MRI FINDINGS IN CHILDREN WITH NEUROFIBROMATOSIS TYPE-1 - A PROSPECTIVE-STUDY

To determine the frequency and nature of MRI lesions in children with neurofibromatosis type I (NF1), 50 patients aged 8 to 16 years were ev aluated prospectively with cranial MRI. Forty-one children were asympt omatic with respect to central nervous system pathology, and 50% were macrocephalic, Sixteen patients (32%) had normal MRI examinations. Thi rty-two patients (64%) had high intensity lesions on T2-weighted image s and 16 patients (32%) had hyperintense lesions on T1-weighted images . Seven patients (14%) had ventricular dilatation (associated with inc reased intracranial pressure in 2) and 11 patients (22%) had optic pat hway lesions (optic glioma in 7). MRI was superior to CT in differenti ating optic sheath thickening and optic nerve tortuosity from optic gl ioma in four patients. An intracranial tumour (ependymoma) and sphenoi d wing dysplasia were evident in individual patients. Findings previou sly unreported in NF1 included an aqueductal web resulting in hydrocep halus intraocular neurofibroma resulting in retinal detachment, and as ymptomatic enlargement of the septum pellucidum. T1 and T2 signal abno rmalities in isolation were not associated with neurological deficits or the occurrence of macrocephaly, and all lesions that required inter vention were suspected clinically. Macrocephaly in the absence of incr eased intracranial pressure or accelerated head growth is not an indic ation for neuroimaging in children with NF1. However, the majority of children (68%) had disease-specific abnormalities and thus MRI may pro vide a useful adjunct to clinical evaluation in the diagnosis of equiv ocal cases.