MRI morphometric analysis and neuropsychological function in patients with neurofibromatosis

Corpus Callosum Morphology and Microstructure Assessed Using Structural MR Imaging and Diffusion Tensor Imaging: Initial Findings in Adults with Neurofibromatosis Type 1

“…It has been postulated in the Zamboni study of pediatric patients with NF-1 on the basis of all 3 eigenvalues being reduced that the primary cause for the reduced FA was related to vacuolation or edema of the myelin, as has been found on pathologic study of the brain. 10,33 However in our study, we have found a preservation of the primary eigenvalue with increases in the minor eigenvalues. The lack of increase in the primary eigenvalue argues against myelin vacuolation as an explanation, given that this random process should affect the diffusion tensor in all directions.…”

“…This has led many groups to look for parts of the brain that may be specifically involved. Said et al 10 found larger gray matter volumes in children with NF-1, but the magnitude was small (Ͻ10%), though greater in the boys with NF-1 than in the girls with NF-1 compared with controls. In contrast, the magnitude of increased white matter volume was much larger in NF-1 (Ͼ18% compared with age-matched controls), and this feature was most apparent in girls compared with controls (Ͼ45% white matter volume compared with age-matched controls).…”

“…4 Children with NF-1 have a high prevalence of intracranial abnormalities with a wide range of pathology, including neoplasms (optic gliomas, 15%-20%, and brain gliomas) 5 ; areas of hyperintensity on T2 images commonly referred to as neurofibromatosis bright objects 6,7 ; and macrocephaly, which occurs in 30%-53% of patients. 8 Larger-than-normal brain volume (as distinct from a large calvaria) has also been found in children with NF-1 compared with healthy controls, 3,9 and both gray 6,10 and white matter structures are larger. 10 The CC is the major commissural structure in the human brain.…”

“…8 Larger-than-normal brain volume (as distinct from a large calvaria) has also been found in children with NF-1 compared with healthy controls, 3,9 and both gray 6,10 and white matter structures are larger. 10 The CC is the major commissural structure in the human brain. Several studies have looked at the size of the CC in children with NF-1, and all have shown increased volumes.…”

Haploinsufficiency for the neurofibromatosis 1 (NF1) tumor suppressor results in increased astrocyte proliferation

“…This minor increase in astrocyte proliferation is not su cient for tumor formation, since no gliomas have been observed in Nf1+/7 mice (Jacks et al, 1994). It may be enough, however, to account for the observation that astrocyterich white matter regions appear to be selectively increased in children with NF1 (Said et al, 1996;Greenwood et al, 1997). Similarly, NF1 haploinsufficiency may also be su cient to result in the increase in astrocyte number observed in NF1 patient brains (Nordlund et al, 1995).…”