Dynamic 31P-MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T
Dynamic 31P-MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T
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DOI：
10.1002/nbm.3662
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发表时间：
2016-12-01
影响因子：
2.9
通讯作者：
Bogner, Wolfgang
中科院分区：
文献类型：
--
作者：
Valkovic, Ladislav;Chmelik, Marek;Bogner, Wolfgang
磷核磁共振成像（P-31-MRSI）采用7 T时的螺旋轨迹读数，用于运动人类骨骼肌的线粒体能力的高时间分辨率制图。研究了该方法的灵敏度和定位精度。研究人员对12名志愿者的体内表现进行了评估，他们在全身7 T MR扫描仪内使用核磁共振兼容的测力仪和表面线圈进行了足底屈曲运动。在五名志愿者中，膝关节被弯曲（-60度）以将主要负荷从腓肠肌转移到比目鱼肌。与相同矩阵大小的椭圆相位编码MRSI相比，螺旋编码MRSI提供了16-25倍的映射速度和更好的点扩展函数。为了提高时间分辨率，不可避免的代价是降低信噪比，但这是可以接受的。在0度膝角运动引起的磷酸肌酸（PCr）耗损在腓肠肌和比目鱼肌中明显高于腓肠肌（即，腓肠肌外侧和内侧肌分别为64.8 +/- 19.6%和65.9 +/- 23.6%，而比目鱼肌为15.3 +/- 8.4%）。螺旋编码的P-31-MRSI是运动肌肉氧化代谢动态制图的强大工具，包括高时空分辨率的PCr浓度、pH和最大氧化通量的局部评估。
Phosphorus MRSI (P-31-MRSI) using a spiral-trajectory readout at 7 T was developed for high temporal resolution mapping of the mitochondrial capacity of exercising human skeletal muscle. The sensitivity and localization accuracy of the method was investigated in phantoms. In vivo performance was assessed in 12 volunteers, who performed a plantar flexion exercise inside a whole-body 7 T MR scanner using an MR-compatible ergometer and a surface coil. In five volunteers the knee was flexed (-60 degrees) to shift the major workload from the gastrocnemii to the soleus muscle.Spiral-encoded MRSI provided 16-25 times faster mapping with a better point spread function than elliptical phase-encoded MRSI with the same matrix size. The inevitable trade-off for the increased temporal resolution was a reduced signal-to-noise ratio, but this was acceptable. The phosphocreatine (PCr) depletion caused by exercise at 0 degrees knee angulation was significantly higher in both gastrocnemii than in the soleus (i.e. 64.8 +/- 19.6% and 65.9 +/- 23.6% in gastrocnemius lateralis and medialis versus 15.3 +/- 8.4% in the soleus).Spiral-encoded P-31-MRSI is a powerful tool for dynamic mapping of exercising muscle oxidative metabolism, including localized assessment of PCr concentrations, pH and maximal oxidative flux with high temporal and spatial resolution.