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2. Defatting of donor transplant livers during normothermic perfusion—a randomised clinical trial: study protocol for the DeFat study

Author

Abbas, Syed Hussain, Ceresa, Carlo D. L., Hodson, Leanne, Nasralla, David, Watson, Christopher J. E., Mergental, Hynek, Coussios, Constantin, Kaloyirou, Fotini, Brusby, Kerrie, Mora, Ana, Thomas, Helen, Kounali, Daphne, Keen, Katie, Pollok, Joerg-Matthias, Gaurav, Rohit, Iype, Satheesh, Jassem, Wayel, Perera, M. Thamara PR, Hakeem, Abdul Rahman, Knight, Simon, and Friend, Peter J.

Published
2024
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5. Heterogeneous tissue characterization using ultrasound: a comparison of fractal analysis backscatter models on liver tumors

Author

Al-Kadi, Omar S., Chung, Daniel Y. F., Coussios, Constantin C., and Noble, J. Alison

Subjects
Electrical Engineering and Systems Science - Image and Video Processing, Computer Science - Computer Vision and Pattern Recognition
Abstract

Assessing tumor tissue heterogeneity via ultrasound has recently been suggested for predicting early response to treatment. The ultrasound backscattering characteristics can assist in better understanding the tumor texture by highlighting local concentration and spatial arrangement of tissue scatterers. However, it is challenging to quantify the various tissue heterogeneities ranging from fine-to-coarse of the echo envelope peaks in tumor texture. Local parametric fractal features extracted via maximum likelihood estimation from five well-known statistical model families are evaluated for the purpose of ultrasound tissue characterization. The fractal dimension (self-similarity measure) was used to characterize the spatial distribution of scatterers, while the Lacunarity (sparsity measure) was applied to determine scatterer number density. Performance was assessed based on 608 cross-sectional clinical ultrasound RF images of liver tumors (230 and 378 demonstrating respondent and non-respondent cases, respectively). Crossvalidation via leave-one-tumor-out and with different k-folds methodologies using a Bayesian classifier were employed for validation. The fractal properties of the backscattered echoes based on the Nakagami model (Nkg) and its extend four-parameter Nakagami-generalized inverse Gaussian (NIG) distribution achieved best results - with nearly similar performance - for characterizing liver tumor tissue. Accuracy, sensitivity and specificity for the Nkg/NIG were: 85.6%/86.3%, 94.0%/96.0%, and 73.0%/71.0%, respectively. Other statistical models, such as the Rician, Rayleigh, and K-distribution were found to not be as effective in characterizing the subtle changes in tissue texture as an indication of response to treatment. Employing the most relevant and practical statistical model could have potential consequences for the design of an early and effective clinical therapy., Comment: 31 pages, 7 figures, 3 tables, journal article

Published
2019
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6. Normothermic Machine Perfusion of Donor Livers for Transplantation in the United States – A Randomized Controlled Trial

Author

Chapman, William C., Barbas, Andrew S., D’Alessandro, Anthony M., Vianna, Rodrigo, Kubal, Chandrashekhar A., Abt, Peter, Sonnenday, Christopher, Barth, Rolf, Alvarez-Casas, Josue, Yersiz, Hasan, Eckhoff, Devin, Cannon, Robert, Genyk, Yuri, Sher, Linda, Singer, Andrew, Feng, Sandy, Roll, Garrett, Cohen, Ari, Doyle, Maria B., Sudan, Debra L., Al-Adra, David, Khan, Adeel, Subramanian, Vijay, Abraham, Nader, Olthoff, Kim, Tekin, Akin, Berg, Lynn, Coussios, Constantin, Morris, Chris, Randle, Lucy, Friend, Peter, and Knechtle, Stuart J.

Published
2023
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7. O132: Impaired oxygen unloading from stored blood results in diffusion-limited oxygen release at tissues: evidence from twinned-circuit human kidney perfusion

Author

Dumbill, Richard, primary, Rabcuka, Julija, additional, Fallon, John, additional, Knight, Simon, additional, Hunter, James, additional, Voyce, Daniel, additional, Barrett, Jacob, additional, Ellen, Matt, additional, Weissenbacher, Annemarie, additional, Ploeg, Rutger, additional, Coussios, Constantin, additional, Friend, Peter, additional, and Swietach, Pawel, additional

Published
2024
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8. Quantification of Ultrasonic Texture heterogeneity via Volumetric Stochastic Modeling for Tissue Characterization

Author

Al-Kadi, O. S., Chung, Daniel Y. F., Carlisle, Robert C., Coussios, Constantin C., and Noble, J. Alison

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

Intensity variations in image texture can provide powerful quantitative information about physical properties of biological tissue. However, tissue patterns can vary according to the utilized imaging system and are intrinsically correlated to the scale of analysis. In the case of ultrasound, the Nakagami distribution is a general model of the ultrasonic backscattering envelope under various scattering conditions and densities where it can be employed for characterizing image texture, but the subtle intra-heterogeneities within a given mass are difficult to capture via this model as it works at a single spatial scale. This paper proposes a locally adaptive 3D multi-resolution Nakagami-based fractal feature descriptor that extends Nakagami-based texture analysis to accommodate subtle speckle spatial frequency tissue intensity variability in volumetric scans. Local textural fractal descriptors - which are invariant to affine intensity changes - are extracted from volumetric patches at different spatial resolutions from voxel lattice-based generated shape and scale Nakagami parameters. Using ultrasound radio-frequency datasets we found that after applying an adaptive fractal decomposition label transfer approach on top of the generated Nakagami voxels, tissue characterization results were superior to the state of art. Experimental results on real 3D ultrasonic pre-clinical and clinical datasets suggest that describing tumor intra-heterogeneity via this descriptor may facilitate improved prediction of therapy response and disease characterization., Comment: Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.media.2014.12. 004

Published
2016
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16. Sonosensitive Cavitation Nuclei—A Customisable Platform Technology for Enhanced Therapeutic Delivery

Author

Lyons, Brian, primary, Balkaran, Joel P. R., additional, Dunn-Lawless, Darcy, additional, Lucian, Veronica, additional, Keller, Sara B., additional, O’Reilly, Colm S., additional, Hu, Luna, additional, Rubasingham, Jeffrey, additional, Nair, Malavika, additional, Carlisle, Robert, additional, Stride, Eleanor, additional, Gray, Michael, additional, and Coussios, Constantin, additional

Published
2023
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24. Sound speed and attenuation of human pancreas and pancreatic tumors and their influence on focused ultrasound thermal and mechanical therapies.

Author

Gray, Michael D., Spiers, Laura, and Coussios, Constantin C.

Subjects
PANCREATIC tumors, ULTRASONIC imaging, PATIENT compliance, ACOUSTICAL materials, ATTENUATION coefficients, SPEED of sound, MICROBUBBLE diagnosis
Abstract

Background: There is increasing interest in using ultrasound for thermal ablation, histotripsy, and thermal or cavitational enhancement of drug delivery for the treatment of pancreatic cancer. Ultrasonic and thermal modelling conducted as part of the treatment planning process requires acoustic property values for all constituent tissues, but the literature contains no data for the human pancreas. Purpose: This study presents the first acoustic property measurements of human pancreatic samples and provides examples of how these properties impact a broad range of ultrasound therapies. Methods: Data were collected on human pancreatic tissue samples at physiological temperature from 23 consented patients in cooperation with a hospital pathology laboratory. Propagation of ultrasound over the 2.1–4.5 MHz frequency range through samples of various thicknesses and pathologies was measured using a set of custom‐built ultrasonic calipers, with the data processed to estimate sound speed and attenuation. The results were used in acoustic and thermal simulations to illustrate the impacts on extracorporeal ultrasound therapies for mild hyperthermia, thermal ablation, and histotripsy implemented with a CE‐marked clinical system operating at 0.96 MHz. Results: The mean sound speed and attenuation coefficient values for human samples were well below the range of values in the literature for non‐human pancreata, while the human attenuation power law exponents were substantially higher. The simulated impacts on ultrasound mediated therapies for the pancreas indicated that when using the human data instead of the literature average, there was a 30% reduction in median temperature elevation in the treatment volume for mild hyperthermia and 43% smaller volume within a 60°C contour for thermal ablation, all driven by attenuation. By comparison, impacts on boiling and intrinsic threshold histotripsy were minor, with peak pressures changing by less than 15% (positive) and 1% (negative) as a consequence of the counteracting effects of attenuation and sound speed. Conclusion: This study provides the most complete set of speed of sound and attenuation data available for the human pancreas, and it reiterates the importance of acoustic material properties in the planning and conduct of ultrasound‐mediated procedures, particularly thermal therapies. [ABSTRACT FROM AUTHOR]

Published
2024
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28. A randomized trial of normothermic preservation in liver transplantation

Author

Nasralla, David, Coussios, Constantin C., Mergental, Hynek, Akhtar, M. Zeeshan, Butler, Andrew J., Ceresa, Carlo D. L., and Chiocchia, Virginia

Subjects
Liver transplantation -- Methods, Aspartate, Enzymes, Surgery, Organ transplantation, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Liver transplantation is a highly successful treatment, but is severely limited by the shortage in donor organs. However, many potential donor organs cannot be used; this is because sub-optimal livers do not tolerate conventional cold storage and there is no reliable way to assess organ viability preoperatively. Normothermic machine perfusion maintains the liver in a physiological state, avoids cooling and allows recovery and functional testing. Here we show that, in a randomized trial with 220 liver transplantations, compared to conventional static cold storage, normothermic preservation is associated with a 50% lower level of graft injury, measured by hepatocellular enzyme release, despite a 50% lower rate of organ discard and a 54% longer mean preservation time. There was no significant difference in bile duct complications, graft survival or survival of the patient. If translated to clinical practice, these results would have a major impact on liver transplant outcomes and waiting list mortality.Normothermic machine perfusion of the liver improved early graft function, demonstrated by reduced peak serum aspartate transaminase levels and early allograft dysfunction rates, and improved organ utilization and preservation times, although no differences were seen in graft or patient survival., Author(s): David Nasralla [sup.1] , Constantin C. Coussios [sup.2] , Hynek Mergental [sup.3] , M. Zeeshan Akhtar [sup.1] [sup.4] , Andrew J. Butler [sup.5] , Carlo D. L. Ceresa [sup.1] [...]

Published
2018
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29. Diffusion-limited O2 release in human kidneys perfused with stored blood

Author

Dumbill, Richard, primary, Rabcuka, Julija, additional, Knight, Simon, additional, Hunter, James, additional, Fallon, John, additional, Voyce, Daniel, additional, Barrett, Jacob, additional, Ellen, Matt, additional, Weissenbacher, Annemarie, additional, Kurniawan, Tetuko, additional, Blonski, Slawomir, additional, Korczyk, Piotr, additional, Ploeg, Rutger, additional, Coussios, Constantin, additional, Friend, Peter, additional, and Swietach, Pawel, additional

Published
2023
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