摘要

Pulmonary hypertension is characterized by elevation of pulmonary artery (PA) pressure (p) and structural remodeling of the PA wall, leading to reduction in arterial compliance (c). As a step towards improving diagnosis of pulmonary disease, we use the PA branch geometry (main pulmonary artery (MPA) branching into left (LPA) and right (RPA) pulmonary arteries) obtained from MRI in conjunction with an inverse algorithm to obtain the pre-stress level in the artery walls. Next, a coupled blood-wall interaction (BWI) calculation provides hemodynamic information as well as compliance of the PA walls. We show that the computed load-free geometry from the inverse algorithm exhibits a 27.8% lower inner diameter (d) and 18.5% lower outer d compared to the in vivo geometry from MRI. Further, the mean p computed from the BWI computation in the main PA (pMPA-n) is within 4% of the mean pMPA-e (n-numerical; e-experimental). Also, the mean Q computed in the left PA (QLPA-n) is within 10% of the mean QLPA-e. Finally, the compliance cMPA-n is computed to be 27% lower than cMPA-e, while the cLPA-n is computed to be 20.4% lower than cLPA-e. Importantly, the PA shows significant intra-vascular variation in compliance, with the MPA showing higher overall compliance compared to the LPA (3.5-4 times).

译文

肺动脉高压的特征是肺动脉 (PA) 压力 (p) 的升高和 PA 壁的结构重塑，导致动脉顺应性 (c) 的降低。作为提高肺部疾病诊断的一步，我们使用 PA 分支几何 (主肺动脉 (MPA) 分支左 (LPA) 和右 (RPA) 肺动脉) 通过 MRI 结合反向算法获得动脉壁的预应力水平。接下来，耦合血壁相互作用 (BWI) 计算提供了血流动力学信息以及 PA 壁的顺应性。我们表明，与 MRI 的体内几何结构相比，反向算法计算出的无负载几何结构显示出内径 (d) 低 27.8%，外径低 18.5%。此外，从主 PA (pMPA-n) 中的 BWI 计算中计算的平均 p 在 pMPA-e (n-数值; e-实验) 的 4% 以内。同样，在左 PA (QLPA-n) 中计算的平均 Q 在平均 QLPA-e 的 10% 以内。最后，计算出的柔度 cMPA-n 比 cMPA-e 低 27%，而计算出的 cLPA-n 比 cLPA-e 低 20.4%。重要的是，PA 显示出显著的血管内顺应性变化，与 LPA 相比，MPA 显示出更高的总体顺应性 (3.5-4 倍)。