正常人骨骼肌运动状态功能的磁共振动态磷谱研究
|
摘要
前言
磷谱(~(31)P-MRS)主要反映人体组织细胞的能量代谢改变,磷化物的浓度与能量代谢密切相关,测定磷代谢产物的浓度和分布可确定细胞的能量状态。因此,磷谱能探测高能磷酸物质和磷脂的含量,对研究活体组织的能量代谢具有不可替的作用,是研究肌肉病变的重要工具。动态磷谱能够测量肌肉在静息状态、收缩期和恢复过程中细胞内高能磷酸化合物的变化,评价骨骼肌做功时能量转换的效率,是研究肌肉功能的有利工具。另外,由于动态磷谱可以在体探测细胞内糖原分解代谢和氧化磷酸化的异常,使其对线粒体功能的研究具有独特的价值。
然而,在研究肌肉能量代谢中,以往国外均采用各代谢物波峰与PCr比值的方法进行间接评价,缺乏直接定量评价的方法与手段。国內~(31)P-MRS刚刚起步,还处于实验研究阶段,许多问题还需亟待解决。对~(31)P-MRS的定量方法及正常肌肉的磁共振磷谱特点尚无系统研究,特别是有关动态磷谱分析的研究受评价指标所限目前尚属空白。
本研究的创新之处在于通过对成年人和青少年大腿股四头肌进行~(31)P-MRS定量研究,分析不同年龄组个体能量代谢特点,为进一步深入研究肌肉病变及全身疾病的病理生理学特征奠定基础。通过对健康受试者的动态磷谱分析,对生理状态骨骼肌运动过程中能量代谢进行定量研究,尝试用活细胞影像学技术无创性在体评价骨骼肌的功能。
目的
本研究分别对健康成年人和健康青少年两个受试组进行静息态磷谱的定量分析,旨在探讨不同年龄组个体能量代谢特点,为进一步深入研究肌肉病变及全身疾病的病理生理学特征奠定基础;同时,通过对健康受试者的动态磷谱分析,对不同年龄组生理状态骨骼肌运动过程中能量代谢进行定量研究,尝试用活细胞影像学技术无创性在体评价骨骼肌的功能。
材料与方法
研究对象包括10例健康成年人和6例健康青少年2个受试组,年龄分别为22～55岁(38岁±12岁)和7～16岁(11岁±3岁)。所有受试者未接受过系统体育训练。在配有多核分析系统(MNS)的Philips Achieva 1.5T磁共振成像系统上对16例受试者进行~(31)P-MRS采集及定量分析。选取具有发射和接收功能的表面线圈进行波谱采集。将表面线圈固定于大腿表面。先用质子频率进行成像,观察磷谱所要采集的范围,进行自动匀场,然后用磷谱线圈进一步匀场和采集谱线。选用容积采集序列。采集参数:TR=2500ms,激励64次,磷谱采集共需3min。通过指数函数拟合计算出TR为无穷大时各化合物的峰下面积,对含磷化合物的纵向弛豫差别进行了标准化。通过测量不同厚度皮下脂肪对肌肉内化合物信号强弱的影响,计算出校正系数,对表面线圈场强不均匀性进行了标准化校正。本研究以健康成年人股四头肌内ATP含量5.5mmol/kg作为标准,对各含磷化合物进行半绝对定量分析。单位为每千克肌肉组织内该化合物的毫摩尔量(mmol/kg)。
动态磷谱研究采集磷谱前先进行股四头肌最大负荷(MVC)测试。采集运动期磷谱时分别用25%MVC(低负荷)和50%MVC(高负荷)。先采集静息期波谱,观察磷谱所要采集的范围,并进行自动匀场,然后用磷谱线圈进一步匀场和采集谱线。选用自旋回波频谱容积采集序列。每帧谱线的完成共需1min。静息期采集6帧磷谱;然后将相当于25%MVC的重量系于脚踝,让受试者在膝关节固定的情况下每5s踢1次小腿,收缩股四头肌,共采集6帧波谱,然后快速将脚踝负荷增加到50%MVC,重复上述过程,再采集6帧波谱。最后去除脚踝负荷,在恢复期采集6～10帧波谱。谱线的处理在Matlab编写的软件包上进行,经过傅立叶转换、基线调整和相位校正等过程,得到频率域的谱线。在每个时期的6帧磷谱里选取后4帧叠加在一起,得到该时期的谱线。根据各化合物的位移,确定磷酸单酯(PME)、无机磷(Pi)、磷酸二酯(PDE)、磷酸肌酸(CP)、γ-ATP、α-ATP和β-ATP共7个波峰,并对峰下面积进行定量。通过肌酸激酶催化的平衡反应,可以计算出ADP的含量;肌肉运动时的做功效率由运动负荷与Pi/CP的比值决定。
结果
一、~(31)P-MRS可直接测量的化合物的浓度
肌肉内未与大分子结合而且含量高于1mmol的代谢物质能够直接被~(31)P-MRS探测到。正常人的磁共振磷谱能清楚观察到7个代谢产物的共振波峰,由左向右依次是磷酸单酯(PME)、无机磷(Pi)、磷酸二酯(PDE)、磷酸肌酸(CP)、γ-ATP、α-ATP和β-ATP。通过计算各自的峰下面积可直接定量分析,青少年PDE含量明显低于成人,而ATP含量明显高于成人。其他化合物组间无显著性差异。
二、~(31)P-MRS可间接测量的与能量代谢相关的化合物浓度
大部分ADP与肌原纤维结合,细胞浆内游离的可溶ADP很少。不能够直接探测到。但是通过肌酸激酶催化的平衡反应,可以计算出ADP的含量。其中青少年组的pH值,镁合ATP及总镁离子含量均明显高于成人,ADP、PP、自由镁离子和游离ATP的含量组间无显著性差异。
三、青少年组与成人组动态~(31)P-MRS的比较
低负荷(25%MVC)运动时,可观察到Pi峰升高,CP峰降低;高负荷(50%MVC)运动时,Pi峰继续升高,CP峰明显降低:恢复期Pi峰降低,CP峰基本恢复到静息水平,而ATP峰在静息期、运动期和恢复期基本保持稳定。定量观察成人组和青少年组Pi、CP和β-ATP运动期的动态变化显示,两组受试者运动时Pi升高、CP降低,运动停止后基本恢复到静息期水平,其中高负荷运动期成人组Pi升高幅度较大。两组ATP相对保持恒定,青少年组的ATP值在各期均高于成人组。两组受试者细胞内总含磷量维持恒定。
成人组和青少年组肌肉静息期、运动期、恢复期各含磷化合物含量的比较:PME和PDE含量动态四期纵向变化不明显。两组间横向比较PME值无明显差别,仅在高负荷运动期,青少年组均值低于成年组。
成人及青少年股四头肌内ADP、PP、含镁离子化合物及肌肉做功效率在静止期、运动期和恢复期的比较:运动期ADP含量升高,PP含量降低,运动停止后恢复到静止期水平,两组间横向比较差异无统计学意义。Mg-ATP和总Mg~(2+)含量与ATP相似,动态四期保持恒定,青少年组含量高于成人组。自山Mg~(2+)和自由ATP两组间差异无统计学意义。肌肉功效由负荷的重量/(Pi/CP)决定,高负荷时肌肉功效增加,虽然成人组负荷较高,但两组肌肉做功效率差异无统计学意义。
结论
1、磷谱可以对多种参与能量代谢的化合物进行定量研究,并能够无创性探测细胞内的微环境,是在体能量代谢的重要工具。
2、本研究通过对肌肉磷谱的定量分析,明确成人和青少年组的能量代谢特点,为客观分析肌肉系统的疾病奠定了良好的基础。
3、骨骼肌细胞内可直接利用的能量较高,但储备能量物质和运动时肌肉做功效率与成人相似;骨骼肌做功时细胞内高能磷酸化合物相互转换维持正常的功能。
4、动态磷谱可以无创性定量评价骨骼肌不同运动状态能量代谢特点,为肌肉的功能影像学提供客观信息。
Preface
Phosphorus MR spectroscopy has special capabilities in the analysis of in vivo energy metabolism of human tissue and cell.The concentration of phosphide is correlated well with energy metabolism,determination of concentration and distribution of phosphorus metabolism can reflect cellular energy status.Therefore,phosphorus MR spectroscopy,which can detect content of both energy-rich phosphate and phospholipids, plays an important role in the study of in vivo energy metabolism of tissues and should be an important tool in the study of diseases associated with muscle.Dynamic phosphorus MR spectroscopy can measure the change of cellular energy-rich phosphate compounds during rest,systolic phase,and restoration process;evaluate the efficiency of energy conversion during working of skeletal muscle.It is useful tool to study of muscle function.In addition,dynamic phosphorus MR spectroscopy is also an important tool to study of mitochondria function due to its capacity of detection of disturbance of intra-cellular glycogenolysis and oxidative phosphorylation in vivo.
However,in the past,the ratios of every metabolite peaks to the peak of PCr were used in similar abroad study to indirectly evaluate the muscular energy metabolism,lack of methods and approach of direct quantitative assessment.Domestic similar study of phosphorus MR spectroscopy is just recently on the way,and most in the experimental and unsolved status.The quantitative method of phosphorus MR spectroscopy and phosphorus MR spectroscopy characteristic of normal muscle have not been systematical studied.Especially,the study of dynamic phosphorus MR spectroscopy is vacant which is limited by evaluated index.
Our studies are to quantitatively evaluate phosphorus MR spectroscopy of quadriceps muscle of thigh in adult and adolescent age groups,to evaluate the energy metabolism of normal muscle in different age group,therefore,it can establish the basis for further study of pathophysiology characteristic of both muscle diseases and systematic diseases.Meanwhile,our studies are to evaluate skeletal muscle function of health volunteers using in vivo dynamic phosphorus MR spectroscopy,to quantitative study of energy metabolism of skeletal muscle in physiological state during exercise.It is the attempt to noninvasively evaluate the skeletal muscle function using living cell imaging technique.
Purpose
Our studies are to evaluate the energy metabolism of normal muscle.In resting state in adult and adolescent age groups,in order to investigate individual energy metabolism feature in different age group,which can establish the basis for further study of pathophysiology characteristic of both muscle diseases and systematic diseases. Meanwhile,our studies are to evaluate skeletal muscle function of health volunteers using in vivo dynamic phosphorus MR spectroscopy(~(31)P-MRS),to quantitative study of energy metabolism of skeletal muscle in physiological state during exercise.It is the attempt to noninvasively evaluate the skeletal muscle function using living cell imaging technique.
Materials and Methods
Noninvasive 31P-MRS was acquired from quadriceps muscles in healthy people including 10 adults and 6juvenile,the ages range from 22 to 55 years old(median age 38±12),and from 7 to 16 years old(median age 11±3).All subjects haven't received systematical physical training and all 16 subjects have received ~(31)P-MRS data collection and quantitative analysis on 1.5T Philips Achieva magnetic resonance system which equipped with polynucleation analysis system.~(31)P-MRS data collection was using surface coil with capacity of both reception and emission surface coil.The surface coil was fixed on the surface of thigh.Imaging was firstly acquired using proton frequency to observe the scope of acquisition of ~(31)P-MRS;and then automatic shimming,further shimming and acquisition of spectral lines were performed respectively.Volume acquisition sequence was used in the course of acquisition of spectral lines.Acquisition parameters were:TR =2500ms,excitation=64 times,total acquisition time=3min. Calculation of the area under every metabolite peak when presence of infinity TR was performed using fitting of exponential function,and standardization of difference of longitudinal relaxation of phosphorus compounds was also performed.Correction factor was calculated by measuring of signal effect of different intramusculary compounds with different layers of subcutaneous fat in order to perform standardized correction of heterogeneity of field strength for surface coil.Content of ATP was 5.5mmol/kg as standard to perform half absolutely quantitive analysis of every phosphorus compound in our study(unit:mmol/kg).
Maximum voluntary contraction(MVC) testing of musculus quadriceps fexoris was performed before dynamic ~(31)P-MRS study.25%of MVC(low-load) and 50%of MVC(high-load) were used respectively during acquisition of ~(31)P-MRS on moving state. Imaging at resting state was firstly acquired using proton frequency to observe the scope of acquisition of ~(31)P-MRS;and then automatic shimming,further shimming and acquisition of spectral lines were performed respectively.Volume acquisition sequence was used in the course of acquisition of spectral lines.Total acquisition time for every spectral line was 1min.Six spectral lines at resting state were acquired.Meanwhile, materials with equivalent weight of 25%MVC was strained to ankle,and the subjects were asked to kick one time every 5s in order to contract musculus quadriceps,total six spectral lines at moving state were acquired.And then,loading of ankle was rapidly increased to 50%MVC,above-mentioned procedures were repeated,another six spectral lines at moving state were acquired.Finally,six to ten spectral lines at convalescence stage were acquired after removal of ankle loading.Processing of spectral lines were performed using package basis on Matlab software.Through the procedure of Fourier transformation,baseline modulation,and phase correction,spectral line with different frequency domain was acquired.Four spectral lines were selected from six spectral lines in every stage and superimposed to form spectral line of stage.The absolute concentration of PME,Pi,PDE,CP and ATP were determined from spectra,and the value of ADP,phosphorylation potential(PP),and enzymatically active Mg-ATP complex were calculated.The work / cost ratios were derived from weight /(Pi / CP) to compare muscle efficiency between adults and young subjects.
Results
1.~(31)P-MRS can directly measure concentration of some of chemical compounds
The content of intramusculary metabolite greater than 1mmol can be detected directly by ~(31)P-MRS when it was without macromolecular binding.Seven resonance peaks of metabolism products were observed:from left to fight one by onehosphomonoesterase (PME),inorganic phosphate(Pi),phosphodiesterase(PDE), phosphocreatine(CP),γ-adenosine triphosphate(ATP),α-ATP,andβ-ATP.Quantitative analysis can be performed by calculation of the area of under every peak,the content of PDE for adolescent was obviously decreased compared with that for adult;while the content of ATP was obviously increased.There was no significant difference for other chemical compounds.
2.~(31)P-MRS can indirectly measure concentration of chemical compounds which were related with energy metabolism
Most of ADP were combined with myofibrillae,therefore,free dissolvable ADP in cytoplasm was less and impossible to detect.However,the content of ADP could be calculated according to equilibrium reaction of enzymatic creatinkinase.The level of PH value,Mg-ATP,and total Mg for adolescent was obviously decreased compared with that for adult,while there were no significant difference for the contents of ADP,PP, free Mg iron,and free ATP when different age group was compared.
3.Comparison of dynamic ~(31)P-MRS results in adolescent group and adult group
The peak of Pi was increased and the peak of CP was decreased when low-load(25 %of MVC) movement was performed;The peak of Pi was continually increased and the peak of CP was obviously decreased when high-load(50%of MVC) movement was performed;The peak of Pi was decreased and the peak of CP was approximately returned to the level of rest state at convalescence stage.However,the level of ATP was approximately constant at rest stage,at moving stage,and at convalescence stage. Quantitative observation of dynamic changes of Pi,CP,andβ-ATP of different age group at moving stage showed that the level of Pi was increased and the level of CP was decreased during the movement for both two groups,and the levels of both Pi and CP were approximately returned to the levels of rest state after the cessation of movement. Among them,the increase of Pi in adult group was greater during high-load movement. However,the level of ATP was approximately constant in these two groups,the level of ATP in adolescent group greater in different stage compared with that in adult group. The total intra-cellular phosphoric content remained constant for two groups of subjects.
Comparison of phosphoric contents in different stage for adolescent group and adult group:There were no significant longitudinal change of PME and PDE.And there was no significant difference of PME for two age group when transversal comparison was performed.Only in high load moving stage,the mean value of PME for adolescent group was lower than that for adult group.
Comparison of the content of ADP,PP,Mg ionic compound in musculus quadriceps fexoris and working efficiency of muscle in different stage for two age groups:
The content of ADP was increased and the content of PP was decreased during the movement;and return to the level of rest stage after the cessation of movement.There was no statistical difference for two different age groups.While the content of Mg-ATP and total Mg iron remains constant,though slightly increased in adolescent group.There was no statistical difference of free Mg iron and free ATP for two different age groups. Muscle efficacy was depend on loading weight/(Pi/CP),muscle efficacy was increased during high loading.There was no statistical difference for two different age groups, though slightly increased in adult group.
Conclusion
Phosphorus MR spectroscopy has special capabilities in the quantitative study of many kinds of chemical compounds which participate in the course of energy metabolism,and it can non-invasively detect intracellular microenvironment.Our studies are to evaluate the energy metabolism of normal muscle in adult and adolescent age groups, and successfully investigate individual energy metabolism feature in different age group, which can establish the basis for further study of pathophysiology characteristic of muscle diseases.
High energy compounds which can be directly utilized in skeletal muscle in juvenile subjects were slightly higher,while capabilities of energy reservation and working efficiency in juvenile subjects were similar with those in adult.Intra-cellular interconversion of energy-rich phosphate plays an important role in the maintaining of normal function of skeletal muscle during exercise.Dynamic ~(31)P-MRS can reflect energy metabolism of skeletal muscle during exercise and provides valuable information to evaluate muscle functional imaging.
磷谱(~(31)P-MRS)主要反映人体组织细胞的能量代谢改变,磷化物的浓度与能量代谢密切相关,测定磷代谢产物的浓度和分布可确定细胞的能量状态。因此,磷谱能探测高能磷酸物质和磷脂的含量,对研究活体组织的能量代谢具有不可替的作用,是研究肌肉病变的重要工具。动态磷谱能够测量肌肉在静息状态、收缩期和恢复过程中细胞内高能磷酸化合物的变化,评价骨骼肌做功时能量转换的效率,是研究肌肉功能的有利工具。另外,由于动态磷谱可以在体探测细胞内糖原分解代谢和氧化磷酸化的异常,使其对线粒体功能的研究具有独特的价值。
然而,在研究肌肉能量代谢中,以往国外均采用各代谢物波峰与PCr比值的方法进行间接评价,缺乏直接定量评价的方法与手段。国內~(31)P-MRS刚刚起步,还处于实验研究阶段,许多问题还需亟待解决。对~(31)P-MRS的定量方法及正常肌肉的磁共振磷谱特点尚无系统研究,特别是有关动态磷谱分析的研究受评价指标所限目前尚属空白。
本研究的创新之处在于通过对成年人和青少年大腿股四头肌进行~(31)P-MRS定量研究,分析不同年龄组个体能量代谢特点,为进一步深入研究肌肉病变及全身疾病的病理生理学特征奠定基础。通过对健康受试者的动态磷谱分析,对生理状态骨骼肌运动过程中能量代谢进行定量研究,尝试用活细胞影像学技术无创性在体评价骨骼肌的功能。
目的
本研究分别对健康成年人和健康青少年两个受试组进行静息态磷谱的定量分析,旨在探讨不同年龄组个体能量代谢特点,为进一步深入研究肌肉病变及全身疾病的病理生理学特征奠定基础;同时,通过对健康受试者的动态磷谱分析,对不同年龄组生理状态骨骼肌运动过程中能量代谢进行定量研究,尝试用活细胞影像学技术无创性在体评价骨骼肌的功能。
材料与方法
研究对象包括10例健康成年人和6例健康青少年2个受试组,年龄分别为22～55岁(38岁±12岁)和7～16岁(11岁±3岁)。所有受试者未接受过系统体育训练。在配有多核分析系统(MNS)的Philips Achieva 1.5T磁共振成像系统上对16例受试者进行~(31)P-MRS采集及定量分析。选取具有发射和接收功能的表面线圈进行波谱采集。将表面线圈固定于大腿表面。先用质子频率进行成像,观察磷谱所要采集的范围,进行自动匀场,然后用磷谱线圈进一步匀场和采集谱线。选用容积采集序列。采集参数:TR=2500ms,激励64次,磷谱采集共需3min。通过指数函数拟合计算出TR为无穷大时各化合物的峰下面积,对含磷化合物的纵向弛豫差别进行了标准化。通过测量不同厚度皮下脂肪对肌肉内化合物信号强弱的影响,计算出校正系数,对表面线圈场强不均匀性进行了标准化校正。本研究以健康成年人股四头肌内ATP含量5.5mmol/kg作为标准,对各含磷化合物进行半绝对定量分析。单位为每千克肌肉组织内该化合物的毫摩尔量(mmol/kg)。
动态磷谱研究采集磷谱前先进行股四头肌最大负荷(MVC)测试。采集运动期磷谱时分别用25%MVC(低负荷)和50%MVC(高负荷)。先采集静息期波谱,观察磷谱所要采集的范围,并进行自动匀场,然后用磷谱线圈进一步匀场和采集谱线。选用自旋回波频谱容积采集序列。每帧谱线的完成共需1min。静息期采集6帧磷谱;然后将相当于25%MVC的重量系于脚踝,让受试者在膝关节固定的情况下每5s踢1次小腿,收缩股四头肌,共采集6帧波谱,然后快速将脚踝负荷增加到50%MVC,重复上述过程,再采集6帧波谱。最后去除脚踝负荷,在恢复期采集6～10帧波谱。谱线的处理在Matlab编写的软件包上进行,经过傅立叶转换、基线调整和相位校正等过程,得到频率域的谱线。在每个时期的6帧磷谱里选取后4帧叠加在一起,得到该时期的谱线。根据各化合物的位移,确定磷酸单酯(PME)、无机磷(Pi)、磷酸二酯(PDE)、磷酸肌酸(CP)、γ-ATP、α-ATP和β-ATP共7个波峰,并对峰下面积进行定量。通过肌酸激酶催化的平衡反应,可以计算出ADP的含量;肌肉运动时的做功效率由运动负荷与Pi/CP的比值决定。
结果
一、~(31)P-MRS可直接测量的化合物的浓度
肌肉内未与大分子结合而且含量高于1mmol的代谢物质能够直接被~(31)P-MRS探测到。正常人的磁共振磷谱能清楚观察到7个代谢产物的共振波峰,由左向右依次是磷酸单酯(PME)、无机磷(Pi)、磷酸二酯(PDE)、磷酸肌酸(CP)、γ-ATP、α-ATP和β-ATP。通过计算各自的峰下面积可直接定量分析,青少年PDE含量明显低于成人,而ATP含量明显高于成人。其他化合物组间无显著性差异。
二、~(31)P-MRS可间接测量的与能量代谢相关的化合物浓度
大部分ADP与肌原纤维结合,细胞浆内游离的可溶ADP很少。不能够直接探测到。但是通过肌酸激酶催化的平衡反应,可以计算出ADP的含量。其中青少年组的pH值,镁合ATP及总镁离子含量均明显高于成人,ADP、PP、自由镁离子和游离ATP的含量组间无显著性差异。
三、青少年组与成人组动态~(31)P-MRS的比较
低负荷(25%MVC)运动时,可观察到Pi峰升高,CP峰降低;高负荷(50%MVC)运动时,Pi峰继续升高,CP峰明显降低:恢复期Pi峰降低,CP峰基本恢复到静息水平,而ATP峰在静息期、运动期和恢复期基本保持稳定。定量观察成人组和青少年组Pi、CP和β-ATP运动期的动态变化显示,两组受试者运动时Pi升高、CP降低,运动停止后基本恢复到静息期水平,其中高负荷运动期成人组Pi升高幅度较大。两组ATP相对保持恒定,青少年组的ATP值在各期均高于成人组。两组受试者细胞内总含磷量维持恒定。
成人组和青少年组肌肉静息期、运动期、恢复期各含磷化合物含量的比较:PME和PDE含量动态四期纵向变化不明显。两组间横向比较PME值无明显差别,仅在高负荷运动期,青少年组均值低于成年组。
成人及青少年股四头肌内ADP、PP、含镁离子化合物及肌肉做功效率在静止期、运动期和恢复期的比较:运动期ADP含量升高,PP含量降低,运动停止后恢复到静止期水平,两组间横向比较差异无统计学意义。Mg-ATP和总Mg~(2+)含量与ATP相似,动态四期保持恒定,青少年组含量高于成人组。自山Mg~(2+)和自由ATP两组间差异无统计学意义。肌肉功效由负荷的重量/(Pi/CP)决定,高负荷时肌肉功效增加,虽然成人组负荷较高,但两组肌肉做功效率差异无统计学意义。
结论
1、磷谱可以对多种参与能量代谢的化合物进行定量研究,并能够无创性探测细胞内的微环境,是在体能量代谢的重要工具。
2、本研究通过对肌肉磷谱的定量分析,明确成人和青少年组的能量代谢特点,为客观分析肌肉系统的疾病奠定了良好的基础。
3、骨骼肌细胞内可直接利用的能量较高,但储备能量物质和运动时肌肉做功效率与成人相似;骨骼肌做功时细胞内高能磷酸化合物相互转换维持正常的功能。
4、动态磷谱可以无创性定量评价骨骼肌不同运动状态能量代谢特点,为肌肉的功能影像学提供客观信息。
Preface
Phosphorus MR spectroscopy has special capabilities in the analysis of in vivo energy metabolism of human tissue and cell.The concentration of phosphide is correlated well with energy metabolism,determination of concentration and distribution of phosphorus metabolism can reflect cellular energy status.Therefore,phosphorus MR spectroscopy,which can detect content of both energy-rich phosphate and phospholipids, plays an important role in the study of in vivo energy metabolism of tissues and should be an important tool in the study of diseases associated with muscle.Dynamic phosphorus MR spectroscopy can measure the change of cellular energy-rich phosphate compounds during rest,systolic phase,and restoration process;evaluate the efficiency of energy conversion during working of skeletal muscle.It is useful tool to study of muscle function.In addition,dynamic phosphorus MR spectroscopy is also an important tool to study of mitochondria function due to its capacity of detection of disturbance of intra-cellular glycogenolysis and oxidative phosphorylation in vivo.
However,in the past,the ratios of every metabolite peaks to the peak of PCr were used in similar abroad study to indirectly evaluate the muscular energy metabolism,lack of methods and approach of direct quantitative assessment.Domestic similar study of phosphorus MR spectroscopy is just recently on the way,and most in the experimental and unsolved status.The quantitative method of phosphorus MR spectroscopy and phosphorus MR spectroscopy characteristic of normal muscle have not been systematical studied.Especially,the study of dynamic phosphorus MR spectroscopy is vacant which is limited by evaluated index.
Our studies are to quantitatively evaluate phosphorus MR spectroscopy of quadriceps muscle of thigh in adult and adolescent age groups,to evaluate the energy metabolism of normal muscle in different age group,therefore,it can establish the basis for further study of pathophysiology characteristic of both muscle diseases and systematic diseases.Meanwhile,our studies are to evaluate skeletal muscle function of health volunteers using in vivo dynamic phosphorus MR spectroscopy,to quantitative study of energy metabolism of skeletal muscle in physiological state during exercise.It is the attempt to noninvasively evaluate the skeletal muscle function using living cell imaging technique.
Purpose
Our studies are to evaluate the energy metabolism of normal muscle.In resting state in adult and adolescent age groups,in order to investigate individual energy metabolism feature in different age group,which can establish the basis for further study of pathophysiology characteristic of both muscle diseases and systematic diseases. Meanwhile,our studies are to evaluate skeletal muscle function of health volunteers using in vivo dynamic phosphorus MR spectroscopy(~(31)P-MRS),to quantitative study of energy metabolism of skeletal muscle in physiological state during exercise.It is the attempt to noninvasively evaluate the skeletal muscle function using living cell imaging technique.
Materials and Methods
Noninvasive 31P-MRS was acquired from quadriceps muscles in healthy people including 10 adults and 6juvenile,the ages range from 22 to 55 years old(median age 38±12),and from 7 to 16 years old(median age 11±3).All subjects haven't received systematical physical training and all 16 subjects have received ~(31)P-MRS data collection and quantitative analysis on 1.5T Philips Achieva magnetic resonance system which equipped with polynucleation analysis system.~(31)P-MRS data collection was using surface coil with capacity of both reception and emission surface coil.The surface coil was fixed on the surface of thigh.Imaging was firstly acquired using proton frequency to observe the scope of acquisition of ~(31)P-MRS;and then automatic shimming,further shimming and acquisition of spectral lines were performed respectively.Volume acquisition sequence was used in the course of acquisition of spectral lines.Acquisition parameters were:TR =2500ms,excitation=64 times,total acquisition time=3min. Calculation of the area under every metabolite peak when presence of infinity TR was performed using fitting of exponential function,and standardization of difference of longitudinal relaxation of phosphorus compounds was also performed.Correction factor was calculated by measuring of signal effect of different intramusculary compounds with different layers of subcutaneous fat in order to perform standardized correction of heterogeneity of field strength for surface coil.Content of ATP was 5.5mmol/kg as standard to perform half absolutely quantitive analysis of every phosphorus compound in our study(unit:mmol/kg).
Maximum voluntary contraction(MVC) testing of musculus quadriceps fexoris was performed before dynamic ~(31)P-MRS study.25%of MVC(low-load) and 50%of MVC(high-load) were used respectively during acquisition of ~(31)P-MRS on moving state. Imaging at resting state was firstly acquired using proton frequency to observe the scope of acquisition of ~(31)P-MRS;and then automatic shimming,further shimming and acquisition of spectral lines were performed respectively.Volume acquisition sequence was used in the course of acquisition of spectral lines.Total acquisition time for every spectral line was 1min.Six spectral lines at resting state were acquired.Meanwhile, materials with equivalent weight of 25%MVC was strained to ankle,and the subjects were asked to kick one time every 5s in order to contract musculus quadriceps,total six spectral lines at moving state were acquired.And then,loading of ankle was rapidly increased to 50%MVC,above-mentioned procedures were repeated,another six spectral lines at moving state were acquired.Finally,six to ten spectral lines at convalescence stage were acquired after removal of ankle loading.Processing of spectral lines were performed using package basis on Matlab software.Through the procedure of Fourier transformation,baseline modulation,and phase correction,spectral line with different frequency domain was acquired.Four spectral lines were selected from six spectral lines in every stage and superimposed to form spectral line of stage.The absolute concentration of PME,Pi,PDE,CP and ATP were determined from spectra,and the value of ADP,phosphorylation potential(PP),and enzymatically active Mg-ATP complex were calculated.The work / cost ratios were derived from weight /(Pi / CP) to compare muscle efficiency between adults and young subjects.
Results
1.~(31)P-MRS can directly measure concentration of some of chemical compounds
The content of intramusculary metabolite greater than 1mmol can be detected directly by ~(31)P-MRS when it was without macromolecular binding.Seven resonance peaks of metabolism products were observed:from left to fight one by onehosphomonoesterase (PME),inorganic phosphate(Pi),phosphodiesterase(PDE), phosphocreatine(CP),γ-adenosine triphosphate(ATP),α-ATP,andβ-ATP.Quantitative analysis can be performed by calculation of the area of under every peak,the content of PDE for adolescent was obviously decreased compared with that for adult;while the content of ATP was obviously increased.There was no significant difference for other chemical compounds.
2.~(31)P-MRS can indirectly measure concentration of chemical compounds which were related with energy metabolism
Most of ADP were combined with myofibrillae,therefore,free dissolvable ADP in cytoplasm was less and impossible to detect.However,the content of ADP could be calculated according to equilibrium reaction of enzymatic creatinkinase.The level of PH value,Mg-ATP,and total Mg for adolescent was obviously decreased compared with that for adult,while there were no significant difference for the contents of ADP,PP, free Mg iron,and free ATP when different age group was compared.
3.Comparison of dynamic ~(31)P-MRS results in adolescent group and adult group
The peak of Pi was increased and the peak of CP was decreased when low-load(25 %of MVC) movement was performed;The peak of Pi was continually increased and the peak of CP was obviously decreased when high-load(50%of MVC) movement was performed;The peak of Pi was decreased and the peak of CP was approximately returned to the level of rest state at convalescence stage.However,the level of ATP was approximately constant at rest stage,at moving stage,and at convalescence stage. Quantitative observation of dynamic changes of Pi,CP,andβ-ATP of different age group at moving stage showed that the level of Pi was increased and the level of CP was decreased during the movement for both two groups,and the levels of both Pi and CP were approximately returned to the levels of rest state after the cessation of movement. Among them,the increase of Pi in adult group was greater during high-load movement. However,the level of ATP was approximately constant in these two groups,the level of ATP in adolescent group greater in different stage compared with that in adult group. The total intra-cellular phosphoric content remained constant for two groups of subjects.
Comparison of phosphoric contents in different stage for adolescent group and adult group:There were no significant longitudinal change of PME and PDE.And there was no significant difference of PME for two age group when transversal comparison was performed.Only in high load moving stage,the mean value of PME for adolescent group was lower than that for adult group.
Comparison of the content of ADP,PP,Mg ionic compound in musculus quadriceps fexoris and working efficiency of muscle in different stage for two age groups:
The content of ADP was increased and the content of PP was decreased during the movement;and return to the level of rest stage after the cessation of movement.There was no statistical difference for two different age groups.While the content of Mg-ATP and total Mg iron remains constant,though slightly increased in adolescent group.There was no statistical difference of free Mg iron and free ATP for two different age groups. Muscle efficacy was depend on loading weight/(Pi/CP),muscle efficacy was increased during high loading.There was no statistical difference for two different age groups, though slightly increased in adult group.
Conclusion
Phosphorus MR spectroscopy has special capabilities in the quantitative study of many kinds of chemical compounds which participate in the course of energy metabolism,and it can non-invasively detect intracellular microenvironment.Our studies are to evaluate the energy metabolism of normal muscle in adult and adolescent age groups, and successfully investigate individual energy metabolism feature in different age group, which can establish the basis for further study of pathophysiology characteristic of muscle diseases.
High energy compounds which can be directly utilized in skeletal muscle in juvenile subjects were slightly higher,while capabilities of energy reservation and working efficiency in juvenile subjects were similar with those in adult.Intra-cellular interconversion of energy-rich phosphate plays an important role in the maintaining of normal function of skeletal muscle during exercise.Dynamic ~(31)P-MRS can reflect energy metabolism of skeletal muscle during exercise and provides valuable information to evaluate muscle functional imaging.
引文
1 Mattei JP, Bendahan D, Cozzone P. 31P Magnetic resonance spectroscopy, a tool for diagnostic purposes and pathophysiological insights in muscle disease. Reumatismo, 2004, 56 (1): 9-14.
2 Prompers JJ, Jeneson JA, DrostMR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed,2006, 19 (7) :927-953.
3 Kuesel AC, Stoyanova R, Aiken NR,et al. Quantitation of resonances in biological 31P NMR spectra via principal component analysis: potential and limitations. NMR Biomed.1996 ; 9(3):93-104.
4 Buchli R, Boesiger P. Comparison of methods for the determination of absolute metabolite concentrations in human muscles by ~(31)P-MRS. Magn Reson Med, 1993, 30 (5):552-558.
5 Chance B, Leigh JS, Clark BJ, et al. Control of oxidative metabolism and oxygen delivery in human skeletal muscle: a steady state analysis of the work /energy cost transfer function. Proc Natl Acad Sci USA, 1985, 82 (24): 8384-8388.
6 Park JH, Olsen NJ, King L. Use of magnetic resonance imaging and ~(31)P magnetic resonance spectroscopy to detect and quantify muscle dysfunction in the amyopathic and myopathic variants of dermatomyositis. Arthritis Rheum, 1995,38 (1): 68 - 77.
7 Gadian DG, Radda GK, Brown TR, et al. The activity of creatine kinase in frog skeletal muscle studied by saturation - transfer nuclear magnetic resonance. Biochem J, 1981, 194 (1): 215 -28.
8 Mosher TJ, Williams GD, Doumen C, et al. Error in the calibration of the Mg-ATP chemical -shift limit: effects on the determination of free magnesium by ~(31)P-NMR spectroscopy. Magn Reson Med, 1992,24 (1): 163-169.
9 Buchli R, MeierD, Martin E, et al. Assessment of absolute metabolite concentrations in human tissue by ~(31)P-MRS in vivo. Part Ⅱ: Muscle, liver, kidney. Magn ResonMed, 1994, 32 (4): 453-458.
10 Redmond OM, Stack JP, O'ConnorNG, et al.~(31)P-MRS as an early prognostic indicator of patient response to chemotherapy. Magn Reson Med, 1992,25 (1): 30-44.
11 Podo F. Tumour phospholipid metabolism. NMR Biomed, 1999,12 (7): 413- 39.
12 Niermann KJ, Olsen NJ, Park JH. Magnesium abnormalities of skeletal muscle in dermatomyositis and juvenile dermatomyositis. Arthritis Rheum, 2002, 46 (2):475-488.
13 Park JH, Niermann KJ, Ryder NM, et al. Muscle abnormalities in juvenile dermatomyositis patients: ~(31)P magnetic resonance spectroscopy studies. Arthritis Rheum, 2000, 43 (10): 2359-2367.
14 Argov Z, Lofberg M, Arnold DL. Insights into muscle diseases gained by phosphorus magnetic resonance spectroscopy. Muscle Nerve, 2000, 23 (9):1316-1334.
1 Kemp GJ, Meyerspeer M, Moser E. Absolute quantification of phosphorus metabolite concentrations in human muscle in vivo by ~(31)P -MRS: a quantitative review. NMR Biomed. 2007 ;20 (6):555-65.
2 Barker A, Welsman J, Welford D, et al. Reliability of ~(31)P-magnetic resonance spectroscopy during an exhaustive incremental exercise test in children. Eur J Appl Physiol. 2006;98(6):556-65.
3 Prompets JJ, Jeneson JA, Drost MR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed. 2006, 19(7): 927-53.
4 Mattei JP, Bendahan D, Cozzone P. ~(31)P Magnetic Resonance Spectroscopy. A tool for diagnostic purposes and pathophysiological insights in muscle disease. Reumatismo. 2004, 56(1):9—14.
5 Argov Z, Ldberg M, Amold DL. Insights into muscle diseases gained by phosphorus magnetic resonance spectroscopy. Muscle Nerve. 2000, 23(9):1316-34.
6 Park JH, Niermann KJ, Ryder NM, et al . Muscle abnormalities in juvenile dermatomyositis patients: ~(31)P magnetic resonance spectroscopy studies. Arthritis& Rheumatism. 2000, 43(10):2359-67.
7 Buchli R, Boesiger P. Comparison of methods for the determination of absolute metabolite concentrations in human muscles by ~(31)P-MRS. Magn Reson Med. 1993, 30(5): 552-8.
8 Taylor DJ, Fore PJ, Styles P, et al. Bioenergetics of intact human muscles: A ~(31)P nuclear magnetic resonance study. Mol Biol Med. 1983, 1(1):77-94.
9 Park JH, Olsen NJ, KingL. Use of magnetic resonance imaging and ~(31)P magnetic resonance spectroscopy to detect and quantify muscle dysfunction in the amyopathic and myopathic variants of dermatomyositis . Arthritis and Rheumatism. 1995 , 38(1): 68-77.
10 Mosher TJ, Wams GD, Doumen C, et al. Error in the calibration of the Mg ATP chemical-shift limit: effects on the determination of free magnesium by ~(31)p-NMR spectroscopy. Magn Reson Med. 1992, 24(1):163-9 .
11 Moiler HE, Kuflemann G, Putzler M, et al. Magnetic resonance spectroscopy in patients with MELAS. J Neurol Sci.2005, Mar 15:229-230:131-9.
12 Kornblum C, Schroder R.Muller K, et al.Creatine has no beneficial effect on skeletal muscle energy metabolism in patients with single mitochondrial DNA deletions: A placebo-controlled, double-blind ~(31)P-MRS crossover study. Eur J Neurol. 2005,12(4):300-9.
13 Barker A, Welsman J, Welford D, et al. Reliability of ~(31)P-magnetic resonance spectroscopy during an exhaustive incremental exercise test in children. Eur J Appl Physiol. 2006;98 (6):556-65.
14 Haseler LJ, Lin AP, Richardson RS. Skeletal muscle oxidative metabolism in sedentary humans: ~(31)P-MRS assessment of 02 supply and demand limitations. J Appl Physiol. 2004;97(3):1077-81.
15 Prompers JJ, Jeneson JA, Drost MR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed. 2006;19(7):927-53.
16 Mancini L, Payne GS, Leach MO. Comparison of polarization transfer sequences for enhancement of signals in clinical ~(31)PMRS studies. Magn Reson Med. 2003;50(3):578-88.
17 Podo F. Tumour phospholipid metabolism. NMR Biomod, 1999, 12: 413.
1 Deicken RF, Calabrese G, Merrin EL,et al. Asymmetry of temporal lobe phosphorous metabolism in schizophrenia: a 31phosphorous magnetic resonance spectroscopic imaging study. 1995;38(5):279-86.
2 Kuesel AC, Stoyanova R, Aiken NR, et al. Quantitation of resonances in biological ~(31)P NMR spectra via principal component analysis: potential and limitations. NMR Biomed. 1996 ;9(3):93-104.
3 McCully K, Mncini D, Levine S, et al. Nuclear magnetic resonance spectroscopy: its role in providing valuable insight into diverse clinical problem. Chest. 1999, 116(5):1434-1441.
4 Kemp GJ, Meyerspeer M, Moser E. Absolute quantification of phosphorus metabolite concentrations in human muscle in vivo by ~(31)P- MRS: a quantitative review. NMR Biomed. 2004 ;20 (6):555-65.
5 Prompers JJ, Jeneson JA, Drost MR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed. 2003;19(7):927-53.
6 Kemp GJ, Roberts N, Bimson WE, et al. Muscle oxygenation and ATP turnover when blood flow is impaired by vascular disease.Mol Biol Rep. 2002;29(1-2):187-91.
7 Mancini L, Payne GS, Leach MO. Comparison of polarization transfer sequences for enhancement of signals in clinical ~(31)P-MRS studies. Magn Reson Med. 2003;50(3):578-88.
8 Rzanny R, Grassme R, Reichenbach JR, et al. Investigations of back muscle fatigue by simultaneous ~(31)P -MRS and surface EMG measurements. Biomed Tech (Berl). 2003; 51(5-6): 305-13.
9 Jeppesen TD, Quistorff B, Wibrand F, et al. ~(31)P-MRS of skeletal muscle is not a sensitive diagnostic test for mitochondrial myopathy. J Neurol. 2004;254(1):29-37.
10 Rossiter HB, Ward SA, Howe FA, et al. Dynamics of intramuscular ~(31)P-MRS P(i) peak splitting and the slow components of PCr and 02 uptake during exercise. J Appl Physiol. 2002;93 (6):2059-69.
11 Malucelli E, Lodi R, Martinuzzi A, et al. Free Mg~(2+)concentration in the calf muscle of glycogen phosphorylase and phosphofructokinase deficiency patients assessed in different metabolic conditions by ~(31)P-MRS. Dyn Med. 2003Jun 6;4:7.
12 Barker A, Welsman J, Welford D, et al. Reliability of ~(31)P-magnetic resonance spectroscopy during an exhaustive incremental exercise test in children. Eur J Appl Physiol. 2004;98(6):556-65.
13 Kimura N, Hamaoka T, Kurosawa Y,et al. Contribution of intramuscular oxidative metabolism to total ATP production during forearm isometric exercise at varying intensities. Tohoku J Exp Med. 2004;208(4):307-20.
14 Brosseau OE, Mahdjoub R, Seurin MJ, et al. Kinetics of anaerobic metabolism in human skeletal muscle: influence of repetitive high-intensity exercise on sedentary dominant and non-dominant forearm. A ~(31)P NMR study. Biochimie. 2003;85(9):885-90.
15 Meyerspeer M, Krssak M, Moser E. Relaxation times of ~(31)P-metabolites in human calf muscle at 3 T. Magn Reson Med. 2003;49(4):620-5.
16 Prompers JJ, Jeneson JA, Drost MR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed. 2003;19(7):927-53.
17 Pedersen BL, Arendrup H, Secher NH, et al. Metabolism of perfused pig intercostal muscles evaluated by ~(31)P-magnetic resonance spectroscopy.Exp Physiol. 2004 ; 91 (4): 755-63.
18 Kornblum C, Schroder R, Muller K,et al. Creatine has no beneficial effect on skeletal muscle energy metabolism in patients with single mitochondrial DNA deletions: a placebo-controlled, double-blind ~(31)P-MRS crossover study. Eur J Neurol. 2003;12(4):300-9.
19 Hug F, Bendahan D, Le Fur Y, et al. Metabolic recovery in professional road cyclists: a ~(31)P-MRS study.Med Sci Sports Exerc. 2002:37(5):846-52.
20 Meyerspeer M, Krssak M, Kemp GJ, et al. Dynamic interleaved ~1H/~(31)P STEAM MRS at 3 Tesla using a pneumatic force-controlled plantar flexion exercise rig. MAGMA. 2004;18(5):257-62.
21 Arias-Mendoza F, Zakian K, Schwartz A, et al. Methodological standardization for a multi-institutional in vivo trial of localized ~(31)P MR spectroscopy in human cancer research. In vitro and normal volunteer studies. NMR Biomed. 2004;17(6):382-91.
22 Kime R, Katsumura T, Hamaoka T, et al. Muscle reoxygenation rate after isometric exercise at various intensities in relation to muscle oxidative capacity. Adv Exp Med Biol. 2003;530:497-507.
23 Hunter GR, Bamman MM, Larson-Meyer DE, et al. Inverse relationship between exercise economy and oxidative capacity in muscle. Eur J Appl Physiol. 2004;94 (5-6): 558-68.
24 In vivo and in vitro characterization of skeletal muscle metbolism in patients with statin-induced adverse effects. Arthritis Rheum. 2003 15;55(4):551-7.
25 Mairiang E, Hanpanich P, Sriboonlue P. In vivo ~(31)P-MRS assessment of muscle-pH, cytolsolic-[Mg~(2+)] and phosphorylation potential after supplementing hypokaliuric renal stone patients with potassium and magnesium salts. Magn Reson Imaging. 2004;22(5):715-9.
26 Greenman RL, Rakow-Penner R. Evaluation of the RF field uniformity of a double-tuned 31P/1H birdcage RF coil for spin-echo MRI/MRS of the diabetic foot. J Magn Reson Imaging. 2003;22 (3):427-32.
27 Schols L, Meyer Ch, Schmid G, et al. Therapeutic strategies in Friedreich' s ataxia. J Neural Transm Suppl. 2004;(68):135-45.
28 Schocke MF, Esterhammer R, Kammerlander C, et al. High-energy phosphate metabolism during incremental calf exercise in humans measured by 31 phosphorus magnetic resonance spectroscopy (~(31)P～MRS). Magn Reson Imaging. 2004;22 (1):109-15.
29 Darques JL, Bendahan D, Roussel M, et al. Combined in situ analysis of metabolic and myoelectrical changes associated with electrically induced fatigue. J Appl Physiol. 2003;95(4):1476-84.
30 Brault JJ, Towse TF, Slade JM, et al. Parallel increases in phosphocreatine and total creatine in human vastus lateralis muscle during creatine supplementation. Int J Sport Nutr Exerc Metab. 2004;17(6):624-34.
31 Sirikul B, Hunter GR, Larson-Meyer DE, et al. Relationship between metabolic function and skeletal muscle fatigue during a 90 s maximal isometric contraction. Appl Physiol Nutr Metab. 2003;32 (3):394-9.
32 Kemp G. Mitochondrial respiration in creatine-loaded muscle: is there ~(31)P-MRS evidence of direct effects of phosphocreatine and creatine in vivo? J Appl Physiol. 2003;100(4):1428-9.
33 Haseler LJ, Lin AP, Richardson RS. Skeletal muscle oxidative metabolism in sedentary humans: ~(31)P-MRS assessment of O2 supply and demand limitations. J Appl Physiol. 2004;97 (3):1077-81.
34 Yoshida T. The rate of phosphocreatine hydrolysis and resynthesis in exercising muscle in humans using 31P-MRS. J Physiol Anthropol Appl Human Sci.2002 ;21(5):247-55.
35 Gabr RE, Ouwerkerk R, Bottomley PA. Quantifying in vivo MR spectra with circles. J Magn Reson. 2004;179(1):152-63.
36 Mattei JP, Bendahan D, Cozzone P. ~(31) P- magnetic resonance spectroscopy. A tool for diagnostic purposes and pathophysiological insights in muscle diseases. Reumatismo. 2004 Jan-Mar; 56(1):9-14.
2 Prompers JJ, Jeneson JA, DrostMR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed,2006, 19 (7) :927-953.
3 Kuesel AC, Stoyanova R, Aiken NR,et al. Quantitation of resonances in biological 31P NMR spectra via principal component analysis: potential and limitations. NMR Biomed.1996 ; 9(3):93-104.
4 Buchli R, Boesiger P. Comparison of methods for the determination of absolute metabolite concentrations in human muscles by ~(31)P-MRS. Magn Reson Med, 1993, 30 (5):552-558.
5 Chance B, Leigh JS, Clark BJ, et al. Control of oxidative metabolism and oxygen delivery in human skeletal muscle: a steady state analysis of the work /energy cost transfer function. Proc Natl Acad Sci USA, 1985, 82 (24): 8384-8388.
6 Park JH, Olsen NJ, King L. Use of magnetic resonance imaging and ~(31)P magnetic resonance spectroscopy to detect and quantify muscle dysfunction in the amyopathic and myopathic variants of dermatomyositis. Arthritis Rheum, 1995,38 (1): 68 - 77.
7 Gadian DG, Radda GK, Brown TR, et al. The activity of creatine kinase in frog skeletal muscle studied by saturation - transfer nuclear magnetic resonance. Biochem J, 1981, 194 (1): 215 -28.
8 Mosher TJ, Williams GD, Doumen C, et al. Error in the calibration of the Mg-ATP chemical -shift limit: effects on the determination of free magnesium by ~(31)P-NMR spectroscopy. Magn Reson Med, 1992,24 (1): 163-169.
9 Buchli R, MeierD, Martin E, et al. Assessment of absolute metabolite concentrations in human tissue by ~(31)P-MRS in vivo. Part Ⅱ: Muscle, liver, kidney. Magn ResonMed, 1994, 32 (4): 453-458.
10 Redmond OM, Stack JP, O'ConnorNG, et al.~(31)P-MRS as an early prognostic indicator of patient response to chemotherapy. Magn Reson Med, 1992,25 (1): 30-44.
11 Podo F. Tumour phospholipid metabolism. NMR Biomed, 1999,12 (7): 413- 39.
12 Niermann KJ, Olsen NJ, Park JH. Magnesium abnormalities of skeletal muscle in dermatomyositis and juvenile dermatomyositis. Arthritis Rheum, 2002, 46 (2):475-488.
13 Park JH, Niermann KJ, Ryder NM, et al. Muscle abnormalities in juvenile dermatomyositis patients: ~(31)P magnetic resonance spectroscopy studies. Arthritis Rheum, 2000, 43 (10): 2359-2367.
14 Argov Z, Lofberg M, Arnold DL. Insights into muscle diseases gained by phosphorus magnetic resonance spectroscopy. Muscle Nerve, 2000, 23 (9):1316-1334.
1 Kemp GJ, Meyerspeer M, Moser E. Absolute quantification of phosphorus metabolite concentrations in human muscle in vivo by ~(31)P -MRS: a quantitative review. NMR Biomed. 2007 ;20 (6):555-65.
2 Barker A, Welsman J, Welford D, et al. Reliability of ~(31)P-magnetic resonance spectroscopy during an exhaustive incremental exercise test in children. Eur J Appl Physiol. 2006;98(6):556-65.
3 Prompets JJ, Jeneson JA, Drost MR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed. 2006, 19(7): 927-53.
4 Mattei JP, Bendahan D, Cozzone P. ~(31)P Magnetic Resonance Spectroscopy. A tool for diagnostic purposes and pathophysiological insights in muscle disease. Reumatismo. 2004, 56(1):9—14.
5 Argov Z, Ldberg M, Amold DL. Insights into muscle diseases gained by phosphorus magnetic resonance spectroscopy. Muscle Nerve. 2000, 23(9):1316-34.
6 Park JH, Niermann KJ, Ryder NM, et al . Muscle abnormalities in juvenile dermatomyositis patients: ~(31)P magnetic resonance spectroscopy studies. Arthritis& Rheumatism. 2000, 43(10):2359-67.
7 Buchli R, Boesiger P. Comparison of methods for the determination of absolute metabolite concentrations in human muscles by ~(31)P-MRS. Magn Reson Med. 1993, 30(5): 552-8.
8 Taylor DJ, Fore PJ, Styles P, et al. Bioenergetics of intact human muscles: A ~(31)P nuclear magnetic resonance study. Mol Biol Med. 1983, 1(1):77-94.
9 Park JH, Olsen NJ, KingL. Use of magnetic resonance imaging and ~(31)P magnetic resonance spectroscopy to detect and quantify muscle dysfunction in the amyopathic and myopathic variants of dermatomyositis . Arthritis and Rheumatism. 1995 , 38(1): 68-77.
10 Mosher TJ, Wams GD, Doumen C, et al. Error in the calibration of the Mg ATP chemical-shift limit: effects on the determination of free magnesium by ~(31)p-NMR spectroscopy. Magn Reson Med. 1992, 24(1):163-9 .
11 Moiler HE, Kuflemann G, Putzler M, et al. Magnetic resonance spectroscopy in patients with MELAS. J Neurol Sci.2005, Mar 15:229-230:131-9.
12 Kornblum C, Schroder R.Muller K, et al.Creatine has no beneficial effect on skeletal muscle energy metabolism in patients with single mitochondrial DNA deletions: A placebo-controlled, double-blind ~(31)P-MRS crossover study. Eur J Neurol. 2005,12(4):300-9.
13 Barker A, Welsman J, Welford D, et al. Reliability of ~(31)P-magnetic resonance spectroscopy during an exhaustive incremental exercise test in children. Eur J Appl Physiol. 2006;98 (6):556-65.
14 Haseler LJ, Lin AP, Richardson RS. Skeletal muscle oxidative metabolism in sedentary humans: ~(31)P-MRS assessment of 02 supply and demand limitations. J Appl Physiol. 2004;97(3):1077-81.
15 Prompers JJ, Jeneson JA, Drost MR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed. 2006;19(7):927-53.
16 Mancini L, Payne GS, Leach MO. Comparison of polarization transfer sequences for enhancement of signals in clinical ~(31)PMRS studies. Magn Reson Med. 2003;50(3):578-88.
17 Podo F. Tumour phospholipid metabolism. NMR Biomod, 1999, 12: 413.
1 Deicken RF, Calabrese G, Merrin EL,et al. Asymmetry of temporal lobe phosphorous metabolism in schizophrenia: a 31phosphorous magnetic resonance spectroscopic imaging study. 1995;38(5):279-86.
2 Kuesel AC, Stoyanova R, Aiken NR, et al. Quantitation of resonances in biological ~(31)P NMR spectra via principal component analysis: potential and limitations. NMR Biomed. 1996 ;9(3):93-104.
3 McCully K, Mncini D, Levine S, et al. Nuclear magnetic resonance spectroscopy: its role in providing valuable insight into diverse clinical problem. Chest. 1999, 116(5):1434-1441.
4 Kemp GJ, Meyerspeer M, Moser E. Absolute quantification of phosphorus metabolite concentrations in human muscle in vivo by ~(31)P- MRS: a quantitative review. NMR Biomed. 2004 ;20 (6):555-65.
5 Prompers JJ, Jeneson JA, Drost MR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed. 2003;19(7):927-53.
6 Kemp GJ, Roberts N, Bimson WE, et al. Muscle oxygenation and ATP turnover when blood flow is impaired by vascular disease.Mol Biol Rep. 2002;29(1-2):187-91.
7 Mancini L, Payne GS, Leach MO. Comparison of polarization transfer sequences for enhancement of signals in clinical ~(31)P-MRS studies. Magn Reson Med. 2003;50(3):578-88.
8 Rzanny R, Grassme R, Reichenbach JR, et al. Investigations of back muscle fatigue by simultaneous ~(31)P -MRS and surface EMG measurements. Biomed Tech (Berl). 2003; 51(5-6): 305-13.
9 Jeppesen TD, Quistorff B, Wibrand F, et al. ~(31)P-MRS of skeletal muscle is not a sensitive diagnostic test for mitochondrial myopathy. J Neurol. 2004;254(1):29-37.
10 Rossiter HB, Ward SA, Howe FA, et al. Dynamics of intramuscular ~(31)P-MRS P(i) peak splitting and the slow components of PCr and 02 uptake during exercise. J Appl Physiol. 2002;93 (6):2059-69.
11 Malucelli E, Lodi R, Martinuzzi A, et al. Free Mg~(2+)concentration in the calf muscle of glycogen phosphorylase and phosphofructokinase deficiency patients assessed in different metabolic conditions by ~(31)P-MRS. Dyn Med. 2003Jun 6;4:7.
12 Barker A, Welsman J, Welford D, et al. Reliability of ~(31)P-magnetic resonance spectroscopy during an exhaustive incremental exercise test in children. Eur J Appl Physiol. 2004;98(6):556-65.
13 Kimura N, Hamaoka T, Kurosawa Y,et al. Contribution of intramuscular oxidative metabolism to total ATP production during forearm isometric exercise at varying intensities. Tohoku J Exp Med. 2004;208(4):307-20.
14 Brosseau OE, Mahdjoub R, Seurin MJ, et al. Kinetics of anaerobic metabolism in human skeletal muscle: influence of repetitive high-intensity exercise on sedentary dominant and non-dominant forearm. A ~(31)P NMR study. Biochimie. 2003;85(9):885-90.
15 Meyerspeer M, Krssak M, Moser E. Relaxation times of ~(31)P-metabolites in human calf muscle at 3 T. Magn Reson Med. 2003;49(4):620-5.
16 Prompers JJ, Jeneson JA, Drost MR, et al. Dynamic MRS and MRI of skeletal muscle function and biomechanics. NMR Biomed. 2003;19(7):927-53.
17 Pedersen BL, Arendrup H, Secher NH, et al. Metabolism of perfused pig intercostal muscles evaluated by ~(31)P-magnetic resonance spectroscopy.Exp Physiol. 2004 ; 91 (4): 755-63.
18 Kornblum C, Schroder R, Muller K,et al. Creatine has no beneficial effect on skeletal muscle energy metabolism in patients with single mitochondrial DNA deletions: a placebo-controlled, double-blind ~(31)P-MRS crossover study. Eur J Neurol. 2003;12(4):300-9.
19 Hug F, Bendahan D, Le Fur Y, et al. Metabolic recovery in professional road cyclists: a ~(31)P-MRS study.Med Sci Sports Exerc. 2002:37(5):846-52.
20 Meyerspeer M, Krssak M, Kemp GJ, et al. Dynamic interleaved ~1H/~(31)P STEAM MRS at 3 Tesla using a pneumatic force-controlled plantar flexion exercise rig. MAGMA. 2004;18(5):257-62.
21 Arias-Mendoza F, Zakian K, Schwartz A, et al. Methodological standardization for a multi-institutional in vivo trial of localized ~(31)P MR spectroscopy in human cancer research. In vitro and normal volunteer studies. NMR Biomed. 2004;17(6):382-91.
22 Kime R, Katsumura T, Hamaoka T, et al. Muscle reoxygenation rate after isometric exercise at various intensities in relation to muscle oxidative capacity. Adv Exp Med Biol. 2003;530:497-507.
23 Hunter GR, Bamman MM, Larson-Meyer DE, et al. Inverse relationship between exercise economy and oxidative capacity in muscle. Eur J Appl Physiol. 2004;94 (5-6): 558-68.
24 In vivo and in vitro characterization of skeletal muscle metbolism in patients with statin-induced adverse effects. Arthritis Rheum. 2003 15;55(4):551-7.
25 Mairiang E, Hanpanich P, Sriboonlue P. In vivo ~(31)P-MRS assessment of muscle-pH, cytolsolic-[Mg~(2+)] and phosphorylation potential after supplementing hypokaliuric renal stone patients with potassium and magnesium salts. Magn Reson Imaging. 2004;22(5):715-9.
26 Greenman RL, Rakow-Penner R. Evaluation of the RF field uniformity of a double-tuned 31P/1H birdcage RF coil for spin-echo MRI/MRS of the diabetic foot. J Magn Reson Imaging. 2003;22 (3):427-32.
27 Schols L, Meyer Ch, Schmid G, et al. Therapeutic strategies in Friedreich' s ataxia. J Neural Transm Suppl. 2004;(68):135-45.
28 Schocke MF, Esterhammer R, Kammerlander C, et al. High-energy phosphate metabolism during incremental calf exercise in humans measured by 31 phosphorus magnetic resonance spectroscopy (~(31)P～MRS). Magn Reson Imaging. 2004;22 (1):109-15.
29 Darques JL, Bendahan D, Roussel M, et al. Combined in situ analysis of metabolic and myoelectrical changes associated with electrically induced fatigue. J Appl Physiol. 2003;95(4):1476-84.
30 Brault JJ, Towse TF, Slade JM, et al. Parallel increases in phosphocreatine and total creatine in human vastus lateralis muscle during creatine supplementation. Int J Sport Nutr Exerc Metab. 2004;17(6):624-34.
31 Sirikul B, Hunter GR, Larson-Meyer DE, et al. Relationship between metabolic function and skeletal muscle fatigue during a 90 s maximal isometric contraction. Appl Physiol Nutr Metab. 2003;32 (3):394-9.
32 Kemp G. Mitochondrial respiration in creatine-loaded muscle: is there ~(31)P-MRS evidence of direct effects of phosphocreatine and creatine in vivo? J Appl Physiol. 2003;100(4):1428-9.
33 Haseler LJ, Lin AP, Richardson RS. Skeletal muscle oxidative metabolism in sedentary humans: ~(31)P-MRS assessment of O2 supply and demand limitations. J Appl Physiol. 2004;97 (3):1077-81.
34 Yoshida T. The rate of phosphocreatine hydrolysis and resynthesis in exercising muscle in humans using 31P-MRS. J Physiol Anthropol Appl Human Sci.2002 ;21(5):247-55.
35 Gabr RE, Ouwerkerk R, Bottomley PA. Quantifying in vivo MR spectra with circles. J Magn Reson. 2004;179(1):152-63.
36 Mattei JP, Bendahan D, Cozzone P. ~(31) P- magnetic resonance spectroscopy. A tool for diagnostic purposes and pathophysiological insights in muscle diseases. Reumatismo. 2004 Jan-Mar; 56(1):9-14.