title: Usefulness of transcranial Doppler-derived cerebral hemodynamic parameters in the noninvasive assessment of intracranial pressure.
abstract: BACKGROUND
  Transcranial Doppler (TCD) ultrasonography is a noninvasive bedside tool that can evaluate cerebral blood flow hemodynamics in major intracranial arteries. TCD-derived pulsatility index (PI) is believed to be influenced by intracranial pressure (ICP).
  
  
  OBJECTIVE
  To correlate TCD-PI with cerebrospinal fluid (CSF) pressure (representing ICP), measured by standard lumbar puncture (LP) manometry.
  
  
  METHODS
  CSF pressures (CSF-P) were measured in 78 patients by LP manometry. Stable TCD spectra were obtained 5 minutes before LP from either middle cerebral arteries using Spencer's head frame and 2-MHz transducer. PI values were calculated from the TCD spectra by an independent neurosonologist.
  
  
  RESULTS
  Factors displaying a significant relationship with CSF-P included age (R = -.426, P < .0005); EDV (R = -.328, P = .002;) and PI (R = .650, P < .0005). On analyzing dichotomized data (CSF-P < 20 vs. ≥ 20 cm H2 0) TCD-PI was an independent determinant (OR per .1 increase in PI = 2.437; 95% CI, 1.573-3.777; P < .0005). PI ≥ 1.26 could reliably predict CSF-P ≥ 20 cm H2 0 (sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy were 81.1%, 96.3%, 93.8%, 88.1%, and 90.1% respectively).
  
  
  CONCLUSIONS
  TCD-derived PI could be used to identify patients with CSF-P ≥ 20 cm H2 0 and may play an important role as a monitoring tool.
authors.affiliation: Division of Neurology, National University Health System, Singapore.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Wakerley
authors.forename: Yohanna
authors.initials: Y
authors.lastname: Kusuma
authors.forename: Leonard L L
authors.initials: LL
authors.lastname: Yeo
authors.forename: Shen
authors.initials: S
authors.lastname: Liang
authors.forename: Komal
authors.initials: K
authors.lastname: Kumar
authors.forename: Arvind K
authors.initials: AK
authors.lastname: Sharma
authors.forename: Vijay K
authors.initials: VK
authors.lastname: Sharma
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001794:Blood Pressure; D001927:Brain Diseases / Q000175:diagnosis* / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D038622:Internationality; D007427:Intracranial Pressure; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013129:Spinal Puncture; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*; D055815:Young Adult
keywords: Transcranial Doppler; intracranial pressure; pulsatility index; resistance index