title: Feasibility of radiological markers in idiopathic normal pressure hydrocephalus.
abstract: BACKGROUND
  Various radiological markers have been proposed for diagnostics in idiopathic normal pressure hydrocephalus (iNPH). We examined the usefulness of radiological markers in the diagnostics and prediction of shunt response in iNPH.
  
  
  METHODS
  In this retrospective cohort study, we evaluated brain CT or MRI scans of 390 patients with suspected iNPH. Based on a 24-h intraventricular pressure monitoring session, patients were classified into a non-NPH (n = 161) or probable iNPH (n = 229) group. Volumes of cerebrospinal fluid compartments (lateral ventricles, sylvian and suprasylvian subarachnoid spaces and basal cisterns) were visually assessed. Disproportionally enlarged subarachnoid spaces, flow void, white matter changes, medial temporal lobe atrophy and focally dilated sulci were evaluated. Moreover, we measured quantitative markers: Evans' index (EI), the modified cella media index, mean width of the temporal horns and callosal angle.
  
  
  RESULTS
  iNPH was more likely in patients with severe volumetric disproportion between the suprasylvian and sylvian subarachnoid spaces than in those without disproportion (OR 7.5, CI 95 % 4.0-14.1, P < 0.0001). Mild disproportion (OR 2.6, CI 95 % 1.4-4.6, P = 0.001) and narrow temporal horns (OR per 1 mm 0.91, CI 95 % 0.84-0.98, P = 0.014) were also associated with an iNPH diagnosis. Other radiological markers had little association with the iNPH diagnosis in the final combined multivariate model. Interestingly, EI was higher in non-NPH than iNPH patients (0.40 vs. 0.38, P = 0.039). Preoperative radiological markers were not associated with shunt response.
  
  
  CONCLUSIONS
  Visually evaluated disproportion was the most useful radiological marker in iNPH diagnostics. Narrower temporal horns also supported an iNPH diagnosis, possibly since atrophy was more pronounced in the non-NPH than iNPH group.
authors.affiliation: Neurosurgery of NeuroCenter, Kuopio University Hospital and University of Eastern Finland, P.O. Box 100, FIN-70029, Kuopio, Finland. mariako@student.uef.fi.
authors.forename: Maria
authors.initials: M
authors.lastname: Kojoukhova
authors.affiliation: Unit of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.|Neurology of NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Koivisto
authors.affiliation: Neurosurgery of NeuroCenter, Kuopio University Hospital and University of Eastern Finland, P.O. Box 100, FIN-70029, Kuopio, Finland.
authors.forename: Riika
authors.initials: R
authors.lastname: Korhonen
authors.affiliation: Unit of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.|Neurology of NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Remes
authors.affiliation: Department of Radiology, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland.
authors.forename: Ritva
authors.initials: R
authors.lastname: Vanninen
authors.affiliation: Unit of Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.|Neurology of NeuroCenter, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Hilkka
authors.initials: H
authors.lastname: Soininen
authors.affiliation: Neurosurgery of NeuroCenter, Kuopio University Hospital and University of Eastern Finland, P.O. Box 100, FIN-70029, Kuopio, Finland.
authors.forename: Juha E
authors.initials: JE
authors.lastname: Jääskeläinen
authors.affiliation: Department of Radiology, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland.
authors.forename: Anna
authors.initials: A
authors.lastname: Sutela
authors.affiliation: Neurosurgery of NeuroCenter, Kuopio University Hospital and University of Eastern Finland, P.O. Box 100, FIN-70029, Kuopio, Finland.
authors.forename: Ville
authors.initials: V
authors.lastname: Leinonen
mesh_terms: D000368:Aged; D002557:Cerebrospinal Fluid Shunts; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed
keywords: Diagnosis; Disproportion; Idiopathic normal pressure hydrocephalus; Marker; Radiology; Shunt response