title: Analysis of the Uncertainty in Microbubble Characterization.
abstract: There is increasing interest in the use of microbubble contrast agents for quantitative imaging applications such as perfusion and blood pressure measurement. The response of a microbubble to ultrasound excitation is, however, extremely sensitive to its size, the properties of its coating and the characteristics of the sound field and surrounding environment. Hence the results of microbubble characterization experiments can be significantly affected by experimental uncertainties, and this can limit their utility in predictive modelling. The aim of this study was to attempt to quantify these uncertainties and their influence upon measured microbubble characteristics. Estimates for the parameters characterizing the microbubble coating were obtained by fitting model data to numerical simulations of microbubble dynamics. The effect of uncertainty in different experimental parameters was gauged by modifying the relevant input values to the fitting process. The results indicate that even the minimum expected uncertainty in, for example, measurements of microbubble radius using conventional optical microscopy, leads to variations in the estimated coating parameters of ∼20%. This should be taken into account in designing microbubble characterization experiments and in the use of data obtained from them.
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, UK.
authors.forename: Caroline
authors.initials: C
authors.lastname: Harfield
authors.affiliation: Acoustics Group, National Physical Laboratory, Teddington, UK; Department of Physics and Astronomy, University College London, London, UK.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Fury
authors.affiliation: Acoustics Group, National Physical Laboratory, Teddington, UK.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Memoli
authors.affiliation: Department of Physics and Astronomy, University College London, London, UK.
authors.forename: Philip
authors.initials: P
authors.lastname: Jones
authors.affiliation: Department of Mathematics, University College London, London, UK.
authors.forename: Nick
authors.initials: N
authors.lastname: Ovenden
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Oxford, UK. Electronic address: eleanor.stride@eng.ox.ac.uk.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Stride
mesh_terms: D003198:Computer Simulation; D045423:Microbubbles; D008853:Microscopy; D013499:Surface Properties; D014465:Ultrasonics; D035501:Uncertainty
keywords: Characterization; Experimental error; Microbubbles; Modelling; Quantitative imaging; Ultrasound contrast agent; Uncertainty