MRI abnormalities in neurofibromatosis type 1 (NF1): a study of men and mice

Hyperintense lesions on T2-weighted MR images of the brain, predominantly l ocated in the basal ganglia, the brainstem and cerebellum, are a frequent f inding in patients with neurofibromatosis type i. Nature and significance o f these lesions are still unknown so that the term 'unidentified bright obj ects' (UBOs) has been introduced to allow an unbiased description. We analy zed brain MRI scans of 31 children with definite diagnosis of neurofibromat osis type 1 according to the NM criteria. High-intensity lesions on T2-weig hted images were present in 86% of the patients. They did not correlate to other MRI findings such as optic pathway gliomas and were not indicative of intellectual impairment. Additionally, brain MR imaging of Nf1 knockout mi ce was performed to find out if similar abnormalities are present in this a nimal model. A total of 9 Nf1 knockout mice was examined on a dedicated ani mal MRI scanner at 4.7 Tesla but no evidence of high-signal intensity lesio ns on T2-weighted images was found. Therefore, the Nf1 mouse model seems to be unhelpful in providing further insights into the histological basis of hyperintense MRI abnormalities in NF1 patients. (C) 1999 Elsevier Science B .V. All rights reserved.