title: Towards a quantitative in vivo evaluation of venous blood echogenicity: image processing versus subjective assessment.
abstract: OBJECTIVE
  Spontaneous blood echogenicity in vein ultrasound images may be a marker for an increased erythrocyte aggregability, but a reliable quantitative evaluation method is a prerequisite for its use in clinical studies. We compared a simple scoring system of blood echogenicity intensity and pattern, with automatic image analysis.
  
  
  METHODS
  157 femoral and popliteal vein digitized ultrasound sequences were reviewed by two independent observers who chose an image, delimited an area of interest (ROI), and graded blood echogenicity intensity and pattern, using a four class score. Each observer reviewed the images selected by the other, without and with ROI. The computer calculated first and second order parameters describing echo intensity and spatial organization.
  
  
  RESULTS
  Inter-observer reproducibility of subjective assessment was poor (Kappa<0.5), whereas the automatically calculated ROI average gray level intensity relatively to the whole image (tau(1)) effectively separated all grades of intensity. No parameter effectively separated patterns.
  
  
  CONCLUSIONS
  Tau(1) is a simple parameter for the in vivo evaluation of blood echogenicity intensity. It should be evaluated in standardized conditions for clinical hemorheology studies in correlation with in vitro erythrocyte aggregation measurements.
authors.affiliation: Laboratory of Cardio-Vascular Physiology, Faculty of Medicine, Montpellier I University, Nimes, France.
authors.forename: Yayha A
authors.initials: YA
authors.lastname: Rabhi
authors.forename: Pascale
authors.initials: P
authors.lastname: Fabbro-Peray
authors.forename: Michel
authors.initials: M
authors.lastname: Dauzat
authors.forename: Philippe
authors.initials: P
authors.lastname: Montesinos
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Oliva-Lauraire
authors.forename: François-Michel
authors.initials: FM
authors.lastname: Lopez
authors.forename: Isabelle
authors.initials: I
authors.lastname: Quéré
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Gris
authors.forename: Jean-Frédéric
authors.initials: JF
authors.lastname: Brun
authors.forename: Léandre
authors.initials: L
authors.lastname: Pourcelot
mesh_terms: D001769:Blood / Q000000981:diagnostic imaging*; D004903:Erythrocyte Aggregation; D005268:Femoral Vein / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000592:standards; D015588:Observer Variation; D011152:Popliteal Vein / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods / Q000592:standards*