0.03）、具有噪声的下采样CFD（0.49±0.26 mW，p=0.03）和4D流式MRI（0.56±0.28 mW，p=0.06）的粘性耗散。然而，不同受试者之间的相对粘性耗散保持不受分辨率和噪声的影响，这表明患者之间的粘性耗散比较仍然是可能的。
Viscous dissipation inside Fontan circulation, a parameter associated with the exercise intolerance of Fontan patients, can be derived from computational fluid dynamics (CFD) or 4D flow MRI velocities. However, the impact of spatial resolution and measurement noise on the estimation of viscous dissipation is unclear. Our aim was to evaluate the influence of these parameters on viscous dissipation calculation. Six Fontan patients underwent whole heart 4D flow MRI. Subject-specific CFD simulations were performed. The CFD velocities were down-sampled to isotropic spatial resolutions of 0.5 mm, 1 mm, 2 mm and to MRI resolution. Viscous dissipation was compared between (1) high resolution CFD velocities, (2) CFD velocities down-sampled to MRI resolution, (3) down-sampled CFD velocities with MRI mimicked noise levels, and (4) in-vivo 4D flow MRI velocities. Relative viscous dissipation between subjects was also calculated. 4D flow MRI velocities (15.6±3.8 cm/s) were higher, although not significantly different than CFD velocities (13.8±4.7 cm/s, p=0.16), down-sampled CFD velocities (12.3±4.4 cm/s, p=0.06) and the down-sampled CFD velocities with noise (13.2±4.2 cm/s, p=0.06). CFD-based viscous dissipation (0.81±0.55 mW) was significantly higher than those based on down-sampled CFD (0.25±0.19 mW, p=0.03), down-sampled CFD with noise (0.49±0.26 mW, p=0.03) and 4D flow MRI (0.56±0.28 mW, p=0.06). Nevertheless, relative viscous dissipation between different subjects was maintained irrespective of resolution and noise, suggesting that comparison of viscous dissipation between patients is still possible.