Diffusion tensor imaging of Parkinson's disease, multiple system atrophy and progressive supranuclear palsy: a tract-based spatial statistics study

Although often clinically indistinguishable in the early stages, Parkinson's disease (PD), Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP) have distinct neuropathological changes. The aim of the current study was to identify white matter tract neurodegeneration characteristic of each of the three syndromes. Tract-based spatial statistics (TBSS) was used to perform a whole-brain automated analysis of diffusion tensor imaging (DTI) data to compare differences in fractional anisotropy (FA) and mean diffusivity (MD) between the three clinical groups and healthy control subjects. Further analyses were conducted to assess the relationship between these putative indices of white matter microstructure and clinical measures of disease severity and symptoms. In PSP, relative to controls, changes in DTI indices consistent with white matter tract degeneration were identified in the corpus callosum, corona radiata, corticospinal tract, superior longitudinal fasciculus, anterior thalamic radiation, superior cerebellar peduncle, medial lemniscus, retrolenticular and anterior limb of the internal capsule, cerebral peduncle and external capsule bilaterally, as well as the left posterior limb of the internal capsule and the right posterior thalamic radiation. MSA patients also displayed differences in the body of the corpus callosum corticospinal tract, cerebellar peduncle, medial lemniscus, anterior and superior corona radiata, posterior limb of the internal capsule external capsule and cerebral peduncle bilaterally, as well as the left anterior limb of the internal capsule and the left anterior thalamic radiation. No significant white matter abnormalities were observed in the PD group. Across groups, MD correlated positively with disease severity in all major white matter tracts. These results show widespread changes in white matter tracts in both PSP and MSA patients, even at a mid-point in the disease process, which are not found in patients with PD

Detection of myocardial disorders by magnetic resonance spectroscopy.

Magnetic resonance spectroscopy (MRS) utilizes magnetic resonance signals from nuclei, such as phosphorus-31, to provide information regarding the biochemical composition and metabolic state of cardiac muscle. This technique is the only method available for noninvasive assessment of cardiac metabolism without the need for the application of external radioactive tracers. MRS provides insights into the role of cardiac energetics in ischemic heart disease, heart failure, hypertrophy, and valve disease. Furthermore, response to therapeutic intervention can be monitored using this method. At present, this technique is used as a research tool, because low spatial and temporal resolution, as well as low reproducibility, precludes its diagnostic use in clinical practice; however, higher-field magnetic resonance systems-using, for example, 7 T-will enable improvements in resolution and reproducibility that may take cardiac MRS into the clinical realm