Local perfusion and metabolic demand during exercise: a noninvasive MRI method of assessment.
Local perfusion and metabolic demand during exercise: a noninvasive MRI method of assessment.
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运动期间的局部灌注和代谢需求：一种无创 MRI 评估方法。
DOI：
10.1152/jappl.2001.91.4.1845
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Frank,LR
中科院分区：
文献类型：
--
作者：
Richardson,RS;Haseler,LJ;Nygren,AT;Bluml,S;Frank,LR
描述了一种用于评估锻炼人体骨骼肌时灌注和代谢需求 (Q˙/V˙o2) 分布的无创磁共振成像 (MRI) 方法。该方法结合了两种 MRI 技术，可以在稳态跖屈运动期间提供准确的 Q˙/V˙o2 多个局部测量。第一种技术，31P化学位移成像，允许同时从多个体素采集可比较的磷光谱。由于磷酸肌酸 (PCr) 消耗与 ATP 水解成正比，因此其相对消耗可用作肌肉 O2 摄取 (V˙o2) 的指标。第二种 MRI 技术允许通过使用动脉自旋标记来测量体内空间和时间分辨的肌肉灌注。这两种 MRI 技术都提供了有希望的有效性和可靠性数据。组合方法的初步结果提供了 Q˙/V˙o2 较大变化的证据，揭示了给定代谢周转的明显灌注不足和过度灌注的区域。以与评估肺部通气与灌注匹配类似的方式对这些数据进行分析，显示了对数尺度上灌注分布和 PCr 分布的相似二阶矩（log SDQ˙ 和 log SDPCr）（0.47）。对可达到的 V˙o2 的 log SDQ˙ 和 log SDPCrin 项中的变化的影响进行建模，假设没有扩散限制，表明 log SDQ˙ 和 log SDPCr 只能实现目标 V˙o2 的 92%。该通讯记录了这种评估 Q˙/V˙o2 的新颖、无创方法，初步数据表明 Q˙/V˙o2 的不匹配可能在确定运动期间的 O2 运输和利用方面发挥重要作用。
A noninvasive magnetic resonance imaging (MRI) method to assess the distribution of perfusion and metabolic demand (Q˙/V˙o2) in exercising human skeletal muscle is described. This method combines two MRI techniques that can provide accurate multiple localized measurements of Q˙/V˙o2during steady-state plantar flexion exercise. The first technique,31P chemical shift imaging, permits the acquisition of comparable phosphorus spectra from multiple voxels simultaneously. Because phosphocreatine (PCr) depletion is directly proportional to ATP hydrolysis, its relative depletion can be used as an index of muscle O2uptake (V˙o2). The second MRI technique allows the measurement of both spatially and temporally resolved muscle perfusion in vivo by using arterial spin labeling. Promising validity and reliability data are presented for both MRI techniques. Initial results from the combined method provide evidence of a large variation in Q˙/V˙o2, revealing areas of apparent under- and overperfusion for a given metabolic turnover. Analysis of these data in a similar fashion to that employed in the assessment of ventilation-to-perfusion matching in the lungs revealed a similar second moment of the perfusion distribution and PCr distribution on a log scale (log SDQ˙and log SDPCr) (0.47). Modeling the effect of variations in log SDQ˙and log SDPCrin terms of attainable V˙o2, assuming no diffusion limits, indicates that the log SDQ˙and log SDPCrwould allow only 92% of the targetV˙o2to be achieved. This communication documents this novel, noninvasive method for assessingQ˙/V˙o2, and initial data suggest that the mismatch in Q˙/V˙o2may play a significant role in determining O2transport and utilization during exercise.