Real-time excitation-enhanced ultrasound contrast imaging.
A new nonlinear contrast specific imaging modality, excitation-enhanced imaging (EEI) has been implemented on commercially-available scanners for real-time imaging. This novel technique employs two acoustic fields: a low-frequency, high-intensity ultrasound field (the excitation field) to actively condition contrast microbubbles, and a second lower-intensity regular imaging field applied shortly afterwards to detect enhanced contrast scattering. A Logiq 9 scanner (GE Healthcare, Milwaukee, WI) with a 3.5C curved linear array and an AN2300 digital ultrasound engine (Analogic Corporation, Peabody, MA) with a P4-2 phased array transducer (Philips Medical Systems, Bothell, WA) were modified to perform EEI on a vector-by-vector basis in fundamental and pulse inversion harmonic grayscale modes. Ultrasound contrast microbubbles within an 8 mm vessel embedded in a tissue-mimicking flow phantom (ATS Laboratories, Bridgeport, CT) were imaged in vitro. While video intensities of scattered signals from the surrounding tissue were unchanged, video intensities of echoes from contrast bubbles within the vessel were markedly enhanced. The maximum enhancement achieved was 10.4 dB in harmonic mode (mean enhancement: 6.3 dB; p = 0.0007). In conclusion, EEI may improve the sensitivity of ultrasound contrast imaging, but further work is required to assess the in vivo potential of this new technique.
Forsberg
Flemming
F
Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA. flemming.forsberg@jefferson.edu
Shi
William T
WT
Knauer
Michael K
MK
Hall
Anne L
AL
Vecchio
Chris
C
Bernardi
Richard
R
D000418:Albumins; D003287:Contrast Media; D005290:Ferric Compounds; D005466:Fluorocarbons; D007089:Image Enhancement / Q000379:methods*; D007501:Iron; D045423:Microbubbles; D010087:Oxides; D019047:Phantoms, Imaging; D014463:Ultrasonography / Q000379:methods*
D000418:Albumins; D003287:Contrast Media; D005290:Ferric Compounds; D005466:Fluorocarbons; D010087:Oxides; C069727:Sonazoid; D007501:Iron