Demi, L Libertario

Mischi, M Massimo

Sloun, RJG Ruud  van

Wijkstra, H Hessel

Zhao, X Xinran

Demi, L.

van Sloun, R.

Zhao, X.

Wijkstra, H.

Mischi, M.

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 Cumulative Phase Delay Imaging - a new contrast enhancedimaging modalityCitation for published version (APA):Demi, L., van Sloun, R., Zhao, X., Wijkstra, H., & Mischi, M. (2015). Cumulative Phase Delay Imaging - a newcontrast enhanced imaging modality. In Proceedings of the 20th European Symposium on Ultrasound ContrastImaging, Rotterdam, 2015 (pp. 100-103)Document status and date:Published: 01/01/2015Document Version:Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the version of the article upon submission and before peer-review. There can beimportant differences between the submitted version and the official published version of record. Peopleinterested in the research are advised to contact the author for the final version of the publication, or visit theDOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and pagenumbers.Link to publicationGeneral rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            • Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            • You may not further distribute the material or use it for any profit-making activity or commercial gain            • You may freely distribute the URL identifying the publication in the public portal.If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, pleasefollow below link for the End User Agreement:www.tue.nl/taverneTake down policyIf you believe that this document breaches copyright please contact us at:openaccess@tue.nlproviding details and we will investigate your claim.Download date: 17. Nov. 2023- 100 -  Cumulative phase delay imaging – a new contrast enhanced imaging modality  Libertario Demi1, Ruud J.G. Van Sloun1, Xinran Zhao1, Hessel Wijkstra2,1,  Massimo Mischi1  1Department of Electrical Engineering, Laboratory of Biomedical Diagnostics,  Eindhoven University of Technology, the Netherlands 2AMC University Hospital, Amsterdam, the Netherlands Introduction Recently, a new marker for ultrasound contrast agents (UCAs) has been introduced [1-2]. A cumulative phase delay (D) between the second harmonic and fundamental pressure component is in fact observable for ultrasound propagating through UCAs. This phenomenon is absent in the case of tissue nonlinearity and is dependent on insonating pressure and frequency, UCA concentration, and propagation path length through UCAs. In this paper, the first ultrasound image based on this marker is presented.  Methods The U A-  research platform [ ], in combination with a A 2 linear array probe ( saote, iren e Italy), has been used to image a gelatin phantom containing a PVC plate (used as a reflector) and a cylindrical cavity with a diameter of 7 mm (placed in between the observation point and the PVC plate), see Figure 1.              Figure 1: Picture (left) and schematic top view (right) of the phantom.  cavity plate opening (observation point) LA332 8 cm 16 cm - 101 -   Figure 2: Total field backscattered at the plate (top) and estimated second harmonic to fundamental component cumulative phase delay profile from five consecutive frames (bottom).  The cavity contained a 2 0  onoVue  UCA concentration. The gelatin phantom was scanned with an insonating frequency f0 = 3 MHz and a mechanical index MI = 0.05, measured in water at the cavity location with a H -0400 hydrophone  (Onda, Sunnyvale, CA). The echoes obtained from the PVC plate were processed as described in [1-2] in order to obtain, for each line imaged, a measure of the cumulative phase delay D=2 0, with t being the time delay between the second harmonic and the fundamental component. Exploiting the employed linear array, as shown in Figure 2, D can be estimated as a function of space in the lateral direction. The axis of the cylindrical cavity was positioned at (z,x)=(80 mm, 0 mm), with z and x being the axial and lateral direction, respectively, and with the center of the linear array aperture coinciding with the center of the coordinate system.   For this particular in-vitro configuration, we can exploit the symmetry of the target and assume consecutive frames as if acquired from different observation angles. Consequently, a sinogram can be constructed, and an ultrasound image generated in a tomographic fashion using the filtered back-projection method [4].   - 102 -   Figure 3: Sinogram (left) and corresponding ultrasound D-image (right) obtained by imaging a 7-mm diameter cavity   Results Figure 2 (top) shows the total field backscattered at the plate. Attenuation of the total field due to the presence of UCAs in the propagation path can be observed.  The bottom plot shows the estimated second harmonic to fundamental cumulative phase delay D from five consecutive frames, as a function of x. This plot shows variations of D in the presence of UCAs along the propagation path, with D increasing for longer propagation path length through UCAs. In particular, a measure of D of approximately -0.3  has been always observed in the absence of UCAs.  Figure 3 shows the sinogram (left) and obtained ultrasound D-image (right) using the filtered back-projection method. Five consecutive frames have been used, and assumed to be acquired at an angle of 0, 36, 72, 108, and 144 degree, respectively.     Conclusion and Discussion We presented the first ultrasound image based on the cumulative phase delay between second harmonic and fundamental component observed for ultrasound propagating through UCAs. Although a simple set-up was adopted, where the symmetry of the imaged target facilitated the image formation, this result confirms the applicability of the presented cumulative delay as an UCA marker for imaging.   Comparison with standard contrast-enhanced ultrasound imaging modalities, together with the optimization of the acquisition parameters will be the focus of future work. Imaging in the presence of flowing rather than static UCAs will also be investigated.   - 103 -  References 1. L. Demi, G. Russo, H. Wijkstra, and M. Mischi "Observed Cumulative Time Delay Between Second Harmonic and Fundamental Component of Pressure Wave Fields Propagating Through Ultrasound Contrast Agents", Proceedings of Meetings on Acoustics 20, San Francisco, 075002, 2013 2. L. Demi, H. Wijkstra, and M. Mischi “Cumulative phase delay between second harmonic and fundamental components - A marker for ultrasound contrast agents”, Journal of the Acoustical Society of America, 136, pp. 2968 - 2975, 2014 3. E. Boni, L. Bassi, A. Dallai, F. Guidi, A. Ramalli, S. Ricci, R. Housden, and P. Tortoli,  “A Reconfigurable and Programmable FPGA based System for non-standard Ultrasound Methods”, IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control, 59, pp. 1378—1385, 2012 4. Paul Suetens. Fundamentals of medical imaging. Cambridge University Press, 2009     

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Cumulative Phase Delay Imaging - a new contrast enhanced imaging modality

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Cumulative Phase Delay Imaging - a new contrast enhanced imaging modality

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