title: Estimation of intra-operator variability in perfusion parameter measurements using DCE-US.
abstract: OBJECTIVE
  To investigate intra-operator variability of semi-quantitative perfusion parameters using dynamic contrast-enhanced ultrasonography (DCE-US), following bolus injections of SonoVue(®).
  
  
  METHODS
  The in vitro experiments were conducted using three in-house sets up based on pumping a fluid through a phantom placed in a water tank. In the in vivo experiments, B16F10 melanoma cells were xenografted to five nude mice. Both in vitro and in vivo, images were acquired following bolus injections of the ultrasound contrast agent SonoVue(®) (Bracco, Milan, Italy) and using a Toshiba Aplio(®) ultrasound scanner connected to a 2.9-5.8 MHz linear transducer (PZT, PLT 604AT probe) (Toshiba, Japan) allowing harmonic imaging ("Vascular Recognition Imaging") involving linear raw data. A mathematical model based on the dye-dilution theory was developed by the Gustave Roussy Institute, Villejuif, France and used to evaluate seven perfusion parameters from time-intensity curves. Intra-operator variability analyses were based on determining perfusion parameter coefficients of variation (CV).
  
  
  RESULTS
  In vitro, different volumes of SonoVue(®) were tested with the three phantoms: intra-operator variability was found to range from 2.33% to 23.72%. In vivo, experiments were performed on tumor tissues and perfusion parameters exhibited values ranging from 1.48% to 29.97%. In addition, the area under the curve (AUC) and the area under the wash-out (AUWO) were two of the parameters of great interest since throughout in vitro and in vivo experiments their variability was lower than 15.79%.
  
  
  CONCLUSIONS
  AUC and AUWO appear to be the most reliable parameters for assessing tumor perfusion using DCE-US as they exhibited the lowest CV values.
authors.affiliation: Marianne Gauthier, Ingrid Leguerney, Jessie Thalmensi, Sarah Parisot, Pierre Peronneau, Alain Roche, Nathalie Lassau, IR4M, UMR 8081, CNRS, Paris-Sud 11 Univ, Gustave Roussy Institute, Villejuif 94805, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Gauthier
authors.forename: Ingrid
authors.initials: I
authors.lastname: Leguerney
authors.forename: Jessie
authors.initials: J
authors.lastname: Thalmensi
authors.forename: Mohamed
authors.initials: M
authors.lastname: Chebil
authors.forename: Sarah
authors.initials: S
authors.lastname: Parisot
authors.forename: Pierre
authors.initials: P
authors.lastname: Peronneau
authors.forename: Alain
authors.initials: A
authors.lastname: Roche
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lassau