Longitudinal study on MRI intensity changes of Machado–Joseph disease: correlation between MRI findings and neuropathological changes

To disclose the neuropathological progression course of Machado-Joseph disease (MJD), magnetic resonance imaging (MRI) findings of six genetically confirmed MJD cases (four males and two females, including an autopsied female, all unrelated to one another) were further investigated on neurodegeneration. Brain MRI studies were repeated in all cases at different stages of the disease. Ages at the first MRI study ranged from 47 to 65 years (55.2 ± 7.1), with observation periods from 4.5 to 10.6 years (6.95 ± 2.48). We paid particular attention to two types of previously reported MRI findings detectable using T2-weighted images. One is located just outside the internal capsules, and another in the pons. A linear high-intensity change along the internal capsules was detected in all cases, and showed progression during the observation period. A comparison between MRI and autopsy findings suggested that the lesion might reflect degeneration with neuronal loss, astrocytosis, and gliosis in the internal segment of the globus pallidus. A cross-shaped high-intensity change in the pons was well advanced but still incomplete in all cases. In this region, pontine transverse fibers were atrophic, while longitudinal fibers remained intact. Pontine nuclei showed apparent nerve cell loss, and the remaining cells had many 1C2-positive intranuclear inclusions. Since these findings were detected both by lifetime images and by postmortem examination, MRI intensity changes could track the progression of neurodegeneration. Based on a comparison between MRI findings and neuropathology, the degeneration of an internal segment of the globus pallidus (one of the pathological features of MJD) had progressed following the initial symptoms.