![]() ![]() It has been thought that this anomaly is caused by aplasia or hypoplasia of the vestibulocochlear nerve that results in ipsilateral congenital sensorineural hearing loss ( 1, 2, 5).Īlthough HRCT is a common technique that is used to evaluate the inner ear and related structures in patients with hearing loss, it has only been able to demonstrate the presence of bony abnormalities in approximately 20% of patients with congenital sensorineural hearing loss ( 3, 4). This malformation comprises 12% of congenital temporal bone anomalies ( 3, 4). A narrow IAC can be diagnosed when the diameter of IAC is less than 2 mm as seen on high-resolution CT (HRCT) of the temporal bone ( 2). ![]() doi:10.3174/ajnr.A narrow internal auditory canal (IAC) with duplication is a rare congenital disorder that is usually associated with other inner ear, middle or external ear abnormalities ( 1). Longitudinal Assessment of Enhancing Foci of Abnormal Signal Intensity in Neurofibromatosis Type 1. Cerebellar radiological abnormalities in children with neurofibromatosis type 1: part 2 - a neuroimaging natural history study with clinical correlations. Salman, Shakhawat Hossain, Samantha Gorun, Lina Alqublan, Martin Bunge, Katya Rozovsky. Cerebellar radiological abnormalities in children with neurofibromatosis type 1: part 1 - clinical and neuroimaging findings. Michael S Salman, Shakhawat Hossain, Lina Alqublan, Martin Bunge, Katya Rozovsky. Evolution of white matter lesions in neurofibromatosis type 1: MR findings. Sevick RJ, Barkovich AJ, Edwards MS, Koch T, Berg B, Lempert T. Differential diagnosis for bilateral abnormalities of the basal ganglia and thalamus. Read it at Google Books - Find it at Amazon Neurofibromatosis type 1: pathologic substrate of high-signal-intensity foci in the brain. DiPaolo DP, Zimmerman RA, Rorke LB et-al. Neurofibromatosis type 1: motor and cognitive function and T2-weighted MRI hyperintensities. Feldmann R, Denecke J, Grenzebach M et-al. Neuropsychological significance of areas of high signal intensity on brain MRIs of children with neurofibromatosis. T2-weighted hyperintensities (unidentified bright objects) in children with neurofibromatosis 1: their impact on cognitive function. T2 hyperintensities in children with neurofibromatosis type 1 and their relationship to cognitive functioning. FOCAL AREAS OF HIGH-SIGNAL INTENSITY ON BRAIN T2-WEIGHTED MAGNETIC RESONANCE IMAGING SCANS ARE SIGNIFICANT FOR THE DIAGNOSIS OF NEUROFIBROMATOSIS VON RECKLINGHAUSEN TYPE 1. Three-dimensional multivoxel proton MR spectroscopy of the brain in children with neurofibromatosis type 1. MR spectroscopy: normal (useful to distinguish from tumors 9)įASI areas do not demonstrate mass effect, and most commonly occur in the basal ganglia, brainstem, thalamus, optic tracts, cerebellum, and infrequently cerebral hemispheres 11,12. T1 C+ (Gd): usually no enhancement, although enhancing FASI (including potential of regression over time) have been reported 13 It remained unclear why FASI areas sometimes regress 7. Further studies are needed to establish the real origin of FASI areas 1. The high T2 signal was explained by the vacuoles being filled with water. Pathologyĭi Paolo et al. published the findings of FASI areas on pathology study as characterized by spongiform myelinopathy or vacuolar change of myelin with no inflammatory reaction in the surrounding tissue and no frank demyelination. However, only the thalamic lesions seem to be strongly associated with cognitive impairment 3-5. The association between these focal areas of high signal and cognitive deficits remains controversial, wherein recent studies have found a favorable relationship with the presence, number and location of FASI areas 3-6. There is considerable debate about its real role within the NF1 spectrum and its potential relationship with cognitive dysfunction 3. FASI areas are the most common neuroimaging feature in NF1 patients 1. A study showed a significant frequency (86%) of one or more FASI in children with NF1 2. Patients younger than 10 commonly have an increase in either size or number lesions, but such an increase beyond 10 years of age raises concern for a neoplasm 10. ![]()
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