title: Reproducibility of retrobulbar blood flow velocity measurements in normal subjects using two different CDI devices.
abstract: OBJECTIVE
  This study was done to evaluate the intra- and inter-operator reproducibility of colour Doppler imaging (CDI) in assessing blood flow velocity in the ophthalmic (OA), central retinal (CRA) and short posterior ciliary arteries (SPCA) in healthy subjects.
  
  
  METHODS
  The right eye of two groups of eight healthy volunteers was examined. Two radiologists and two ophthalmologists, divided into pairs, measured peak systolic velocity (PSV), end-diastolic velocity (EDV) and resistivity index (RI) of each vessel using a different CDI device for each group. The concordance between two measurements was evaluated with Lin's concordance correlation coefficient (CCC).
  
  
  RESULTS
  Globally, very good degrees of intra-operator concordance were obtained for the PSV (0.859 cm/s), EDV (0.834 cm/s) and RI (0.859) of the OA. There was moderate concordance for PSV (0.574 cm/s) and EDV (0.594 cm/s) and good concordance for RI (0.694) for the CRA. Good degrees of concordance were obtained for the SPCA measurements. However, inter-operator concordance was found globally poor.
  
  
  CONCLUSIONS
  These data show that CDI measurements in retrobulbar vessels are operator dependent. To increase the intra-operator and inter-operator concordance, rules should be adopted for timing of the examination and positioning of the probe to minimise the pressure applied on the eye.
authors.affiliation: Institute of Radiology, Foundation IRCCS Policlinico San Matteo, Pavia, Italy, carolina.dellafiore@libero.it.
authors.forename: Carolina
authors.initials: C
authors.lastname: Dellafiore
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Lava
authors.forename: Alice Chandra
authors.initials: AC
authors.lastname: Verticchio Vercellin
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Cutolo
authors.forename: Carmine
authors.initials: C
authors.lastname: Tinelli
authors.forename: Annalisa
authors.initials: A
authors.lastname: De Silvestri
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Calliada
authors.forename: Giovanni
authors.initials: G
authors.lastname: Milano
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D019842:Ciliary Arteries / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009880:Ophthalmic Artery / Q000502:physiology*; D015203:Reproducibility of Results; D012161:Retinal Artery / Q000502:physiology*; D018615:Ultrasonography, Doppler, Color / Q000379:methods*