Proton MRS in Kennedy disease: absolute metabolite and macromolecular concentrations

PURPOSE: To investigate whether glutamine and glutamate (Glx) were elevated in Kennedy Disease (KD), and whether pathological proteins were spectroscopically visible as altered macromolecular (MM) resonances. MATERIALS AND METHODS: Ten patients with KD and twelve healthy volunteers were investigated using a stimulated echo acquisition mode (STEAM) spectroscopy sequence with metabolite-nulling. RESULTS: The concentrations of Glx remained unchanged in KD. An increased myo-inositol (Ins), and elevated MM at 0.9 ppm were found within the motor area. The N-acetyl-aspartate (NAA)/creatine (Cr) ratio was negatively correlated to the number of cytosine adenosine guanine (CAG) repeats in the motor area. CONCLUSION: The elevated MM at 0.9 ppm may be attributed to a pathologically altered protein in KD. Additionally, the changes of Ins point to a clinically unexpected involvement of the motor cortex. The correlation of NAA/Cr with the number of CAG repeats indicates a link between metabolites and genetic failure.