title: Ultrafast imaging of ultrasound contrast agents.
abstract: The disappearance of ultrasound contrast agents after disruption can provide useful information on their environment. However, in vivo acoustical imaging of this transient phenomenon, which has a duration on the order of milliseconds, requires high frame rates that are unattainable by conventional ultrasound scanners. In this article, ultrafast imaging is applied to microbubble tracking using a 128-element linear array and an elastography scanner. Contrast agents flowing in a wall-less tissue phantom are insonified with a high-intensity disruption pulse followed by a series of plane waves emitted at a 5kHz PRF. A collection of compounded images depicting the evolution of microbubbles is obtained after the echoes are beamformed in silico. The backscattering of the microbubbles appears to increase in the first image after disruption (4 ms) and decrease following an exponential decay in the next hundred milliseconds. This microbubble dynamic depends on the length and amplitude of the high-intensity pulse. Furthermore, confined microbubbles are found to differ significantly from their free-flowing counterparts in their dissolution curves. The high temporal resolution provided by ultrafast imaging could help distinguish targeted microbubbles during molecular imaging.
authors.affiliation: Institut Langevin Ondes et Images (CNRS UMR 7587), Ecole Supérieure de Physique et de Chimie Industrielle, Paris 75005, France. olicou@gmail.com
authors.forename: Olivier
authors.initials: O
authors.lastname: Couture
authors.forename: Souad
authors.initials: S
authors.lastname: Bannouf
authors.forename: Gabriel
authors.initials: G
authors.lastname: Montaldo
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Aubry
authors.forename: Mathias
authors.initials: M
authors.lastname: Fink
authors.forename: Mickael
authors.initials: M
authors.lastname: Tanter
mesh_terms: D003287:Contrast Media / Q000737:chemistry*; D054459:Elasticity Imaging Techniques / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D045423:Microbubbles; D019047:Phantoms, Imaging; D013997:Time Factors
chemical_list: D003287:Contrast Media