title: Second harmonic and subharmonic for non-linear wideband contrast imaging using a capacitive micromachined ultrasonic transducer array.
abstract: When insonified with suitable ultrasound excitation, contrast microbubbles generate various non-linear scattered components, such as the second harmonic (2H) and the subharmonic (SH). In this study, we exploit the wide frequency bandwidth of capacitive micromachined ultrasonic transducers (CMUTs) to enhance the response from ultrasound contrast agents by selective imaging of both the 2H and SH components simultaneously. To this end, contrast images using the pulse inversion method were recorded with a 64-element CMUT linear array connected to an open scanner. In comparison to imaging at 2H alone, the wideband imaging including both the 2H and SH contributions provided up to 130% and 180% increases in the signal-to-noise and contrast-to-tissue ratios, respectively. The wide-frequency band of CMUTs offers new opportunities for improved ultrasound contrast agent imaging.
authors.affiliation: UMR Inserm U 930, Université François-Rabelais de Tours, PRES Centre-Val de Loire Université, Tours, France.
authors.forename: Anthony
authors.initials: A
authors.lastname: Novell
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Escoffre
authors.forename: Ayache
authors.initials: A
authors.lastname: Bouakaz
mesh_terms: D016477:Artifacts; D025802:Electric Capacitance; D007089:Image Enhancement / Q000295:instrumentation*; D008904:Miniaturization; D017711:Nonlinear Dynamics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*
keywords: Capacitive micromachined ultrasonic transducer; Contrast agent imaging; Contrast-to-tissue ratio; Harmonic; Pulse inversion; Signal-to-noise ratio; Subharmonic; Wideband imaging