Trace of diffusion tensor differentiates the Parkinson variant of multiple system atrophy and Parkinson's disease. - Michael F. H. Schocke; Klaus Seppi; Regina Esterhammer; Christian Kremser; Katherina J. Mair; Benedikt V. Czermak; Werner Jaschke; Werner Poewe; Gregor K. Wenning (NeuroImage, 2004)