Ventricular Volume Is More Strongly Associated with Clinical Improvement Than the Evans Index after Shunting in Idiopathic Normal Pressure Hydrocephalus
- 11 June 2020
- journal article
- research article
- Published by American Society of Neuroradiology (ASNR) in American Journal Of Neuroradiology
- Vol. 41 (7), 1187-1192
- https://doi.org/10.3174/ajnr.a6620
Abstract
BACKGROUND AND PURPOSE: Ventricular enlargement in idiopathic normal pressure hydrocephalus is often estimated using the Evans index. However, the sensitivity of the Evans index to estimate changes in ventricular size postoperatively has been questioned. Here, we evaluated the postoperative change in ventricle size in relation to shunt response in patients with idiopathic normal pressure hydrocephalus, by comparing ventricular volume and the Evans index. MATERIALS AND METHODS: Fifty-seven patients with idiopathic normal pressure hydrocephalus underwent high-resolution MR imaging preoperatively and 6 months after shunt insertion. Clinical symptoms of gait, balance, cognition, and continence were assessed according to the idiopathic normal pressure hydrocephalus scale. The ventricular volume of the lateral and third ventricles and the Evans index were measured using ITK-SNAP software. Semiautomatic volumetric analysis was performed, and postoperative changes in ventricular volume and the Evans index and their relationships to postoperative clinical improvement were compared. RESULTS: The median postoperative ventricular volume decrease was 25 mL (P < .001). The proportional decrease in ventricular volume was greater than that in the Evans index (P < .001). The postoperative decrease in ventricular volume was associated with a postoperative increase in the idiopathic normal pressure hydrocephalus scale score (P = .004). Shunt responders (75%) demonstrated a greater ventricular volume decrease than nonresponders (P = .002). CONCLUSIONS: Clinical improvement after shunt surgery in idiopathic normal pressure hydrocephalus is associated with a reduction of ventricular size. Ventricular volume is a more sensitive estimate than the Evans index and, therefore, constitutes a more precise method to evaluate change in ventricle size after shunt treatment in idiopathic normal pressure hydrocephalus.Keywords
This publication has 36 references indexed in Scilit:
- Use of the proGAV Shunt Valve in Normal-Pressure HydrocephalusOperative Neurosurgery, 2011
- Evans' Index Revisited: The Need for an Alternative in Normal Pressure HydrocephalusNeurosurgery, 2011
- Changes in the volumes of the brain and cerebrospinal fluid spaces after shunt surgery in idiopathic normal-pressure hydrocephalusJournal of the Neurological Sciences, 2010
- LONG-TERM OUTCOME IN PATIENTS WITH SUSPECTED NORMAL PRESSURE HYDROCEPHALUSNeurosurgery, 2007
- CSF outflow resistance as predictor of shunt function. A long-term studyActa Neurologica Scandinavica, 2004
- Correlation between decreased ventricular size and positive clinical outcome following shunt placement in patients with normal-pressure hydrocephalusJournal of Neurosurgery, 2004
- Volumetric measurements in the detection of reduced ventricular volume in patients with normal-pressure hydrocephalus whose clinical condition improved after ventriculoperitoneal shunt placementJournal of Neurosurgery, 2002
- Dutch normal pressure hydrocephalus study: baseline characteristics with emphasis on clinical findingsEuropean Journal of Neurology, 1997
- Reduction of ventricular size after shunting for normal pressure hydrocephalus related to CSF dynamics before shunting.Journal of Neurology, Neurosurgery & Psychiatry, 1988
- “SHUNTOGRAPHY” - A RADIONUCLIDE SCANNING METHOD FOR EVALUATION OF CEREBROSPINAL FLUID SHUNT PATENCYNuclear Medicine Communications, 1983