Abstract：
4D-flow MRI is a promising technique for assessing vessel hemodynamics. However, its utilization is currently limited by the lack of reference values, particularly for pulmonary vessels. In this work, we have analysed flow and velocity in the pulmonary trunk (PT), left and right pulmonary arteries (LPA and RPA, respectively) in Landrace pigs at both rest and stress through the software MEVISFlow. Nine healthy Landrace pigs were acutely instrumented closed-chest and transported to the CMR facility for evaluation. After rest measurements, dobutamine was administered to achieve a 25% increase in heart rate compared to rest. 4D-flow MRI images have been analysed through MEVISFlow by two independent observers. Inter- and intra-observer reproducibility was quantified using intraclass correlation coefficient. A significant difference between rest and stress regarding flow and velocity in all the pulmonary vessels was observed. Mean flow increased 55% in PT, 75% in LPA and 40% in RPA. Mean peak velocity increased 55% in PT, 75% in LPA and 66% in RPA. A good-to-excellent reproducibility was observed in rest and stress for flow measurements in all three arteries. An excellent reproducibility for velocity was found in PT at rest and stress, a good one for LPA and RPA at rest, while poor reproducibility was found at stress. The current study showed that pulmonary flow and velocity assessed through 4D-flow MRI follow the physiological alterations during cardiac cycle and after stress induced by dobutamine. A clinical translation to assess pulmonary diseases with 4D-flow MRI under stress conditions needs investigation.
摘要：
4D-flowMRI是评估血管血液动力学的有前途的技术。然而,它的利用目前受到缺乏参考价值的限制，特别是肺血管。在这项工作中,我们已经分析了肺动脉干（PT）的流量和速度，左肺动脉和右肺动脉（LPA和RPA，分别）通过软件MEVISFlow在休息和压力下的长白猪中。对9头健康的长白猪进行了严格的闭胸仪器检查，并将其运送到CMR设施进行评估。在休息测量之后,与休息相比,给予多巴酚丁胺使心率增加25%.两个独立的观察者通过MEVISFlow分析了4D流MRI图像。使用组内相关系数量化观察者间和观察者内的再现性。观察到所有肺血管的静息和压力之间的流量和速度存在显着差异。PT平均流量增加55%，75%的LPA和40%的RPA。平均峰值速度在PT中增加了55%，75%的LPA和66%的RPA。在所有三个动脉的流量测量中，在休息和应力方面观察到良好到出色的可重复性。在静止和应力下的PT中发现了速度的极好的再现性，一个好的LPA和RPA在休息，而在压力下发现重现性差。当前的研究表明，通过4D-flowMRI评估的肺流量和速度遵循心动周期和多巴酚丁胺引起的压力后的生理变化。需要研究在压力条件下使用4D-flowMRI评估肺部疾病的临床翻译。
