Print Email Facebook Twitter Ultrasound contrast agent imaging: Real-time imaging of the superharmonics Title Ultrasound contrast agent imaging: Real-time imaging of the superharmonics Author Peruzzini, D. Viti, J. Tortoli, P. Verweij, M.D. De Jong, N. Vos, H.J. Faculty Applied Sciences Department ImPhys/Imaging Physics Date 2015-12-31 Abstract Currently, in medical ultrasound contrast agent (UCA) imaging the second harmonic scattering of the microbubbles is regularly used. This scattering is in competition with the signal that is caused by nonlinear wave propagation in tissue. It was reported that UCA imaging based on the third or higher harmonics, i.e. “superharmonic” imaging, shows better contrast. However, the superharmonic scattering has a lower signal level compared to e.g. second harmonic signals. This study investigates the contrast-to-tissue ratio (CTR) and signal to noise ratio (SNR) of superharmonic UCA scattering in a tissue/vessel mimicking phantom using a real-time clinical scanner. Numerical simulations were performed to estimate the level of harmonics generated by the microbubbles. Data were acquired with a custom built dual-frequency cardiac phased array probe. Fundamental real-time images were produced while beam formed radiofrequency (RF) data was stored for further offline processing. The phantom consisted of a cavity filled with UCA surrounded by tissue mimicking material. The acoustic pressure in the cavity of the phantom was 110 kPa (MI = 0.11) ensuring non-destructivity of UCA. After processing of the acquired data from the phantom, the UCA-filled cavity could be clearly observed in the images, while tissue signals were suppressed at or below the noise floor. The measured CTR values were 36 dB, >38 dB, and >32 dB, for the second, third, and fourth harmonic respectively, which were in agreement with those reported earlier for preliminary contrast superharmonic imaging. The single frame SNR values (in which ‘signal’ denotes the signal level from the UCA area) were 23 dB, 18 dB, and 11 dB, respectively. This indicates that noise, and not the tissue signal, is the limiting factor for the UCA detection when using the uperharmonics in nondestructive mode. To reference this document use: http://resolver.tudelft.nl/uuid:225e1adc-2f3a-4ef4-9f41-9d63e7328e83 DOI https://doi.org/http://dx.doi.org/10.1063/1.4934406 Publisher American Institute of Physics ISBN 978-0-7354-1332-0 Source AIP Conference Proceedings 1685, Recent developments in nonlinear acoustics; 20th International Symposium on Nonlinear Acoustics including 2nd International Sonic Boom Forum, Ecully (France(), 29 June-3 July, 2015 Part of collection Institutional Repository Document type conference paper Rights (c) 2015 The Authors and American Institute of Physics Files PDF 321464.pdf 748.08 KB Close viewer /islandora/object/uuid:225e1adc-2f3a-4ef4-9f41-9d63e7328e83/datastream/OBJ/view