PROTON MAGNETIC-RESONANCE SPECTROSCOPIC IMAGING IN PATIENTS WITH CEREBELLAR DEGENERATION

Using proton magnetic resonance spectroscopic imaging, we studied the cerebellum of 9 patients with cerebellar degeneration and of 9 age-mat ched normal control subjects. This technique permits the simultaneous measurement of N-acetylaspartate, choline-containing compounds, creati ne/phosphocreatine, and lactate signal intensities from four 15-mm sli ces divided into 0.84-ml single-volume elements. Because patients with cerebellar degeneration often show substantial atrophy on magnetic re sonance imaging (MRI), we specifically chose to analyze the spectrosco pic signals only from tissue that did not have an atrophic appearance on the MRI. The spectroscopic findings showed a significant reduction of N-acetylaspartate in all parts of the cerebellum, a significant cor relation with MRI scores of cerebellar atrophy, and a significant corr elation with clinical rating scores of cerebellar disturbance. Our met hod of analysis suggests the presence of a neuodegenerative process in cerebellar areas that do not appear to be atrophic on the MRI. Some l imitations of proton magnetic resonance spectroscopic imaging in the p resent study were related to the partial field inhomogeneity character istics of the posterior fossa, the anatomical location of the cerebell um, and the particularly severe cerebellar atrophy in some of the pati ents.