title: A Simplified Callosal Angle Measure Best Differentiates Idiopathic-Normal Pressure Hydrocephalus from Neurodegenerative Dementia.
abstract: BACKGROUND
  Idiopathic normal-pressure hydrocephalus (iNPH) can resemble or occur in combination with other brain disorders frequently present in the elderly such as Alzheimer's disease (AD) and dementia with Lewy bodies (DLB).
  
  
  OBJECTIVE
  To study the accuracy of a simplified callosal angle measure in differentiating iNPH from DLB and AD using conventional brain MRI.
  
  
  METHODS
  76 patients (24 iNPH, 30 DLB, 22 AD) and 40 healthy controls served as discovering cohort. The callosal angle measure was obtained on standard coronal brain MRI images crossing the corpus callosum midpoint. 41 patients (21 iNPH and 20 DLB/AD) were used as independent validation cohort. A set of other conventional MRI markers of iNPH was also evaluated.
  
  
  RESULTS
  iNPH showed a significantly decreased mean callosal angle value compared to both disease groups and controls (iNPH = 109±9; DLB = 136.9±8.2; AD = 135.4±11.3; Controls = 138.5±5.2; p <  0.00001). Using a cut off angle of 123, derived by the mean -3SD of the control group, an accuracy of 96% (sensitivity 100% , specificity 95.4% ) was obtained. By ROC analysis, the area under the curve was 0.99 (95% CI: 0.97-1). The measure was consistent (intra-rater: r = 0.94) and reproducible (inter-rater: r = 0.89). In the validation cohort, this cut off angle value discriminated iNPH from DLB/AD with 97.5% accuracy. None of the conventional MRI signs reached the same accuracy.
  
  
  CONCLUSIONS
  This simplified callosal angle measure represents an accurate, reproducible, and easy marker of iNPH.
authors.affiliation: Department of Neurosciences, University of Padova, Padova, Italy.|IRCCS San Camillo Hospital Foundation, Venice, Italy.
authors.forename: Annachiara
authors.initials: A
authors.lastname: Cagnin
authors.affiliation: Department of Neurosciences, University of Padova, Padova, Italy.
authors.forename: Mariachiara
authors.initials: M
authors.lastname: Simioni
authors.affiliation: Department of Neurosciences, University of Padova, Padova, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Tagliapietra
authors.affiliation: IRCCS San Camillo Hospital Foundation, Venice, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Citton
authors.affiliation: Department of Neurosciences, University of Padova, Padova, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Pompanin
authors.affiliation: Neurosurgical Unit, Padova Hospital, Padova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Della Puppa
authors.affiliation: Department of Neurosciences, University of Padova, Padova, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Ermani
authors.affiliation: Neuroradiology, Section of Neurosciences, University of Salerno, Salerno, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Manara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015331:Cohort Studies; D003337:Corpus Callosum / Q000473:pathology*; D003704:Dementia / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000175:diagnosis*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000175:diagnosis*; D018709:Statistics, Nonparametric
keywords: Alzheimer’s disease; MRI marker; dementia with Lewy bodies; idiopathic normal-pressure hydrocephalus