The anatomy of the brain is extremely complex, and certain, even large structures, such as the corticospinal tract (CST), remain poorly understood. Diffusion tractography provides an opportunity to explore the white matter tracts in a fundamentally new way. In the current paper, we show how this technique has already added to our understanding of the anatomy of the CST. We also explore the future projects involving diffusion tractography of the motor white matter tracts that will advance this method and further our understanding of brain anatomy.

Aims-To evaluate a possible association between clinical outcome in patients with glioblastoma and expression of some immunohistochemical variables and apoptosis. Methods-168 selected patients with cerebral glioblastomas were studied retrospectively. Tumour specimens were examined immunohistochemically with antibodies to proliferating cell nuclear antigen (PCNA), p53, bcl-2, and epidermal growth factor receptor (EGFR) to detect the intracellular receptor domain. Apoptosis was detected by in situ end labelling. Multivariate analysis was performed using the Cox proportional hazard model. Results-On univariate analysis the PCNA labelling index, immunoexpression of EGFR, and the apoptotic index were significantly related to glioblastoma outcome. Survival time was reduced as PCNA labelling index increased and apoptotic index decreased (p = 0.0073 and p = 0.00031, respectively). Survival time in patients with EGFR positive tumours was found to be reduced (p = 0.00024). Multivariate analysis showed independent prognostic value for the EGFR positivity and apoptotic index only (p = 0.0053 and p = 0.0039, respectively).There was no association between clinical outcome of glioblastoma and p53 or bcl-2 immunostaining. Conclusions-EGFRimmunoreactivity and apoptotic index were found to be useful for assessing prognosis of individual glioblastomas but it seems unlikely that p53 and bcl-2 immunohistochemistry will be of value in determining survival in such patients. (J Clin Pathol 1999;52:574-580)

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Recently, a novel leukoencephalopathy syndrome was described in eight patients with a distinct pattern of MRI abnormalities. Here we describe the clinical, laboratory, and MRI findings in five new, unrelated patients. The clinical picture was homogeneous with onset in childhood, a slowly progressive course, variable mental deficits, signs of pyramidal and cerebellar dysfunction and sometimes dorsal column dysfunction. In two patients, a minor head trauma was followed by neurological deterioration and fever. No underlying metabolic defect was found. In two patients serum lactate was elevated, but no evidence of a mitochondrial defect was found. MRI showed variably extensive, diffuse, or spotty cerebral white matter abnormalities and a selective involvement of particular brainstem tracts. The tracts involved included the pyramidal tracts, sensory tracts, superior and inferior cerebellar peduncles, and intraparenchymal trajectories of the trigeminal nerve. In four patients spinal MRI was performed and revealed involvement of tracts over the entire length depicted. Single voxel proton MRS in three patients revealed increased lactate within the abnormal white matter. The uniform and highly characteristic MRI findings, in combination with the similarities in clinical and MRS findings, provide evidence for a distinct nosological entity.

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