Focal areas of signal intensity in neurofibromatosis type 1: Correlation between MRI findings and cognitive function.

Background: Focal areas of signal intensity (FASI) are T2-weighted hyperintensities detected on brain MRI in 43 %-93 % of children with neurofibromatosis type 1 (NF1). Their association with cognitive impairment, a common feature of NF1, remains controversial.

Objective: To investigate potential correlations between the presence, number, and location of FASI and cognitive performance in children with NF1.

Materials And Methods: Brain MRIs and neuropsychological reports of 17 patients with NF1 (mean age 9.29 ± 3.7 SD) were retrospectively reviewed. Cognitive profiles were assessed using standardized Wechsler scales (WPPSI-III, WISC-III, WAIS-R).

Results: The mean Full Scale Intelligence Quotient (FSIQ) was 84 ± 14.54, within the borderline range; 11.76 % of patients had a diagnosis of Intellectual Disability (ID). A clinically significant discrepancy between Verbal and Performance Intelligence Quotient (PIQ) was observed in 64.7 % of patients, favoring PIQ. The mean number of FASI per patient was 3.94 ± 1.76. Pearson's correlation revealed a non-significant inverse association between total FASI count and FSIQ (r = -0.12, p = 0.621). The cerebellum was the most frequently affected region (70.6 %). Patients with FASI in the cerebellum or brainstem had significantly higher PIQ than those with FASI elsewhere (p < 0.05). The two patients with ID both had thalamic FASI.

Conclusions: This exploratory study suggests that FASI location and number may be associated with cognitive variability in NF1, but larger studies are needed to confirm these trends.