Normal Pressure Hydrocephalus Following Cranial Radiation: Identification of Shunting Responders

Abstract

Background: We examined cognitive, brain MRI, and lumbar infusion test (LIT) features to identify predictors of response to ventriculoperitoneal shunting (VPS) in long-term cancer survivors with suspected normal pressure hydrocephalus (NPH) following cranial radiotherapy (RT). Methods: Patients who completed cranial RT at least 2 years before with clinically suspected NPH and an Evans’ index (EI) ≥ 0.30 underwent a cognitive and a cerebrospinal fluid (CSF) volumetric (MRI) analysis (n = 36). For those in whom VPS was placed (n = 14), we explored whether adding a CSF volumetric analysis to classical MRI and LIT (Tap Test) features would better identify VPS responders. Results: Nearly 80% exhibited cognitive impairment. The CSF volume at NPH diagnoses was significantly larger in the group of VPS responders (p = 0.04). The addition of CSF volume to NPH diagnoses increased accuracy to 93%, with a positive and negative predictive value of 91% and 100%, respectively. Conclusion: The addition of a quantitative MRI analysis of CSF volume to classical MRI and LIT NPH criteria, along with a high clinical suspicion of NPH, may help to identify VPS responders, thus improving the clinical management and prognosis of long-term survivors.