Metabolic Abnormalities in Patients with Mitochondrial Myopathy Evaluated by In Vivo 31P Magnetic Resonance Spectroscopy

ABSTRACT

PURPOSE: To investigate the phosphorus metabolic abnormalities in skeletal muscle of patients with mitochondrial myopathy using in vivo 31P magnetic resonance spectroscopy(MRS). MATERIAL AND METHODS: Patients with mitochondrial myopathy(N=10) and normal control subjects (N=10) participated. All in vivo 31P MRS examinations were performed on 1.5T whole-body MRI/MRS system by using an image selected in vivo spectroscopy (ISIS) pulse sequence that provided a 4 X 4 X 4 cm3 volume of interest (VOI) in the right thigh muscle tissue. Peak areas for each phophorus methabolite were measured using a Marquart algorithm. RESULTS: The specific features in patients with mitochondrial myopathy were a significant increase of Pi/PCr ratio (p=0.003) and a significant decrease of ATP/PCr ratio (p=0.004) as compared with normal controls. In particular, the beta-ATP/PCr ratio between controls and patients with mitochondrial myopathy was predominantly altered. CONCLUSIONS: In vivo 31P MRS may be a useful modality in the clinical evaluation of patients with mitochondrial myopathy based on ATP/PCr and Pi/PCr ratios in skeletal muscle tissue and provides a valuable information in further understanding disorders of muscle metabolism.