title: Interobserver and intraobserver reliability of venous transcranial color-coded flow velocity measurements.
abstract: OBJECTIVE
  Venous transcranial color-coded duplex sonography is a new technique for noninvasive evaluation of the intracranial venous system. However, the interobserver and intraobserver reliability of this method is unclear.
  
  
  METHODS
  In 23 healthy volunteers (30 +/- 7.3 years of age), the deep middle cerebral vein (dMCV), basal vein (BV), vein of Galen (VG), and straight (SRS), transverse (TS), and superior sagittal (SSS) sinuses in addition to the arterial segments of the circle of Willis were insonated through the temporal bone window on 2 consecutive days by 2 experienced examiners. The examiners were blinded to each other's results. The interobserver and intraobserver reliability was calculated using a method described by Bland and Altman, resulting in 2-SD confidence intervals.
  
  
  RESULTS
  Non-angle-corrected and angle-corrected systolic and end diastolic venous flow velocities (FV) were in good accordance with published normal values, ranging between 8.6 and 19.2 cm/s. The interobserver reliabilities for non-angle-corrected systolic FVs in the dMCV, BV, VG, SRS, and TS were +/- 1.8, 2.4, 2.6, 3.3, and 4.6 cm/s; for angle-corrected systolic FVs, the interobserver reliabilities were +/- 2.5, 3.1, 13.9, 11.6, and 7.7 cm/s. The intraobserver reliabilities for non-angle-corrected systolic FVs in the dMCV, BV, VG, SRS, and TS were +/- 2.9, 3.2, 2.6, 3.2, and 6.1 cm/s; for angle-corrected systolic FVs, the intraobserver reliabilities were 3.2, 3.7, 13.9, 11.6, and 7.5 cm/s. Angle correction was not attempted for the SSS. The interobserver and intraobserver reliabilities for systolic FVs in the SSS were +/- 3.3 and +/- 3.3 cm/s, respectively.
  
  
  CONCLUSIONS
  Intracranial venous FVs can be measured with a high interobserver and intraobserver reliability in healthy human subjects. Intraobserver reliability was higher for cerebral veins than for dural sinuses, predisposing them for follow-up examinations; however, angle correction for venous FVs in the VG and the SRS is not advisable.
authors.affiliation: Department of Neurology, Justus-Liebig-University, Am Steg 14, D-35385 Giessen, Germany. erwin.stolz@neuro.med.uni-giessen.de
authors.forename: E
authors.initials: E
authors.lastname: Stolz
authors.forename: S S
authors.initials: SS
authors.lastname: Babacan
authors.forename: R H
authors.initials: RH
authors.lastname: Bödeker
authors.forename: T
authors.initials: T
authors.lastname: Gerriets
authors.forename: M
authors.initials: M
authors.lastname: Kaps
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D002550:Cerebral Veins / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D015588:Observer Variation; D012039:Regional Blood Flow / Q000502:physiology; D018709:Statistics, Nonparametric; D016683:Supine Position; D018615:Ultrasonography, Doppler, Color; D017585:Ultrasonography, Doppler, Transcranial