Normal pressure hydrocephalus versus atrophic dilatation to distinguish and predict the benefits of surgical intervention with a phase-contrast MRI technique

To compare mean cerebrospinal fluid (CSF) volume in the aqueduct by using phase-contrast magnetic resonance imaging for the patients with idiopathic normal pressure hydrocephalus (INPH) and atrophic dilation (AD) to investigate the efficacy of this technique in predicting surgery. The MR images of a total of 80 individuals, consisting of 30 patients considered to have INPH, 20 patients with AD not proportional with cerebral sulci, and 30 control cases without a hydrocephalus clinical picture, were evaluated retrospectively. The minute mean aqueductal CSF flow rates of the three groups were compared using the Kruskall-Wallis analysis of variance, and the inter-group statistical comparisons were made using the Mann-Whitney U test. The mean aqueductal flow rates were 46.56 ± 25.06 ml/min for the INPH group, 9.28 ± 4.68 ml/min for the AD group, and 8.68 ± 3.40 ml/min for the control group. The mean flow rate of the INPH group was significantly higher than those of the control and ADH groups (p < 0.001). The mean CSF flow rate may be useful in the diagnosis and differential diagnosis, and the prediction of the potential benefits of surgical intervention for patients considered to have INPH.