Use of MR Perfusion Imaging to predict treatment effects in patients with Idiopathic Normal Pressure Hydrocephalus

Abstract

Title: Use of magnetic resonance imaging to predict treatment effect in patients with Idiopathic Normal Pressure Hydrocephalus. Author, year: Anna Bogdanoff, 2018. Institution, city, country: Department of Neurology, Sahlgrenska University Hospital, Gothenburg, Sweden AND Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden. Background: Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disease characterized by disturbed cerebrospinal fluid dynamics that result in ventricular enlargement although the intracranial pressure remains normal. The disorder causes gait, balance, cognitive and urinary dysfunction and is one of few causes of treatable dementia. More than 80 % of the patients improve clinically after neurosurgical treatment with peritoneal- or ventriculo-artrial shunt. However, reliable markers for diagnosis and prediction of outcome after shunt surgery are lacking. There is a general agreement that cerebral blood flow (CBF) changes play a central role in the pathophysiology and in association with clinical symptoms. Perfusion patterns that predict good shunt outcome has not yet been identified. Aim: To investigate whether periventricular perfusion changes, measured with magnetic resonance imaging (MRI), can predict the effect of shunt treatment in patients with iNPH. Methods: Prospective, observational study with 24 consecutive patients (median age 76). The participants were all diagnosed with iNPH according to international Use of MR Perfusion Imaging to predict treatment effect in patients with Idiopathic Normal Pressure Hydrocephalus 6 6 guidelines and subjected to shunt surgery. All patients underwent preoperative examination of clinical symptoms and a four-month postoperative follow-up. Perfusion evaluations were based on regions of interest analysis. Results: No significant correlation could be found between preoperative periventricular CBF and preoperative clinical performance or postoperative clinical improvement. The CBF did not differ between shunt treatment responders and non-responders. However, a linear relationship was observed comparing the pre- and postoperative CBF in six patients available (p=0.03). Unexpectedly, comorbidity was associated with a poor clinical improvement after shunt treatment (p=0.006). Conclusion: This study could not show a predictive value of periventricular perfusion with regard to outcome after shunt surgery. The results may support our hypothesis of a relationship between improved periventricular perfusion and clinical improvement. However, statistical power is lacking due to the small sample size. Further studies with larger sample sizes are warranted.