2014年5月10日から16日までイタリア•ミラノにあるMilano Congressiで開催されたJOINT ANNUAL MEETING ISMRM （International Society for Magnetic Resonance in Medicine）-ESMRMBx（European Society for Magnetic Resonance in Medicine and Biology）に平成26年度前期国際研究集会派遣会員として参加したので報告する.今回，ISMRMへの参加と発表は昨年のソルトレイクシティ開催に続いて2回目となる.%Purpose: Assessment of pulmonary arterial hypertension (PAH) is drawing more and more attentions from respiratory and cardiovascular clinicians. Pulmonary artery flow velocities, flow volume and their derived parameters, such as acceleration time (AT), acceleration volumes (AV) and maximum flow (MF) vary depending on the degree of pulmonary diseases including PAH. For conclusive assessment of pulmonary arterial pressures, right heart catheterization (RHC) is the gold standard; however, RHC is relatively invasive; Although hemodynamic analysis based on 2D PC MRI is a non-invasive alternative, it requires complicated prospective slice settings and may suffer from slice dependent inconsistent data. The purpose of our study was to assess hemodynamic parameters measured in potential PAH patients with three-dimensional cine phase contrast magnetic resonance (MR) imaging (4D-Flow), and to seek new potential hemodynamic biomarkers that for PAH can be measured simply and objectively. Method and Materials: The IRB approved prospective study employed 16 consecutive patients who were suspected of suffering from PAH. Blinded to the results of 4D-Flow, RHC was performed in each individuals, and then,12 non-PAH patients (median age of 74 years old) and 4 PAH patients (median age of 79 years old) were determined according to the RHC data. 4D-Flow was performed by a 3.0T MR Imager (Signa HDx, GEHCJ) with the following parameters of respiratory compensated ECG gated GRE, TR (ms)/TE (ms)/FA (degree) of 5.6/2.8/9, matrix of 256×224, section thickness (mm) of 2, cardiac phase of 20. Velocity encoding (cm/s) of 150, imaging time of 8.2 min. MR fluid dynamic assessments based on 4D-Flow data set with the aid of flow visualization software (Flova2 software; R'tech, Japan), Pulmonary arterial boundary was segmented based on the intensities of both magnitude images and phase images obtained with 4D-Flow. We then calculated and compared the hemodynamic parameters including geometrically averaged systolic wall shear stress (sWSS), mean WSS (mWSS), oscillatory shear index (OSI) and blood vessel section area (BVSA) in the pulmonary artery trunk based on 4D-Flow for all patients. We also created streamline images in pulmonary arteries. For statistical analysis between both groups, the Mann-Whitney U test was used. Moreover, we compared the correlation of regression analysis between hemodynamic parameters and pulmonary arterial pressure (PAP) or BVSA. For the correlation between flow parameters and RHC, the Spearman's rank-correlation coefficient test was used. P ＜ 0.05 was considered to be significant. Results: The mean sWSSs of non-PAH and PAH were significantly different (1.034 N/m~2 and 0.618 N/m~2, respectively; P ＜ 0.01) (Fig. 1a). The mean OSIs of non-PAH and PAH were also significantly different (0.125% and 0.182%, respectively; 0.01＜ P ＜ 0.05)(Fig. 1b). The r values of Spearman's rank-correlation coefficient test in comparison between hemodynamic parameters and PAP were -0.62, -0.63 and 0.42 for sWSS, mWSS and OSI respectively (Fig. 2, 3). The r values in comparison between the parameters and BVSA were 0.61(P ＜ 0.01) and -0.47 (0.01＜ P ＜ 0.05) for sWSS and OSI respectively. Vortex or helical flows were observed in two out of four PAH patients (Fig. 4) but not in any of the non-PAH patients.Discussion: In this study, there was a statistically significant differences between non-PAH and PAH patients in terms of sWSS and OSI. The sWSS showed inverse and linear correlation to PAP and was linearly related with BVSA. This may be due to decreased pulmonary velocities caused by a dilation of pulmonary artery trunk. OSI was linearly correlated to PAP, which may be due to the vortex or helical flow reflecting disturbed hemodynamics caused by high PAP conditions. Conclusion: The sWSS and OSI measured with an aid of 4D-Flow were considered to be potential hemodynamic biomarkers for PAH diseases.
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机译：2014年5月10日至16日，联合年度会议ISMRM（国际磁共振医学学会）-ESMRMBx（欧洲磁共振医学和生物学学会）在意大利米兰的米兰会议上举行我报告说我在本财年上半年参加了国际研究会议，这是我第二次参加ISMRM并在去年的盐湖城之后宣布。％目的：评估肺动脉高压（PAH）肺动脉流速，流量及其派生参数（如加速时间（AT），加速量（AV）和最大流量（MF））因肺部疾病的程度而异，包括PAH：对于肺动脉压的结论性评估，右心导管检查（RHC）是金标准；但是，RHC是相对侵入性的；尽管基于2D PC MRI的血液动力学分析是一种非侵入性替代方法，但它需要复杂的前瞻性切片设置和可能遭受切片相关的不一致数据的影响。我们的研究旨在通过三维电影相衬磁共振（MR）成像（4D-Flow）评估潜在PAH患者的血流动力学参数，并寻找可以简单，客观地测量PAH的潜在血液动力学生物标志物。材料和材料：IRB批准的前瞻性研究连续纳入了16位怀疑患有PAH的患者，对4D-Flow的结果视而不见，对每个人进行RHC，然后再进行12位非PAH患者（中位年龄为74岁）根据RHC数据确定了4例PAH患者（中位年龄为79岁）。采用3.0T MR成像仪（Signa HDx，GEHCJ）执行4D-Flow，具有以下参数的呼吸补偿ECG门控GRE， TR（ms）/ TE（ms）/ FA（度）为5.6 / 2.8 / 9，矩阵为256×224，截面厚度（mm）为2，心脏相位为20。速度编码（cm / s）为150，基于4D-Flow数据集的MR流体动力学评估的成像时间为8.2分钟流动可视化软件（Flova2软件； R'tech，日本），根据通过4D-Flow获得的幅值图像和相图像的强度对肺动脉边界进行分割，然后计算和比较包括几何平均收缩期壁切变在内的血液动力学参数基于4D-Flow对所有患者的肺动脉主干的压力（sWSS），平均WSS（mWSS），振荡剪切指数（OSI）和血管截面面积（BVSA），还创建了肺动脉的流线图像以进行统计此外，我们比较了血液动力学参数与肺动脉压（PAP）或BVSA之间的回归分析的相关性；对于血流动力学参数与RHC的相关性，Spearman的等级相关性结果：非PAH和PAH的平均sWSSs显着不同（1.034 N / m〜2和0.618 N / m 〜2; P <0.01）（图1a）。非PAH和PAH的平均OSI也有显着差异（分别为0.125％和0.182％; 0.01
