Introduction: To determine the predictor for shunt responsive cases in patients with normal pressure hydrocephalus (NPH) by means of conventional MRI and CSF flow study at Siriraj hospital.
Methods: The retrospective study was performed in patients suspected NPH and underwent MRI CSF flow measurement. The routine brain MRI was performed for anatomical assessment (narrowing parasagittal high convexity, bowing corpus callosum, widening sylvian fissure, callosal angle, Evans index, focal dilated sulci, and white matter change in term of Fazeka’s core) and 2D-phase contrast technique was used as CSF flow analysis at the aqueduct of sylvius (Achieva, 3 Tesla Philips, Best, the Netherlands). The preoperative and postoperative clinical outcomes (cognitive, gait, urinary incontinence) according to the iNPHGS (idiopathic normal pressure hydrocephalus grading scale) were collected and analyzed to determine predictive value of MRI study in shunt responsive patients.
Results: During 5 years periods (2006-2011), 33 patients with clinical diagnosis of NPH were treated by ventriculoperitoneal shunt placement. Twenty-one cases were defined as significant responsive group for overall improvement of outcome (sum of Japanese NPH score = 3). Only Fazeka’s score and CSF flow measurement showed significant difference between shunt responsive and non-responsive group (p<0.05). Using a mean velocity threshold 27 mm/sec to identify the significant responsive group, the sensitivity was 70%, specificity 80%, positive predictive value 87.5% and accuracy 73.3%. With the peak velocity threshold of 62 mm/sec, the sensitivity, specificity, positive predictive value and accuracy were 76.2%, 75%, 84.2%, 75.8% respectively. Less patients with severe white matter change(Fazeka grade 3,4) were shunt responsive (36.3% VS 66.7%). Five of six cases with clinical diagnosis of Alzheimer’s disease were improved in cognitive outcome.
Conclusions: Using available commercial software in the authors’ institute, the mean velocity as well as the peak velocity was a specific value that predicted significant shunt responsiveness in NPH patients. Comorbidity should be considered for the outcome of patients with these syndromes.
Patient Care: to find out the predictive value for NPH patients in our institution.
Learning Objectives: By the conclusion of this session, participants should be able to predict shunt responsive in NPH patients using conventional MRI and CSF flow study.
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