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818 results on '"Graves, Martin J"'

2. Learning the Sampling Pattern for MRI

Author

Sherry, Ferdia, Benning, Martin, Reyes, Juan Carlos De los, Graves, Martin J., Maierhofer, Georg, Williams, Guy, Schönlieb, Carola-Bibiane, and Ehrhardt, Matthias J.

Subjects
Electrical Engineering and Systems Science - Image and Video Processing, Computer Science - Computer Vision and Pattern Recognition, Mathematics - Numerical Analysis, Mathematics - Optimization and Control
Abstract

The discovery of the theory of compressed sensing brought the realisation that many inverse problems can be solved even when measurements are "incomplete". This is particularly interesting in magnetic resonance imaging (MRI), where long acquisition times can limit its use. In this work, we consider the problem of learning a sparse sampling pattern that can be used to optimally balance acquisition time versus quality of the reconstructed image. We use a supervised learning approach, making the assumption that our training data is representative enough of new data acquisitions. We demonstrate that this is indeed the case, even if the training data consists of just 7 training pairs of measurements and ground-truth images; with a training set of brain images of size 192 by 192, for instance, one of the learned patterns samples only 35% of k-space, however results in reconstructions with mean SSIM 0.914 on a test set of similar images. The proposed framework is general enough to learn arbitrary sampling patterns, including common patterns such as Cartesian, spiral and radial sampling., Comment: The main document is 12 pages, the supporting document is 2 pages and attached at the end of the main document

Published
2019

3. Somatostatin Receptor PET/MR Imaging of Inflammation in Patients With Large Vessel Vasculitis and Atherosclerosis

Author

Ćorović, Andrej, Wall, Christopher, Nus, Meritxell, Gopalan, Deepa, Huang, Yuan, Imaz, Maria, Zulcinski, Michal, Peverelli, Marta, Uryga, Anna, Lambert, Jordi, Bressan, Dario, Maughan, Robert T., Pericleous, Charis, Dubash, Suraiya, Jordan, Natasha, Jayne, David R., Hoole, Stephen P., Calvert, Patrick A., Dean, Andrew F., Rassl, Doris, Barwick, Tara, Iles, Mark, Frontini, Mattia, Hannon, Greg, Manavaki, Roido, Fryer, Tim D., Aloj, Luigi, Graves, Martin J., Gilbert, Fiona J., Dweck, Marc R., Newby, David E., Fayad, Zahi A., Reynolds, Gary, Morgan, Ann W., Aboagye, Eric O., Davenport, Anthony P., Jørgensen, Helle F., Mallat, Ziad, Bennett, Martin R., Peters, James E., Rudd, James H.F., Mason, Justin C., and Tarkin, Jason M.

Published
2023
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4. Compressed Sensing Plus Motion (CS+M): A New Perspective for Improving Undersampled MR Image Reconstruction

Author

Aviles-Rivero, Angelica I., Debroux, Noémie, Williams, Guy, Graves, Martin J., and Schonlieb, Carola-Bibiane

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

We address the problem of reconstructing high quality images from undersampled MRI data. This is a challenging task due to the highly ill-posed nature of the problem. In particular, in dynamic MRI scans, the interaction between the target structure and the physical motion affects the acquired measurements leading to blurring artefacts and loss of fine details. In this work, we propose a framework for dynamic MRI reconstruction framed under a new multi-task optimisation model called Compressed Sensing Plus Motion (CS+M). Firstly, we propose a single optimisation problem that simultaneously computes the MRI reconstruction and the physical motion. Secondly, we show our model can be efficiently solved by breaking it up into two more computationally tractable problems. The potentials and generalisation capabilities of our approach are demonstrated in different clinical applications including cardiac cine, cardiac perfusion and brain perfusion imaging. We show, through numerical and graphical experiments, that the proposed scheme reduces blurring artefacts and preserves the target shape and fine details. We also report the highest quality reconstruction under highly undersampling rates in comparison to several state of the art techniques.

Published
2018

7. Measuring cerebral enzymatic activity, brain pH and extracranial muscle metabolism with hyperpolarized 13C‐pyruvate.

Author

Khan, Alixander S., McLean, Mary A., Kaggie, Joshua D., Horvat‐Menih, Ines, Matys, Tomasz, Schulte, Rolf F., Locke, Matthew J., Grimmer, Ashley, Wodtke, Pascal, Latimer, Elizabeth, Frary, Amy, Graves, Martin J., and Gallagher, Ferdia A.

Subjects
MAGNETIC resonance imaging, CARBONIC anhydrase, PYRUVATE carboxylase, MUSCLE metabolism, ASPARTATE aminotransferase, BICARBONATE ions
Abstract

Hyperpolarized carbon‐13 (13C) magnetic resonance imaging (MRI) has shown promise for non‐invasive assessment of the cerebral metabolism of [1‐13C]pyruvate in both healthy volunteers and patients. The exchange of pyruvate to lactate catalysed by lactate dehydrogenase (LDH) and that of pyruvate flux to bicarbonate through pyruvate dehydrogenase (PDH) are the most widely studied reactions in vivo. Here we show the potential of the technique to probe additional enzymatic activity within the brain. Approximately 50 s after intravenous injection of hyperpolarized pyruvate, high‐flip‐angle pulses were used to detect cerebral 13C‐labelled carbon dioxide (13CO2), in addition to the 13C‐bicarbonate (H13CO3−) subsequently formed by carbonic anhydrase (CA). Brain pH measurements, which were weighted towards the extracellular compartment, were calculated from the ratio of H13CO3− to 13CO2 in seven volunteers using the Henderson–Hasselbalch equation, demonstrating an average pH ± SD of 7.40 ± 0.02, with inter‐observer reproducibility of 0.04. In addition, hyperpolarized [1‐13C]aspartate was also detected, demonstrating irreversible pyruvate carboxylation to oxaloacetate by pyruvate carboxylase (PC) and subsequent transamination by aspartate aminotransferase (AST), with the average flux being on average 11% ± 3% of that through PDH. A hyperpolarized [1‐13C]alanine signal was also detected, but this was localized to extracranial muscle tissue in keeping with skeletal alanine aminotransferase (ALT) activity. The results demonstrate the potential of hyperpolarized 13C‐MRI to assess cerebral and extracerebral [1‐13C]pyruvate metabolism in addition to LDH and PDH activity. Non‐invasive measurements of brain pH could be particularly important in assessing cerebral pathology given the wide range of disease processes that alter acid–base balance. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Author Correction: Hyperpolarised 13C-MRI identifies the emergence of a glycolytic cell population within intermediate-risk human prostate cancer

Author

Sushentsev, Nikita, McLean, Mary A., Warren, Anne Y., Benjamin, Arnold J. V., Brodie, Cara, Frary, Amy, Gill, Andrew B., Jones, Julia, Kaggie, Joshua D., Lamb, Benjamin W., Locke, Matthew J., Miller, Jodi L., Mills, Ian G., Priest, Andrew N., Robb, Fraser J. L., Shah, Nimish, Schulte, Rolf F., Graves, Martin J., Gnanapragasam, Vincent J., Brindle, Kevin M., Barrett, Tristan, and Gallagher, Ferdia A.

Published
2022
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9. Hyperpolarised 13C-MRI identifies the emergence of a glycolytic cell population within intermediate-risk human prostate cancer

Author

Sushentsev, Nikita, McLean, Mary A., Warren, Anne Y., Benjamin, Arnold J. V., Brodie, Cara, Frary, Amy, Gill, Andrew B., Jones, Julia, Kaggie, Joshua D., Lamb, Benjamin W., Locke, Matthew J., Miller, Jodi L., Mills, Ian G., Priest, Andrew N., Robb, Fraser J. L., Shah, Nimish, Schulte, Rolf F., Graves, Martin J., Gnanapragasam, Vincent J., Brindle, Kevin M., Barrett, Tristan, and Gallagher, Ferdia A.

Published
2022
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10. Low‐rank iterative infilling for zero echo‐time (ZTE) imaging.

Author

Huo, Zimu, de Arcos, José, Wiesinger, Florian, Kaggie, Joshua D., and Graves, Martin J.

Subjects
INVERSE problems, TEST methods, COMPARATIVE studies, BANDWIDTHS, SPEED
Abstract

Purpose: A new referenceless low‐rank reconstruction technique has been introduced to address the issue of missing samples within the Zero Echo Time (ZTE) dead‐time gap. Methods: The proposed method reformulates the in‐filling of the missing samples as an inverse problem subject to low‐rank constraints. Its performance and robustness are evaluated through a comparative analysis that combines Monte Carlo computational simulations and data obtained from in vivo experiments. Results: The proposed method is tested for dead‐time gaps ranging up to 4.5 Nyquist dwells, across signal‐to‐noise ratio levels of 5, 10, 15, and 20 dB. Consistently superior performance is observed across all cases compared to algebraic and parallel imaging methods. The speed for convergence decreases exponentially as the dead‐time gap expands. Conclusion: The proposed method enables artifact‐free reconstruction up to dead‐time gap of 4 Nyquist dwells and thereby supports ZTE imaging up to an imaging bandwidth of ±41.67$$ \pm 41.67 $$ kHz (assuming transmit and receive switching less than 30 μ$$ \mu $$s). It demonstrates superior performance compared to algebraic and parallel imaging methods. [ABSTRACT FROM AUTHOR]

Published
2025
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14. Coronavirus disease 2019–related myocardial injury is associated with immune dysregulation in symptomatic patients with cardiac magnetic resonance imaging abnormalities.

Author

Ćorović, Andrej, Zhao, Xiaohui, Huang, Yuan, Newland, Stephen R, Gopalan, Deepa, Harrison, James, Giakomidi, Despina, Chen, Shanna, Yarkoni, Natalia S, Wall, Christopher, Peverelli, Marta, Sriranjan, Rouchelle, Gallo, Arianna, Graves, Martin J, Sage, Andrew, Lyons, Paul A, Sithole, Nyarie, Bennett, Martin R, Rudd, James H F, and Mallat, Ziad

Subjects
CARDIAC magnetic resonance imaging, POST-acute COVID-19 syndrome, PROGRAMMED cell death 1 receptors, TRANSVERSE electromagnetic cells, COVID-19
Abstract

Aims While acute cardiovascular complications of coronavirus disease 2019 (COVID-19) are well described, less is known about longer-term cardiac sequelae. For many individuals with cardiac signs or symptoms arising after COVID-19 infection, the aetiology remains unclear. We examined immune profiles associated with magnetic resonance imaging (MRI) abnormalities in patients with unexplained cardiac injury after COVID-19. Methods and results Twenty-one participants {mean age 47 [standard deviation (SD) 13] years, 71% female} with long COVID-19 (n = 17), raised troponin (n = 2), or unexplained new-onset heart failure (n = 2), who did not have pre-existing heart conditions or recent steroid/immunosuppression treatment, were enrolled a mean 346 (SD 191) days after COVID-19 infection in a prospective observational study. Cardiac MRI and blood sampling for deep immunophenotyping using mass cytometry by time of flight and measurement of proteomic inflammatory markers were performed. Nine of the 21 (43%) participants had MRI abnormalities (MRI(+)), including non-ischaemic patterns of late gadolinium enhancement and/or visually overt myocardial oedema in 8 people. One patient had mildly impaired biventricular function without fibrosis or oedema, and two had severe left ventricular (LV) impairment. MRI(+) individuals had higher blood CCL3, CCL7, FGF-23, and CD4 Th2 cells, and lower CD8 T effector memory (TEM) cells, than MRI(−). Cluster analysis revealed lower expression of inhibitory receptors PD1 and TIM3 in CD8 TEM cells from MRI(+) patients than MRI(−) patients, and functional studies of CD8 T αβ cells showed higher proportions of cytotoxic granzyme B+(GZB+)-secreting cells upon stimulation. CD8 TEM cells and CCL7 were the strongest predictors of MRI abnormalities in a least absolute shrinkage and selection operator regression model (composite area under the curve 0.96, 95% confidence interval 0.88–1.0). CCL7 was correlated with diffuse myocardial fibrosis/oedema detected by quantitative T1 mapping (r = 0.47, P = 0.04). Conclusion COVID-19-related cardiac injury in symptomatic patients with non-ischaemic myocarditis-like MRI abnormalities is associated with immune dysregulation, including decreased peripheral CD8 TEM cells and increased CCL7, persisting long after the initial infection. [ABSTRACT FROM AUTHOR]

Published
2024
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19. Characterizing Diffusion from Microdialysis Catheters in the Human Brain: A Magnetic Resonance Imaging Study With Gadobutrol

Author

Stovell, Matthew G., primary, Ruetten, Pascal P.R., additional, Tozer, Daniel J., additional, Launey, Yoann, additional, Zimphango, Chisomo, additional, Thelin, Eric P., additional, Lupson, Victoria C., additional, Giorgi-Coll, Susan, additional, Carpenter, T. Adrian, additional, Mada, Marius O., additional, Jalloh, Ibrahim, additional, Helmy, Adel, additional, Wilson, Mark H., additional, Graves, Martin J., additional, Menon, David K., additional, Carpenter, Keri L.H., additional, and Hutchinson, Peter J., additional

Published
2024
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20. MINocyclinE to Reduce inflammation and blood‐brain barrier leakage in small Vessel diseAse (MINERVA): A phase II, randomized, double‐blind, placebo‐controlled experimental medicine trial

Author

Brown, Robin B., primary, Tozer, Daniel J., additional, Loubière, Laurence, additional, Harshfield, Eric L., additional, Hong, Young T., additional, Fryer, Tim D., additional, Williams, Guy B., additional, Graves, Martin J., additional, Aigbirhio, Franklin I., additional, O'Brien, John T., additional, and Markus, Hugh S., additional

Published
2024
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21. Imaging breast cancer using hyperpolarized carbon-13 MRI

Author

Gallagher, Ferdia A., Woitek, Ramona, McLean, Mary A., Gill, Andrew B., Garcia, Raquel Manzano, Provenzano, Elena, Riemer, Frank, Kaggie, Joshua, Chhabra, Anita, Ursprung, Stephan, Grist, James T., Daniels, Charlie J., Zaccagna, Fulvio, Laurent, Marie-Christine, Locke, Matthew, Hilborne, Sarah, Frary, Amy, Torheim, Turid, Boursnell, Chris, Schiller, Amy, Patterson, Ilse, Slough, Rhys, Carmo, Bruno, Kane, Justine, Biggs, Heather, Harrison, Emma, Deen, Surrin S., Patterson, Andrew, Lanz, Titus, Kingsbury, Zoya, Ross, Mark, Basu, Bristi, Baird, Richard, Lomas, David J., Sala, Evis, Wason, James, Rueda, Oscar M., Chin, Suet-Feung, Wilkinson, Ian B., Graves, Martin J., Abraham, Jean E., Gilbert, Fiona J., Caldas, Carlos, and Brindle, Kevin M.

Published
2020

25. Quantifying normal human brain metabolism using hyperpolarized [1–13C]pyruvate and magnetic resonance imaging

Author

Grist, James T., McLean, Mary A., Riemer, Frank, Schulte, Rolf F., Deen, Surrin S., Zaccagna, Fulvio, Woitek, Ramona, Daniels, Charlie J., Kaggie, Joshua D., Matys, Tomasz, Patterson, Ilse, Slough, Rhys, Gill, Andrew B., Chhabra, Anita, Eichenberger, Rose, Laurent, Marie-Christine, Comment, Arnaud, Gillard, Jonathan H., Coles, Alasdair J., Tyler, Damian J., Wilkinson, Ian, Basu, Bristi, Lomas, David J., Graves, Martin J., Brindle, Kevin M., and Gallagher, Ferdia A.

Published
2019
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26. Sodium MRI with 3D-cones as a measure of tumour cellularity in high grade serous ovarian cancer

Author

Deen, Surrin S., Riemer, Frank, McLean, Mary A., Gill, Andrew B., Kaggie, Joshua D., Grist, James T., Crawford, Robin, Latimer, John, Baldwin, Peter, Earl, Helena M., Parkinson, Christine A., Smith, Sarah A., Hodgkin, Charlotte, Moore, Elizabeth, Jimenez-Linan, Mercedes, Brodie, Cara R., Addley, Helen C., Freeman, Susan J., Moyle, Penelope L., Sala, Evis, Graves, Martin J., Brenton, James D., and Gallagher, Ferdia A.

Published
2019
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40. A medical device-grade T1 and ECV phantom for global T1 mapping quality assurance—the T1 Mapping and ECV Standardization in cardiovascular magnetic resonance (T1MES) program

Author

Captur, Gabriella, Gatehouse, Peter, Keenan, Kathryn E., Heslinga, Friso G., Bruehl, Ruediger, Prothmann, Marcel, Graves, Martin J., Eames, Richard J., Torlasco, Camilla, Benedetti, Giulia, Donovan, Jacqueline, Ittermann, Bernd, Boubertakh, Redha, Bathgate, Andrew, Royet, Celine, Pang, Wenjie, Nezafat, Reza, Salerno, Michael, Kellman, Peter, and Moon, James C.

Published
2016
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43. Diffusion kurtosis MRI as a predictive biomarker of response to neoadjuvant chemotherapy in high grade serous ovarian cancer

Author

Deen, Surrin S., Priest, Andrew N., McLean, Mary A., Gill, Andrew B., Brodie, Cara, Crawford, Robin, Latimer, John, Baldwin, Peter, Earl, Helena M., Parkinson, Christine, Smith, Sarah, Hodgkin, Charlotte, Patterson, Ilse, Addley, Helen, Freeman, Susan, Moyle, Penny, Jimenez-Linan, Mercedes, Graves, Martin J., Sala, Evis, Brenton, James D., and Gallagher, Ferdia A.

Published
2019
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44. Integrating Artificial Intelligence Tools in the Clinical Research Setting : The Ovarian Cancer Use Case

Author

Sanchez, Lorena Escudero, Buddenkotte, Thomas, Al Sa'd, Mohammad, McCague, Cathal, Darcy, James, Rundo, Leonardo, Samoshkin, Alex, Graves, Martin J., Hollamby, Victoria, Browne, Paul, Crispin-Ortuzar, Mireia, Woitek, Ramona, Sala, Evis, Schonlieb, Carola-Bibiane, Doran, Simon J., Öktem, Ozan, Sanchez, Lorena Escudero, Buddenkotte, Thomas, Al Sa'd, Mohammad, McCague, Cathal, Darcy, James, Rundo, Leonardo, Samoshkin, Alex, Graves, Martin J., Hollamby, Victoria, Browne, Paul, Crispin-Ortuzar, Mireia, Woitek, Ramona, Sala, Evis, Schonlieb, Carola-Bibiane, Doran, Simon J., and Öktem, Ozan

Abstract

Artificial intelligence (AI) methods applied to healthcare problems have shown enormous potential to alleviate the burden of health services worldwide and to improve the accuracy and reproducibility of predictions. In particular, developments in computer vision are creating a paradigm shift in the analysis of radiological images, where AI tools are already capable of automatically detecting and precisely delineating tumours. However, such tools are generally developed in technical departments that continue to be siloed from where the real benefit would be achieved with their usage. Significant effort still needs to be made to make these advancements available, first in academic clinical research and ultimately in the clinical setting. In this paper, we demonstrate a prototype pipeline based entirely on open-source software and free of cost to bridge this gap, simplifying the integration of tools and models developed within the AI community into the clinical research setting, ensuring an accessible platform with visualisation applications that allow end-users such as radiologists to view and interact with the outcome of these AI tools., QC 20230922

Published
2023
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46. Data from Hyperpolarized Carbon-13 MRI for Early Response Assessment of Neoadjuvant Chemotherapy in Breast Cancer Patients

Author

Woitek, Ramona, primary, McLean, Mary A., primary, Ursprung, Stephan, primary, Rueda, Oscar M., primary, Manzano Garcia, Raquel, primary, Locke, Matthew J., primary, Beer, Lucian, primary, Baxter, Gabrielle, primary, Rundo, Leonardo, primary, Provenzano, Elena, primary, Kaggie, Joshua, primary, Patterson, Andrew, primary, Frary, Amy, primary, Field-Rayner, Johanna, primary, Papalouka, Vasiliki, primary, Kane, Justine, primary, Benjamin, Arnold J.V., primary, Gill, Andrew B., primary, Priest, Andrew N., primary, Lewis, David Y., primary, Russell, Roslin, primary, Grimmer, Ashley, primary, White, Brian, primary, Latimer-Bowman, Beth, primary, Patterson, Ilse, primary, Schiller, Amy, primary, Carmo, Bruno, primary, Slough, Rhys, primary, Lanz, Titus, primary, Wason, James, primary, Schulte, Rolf F., primary, Chin, Suet-Feung, primary, Graves, Martin J., primary, Gilbert, Fiona J., primary, Abraham, Jean E., primary, Caldas, Carlos, primary, Brindle, Kevin M., primary, Sala, Evis, primary, and Gallagher, Ferdia A., primary

Published
2023
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47. Supplementary Materials from Hyperpolarized Carbon-13 MRI for Early Response Assessment of Neoadjuvant Chemotherapy in Breast Cancer Patients

Author

Woitek, Ramona, primary, McLean, Mary A., primary, Ursprung, Stephan, primary, Rueda, Oscar M., primary, Manzano Garcia, Raquel, primary, Locke, Matthew J., primary, Beer, Lucian, primary, Baxter, Gabrielle, primary, Rundo, Leonardo, primary, Provenzano, Elena, primary, Kaggie, Joshua, primary, Patterson, Andrew, primary, Frary, Amy, primary, Field-Rayner, Johanna, primary, Papalouka, Vasiliki, primary, Kane, Justine, primary, Benjamin, Arnold J.V., primary, Gill, Andrew B., primary, Priest, Andrew N., primary, Lewis, David Y., primary, Russell, Roslin, primary, Grimmer, Ashley, primary, White, Brian, primary, Latimer-Bowman, Beth, primary, Patterson, Ilse, primary, Schiller, Amy, primary, Carmo, Bruno, primary, Slough, Rhys, primary, Lanz, Titus, primary, Wason, James, primary, Schulte, Rolf F., primary, Chin, Suet-Feung, primary, Graves, Martin J., primary, Gilbert, Fiona J., primary, Abraham, Jean E., primary, Caldas, Carlos, primary, Brindle, Kevin M., primary, Sala, Evis, primary, and Gallagher, Ferdia A., primary

Published
2023
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48. Measuring extracellular human brain pH and amino acid metabolism with hyperpolarized [1-13C]pyruvate

Author

Khan, Alixander S, primary, McLean, Mary A, additional, Kaggie, Joshua D, additional, Horvat-Menih, Ines, additional, Matys, Tomasz, additional, Schulte, Rolf F, additional, Locke, Matthew J, additional, Grimmer, Ashley, additional, Wodtke, Pascal, additional, Latimer, Elizabeth, additional, Frary, Amy, additional, Graves, Martin J, additional, and Gallagher, Ferdia A, additional

Published
2023
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