Hyperemic flow heterogeneity within the calf, foot, and forearm measured with continuous arterial spin labeling MRI
Hyperemic flow heterogeneity within the calf, foot, and forearm measured with continuous arterial spin labeling MRI
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DOI：
10.1152/ajpheart.01399.2007
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发表时间：
2008-05-01
影响因子：
4.8
通讯作者：
Floyd, Thomas F.
中科院分区：
文献类型：
--
作者：
Wu, Wen-Chau;Wang, Jiongjiong;Floyd, Thomas F.
动脉自旋标记（ASL）是一种无创的磁共振成像（MRI）技术，用于微血管血流测量。我们使用连续ASL方案（CASL）来研究人体四肢主要肌群之间的充血流量差异。招募了24名无血管疾病证据的健康受试者。MRI在3.0特斯拉Siemens Trio全身系统上进行，该系统具有发射/接收膝关节线圈。使用止血带骨科止血带系统造成5分钟的缺血期，随后是一段时间的充血流（闭塞压= 250 mmHg）。CASL成像，从袖带充气前2分钟持续到袖带放气后3分钟，在小腿中部，足中部和前臂中部进行单独的会议，从血流量定量与有效的时间分辨率为16秒。当在相同的解剖位置的肌肉进行比较，充血流量被发现是显着较高的隔间包含肌肉已知具有相对较高的慢收缩I型纤维成分，如比目鱼肌在小腿和前臂的伸肌。在足部，跖屈肌表现出轻微延迟充血反应相对于背侧间室，但没有观察到组间流量差异。这些结果表明，CASL是敏感的不同肌肉群之间的流量异质性和不均匀充血的流动模式，缺血的范例与相对的纤维型优势。
Arterial spin labeling (ASL) is a noninvasive magnetic resonance imaging (MRI) technique for microvascular blood flow measurement. We used a continuous ASL scheme (CASL) to investigate the hyperemic flow difference between major muscle groups in human extremities. Twenty-four healthy subjects with no evidence of vascular disease were recruited. MRI was conducted on a 3.0 Tesla Siemens Trio whole body system with a transmit/receive knee coil. A nonmagnetic orthopedic tourniquet system was used to create a 5-min period of ischemia followed by a period of hyperemic flow (occlusion pressure = 250 mmHg). CASL imaging, lasting from 2 min before cuff inflation to 3 min after cuff deflation, was performed on the midcalf, midfoot, and midforearm in separate sessions from which blood flow was quantified with an effective temporal resolution of 16 s. When muscles in the same anatomic location were compared, hyperemic flow was found to be significantly higher in the compartments containing muscles known to have relatively higher slow-twitch type I fiber compositions, such as the soleus muscle in the calf and the extensors in the forearm. In the foot, the plantar flexors exhibited a slightly delayed hyperemic response relative to that of the dorsal compartment, but no between-group flow difference was observed. These results demonstrate that CASL is sensitive to flow heterogeneity between diverse muscle groups and that nonuniform hyperemic flow patterns following an ischemic paradigm correlate with relative fiber-type predominance.