RT Journal Article SR Electronic T1 High T2 Signal in Primary Lateral Sclerosis Supports the Topographic Distribution of Fibers in the Corpus Callosum: Assessing Disease in the Primary Motor Segment JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP E61 OP E64 DO 10.3174/ajnr.A2067 VO 32 IS 4 A1 Riad, S.M. A1 Hathout, H. A1 Huang, J.C. YR 2011 UL http://www.ajnr.org/content/32/4/E61.abstract AB SUMMARY: PLS is a disease of the UMN, distinguished from ALS in prognosis and absence of LMN signs. We present, to our knowledge, the first conventional MR imaging visualization of the callosal motor segment, a concept previously supported by primate models, electrophysiologic studies, and postmortem examinations. Modification of the Witelson topographic scheme of the CC is supported by MR tractography. On the basis of 2 cases of PLS, we present conventional imaging confirmation of the revised topographic scheme of fiber distribution across the CC. ALSamyotrophic lateral sclerosisCCcorpus callosumCSTcorticospinal tractDTIdiffusion tensor imagingFAfractional anisotropyFLAIRfluid-attenuated inversion recoveryLMNlower motor neuronPLSprimary lateral sclerosisUMNupper motor neuron