Availability of MRI and MRS for talent identification in terms of muscle properties.

为了提高日本体育的国际竞争力，有必要有效、恰当地识别出具有优秀体育能力的个人。骨骼肌方面的天赋鉴定尤其重要，因为肌肉表现会影响运动表现。本研究旨在探讨核磁共振成像(MRI)和磁共振波谱(MRS)用于评价肌肉特性的有效性，以确定有运动天赋的个体。我们对志愿者的骨骼肌进行了MRI、磷(^&lt；31&gt；P)和碳(^&lt；13&gt；C)-MRS和生化分析。磷酸肌酸(PC)/三磷酸腺苷(ATP)、(聚合酶链式反应+无机磷酸(PI))/ATP、横向松弛时间(T2)与肌纤维类型组成呈显著正相关。在比较短跑运动员和耐力跑运动员的MRI和~(31)P-MRS数据的实验中，前者的PCR/ATP、(PCR+PI)/ATP、细胞内pH值显著高于后者，而T2则显著低于后者。我们证明，使用普通1.5特斯拉临床扫描仪的13&gt；C-MRS能够非侵入性地测量肌肉糖原浓度。此外，我们找到了评价骨骼肌扩散能力的最佳条件，以区分具有明显扩散特性的肌肉。为了研究运动过程中肌肉的能量学，我们同时进行了P-MRS和近红外光谱分析，结果表明具有较高氧化能力的肌肉表现出更好的氧可利用性。这些结果表明，MRI和MRS可以无创性地评估人体骨骼肌的纤维类型组成、能量底物浓度、微循环和氧化能力。

It is necessary to identify effectually and properly individuals who are endowed with outstanding sports capabilities in order to improve Japan's international competitiveness in sports. Talent identification in terms of skeletal muscle is especially important because the muscle performance affects sports performance. This study investigated the availability of magnetic resonance imaging(MRI) and magnetic resonance spectroscopy(MRS) for evaluation of muscle properties in order to identify individuals with a talent for sports.We performed MRI, phosphorus (^<31>P)- and carbon (^<13>C)-MRS, and biochemical assay of the skeletal muscle in volunteers. There were significant correlations between phosphocreatine (PC) / adenosine triphosphate (ATP), (PCr + inorganic phosphate (Pi) ) /ATP, transverse relaxation time (T2) and muscle fiber type composition. In the experiment comparing MRI and ^<31>P-MRS data between sprinters and endurance runners, the former showed significantly higher PCr/ATP, (PCr+Pi)/ATP, intracellular pH and lower T2 than the latter. We demonstrated that ^<13>C-MRS using normal 1.5-tesla clinical scanner enables noninvasive measurement of the muscle glycogen concentration. Moreover, we found an optimal condition for evaluating the diffusion capacity of skeletal muscle, which distinguished muscles that have a distinct diffusion property.To investigate muscle energetics during exercise, we performed ^<31>P-MRS and near infrared spectroscopy simultaneously and demonstrated that muscles possessing higher oxidative capacity show superior oxygen availability.These findings suggest that MRI and MRS can noninvasively evaluate the fiber type composition, concentration of energy substrates, microcirculation and oxidative capacity in human skeletal muscle.