title: Correlation between tap test and CSF aqueductal stroke volume in idiopathic normal pressure hydrocephalus.
abstract: BACKGROUND
  The diagnosis and management of idiopathic normal pressure hydrocephalus (INPH) remains unclear despite the development of guidelines. In addition, the role of cerebrospinal fluid (CSF) aqueductal stroke volume (ASV) remains unspecified.
  
  
  OBJECTIVE
  The aim of this study was to compare the results of the tap test (TT) and ASV in patients with possible INPH.
  
  
  METHODS
  Among 21 patients investigated with both TT and phase-contrast (PC) MRI, we identified two groups, with either (1) a positive TT (PTT) or (2) a negative one (NTT), and we compared their ASV as measured by PC-MRI. ASV cutoff value was set at 70 μL/cardiac cycle (mean value +2 standard deviations in age-matched healthy subjects).
  
  
  RESULTS
  In the PTT group (n = 9), the mean ASV was 175 ± 71 μL. Among these patients, four were shunted, and improved after surgery. In the NTT group, two patients were finally diagnosed with aqueductal stenosis and excluded. Among the remaining patients (n = 10), the mean ASV was 96 ± 93 μL (p < 0.05). However, three of these patients presented with hyperdynamic ASV, and an associated neurodegenerative disorder was diagnosed. Two patients had ventriculoperitoneal shunting despite their NTT, and improved.
  
  
  CONCLUSIONS
  In our patient population, the noninvasive measurement of hyperdynamic ASV correlated with PTT, suggesting PC-MRI could be utilized to select those patients who would benefit from shunting. ASV may therefore be an interesting supplemental diagnosis tool.
authors: Amiens University Hospital, Amiens, France. sorayaelsankari560@hotmail.com
authors: Souraya
authors: S
authors: El Sankari
authors: A
authors: A
authors: Fichten
authors: C
authors: C
authors: Gondry-Jouet
authors: M
authors: M
authors: Czosnyka
authors: D
authors: D
authors: Legars
authors: H
authors: H
authors: Deramond
authors: Olivier
authors: O
authors: Balédent
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002535:Cerebral Aqueduct / Q000503:physiopathology*; D003287:Contrast Media; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013129:Spinal Puncture / Q000379:methods; D013223:Statistics as Topic; D013318:Stroke Volume / Q000502:physiology*
chemical_list: D003287:Contrast Media