Role of cine phase-contrast magnetic resonance imaging in the management of normal pressure hydrocephalus

Background and Aim: There are several unanswered queries related to normal pressure hydrocephalus (NPH) regarding the diagnostic criteria and selection of appropriate patients for shunt surgery. This study aimed to evaluate the utility of cine phase-contrast (CPC) magnetic resonance imaging (MRI) in the management of patients with NPH. Patients and Methods: In this prospective study, MRI analysis was done on 1.5 Tesla scanner in 20 patients who presented with clinical features and routine MRI findings which were suggestive of NPH. CPC MRI and clinical assessment were performed before and after a high-volume cerebrospinal fluid (CSF) tap by lumbar puncture. Out of these twenty participants, ten underwent ventriculoperitoneal (VP) shunting. Clinical assessment was also done after VP shunting. CSF flow through the aqueduct was also evaluated in twenty age- and sex-matched controls. Results: There was a statistically significant difference between aqueductal flow void score in cases and controls. However, no significant difference in flow void was seen after the tap or after the shunt. There was also a statistically significant difference between the values of stroke volume (SV) in cases and controls. Very high SVs (>50 μL) correlated with marked clinical improvement after the tap and after the shunt. Mildly elevated SV did not help in making any interpretation regarding the usefulness of shunt. There was also a statistically significant difference between the values of peak velocity (PV) in cases and controls. Patients with PV >10 cm/s and with a fall of ≥2 cm/s after tap significantly correlated with clinical improvement. Conclusions: CPC MRI is a useful adjunctive technique to support the diagnosis of NPH as well as in predicting a favorable response to shunt surgery in these patients.