Simond G, Bendahan D, Cozzone P J
Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS 6612, Faculté de Médecine de Marseille, 27 boulevard Jean Moulin, Marseille, 13005, France.
J Magn Reson. 2001 Mar;149(1):1-7. doi: 10.1006/jmre.2000.2273.
We present an exact analytical method dedicated to fitting time-dependent exponential-like changes in MR spectra. As an illustration, this method has been applied to fitting metabolic changes recorded by 31P MRS in human skeletal muscle occurring during a rest-exercise-recovery protocol. When recording metabolic changes with the accumulative method, the time averaging of the MR signals implies the choice of a time index for fitting any changes in the features of the associated MR spectra. A critical examination of the different ways (constant, linear, and exponential) of choosing the time index is reported. By numerical analysis, we have calculated the errors generated by the three methods and we have compared their sensitivity to noise. In the case of skeletal muscle, both constant and linear methods introduce large and uncontrolled errors for the whole set of metabolic parameters derived from [PCr] changes. In contrast, the exponential method affords a reliable estimation of critical parameters in muscle bioenergetics in both normal and pathological situations. This method is very easy to implement and provides an exact analytical solution to fitting changes in MR spectra recorded by the accumulative method.
我们提出了一种精确的分析方法，专门用于拟合磁共振波谱中随时间变化的指数型变化。作为例证，该方法已应用于拟合在静息-运动-恢复方案期间人体骨骼肌中通过31P磁共振波谱记录的代谢变化。当用累积法记录代谢变化时，磁共振信号的时间平均意味着要选择一个时间索引来拟合相关磁共振波谱特征中的任何变化。本文报道了对选择时间索引的不同方式（常数、线性和指数）的批判性研究。通过数值分析，我们计算了这三种方法产生的误差，并比较了它们对噪声的敏感性。在骨骼肌的情况下，常数法和线性法对于从[PCr]变化得出的整套代谢参数都会引入巨大且无法控制的误差。相比之下，指数法在正常和病理情况下都能可靠地估计肌肉生物能量学中的关键参数。该方法非常易于实施，并为拟合通过累积法记录的磁共振波谱变化提供了精确的解析解。
