Kogan Feliks, Haris Mohammad, Debrosse Catherine, Singh Anup, Nanga Ravi P, Cai Kejia, Hariharan Hari, Reddy Ravinder
Center for Magnetic Resonance and Optical Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
J Magn Reson Imaging. 2014 Sep;40(3):596-602. doi: 10.1002/jmri.24412. Epub 2013 Oct 31.
To characterize the chemical exchange saturation transfer (CEST)-based technique to measure free creatine (Cr), a key component of muscle energy metabolism, distribution in skeletal muscle with high spatial resolution before and after exercise at 3T.
CrCEST saturation parameters were empirically optimized for 3T. CEST, T2 , magnetization transfer ratio (MTR), and (31) P magnetic resonance spectroscopy (MRS) acquisitions of the lower leg were performed before and after mild plantar flexion exercise on a 3T whole-body MR scanner on six healthy volunteers.
The feasibility of imaging Cr changes in skeletal muscle following plantar flexion exercise using CrCEST was demonstrated at 3T. This technique exhibited good spatial resolution and was able to differentiate differences in muscle use among subjects. The CrCEST results were compared with (31) P MRS results, showing good agreement in the Cr and PCr recovery kinetics. A relationship of 0.45% CrCESTasym /mM Cr was observed across all subjects.
It is demonstrated that the CrCEST technique could be applied at 3T to measure dynamic changes in creatine in muscle in vivo. The widespread availability and clinical applicability of 3T scanners has the potential to clinically advance this method.
表征基于化学交换饱和转移（CEST）的技术，以在3T场强下，高空间分辨率地测量肌肉能量代谢的关键成分——游离肌酸（Cr）在运动前后骨骼肌中的分布。
针对3T场强，根据经验对CrCEST饱和参数进行了优化。在3T全身磁共振成像仪上，对6名健康志愿者进行轻度跖屈运动前后小腿的CEST、T2、磁化传递率（MTR）以及磷-31磁共振波谱（MRS）采集。
在3T场强下，证实了使用CrCEST成像观察跖屈运动后骨骼肌中Cr变化的可行性。该技术具有良好的空间分辨率，能够区分不同受试者之间肌肉使用情况的差异。将CrCEST结果与磷-31 MRS结果进行比较，结果显示在Cr和磷酸肌酸（PCr）恢复动力学方面具有良好的一致性。在所有受试者中观察到CrCEST不对称性与Cr的关系为0.45%/mM Cr。
证明了CrCEST技术可在3T场强下用于测量体内肌肉中肌酸的动态变化。3T扫描仪的广泛可用性和临床适用性有可能推动该方法在临床上的应用。
