Normal pressure hydrocephalus following cranial radiation: identification of shunting responders

Abstract Purpose Normal pressure hydrocephalus (NPH) following cranial radiotherapy (RT) has a deleterious effect on patient’s daily functioning. However, there is no consensus on its management in cancer population. The aim of our study is to examine cognitive, brain MRI and lumbar infusion test (LIT) features and to identify predictors of response to ventricular shunting (VPS) in long-term cancer survivors. Methods Patients who completed cranial RT at least 2 years before, with clinically suspected NPH and an Evans’ index (EI) ≥ 0.30, undergo a cognitive and a cerebrospinal fluid (CSF) volumetric (MRI) analysis (n = 36). For those in whom VPS was placed (n = 14), we explore whether adding a CSF volumetric analysis to classical MRI and LIT (Tap Test) features would better identify VPS responders. Results Nearly 80% of our cohort exhibited cognitive impairment, especially focused on executive functioning. There were no differences regarding clinical, LIT or MRI classical features between those who improved or were not following VPS. In contrast, CSF volume at NPH diagnoses resulted 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 PPV of 91% and NPV of 100%, resulting in a predictive factor of response to VPS. Conclusion The addition of a quantitative MRI analysis of CSF volume to classical MRI and LIT NPH criteria, together with a high clinical suspicion of NPH in long-term survivors following cranial RT, may help to identify VPS responders, thus improving the clinical management and prognosis of this population.