title: Subharmonic, non-linear fundamental and ultraharmonic imaging of microbubble contrast at high frequencies.
abstract: There is increasing use of ultrasound contrast agent in high-frequency ultrasound imaging. However, conventional contrast detection methods perform poorly at high frequencies. We performed systematic in vitro comparisons of subharmonic, non-linear fundamental and ultraharmonic imaging for different depths and ultrasound contrast agent concentrations (Vevo 2100 system with MS250 probe and MicroMarker ultrasound contrast agent, VisualSonics, Toronto, ON, Canada). We investigated 4-, 6- and 10-cycle bursts at three power levels with the following pulse sequences: B-mode, amplitude modulation, pulse inversion and combined pulse inversion/amplitude modulation. The contrast-to-tissue (CTR) and contrast-to-artifact (CAR) ratios were calculated. At a depth of 8 mm, subharmonic pulse-inversion imaging performed the best (CTR = 26 dB, CAR = 18 dB) and at 16 mm, non-linear amplitude modulation imaging was the best contrast imaging method (CTR = 10 dB). Ultraharmonic imaging did not result in acceptable CTRs and CARs. The best candidates from the in vitro study were tested in vivo in chicken embryo and mouse models, and the results were in a good agreement with the in vitro findings.
authors.affiliation: Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands. Electronic address: v.daeichin@erasmusmc.nl.
authors.forename: Verya
authors.initials: V
authors.lastname: Daeichin
authors.affiliation: Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Johan G
authors.initials: JG
authors.lastname: Bosch
authors.affiliation: VisualSonics Inc., Toronto, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Needles
authors.affiliation: Sunnybrook Research Institute and Department of Medical Biophysics, University of Toronto, Toronto, Canada.
authors.forename: F Stuart
authors.initials: FS
authors.lastname: Foster
authors.affiliation: Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands; Technical University Delft, Delft, The Netherlands.
authors.forename: Antonius
authors.initials: A
authors.lastname: van der Steen
authors.affiliation: Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands; Technical University Delft, Delft, The Netherlands; Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands.
authors.forename: Nico
authors.initials: N
authors.lastname: de Jong
mesh_terms: D000818:Animals; D016477:Artifacts; D002642:Chick Embryo / Q000000981:diagnostic imaging; D003287:Contrast Media / Q000008:administration & dosage*; D004452:Echocardiography; D007089:Image Enhancement / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007668:Kidney / Q000000981:diagnostic imaging; D051379:Mice; D045423:Microbubbles; D019047:Phantoms, Imaging; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Chicken embryo; Contrast imaging; Contrast-to-tissue ratio; High-frequency ultrasound; In vitro; In vivo; Non-linear propagation artifact; Ultrasound contrast agent