Phosphorus 31 Magnetic Resonance Spectroscopy for Quantitative Evaluation of Therapeutic Regimens in Dermatomyositis

Magnetic Resonance Imaging of the Idiopathic Inflammatory Myopathies

“…Information on biochemical changes in muscle can be obtained using magnetic resonance spectroscopy (MRS). 31 P MRS is most commonly utilized, as it allows the measurement of several metabolites that are important for muscle contraction. Reduced levels of phosphocreatine (PC) and ATP have been demonstrated in myositis patients assessed at rest, and the reductions become even more pronounced after exercise 29,30 .…”

“…As biochemical changes usually precede morphologic or functional changes, 31 P MRS may have potential as a sensitive indicator of a modified clinical status or as a monitor for early evaluation of therapeutic protocols for inflammatory myopathies. In a few longitudinal studies, positive changes in the levels of energy metabolites were recorded in the muscles of patients with inflammatory myopathies after immunosuppressive treatment, which correlated with clinical improvement 31,32 . In their landmark paper, Park et al demonstrated that the concentrations of ATP and PC in diseased muscles were 30% below normal values.…”

“…Successful response to therapy has been monitored with 31 P MRS in different types of ischemic metabolic disorders, featuring a decreased Pi/PC ratio and faster rates of recovery after exercise. The biochemical changes were accompanied by increased strength and improved muscular performance 29,31,32 …”

“…An elevated Pi/CP ratio relative to normal values is indicative of myopathy. As biochemical changes usually precede morphologic or functional changes, 31 P MRS may have potential as a sensitive indicator of a modified clinical status or as a monitor for early evaluation of therapeutic protocols for inflammatory myopathies. In a few longitudinal studies, positive changes in the levels of Figure 7.…”

“…Axial T1-weighted images with fat saturation were performed energy metabolites were recorded in the muscles of patients with inflammatory myopathies after immunosuppressive treatment, which correlated with clinical improvement. 31,32 In their landmark paper, Park et al demonstrated that the concentrations of ATP and PC in diseased muscles were 30% below normal values. The Pi/PC ratios were significantly increased in the patients' muscles at rest and throughout exercise.…”