Object: The goal of this study was to determine the influence of hydrocephalus on intelligence quotient (IQ) in children with infratentorial ependymoma before and after the administration of focal radiation.
Methods: Measurements of ventricular size, including Evans index (EI), cella media index (CMI), frontal horn diameter (FHD), and ventricular angle, were performed using magnetic resonance imaging at the time of diagnosis and again at 3, 6, 9, and 12 months after the initiation of radiation therapy. Of the 59 patients (median age at time of radiation treatment, 4.1 years), the clinical diagnosis established in 50 (85%) was hydrocephalus and 23 (39%) required placement of a cerebrospinal fluid (CSF) shunt. Extent of resection was gross or near total in 50 (85%). Before and after radiation treatment, IQ was measured using age-appropriate testing. The correlation between multiple ventricular measurements and IQ was investigated using standard regression techniques and a generalized linear model. Patients with a higher EI (p = 0.04), CMI (p = 0.001), and FHD (p = 0.0002) at the time of diagnosis were more likely to have lower IQ scores before radiation treatment. Patients with higher CMI (p = 0.04) and FHD (p = 0.01) at the time of diagnosis were more likely to exhibit an increase in IQ score after radiotherapy. The rate of change in IQ after radiation treatment was positively correlated with the CMI intercept (p = 0.015) and negatively correlated with the rate of FHD change (p = 0.006).
Conclusions: Changes in IQ score before and after radiation treatment are significantly influenced by the extent and treatment of hydrocephalus at the time of diagnosis. Hydrocephalus is an important factor to include when analyzing the effects of treatment. Patients who undergo a second surgery for ependymoma are more likely to require the placement of a CSF shunt (p = 0.0001).