IMG-01. LONGITUDINAL FMRI OF VISUAL, AUDITORY AND MOTOR FUNCTION IN PEDIATRIC CRANIOPHARYNGIOMA AFTER TREATMENT WITH PROTON RADIOTHERAPY

INTRODUCTION: Craniopharyngioma accounts for approximately 4% of childhood central nervous system tumors and has a 5-year overall survival rate exceeding 90%. Survivors of childhood craniopharyngioma may experience neurologic sequalae, including visual and fine motor deficits, and subclinical hearing loss associated with tumor and treatment. Contemporary treatment includes radical surgery or more limited surgery and proton radiotherapy (PRT). Here we report on a longitudinal fMRI study probing visual, auditory, and motor function in pediatric craniopharyngioma patients. METHOD: The study (NCT01419067) was IRB approved and informed consent was obtained for each patient. Functional MR images were acquired at 4 time points: after surgery and before PRT (TP1), and 18-months (TP2), 36-months (TP3), and 60-months (TP4) after PRT. Data from a sensory survey fMRI task (visual: flashing checkerboard; auditory: dissonant ascending/descending pure tones; and sensory/motor: button pushing when stimuli were on) for 67 patients were analyzed at the 4 time points. The median age was 11.7 years (range 8.3-20.2 years) and the female/male ratio was 37/30. RESULTS: Significant brain activation was seen in visual cortices, auditory cortices, and supplementary motor area (SMA) and motor cortices for all 4 time points. Over the time, visual and motor cortices showed minimum changes in activation; however, there was a small increase in SMA. For the auditory cortices, the activation volume in Heschl’s gyri increased bilaterally, and the lateralization index decreased (TP1: 70%; TP2: 46%; TP3: 39%; and TP4: 26%) due to larger increases in the right Heschl’s gyrus. CONCLUSION: Increasing activation in Heschl’s gyri, especially on the right side, after PRT suggests decreasing efficiency in distinguishing tones in these patients. These findings may be associated with late effects involving the specific gyri or neuropathways affected by surgery or irradiation.