Biomedical subjects
Publications and source records attributed to J Valk.
Two patients with synovial sarcoma in paravertebral location (cervical and lumbar areas) presented with soft tissue masses that exhibited calcifications on CT. In one patient an unusual pattern of metastasis was found in the pancreas.
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A classification of congenital cerebral, cerebellar, and spinal malformations is presented with a view to its practical application in neuroradiology. The classification is based on the MR appearance of the morphologic abnormalities, arranged according to the embryologic time the derangement occurred. The normal embryology of the brain is briefly reviewed, and comments are made to explain the classification. MR images illustrating each subset of abnormalities are presented.
OBJECTIVE: The MR findings in a characteristic pattern of hypoxic-ischemic brain damage in term infants are described. MATERIALS AND METHODS: The MR images of seven patients with cerebral palsy and a specific pattern of central cortico-subcortical cerebral damage were studied retrospectively and correlated with clinical findings. RESULTS: All seven patients were born at term. Five of the seven patients had a clear history of severe perinatal asphyxia. All children had severe encephalopathic symptomatology, including spastic tetraplegia, extrapyramidal symptoms, and a mental deficit. The MR showed localized atrophy of the cortex and in addition cystic changes, gliosis, and tissue loss of the adjacent white matter. In all patients, the lesions were band shaped in the left-right direction and characteristically located in areas bordering the central sulcus. The segment of the corpus callosum underlying the affected area was always thin. In some patients, lesions were also found bilaterally in the occipital regions, hippocampus, and basal ganglia. The areas involved match the regions that are known to show active myelination on MR in the term neonate. CONCLUSION: Recognition of this specific pattern on MR in children with cerebral palsy enables the classification of such lesions as resulting from peri- or postnatal asphyxia, even if the perinatal history is unknown or equivocal, and makes other etiologies less likely.
PURPOSE: To determine whether the MR appearance of the spinal cord in patients with multiple sclerosis (MS) differs according to clinical subtype. METHODS: The spinal cords of 20 healthy control subjects and 60 patients with MS (22 with relapsing-remitting disease, 22 with secondary-progressive disease, and 16 with primary-progressive disease) were examined with sagittal dual-echo spin-echo MR imaging and with axial T2*-weighted gradient-echo MR imaging. Two interpreters scored the images for focal lesions and for diffuse abnormalities. Cross-sectional areas of the cords were measured at the C-2 level. RESULTS: No abnormalities were found in any of the control subjects nor in two of the patients. Fifty (83%) of 60 patients had focal lesions. Diffuse abnormality and focal lesions were found in 50% of patients with secondary-progressive MS, in 25% of patients with primary-progressive disease, and in 18% of patients with relapsing-remitting disease. Diffuse abnormality without focal lesions was found in seven patients with primary-progressive MS and in one patient with secondary-progressive MS. Patients with diffuse abnormalities had a smaller cross-sectional area of the spinal cord and they suffered from more disability than did patients without diffuse abnormalities. CONCLUSION: The MR appearance of the spinal cord differs among clinical subgroups of MS. Diffuse abnormality of the spinal cord is associated with a progressive clinical course and greater disability.