The effect of supine exercise on the distribution of regional pulmonary blood flow measured using proton MRI.
The effect of supine exercise on the distribution of regional pulmonary blood flow measured using proton MRI.
复制标题
仰卧运动对使用质子 MRI 测量的局部肺血流分布的影响。
DOI：
10.1152/japplphysiol.00659.2013
复制
发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Hopkins,SR
中科院分区：
文献类型：
--
作者：
Hall,ET;Sá,RC;Holverda,S;Arai,TJ;Dubowitz,DJ;Theilmann,RJ;Prisk,GK;Hopkins,SR
肺灌注的区域模型预测，运动降低了灌注的异质性，因为血管压力的增加使血流重新分配到不依赖重力的肺部，并引起血管的扩张和募集。然而，在动物运动过程中，通过相对弥散度（RD, SD/mean）测量的灌注异质性并未显著降低。我们利用磁共振成像（MRI）评估了运动对6名健康仰卧人肺灌注的影响。数据在休息时、运动时（最大耗氧量的27%）使用mri兼容的测功仪和恢复时获得。使用配备躯干线圈的1.5 t MR扫描仪在功能剩余容量下获得右肺大部分矢状面图像。灌注测量采用动脉自旋标记（asl - fair）和区域质子密度使用快速多回声梯度回声序列。对灌注图像进行校正，消除基于线圈的信号不均匀性，去除大导管血管并量化（单位：ml·min−1·ml−1）（灌注），并对密度进行归一化和量化（单位：ml·min−1·g−1）（密度归一化灌注，DNP），考虑组织重新分布。运动时DNP升高（休息11.1±3.5，运动18.8±2.3，恢复13.2±2.2,ml·min−1·g−1，P< 0.0001），非依赖组DNP升高最大（非依赖组DNP升高110±61%，中期DNP升高63±35%，依赖组DNP升高70±33%，P< 0.005）。运动时灌注RD降低（休息0.93±0.21，运动0.73±0.13，恢复0.94±0.18，P< 0.005）。DNP的RD（休息0.82±0.14，运动0.75±0.09，恢复0.81±0.10，P= 0.13）也有相似的变化趋势。总之，与动物研究相比，在仰卧的人类中，轻度运动降低了灌注异质性，与Zone模型预测一致。
The Zone model of pulmonary perfusion predicts that exercise reduces perfusion heterogeneity because increased vascular pressure redistributes flow to gravitationally nondependent lung, and causes dilation and recruitment of blood vessels. However, during exercise in animals, perfusion heterogeneity as measured by the relative dispersion (RD, SD/mean) is not significantly decreased. We evaluated the effect of exercise on pulmonary perfusion in six healthy supine humans using magnetic resonance imaging (MRI). Data were acquired at rest, while exercising (∼27% of maximal oxygen consumption) using a MRI-compatible ergometer, and in recovery. Images were acquired in most of the right lung in the sagittal plane at functional residual capacity, using a 1.5-T MR scanner equipped with a torso coil. Perfusion was measured using arterial spin labeling (ASL-FAIRER) and regional proton density using a fast multiecho gradient-echo sequence. Perfusion images were corrected for coil-based signal heterogeneity, large conduit vessels removed and quantified (in ml·min−1·ml−1) (perfusion), and also normalized for density and quantified (in ml·min−1·g−1) (density-normalized perfusion, DNP) accounting for tissue redistribution. DNP increased during exercise (11.1 ± 3.5 rest, 18.8 ± 2.3 exercise, 13.2 ± 2.2 recovery, ml·min−1·g−1,P< 0.0001), and the increase was largest in nondependent lung (110 ± 61% increase in nondependent, 63 ± 35% in mid, 70 ± 33% in dependent,P< 0.005). The RD of perfusion decreased with exercise (0.93 ± 0.21 rest, 0.73 ± 0.13 exercise, 0.94 ± 0.18 recovery,P< 0.005). The RD of DNP showed a similar trend (0.82 ± 0.14 rest, 0.75 ± 0.09 exercise, 0.81 ± 0.10 recovery,P= 0.13). In conclusion, in contrast to animal studies, in supine humans, mild exercise decreased perfusion heterogeneity, consistent with Zone model predictions.