Exercise-induced calf muscle hyperemia: quantitative mapping with low-dose dynamic contrast enhanced magnetic resonance imaging.
Exercise-induced calf muscle hyperemia: quantitative mapping with low-dose dynamic contrast enhanced magnetic resonance imaging.
复制标题
运动引起的小腿肌肉充血：低剂量动态对比增强磁共振成像定量绘图。
DOI：
10.1152/ajpheart.00537.2018
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Lee,VivianS
中科院分区：
文献类型：
--
作者：
Zhang,JeffL;Layec,Gwenael;Hanrahan,Christopher;Conlin,ChristopherC;Hart,Corey;Hu,Nan;Khor,Lillian;Mueller,Michelle;Lee,VivianS
下肢外周动脉疾病（PAD）常常导致间歇性跛行。在本研究中，我们提出了一种低剂量 DCE MRI 协议，用于量化跖屈刺激的小腿肌肉灌注，以及用于解释灌注图的多个新指标，包括腓肠肌与比目鱼肌灌注的比率（G/S；用于评估两块肌肉之间的血管重新分布）和通过全身灌注标准化的肌肉灌注（用于量化肌肉的活动充血）。 28 名人类受试者参与了这项经机构审查委员会批准的研究，其中 10 名健康受试者（A 组）用于评估日间再现性，8 名健康受试者（B 组）用于探索跖屈负荷与诱导肌肉灌注之间的关系。在由 5 名老年健康受试者和 5 名 PAD 患者（C 组）组成的试点组中，我们提出了一种方案，在单次 MRI 会话中测量低强度运动和力竭运动的灌注。在 A 组中，小腿肌肉的灌注估计具有高度可重复性，相关系数为 0.90-0.93。 B组腓肠肌灌注随运动负荷呈线性增加（P<0.05）。通过低强度运动，C组PAD患者的腓肠肌灌注量明显低于老年健康受试者[43.4 (SD 23.5) vs. 106.7 (SD 73.2) ml·min−1·100 g−1]。在力竭运动中，PAD患者的G/S [1.0 (SD 0.4)]低于其低强度水平[1.9 (SD 1.3)]和老年健康受试者的水平[2.7 (SD 2.1)]。总之，所提出的 MRI 协议和新指标对于量化运动引起的肌肉充血是可行的，这是一种有前途的 PAD 功能测试。新和值得注意的是为了定量绘制小腿肌肉运动引起的充血，我们提出了一种高分辨率 MRI 方法，该方法具有高度可重复性且对运动负荷敏感。通过使用低对比度，可以在单次 MRI 会话中测量低强度和力竭运动的小腿肌肉充血情况。新提出的用于解释灌注图的指标有望量化肌间血管重新分布或肌肉的主动充血。
Peripheral artery disease (PAD) in the lower extremities often leads to intermittent claudication. In the present study, we proposed a low-dose DCE MRI protocol for quantifying calf muscle perfusion stimulated with plantar flexion and multiple new metrics for interpreting perfusion maps, including the ratio of gastrocnemius over soleus perfusion (G/S; for assessing the vascular redistribution between the two muscles) and muscle perfusion normalized by whole body perfusion (for quantifying the muscle’s active hyperemia). Twenty-eight human subjects participated in this Institutional Review Board-approved study, with 10 healthy subjects (group A) for assessing interday reproducibility and 8 healthy subjects (group B) for exploring the relationship between plantar-flexion load and induced muscle perfusion. In a pilot group of five elderly healthy subjects and five patients with PAD (group C), we proposed a protocol that measured perfusion for a low-intensity exercise and for an exhaustion exercise in a single MRI session. Ingroup A, perfusion estimates for calf muscles were highly reproducible, with correlation coefficients of 0.90–0.93. Ingroup B, gastrocnemius perfusion increased linearly with the exercise workload (P< 0.05). With the low-intensity exercise, patients with PAD ingroup Cshowed substantially lower gastrocnemius perfusion compared with elderly healthy subjects [43.4 (SD 23.5) vs. 106.7 (SD 73.2) ml·min−1·100 g−1]. With exhaustion exercise, G/S [1.0 (SD 0.4)] for patients with PAD was lower than both its low-intensity level [1.9 (SD 1.3)] and the level in elderly healthy subjects [2.7 (SD 2.1)]. In conclusion, the proposed MRI protocol and the new metrics are feasible for quantifying exercise-induced muscle hyperemia, a promising functional test of PAD.NEW & NOTEWORTHYTo quantitatively map exercise-induced hyperemia in calf muscles, we proposed a high-resolution MRI method shown to be highly reproducible and sensitive to exercise load. With the use of low contrast, it is feasible to measure calf muscle hyperemia for both low-intensity and exhaustion exercises in a single MRI session. The newly proposed metrics for interpreting perfusion maps are promising for quantifying intermuscle vascular redistribution or a muscle’s active hyperemia.