title: Quantification of tumor perfusion using dynamic contrast-enhanced ultrasound: impact of mathematical modeling.
abstract: Dynamic contrast-enhanced ultrasound has been proposed to monitor tumor therapy, as a complement to volume measurements. To assess the variability of perfusion parameters in ideal conditions, four consecutive test-retest studies were acquired in a mouse tumor model, using controlled injections. The impact of mathematical modeling on parameter variability was then investigated. Coefficients of variation (CV) of tissue blood volume (BV) and tissue blood flow (BF) based-parameters were estimated inside 32 sub-regions of the tumors, comparing the log-normal (LN) model with a one-compartment model fed by an arterial input function (AIF) and improved by the introduction of a time delay parameter. Relative perfusion parameters were also estimated by normalization of the LN parameters and normalization of the one-compartment parameters estimated with the AIF, using a reference tissue (RT) region. A direct estimation (rRTd) of relative parameters, based on the one-compartment model without using the AIF, was also obtained by using the kinetics inside the RT region. Results of test-retest studies show that absolute regional parameters have high CV, whatever the approach, with median values of about 30% for BV, and 40% for BF. The positive impact of normalization was established, showing a coherent estimation of relative parameters, with reduced CV (about 20% for BV and 30% for BF using the rRTd approach). These values were significantly lower (p  <  0.05) than the CV of absolute parameters. The rRTd approach provided the smallest CV and should be preferred for estimating relative perfusion parameters.
authors.affiliation: Laboratoire d'Imagerie Biomédicale (LIB), CNRS, Inserm, UPMC Univ. Paris 06, Sorbonne Universités, Paris, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Doury
authors.forename: Alexandre
authors.initials: A
authors.lastname: Dizeux
authors.forename: Alain
authors.initials: A
authors.lastname: de Cesare
authors.forename: Olivier
authors.initials: O
authors.lastname: Lucidarme
authors.forename: Claire
authors.initials: C
authors.lastname: Pellot-Barakat
authors.forename: S Lori
authors.initials: SL
authors.lastname: Bridal
authors.forename: Frédérique
authors.initials: F
authors.lastname: Frouin
mesh_terms: D000465:Algorithms; D000818:Animals; D001810:Blood Volume; D018827:Carcinoma, Lewis Lung / Q000098:blood supply / Q000000981:diagnostic imaging*; D003287:Contrast Media; D051379:Mice; D008807:Mice, Inbred BALB C; D008962:Models, Theoretical; D055420:Perfusion Imaging / Q000379:methods* / Q000592:standards; D014463:Ultrasonography / Q000379:methods* / Q000592:standards
chemical_list: D003287:Contrast Media