Agenesis of the arcuate fasciculi in congenital bilateral perisylvian syndrome: a diffusion tensor imaging and tractography study.

OBJECTIVE To describe the absence of the arcuate fasciculi in 2 cases of congenital bilateral perisylvian syndrome (CBPS). DESIGN Case series. SETTING Pediatric referral hospital-based study. PATIENTS Two patients with CBPS, referred to our institution as candidates for surgical treatment of epilepsy. Intervention Diffusion tensor imaging (1.5-T scanner; 15 encoding directions; b = 800 s/mm(2)) and deterministic tractography of the main projection and association tracts. MAIN OUTCOME MEASURES Neuropsychology evaluation; fractional anisotropy, apparent diffusion coefficients, and anatomical aspect of the tracts. RESULTS Absence of the arcuate fasciculus was observed in both subjects. Ancillary findings were complete absence of the superior longitudinal fasciculi in 1 case and underdevelopment in the other. Low fractional anisotropy of the left inferior occipitofrontal fasciculus was found in both cases. The same tract was maloriented in 1 of the cases. CONCLUSION Agenesis of the arcuate fasciculus may accompany CBPS.