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Regensburger AP, Eckstein M, Wetzl M, Raming R, Paulus LP, Buehler A, Nedoschill E, Danko V, Jüngert J, Wagner AL, Schnell A, Rückel A, Rother U, Rompel O, Uder M, Hartmann A, Neurath MF, Woelfle J, Waldner MJ, Hoerning A, Knieling F. Multispectral optoacoustic tomography enables assessment of disease activity in paediatric inflammatory bowel disease. PHOTOACOUSTICS 2024; 35:100578. [PMID: 38144890 PMCID: PMC10746560 DOI: 10.1016/j.pacs.2023.100578] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/01/2023] [Accepted: 11/29/2023] [Indexed: 12/26/2023]
Abstract
Multispectral optoacoustic tomography (MSOT) allows non-invasive molecular disease activity assessment in adults with inflammatory bowel disease (IBD). In this prospective pilot-study, we investigated, whether increased levels of MSOT haemoglobin parameters corresponded to inflammatory activity in paediatric IBD patients, too. 23 children with suspected IBD underwent MSOT of the terminal ileum and sigmoid colon with standard validation (e.g. endoscopy). In Crohn`s disease (CD) and ulcerative colitis (UC) patients with endoscopically confirmed disease activity, MSOT total haemoglobin (HbT) signals were increased in the terminal ileum of CD (72.1 ± 13.0 a.u. vs. 32.9 ± 15.4 a.u., p = 0.0049) and in the sigmoid colon of UC patients (62.9 ± 13.8 a.u. vs. 35.1 ± 16.3 a.u., p = 0.0311) as compared to controls, respectively. Furthermore, MSOT haemoglobin parameters correlated well with standard disease activity assessment (e.g. SES-CD and MSOT HbT (rs =0.69, p = 0.0075). Summarizing, MSOT is a novel technology for non-invasive molecular disease activity assessment in paediatric patients with inflammatory bowel disease.
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Affiliation(s)
- Adrian P. Regensburger
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Paediatric Experimental and Translational Imaging Laboratory (PETI-Lab), Department of Paediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Markus Eckstein
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Matthias Wetzl
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Roman Raming
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Paediatric Experimental and Translational Imaging Laboratory (PETI-Lab), Department of Paediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Lars-Philip Paulus
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Paediatric Experimental and Translational Imaging Laboratory (PETI-Lab), Department of Paediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Adrian Buehler
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Paediatric Experimental and Translational Imaging Laboratory (PETI-Lab), Department of Paediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Emmanuel Nedoschill
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Paediatric Experimental and Translational Imaging Laboratory (PETI-Lab), Department of Paediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Vera Danko
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Paediatric Experimental and Translational Imaging Laboratory (PETI-Lab), Department of Paediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Jörg Jüngert
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Alexandra L. Wagner
- Paediatric Experimental and Translational Imaging Laboratory (PETI-Lab), Department of Paediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Alexander Schnell
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Aline Rückel
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Ulrich Rother
- Department of Vascular Surgery, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Oliver Rompel
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Michael Uder
- Department of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Arndt Hartmann
- Institute of Pathology, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Markus F. Neurath
- Department of Medicine 1 and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Joachim Woelfle
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Maximilian J. Waldner
- Department of Medicine 1 and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - André Hoerning
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Ferdinand Knieling
- Department of Paediatrics and Adolescent Medicine and German Center Immunotherapy (DZI), University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Paediatric Experimental and Translational Imaging Laboratory (PETI-Lab), Department of Paediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
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2
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Vogt WC, Wear KA, Pfefer TJ. Phantoms for evaluating the impact of skin pigmentation on photoacoustic imaging and oximetry performance. BIOMEDICAL OPTICS EXPRESS 2023; 14:5735-5748. [PMID: 38021140 PMCID: PMC10659791 DOI: 10.1364/boe.501950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/25/2023] [Accepted: 09/11/2023] [Indexed: 12/01/2023]
Abstract
Recent reports have raised concerns of potential racial disparities in performance of optical oximetry technologies. To investigate how variable epidermal melanin content affects performance of photoacoustic imaging (PAI) devices, we developed plastisol phantoms combining swappable skin-mimicking layers with a breast phantom containing either India ink or blood adjusted to 50-100% SO2 using sodium dithionite. Increasing skin pigmentation decreased maximum imaging depth by up to 25%, enhanced image clutter, and increased root-mean-square error in SO2 from 8.0 to 17.6% due to signal attenuation and spectral coloring effects. This phantom tool can aid in evaluating PAI device robustness to ensure high performance in all patients.
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Affiliation(s)
- William C. Vogt
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA
| | - Keith A. Wear
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA
| | - T. Joshua Pfefer
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, MD 20993, USA
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Morsink CF, Dam-Vervloet AJ, Krommendijk ME, Kaya M, Cuartas-Vélez C, Knop T, Francis KJ, Bosschaart N. Design and characterization of color printed polyurethane films as biomedical phantom layers. BIOMEDICAL OPTICS EXPRESS 2023; 14:4485-4506. [PMID: 37791261 PMCID: PMC10545194 DOI: 10.1364/boe.491695] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/30/2023] [Accepted: 07/05/2023] [Indexed: 10/05/2023]
Abstract
We propose a new, user-friendly and accessible approach for fabricating thin phantoms with controllable absorption properties in magnitude, spectral shape, and spatial distribution. We utilize a standard office laser color printer to print on polyurethane thin films (40 - 60 μm), commonly available as medical film dressings and ultrasound probe covers. We demonstrate that the optical attenuation and absorption of the printed films correlate linearly with the printer input settings (opacity), which facilitates a systematic phantom design. The optical and acoustic properties of these polyurethane films are similar to biological tissue. We argue that these thin phantoms are applicable to a wide range of biomedical applications. Here, we introduce two potential applications: (1) homogeneous epidermal melanin phantoms and (2) spatially resolved absorbers for photoacoustic imaging. We characterize the thin phantoms in terms of optical properties, thickness, microscopic structure, and reproducibility of the printing process.
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Affiliation(s)
- Claudia F. Morsink
- Biomedical Photonic Imaging Group, Technical Medical Center, University of Twente, The Netherlands
| | - Alida J. Dam-Vervloet
- Biomedical Photonic Imaging Group, Technical Medical Center, University of Twente, The Netherlands
- Medical Physics Department, Isala Hospital, Zwolle, The Netherlands
| | - Marleen E. Krommendijk
- Biomedical Photonic Imaging Group, Technical Medical Center, University of Twente, The Netherlands
| | - Michael Kaya
- Biomedical Photonic Imaging Group, Technical Medical Center, University of Twente, The Netherlands
| | - Carlos Cuartas-Vélez
- Biomedical Photonic Imaging Group, Technical Medical Center, University of Twente, The Netherlands
| | - Tom Knop
- Biomedical Photonic Imaging Group, Technical Medical Center, University of Twente, The Netherlands
| | - Kalloor Joseph Francis
- Biomedical Photonic Imaging Group, Technical Medical Center, University of Twente, The Netherlands
| | - Nienke Bosschaart
- Biomedical Photonic Imaging Group, Technical Medical Center, University of Twente, The Netherlands
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4
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Assi H, Cao R, Castelino M, Cox B, Gilbert FJ, Gröhl J, Gurusamy K, Hacker L, Ivory AM, Joseph J, Knieling F, Leahy MJ, Lilaj L, Manohar S, Meglinski I, Moran C, Murray A, Oraevsky AA, Pagel MD, Pramanik M, Raymond J, Singh MKA, Vogt WC, Wang L, Yang S, Members of IPASC, Bohndiek SE. A review of a strategic roadmapping exercise to advance clinical translation of photoacoustic imaging: From current barriers to future adoption. PHOTOACOUSTICS 2023; 32:100539. [PMID: 37600964 PMCID: PMC10432856 DOI: 10.1016/j.pacs.2023.100539] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/27/2023] [Accepted: 07/27/2023] [Indexed: 08/22/2023]
Abstract
Photoacoustic imaging (PAI), also referred to as optoacoustic imaging, has shown promise in early-stage clinical trials in a range of applications from inflammatory diseases to cancer. While the first PAI systems have recently received regulatory approvals, successful adoption of PAI technology into healthcare systems for clinical decision making must still overcome a range of barriers, from education and training to data acquisition and interpretation. The International Photoacoustic Standardisation Consortium (IPASC) undertook an community exercise in 2022 to identify and understand these barriers, then develop a roadmap of strategic plans to address them. Here, we outline the nature and scope of the barriers that were identified, along with short-, medium- and long-term community efforts required to overcome them, both within and beyond the IPASC group.
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Affiliation(s)
- Hisham Assi
- Department of Physics, Toronto Metropolitan University, Toronto, Canada
| | - Rui Cao
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Madhura Castelino
- Department of Rheumatology, University College London Hospital, London, UK
| | - Ben Cox
- Department of Medical Physics and Bioengineering, University College London, London, UK
| | | | - Janek Gröhl
- Department of Physics, University of Cambridge, Cambridge, UK
- CRUK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Kurinchi Gurusamy
- Department of Surgical Biotechnology, University College London, London, UK
| | - Lina Hacker
- Department of Physics, University of Cambridge, Cambridge, UK
- CRUK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Aoife M. Ivory
- Department of Medical, Marine and Nuclear Physics, National Physical Laboratory, Teddington, UK
| | - James Joseph
- School of Science and Engineering, University of Dundee, Dundee, UK
| | - Ferdinand Knieling
- Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander-Universität, Erlangen-Nürnberg, Germany
| | - Martin J. Leahy
- School of Natural Sciences – Physics, University of Galway, Galway, Ireland
| | | | | | - Igor Meglinski
- College of Engineering and Physical Sciences, Aston University, Birmingham, UK
| | - Carmel Moran
- Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Andrea Murray
- Centre for Musculoskeletal Research, University of Manchester, Manchester Academic Health Science Centre (MAHSC), Salford Care Organisation, NCA NHS Foundation Trust, UK
| | | | - Mark D. Pagel
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Manojit Pramanik
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA, USA
| | - Jason Raymond
- Department of Engineering Science, University of Oxford, UK
| | | | - William C. Vogt
- Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD, USA
| | - Lihong Wang
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Shufan Yang
- School of Computing, Edinburgh Napier University, UK
| | - Members of IPASC
- Department of Physics, University of Cambridge, Cambridge, UK
- CRUK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Sarah E. Bohndiek
- Department of Physics, University of Cambridge, Cambridge, UK
- CRUK Cambridge Institute, University of Cambridge, Cambridge, UK
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5
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Liu S, Zhang R, Han T, Pan Y, Zhang G, Long X, Zhao C, Wang M, Li X, Yang F, Sang Y, Zhu L, He X, Li J, Zhang Y, Li C, Jiang Y, Yang M. Validation of photoacoustic/ultrasound dual imaging in evaluating blood oxygen saturation. BIOMEDICAL OPTICS EXPRESS 2022; 13:5551-5570. [PMID: 36425613 PMCID: PMC9664893 DOI: 10.1364/boe.469747] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/16/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
Photoacoustic imaging (PAI) was performed to evaluate oxygen saturation (sO2) of blood-mimicking phantoms, femoral arteries in beagles, and radial arteries in humans at various sO2 plateaus. The accuracy (root mean square error, RMSE) of PAI sO2 compared with reference sO2 was calculated. In blood-mimicking phantoms, PAI achieved an accuracy of 1.49% and a mean absolute error (MAE) of 1.09% within 25 mm depth, and good linearity (R = 0.968; p < 0.001) was obtained between PAI sO2 and reference sO2. In canine femoral arteries, PAI achieved an accuracy of 2.16% and an MAE of 1.58% within 8 mm depth (R = 0.965; p < 0.001). In human radial arteries, PAI achieved an accuracy of 3.97% and an MAE of 3.28% in depth from 4 to 14 mm (R = 0.892; p < 0.001). For PAI sO2 evaluation at different depths in healthy volunteers, the RMSE accuracy of PAI sO2 increased from 2.66% to 24.96% with depth increasing from 4 to 14 mm. Through the multiscale method, we confirmed the feasibility of the hand-held photoacoustic/ultrasound (PA/US) in evaluating sO2. These results demonstrate the potential clinical value of PAI in evaluating blood sO2. Consequently, protocols for verifying the feasibility of medical devices based on PAI may be established.
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Affiliation(s)
- Sirui Liu
- Department of Ultrasound, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- The authors contributed equally to this manuscript
| | - Rui Zhang
- Department of Ultrasound, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
- The authors contributed equally to this manuscript
| | - Tao Han
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Yinhao Pan
- Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China
| | - Guangjie Zhang
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Xing Long
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Chenyang Zhao
- Department of Ultrasound, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Ming Wang
- Department of Ultrasound, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xuelan Li
- Department of Ultrasound, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Fang Yang
- Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China
| | - Yuchao Sang
- Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China
| | - Lei Zhu
- Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China
| | - Xujin He
- Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China
| | - Jianchu Li
- Department of Ultrasound, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yewei Zhang
- Hepatopancreatobiliary Center, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Changhui Li
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Yuxin Jiang
- Department of Ultrasound, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Meng Yang
- Department of Ultrasound, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
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Palma-Chavez J, Wear KA, Mantri Y, Jokerst JV, Vogt WC. Photoacoustic imaging phantoms for assessment of object detectability and boundary buildup artifacts. PHOTOACOUSTICS 2022; 26:100348. [PMID: 35360521 PMCID: PMC8960980 DOI: 10.1016/j.pacs.2022.100348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/18/2022] [Accepted: 03/17/2022] [Indexed: 05/05/2023]
Abstract
Standardized phantoms and test methods are needed to accelerate clinical translation of emerging photoacoustic imaging (PAI) devices. Evaluating object detectability in PAI is challenging due to variations in target morphology and artifacts including boundary buildup. Here we introduce breast fat and parenchyma tissue-mimicking materials based on emulsions of silicone oil and ethylene glycol in polyacrylamide hydrogel. 3D-printed molds were used to fabricate solid target inclusions that produced more filled-in appearance than traditional PAI phantoms. Phantoms were used to assess understudied image quality characteristics (IQCs) of three PAI systems. Object detectability was characterized vs. target diameter, absorption coefficient, and depth. Boundary buildup was quantified by target core/boundary ratio, which was higher in transducers with lower center frequency. Target diameter measurement accuracy was also size-dependent and improved with increasing transducer frequency. These phantoms enable evaluation of multiple key IQCs and may support development of comprehensive standardized test methods for PAI devices.
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Affiliation(s)
- Jorge Palma-Chavez
- Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Keith A. Wear
- Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD 20993, USA
| | - Yash Mantri
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jesse V. Jokerst
- Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA
- Department of Radiology, University of California San Diego, La Jolla, CA 92093, USA
- Material Science Program, University of California San Diego, La Jolla, CA 92093, USA
- Corresponding author at: Department of NanoEngineering, University of California San Diego, La Jolla, CA 92093, USA.
| | - William C. Vogt
- Center for Devices and Radiological Health, US Food and Drug Administration, Silver Spring, MD 20993, USA
- Corresponding author.
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Mahmoodkalayeh S, Kratkiewicz K, Manwar R, Shahbazi M, Ansari MA, Natarajan G, Asano E, Avanaki K. Wavelength and pulse energy optimization for detecting hypoxia in photoacoustic imaging of the neonatal brain: a simulation study. BIOMEDICAL OPTICS EXPRESS 2021; 12:7458-7477. [PMID: 35003846 PMCID: PMC8713673 DOI: 10.1364/boe.439147] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/10/2021] [Accepted: 10/20/2021] [Indexed: 05/03/2023]
Abstract
Cerebral hypoxia is a severe injury caused by oxygen deprivation to the brain. Hypoxia in the neonatal period increases the risk for the development of neurological disorders, including hypoxic-ischemic encephalopathy, cerebral palsy, periventricular leukomalacia, and hydrocephalus. It is crucial to recognize hypoxia as soon as possible because early intervention improves outcomes. Photoacoustic imaging, using at least two wavelengths, through a spectroscopic analysis, can measure brain oxygen saturation. Due to the spectral coloring effect arising from the dependency of optical properties of biological tissues to the wavelength of light, choosing the right wavelength-pair for efficient and most accurate oxygen saturation measurement and consequently quantifying hypoxia at a specific depth is critical. Using a realistic neonate head model and Monte Carlo simulations, we found practical wavelength-pairs that quantified regions with hypoxia most accurately at different depths down to 22 mm into the cortex neighboring the lateral ventricle. We also demonstrated, for the first time, that the accuracy of the sO2 measurement can be increased by adjusting the level of light energy for each wavelength-pair. Considering the growing interest in photoacoustic imaging of the brain, this work will assist in a more accurate use of photoacoustic spectroscopy and help in the clinical translation of this promising imaging modality. Please note that explaining the effect of acoustic aberration of the skull is not in the scope of this study.
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Affiliation(s)
- Sadreddin Mahmoodkalayeh
- Department of Physics, Shahid Beheshti University, Tehran, Iran
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
- These authors have contributed equally
| | - Karl Kratkiewicz
- Wayne State University, Bioengineering Department, Detroit, Michigan 48201, USA
| | - Rayyan Manwar
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Meysam Shahbazi
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
| | - Mohammad Ali Ansari
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, Iran
| | - Girija Natarajan
- Wayne State University School of Medicine, Department of Neurology, Detroit, Michigan 48201, USA
- Wayne State University School of Medicine, Department of Pediatrics, Detroit, Michigan 48201, USA
| | - Eishi Asano
- Wayne State University School of Medicine, Department of Neurology, Detroit, Michigan 48201, USA
- Wayne State University School of Medicine, Department of Pediatrics, Detroit, Michigan 48201, USA
| | - Kamran Avanaki
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
- Department of Dermatology, University of Illinois at Chicago, Chicago, Illinois 60607, USA
- These authors have contributed equally
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8
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Dantuma M, Kruitwagen SC, Weggemans MJ, Op’t Root TJPM, Manohar S. Suite of 3D test objects for performance assessment of hybrid photoacoustic-ultrasound breast imaging systems. JOURNAL OF BIOMEDICAL OPTICS 2021; 27:JBO-210239SSR. [PMID: 34889084 PMCID: PMC8655513 DOI: 10.1117/1.jbo.27.7.074709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE During the development and early testing phases of new photoacoustic (PA) breast imaging systems, several choices need to be made in aspects of system design and measurement sequences. Decision-making can be complex for state-of-the-art systems such as 3D hybrid photoacoustic-ultrasound (PA-US) breast imagers intended for multispectral quantitative imaging. These systems have a large set of design choices and system settings that affect imaging performance in different ways and often require trade-offs. Decisions have to be made carefully as they can strongly influence the imaging performance. AIM A systematic approach to assess the influence of various choices on the imaging performance in carefully controlled laboratory situations is crucial before starting with human studies. Test objects and phantoms are used for first imaging studies, but most reported structures have a 2D geometry and are not suitable to assess all the image quality characteristics (IQCs) of 3D hybrid PA-US systems. APPROACH Our work introduces a suite of five test objects designed for hybrid PA-US systems with a 3D detection aperture. We present the test object designs and production protocols and explain how they can be used to study various performance measures. To demonstrate the utility of the developed objects, measurements are made with an existing tomographic PA system. RESULTS Two test objects were developed for measurements of the US detectors' impulse responses and light distribution on the breast surface. Three others were developed to assess image quality and quantitative accuracy of the PA and US modes. Three of the five objects were imaged to demonstrate their use. CONCLUSIONS The developed test objects allow one to study influences of various choices in design and system settings. With this, IQCs can be assessed as a function of measurement sequence settings for the PA and US modes in a controlled way. Systematic studies and measurements using these objects will help to optimize various system settings and measurement protocols in laboratory situations before embarking on human studies.
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Affiliation(s)
- Maura Dantuma
- University of Twente, Multi-Modality Medical Imaging, Technical Medical Centre, Enschede, The Netherlands
| | - Saskia C. Kruitwagen
- University of Twente, Multi-Modality Medical Imaging, Technical Medical Centre, Enschede, The Netherlands
- Medisch Spectrum Twente Hospital, Enschede, The Netherlands
| | - Marlies J. Weggemans
- University of Twente, Multi-Modality Medical Imaging, Technical Medical Centre, Enschede, The Netherlands
| | | | - Srirang Manohar
- University of Twente, Multi-Modality Medical Imaging, Technical Medical Centre, Enschede, The Netherlands
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van Hees R, Muller JW, van de Vosse F, Rutten M, van Sambeek M, Wu M, Lopata R. SVD-based filtering to detect intraplaque hemorrhage using single wavelength photoacoustic imaging. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210198RR. [PMID: 34743446 PMCID: PMC8571807 DOI: 10.1117/1.jbo.26.11.116003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Intraplaque hemorrhage (IPH) is an important indicator of plaque vulnerability. Early detection could aid the prevention of stroke. AIM We aim to detect IPH with single wavelength PA imaging in vivo and to improve image quality. APPROACH We developed a singular value decomposition (SVD)-based filter to detect the nonstationary and stationary components in ultrasound data. A PA mask was created to detect stationary (IPH) sources. The method was tested ex vivo using phantoms and in vivo in patients. RESULTS The flow and IPH channels were successfully separated in the phantom data. We can also detect the PA signals from IPH and reject signals from the carotid lumen in vivo. Generalized contrast-to-noise ratio improved in both ex vivo and in vivo in US imaging. CONCLUSIONS SVD-based filtering can successfully detect IPH using a single laser wavelength, opening up opportunities for more economical and cost-effective laser sources.
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Affiliation(s)
- Roy van Hees
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Jan-Willem Muller
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Frans van de Vosse
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Marcel Rutten
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Marc van Sambeek
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven, The Netherlands
- Catharina Hospital, Eindhoven, The Netherlands
| | - Min Wu
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven, The Netherlands
| | - Richard Lopata
- Eindhoven University of Technology, Photoacoustics and Ultrasound Laboratory Eindhoven (PULS/e), Department of Biomedical Engineering, Eindhoven, The Netherlands
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10
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Cabrelli LC, Uliana JH, da Cruz Junior LB, Bachmann L, Carneiro AAO, Pavan TZ. Glycerol-in-SEBS gel as a material to manufacture stable wall-less vascular phantom for ultrasound and photoacoustic imaging. Biomed Phys Eng Express 2021; 7. [PMID: 34496358 DOI: 10.1088/2057-1976/ac24d6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/08/2021] [Indexed: 11/12/2022]
Abstract
Styrene-ethylene/butylene-styrene (SEBS) copolymer-in-mineral oil gel is an appropriate tissue-mimicking material to manufacture stable phantoms for ultrasound and photoacoustic imaging. Glycerol dispersion has been proposed to further tune the acoustic properties and to incorporate hydrophilic additives into SEBS gel. However, this type of material has not been investigated to produce wall-less vascular flow phantom for these imaging modalities. In this paper, the development of a wall-less vascular phantom for ultrasound and photoacoustic imaging is reported. Mixtures of glycerol/TiO2-in-SEBS gel samples were manufactured at different proportions of glycerol (10%, 15%, and 20%) and TiO2(0% to 0.5%) to characterize their optical and acoustic properties. Optical absorption in the 500-950 nm range was independent of the amount of glycerol and TiO2, while optical scattering increased linearly with the concentration of TiO2. Acoustic attenuation and speed of sound were not influenced by the presence of TiO2. The sample manufactured using weight percentages of 10% SEBS, 15% glycerol, and 0.2% TiO2was selected to make the vascular phantom. The phantom proved to be stable during the pulsatile blood-mimicking fluid (BMF) flow, without any observed damage to its structure or leaks. Ultrasound color Doppler images showed a typical laminar flow, while the B-mode images showed a homogeneous speckled pattern due to the presence of the glycerol droplets in the gel. The photoacoustic images of the phantom showed a well-defined signal coming from the surface of the phantom and from the vessels where BMF was flowing. The Spearman's correlations between the photoacoustic and tabulated spectra calculated from the regions containing BMF, in this case a mixture of salt solutions (NiCl2and CuSO4), were higher than 0.95. Our results demonstrated that glycerol-in-SEBS gel was an adequate material to make a stable vascular flow phantom for ultrasound photoacoustic imaging.
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Affiliation(s)
- Luciana C Cabrelli
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Joao H Uliana
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | | | - Luciano Bachmann
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Antonio A O Carneiro
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Theo Z Pavan
- Departamento de Física, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
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11
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Palma-Chavez J, Pfefer TJ, Agrawal A, Jokerst JV, Vogt WC. Review of consensus test methods in medical imaging and current practices in photoacoustic image quality assessment. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210176VSSR. [PMID: 34510850 PMCID: PMC8434148 DOI: 10.1117/1.jbo.26.9.090901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/17/2021] [Indexed: 05/06/2023]
Abstract
SIGNIFICANCE Photoacoustic imaging (PAI) is a powerful emerging technology with broad clinical applications, but consensus test methods are needed to standardize performance evaluation and accelerate translation. AIM To review consensus image quality test methods for mature imaging modalities [ultrasound, magnetic resonance imaging (MRI), x-ray CT, and x-ray mammography], identify best practices in phantom design and testing procedures, and compare against current practices in PAI phantom testing. APPROACH We reviewed scientific papers, international standards, clinical accreditation guidelines, and professional society recommendations describing medical image quality test methods. Observations are organized by image quality characteristics (IQCs), including spatial resolution, geometric accuracy, imaging depth, uniformity, sensitivity, low-contrast detectability, and artifacts. RESULTS Consensus documents typically prescribed phantom geometry and material property requirements, as well as specific data acquisition and analysis protocols to optimize test consistency and reproducibility. While these documents considered a wide array of IQCs, reported PAI phantom testing focused heavily on in-plane resolution, depth of visualization, and sensitivity. Understudied IQCs that merit further consideration include out-of-plane resolution, geometric accuracy, uniformity, low-contrast detectability, and co-registration accuracy. CONCLUSIONS Available medical image quality standards provide a blueprint for establishing consensus best practices for photoacoustic image quality assessment and thus hastening PAI technology advancement, translation, and clinical adoption.
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Affiliation(s)
- Jorge Palma-Chavez
- University of California San Diego, Department of NanoEngineering, La Jolla, California, United States
| | - T. Joshua Pfefer
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Anant Agrawal
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, United States
| | - Jesse V. Jokerst
- University of California San Diego, Department of NanoEngineering, La Jolla, California, United States
- University of California San Diego, Department of Radiology, La Jolla, California, United States
- University of California San Diego, Materials Science and Engineering Program, La Jolla, California, United States
| | - William C. Vogt
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, Maryland, United States
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12
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Kirchner T, Frenz M. Multiple illumination learned spectral decoloring for quantitative optoacoustic oximetry imaging. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210069RR. [PMID: 34350736 PMCID: PMC8336722 DOI: 10.1117/1.jbo.26.8.085001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 07/16/2021] [Indexed: 06/13/2023]
Abstract
SIGNIFICANCE Quantitative measurement of blood oxygen saturation (sO2) with optoacoustic (OA) imaging is one of the most sought after goals of quantitative OA imaging research due to its wide range of biomedical applications. AIM A method for accurate and applicable real-time quantification of local sO2 with OA imaging. APPROACH We combine multiple illumination (MI) sensing with learned spectral decoloring (LSD). We train LSD feedforward neural networks and random forests on Monte Carlo simulations of spectrally colored absorbed energy spectra, to apply the trained models to real OA measurements. We validate our combined MI-LSD method on a highly reliable, reproducible, and easily scalable phantom model, based on copper and nickel sulfate solutions. RESULTS With this sulfate model, we see a consistently high estimation accuracy using MI-LSD, with median absolute estimation errors of 2.5 to 4.5 percentage points. We further find fewer outliers in MI-LSD estimates compared with LSD. Random forest regressors outperform previously reported neural network approaches. CONCLUSIONS Random forest-based MI-LSD is a promising method for accurate quantitative OA oximetry imaging.
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Affiliation(s)
- Thomas Kirchner
- University of Bern, Biomedical Photonics, Institute of Applied Physics, Bern, Switzerland
| | - Martin Frenz
- University of Bern, Biomedical Photonics, Institute of Applied Physics, Bern, Switzerland
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13
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Attia ABE, Moothanchery M, Li X, Yew YW, Thng STG, Dinish U, Olivo M. Microvascular imaging and monitoring of hemodynamic changes in the skin during arterial-venous occlusion using multispectral raster-scanning optoacoustic mesoscopy. PHOTOACOUSTICS 2021; 22:100268. [PMID: 34026491 PMCID: PMC8122174 DOI: 10.1016/j.pacs.2021.100268] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 05/18/2023]
Abstract
The ability to monitor oxygen delivery in microvasculature plays a vital role in measuring the viability of skin tissue and the probability of recovery. Using currently available clinical imaging tools, it is difficult to observe non-invasive hemodynamic regulation in the peripheral vessels. Here we propose the use of a novel multispectral raster-scanning optoacoustic mesoscopy (RSOM) system for noninvasive clinical monitoring of hemodynamic changes in the skin microvasculature's oxy- (HbO2) and deoxy-hemoglobin (Hb), total hemoglobin (HbT) and oxygen saturation (rsO2). High resolution images of hemoglobin distribution in the skin microvasculature from six healthy volunteers during venous and arterial occlusion, simulating systemic vascular diseases are presented. During venous occlusion, Hb and HbO2 optoacoustic signals showed an increasing trend with time, followed by a drop in the values after cuff deflation. During arterial occlusion, an increase in Hb value and decrease in HbO2 values was observed, followed by a drop in Hb and jump in HbO2 values after the cuff deflation. A decrease in rsO2 values during both venous and arterial occlusion was observed with an increase in value after occlusion release. Using this proof of concept study, hereby we propose multispectral RSOM as a novel tool to measure high resolution hemodynamic changes in microvasculature for investigating systemic vascular diseases on peripheral tissues and also for monitoring inflammatory skin diseases, and its therapeutic interventions.
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Affiliation(s)
- Amalina Binte Ebrahim Attia
- Laboratory of Bio Optical Imaging, Singapore Bioimaging Consortium, Agency of Science, Technology and Research (A*STAR), Singapore
| | - Mohesh Moothanchery
- Laboratory of Bio Optical Imaging, Singapore Bioimaging Consortium, Agency of Science, Technology and Research (A*STAR), Singapore
| | - Xiuting Li
- Laboratory of Bio Optical Imaging, Singapore Bioimaging Consortium, Agency of Science, Technology and Research (A*STAR), Singapore
| | | | | | - U.S. Dinish
- Laboratory of Bio Optical Imaging, Singapore Bioimaging Consortium, Agency of Science, Technology and Research (A*STAR), Singapore
- Corresponding authors.
| | - Malini Olivo
- Laboratory of Bio Optical Imaging, Singapore Bioimaging Consortium, Agency of Science, Technology and Research (A*STAR), Singapore
- Corresponding authors.
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14
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Dantuma M, Kruitwagen S, Ortega-Julia J, Pompe van Meerdervoort RP, Manohar S. Tunable blood oxygenation in the vascular anatomy of a semi-anthropomorphic photoacoustic breast phantom. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200370RR. [PMID: 33728828 PMCID: PMC7961914 DOI: 10.1117/1.jbo.26.3.036003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/19/2021] [Indexed: 05/21/2023]
Abstract
SIGNIFICANCE Recovering accurate oxygenation estimations in the breast with quantitative photoacoustic tomography (QPAT) is not straightforward. Accurate light fluence models are required, but the unknown ground truth of the breast makes it difficult to validate them. Phantoms are often used for the validation, but most reported phantoms have a simple architecture. Fluence models developed in these simplistic objects are not accurate for application on the complex tissues of the breast. AIM We present a sophisticated breast phantom platform for photoacoustic (PA) and ultrasound (US) imaging in general, and specifically for QPAT. The breast phantom is semi-anthropomorphic in distribution of optical and acoustic properties and contains wall-less channels with blood. APPROACH 3D printing approaches are used to develop the solid 3D breast phantom from custom polyvinyl chloride plastisol formulations and additives for replicating the tissue optical and acoustic properties. A flow circuit was developed to flush the channels with bovine blood with a controlled oxygen saturation level. To showcase the phantom's functionality, PA measurements were performed on the phantom with two oxygenation levels. Image reconstructions with and without fluence compensation from Monte Carlo simulations were analyzed for the accuracy of oxygen saturation estimations. RESULTS We present design aspects of the phantom, demonstrate how it is developed, and present its breast-like appearance in PA and US imaging. The oxygen saturations were estimated in two regions of interest with and without using the fluence models. The fluence compensation positively influenced the SO2 estimations in all cases and confirmed that highly accurate fluence models are required to minimize estimation errors. CONCLUSIONS This phantom allows studies to be performed in PA in carefully controlled laboratory settings to validate approaches to recover both qualitative and quantitative features sought after in in-vivo studies. We believe that testing with phantoms of this complexity can streamline the transition of new PA technologies from the laboratory to studies in the clinic.
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Affiliation(s)
- Maura Dantuma
- University of Twente, Multi-Modality Medical Imaging, Techmed Centre, Enschede, The Netherlands
- Address all correspondence to Maura Dantuma,
| | - Saskia Kruitwagen
- University of Twente, Multi-Modality Medical Imaging, Techmed Centre, Enschede, The Netherlands
- Medisch Spectrum Twente, Enschede, The Netherlands
| | - Javier Ortega-Julia
- University of Twente, Multi-Modality Medical Imaging, Techmed Centre, Enschede, The Netherlands
| | | | - Srirang Manohar
- University of Twente, Multi-Modality Medical Imaging, Techmed Centre, Enschede, The Netherlands
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15
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Chandramoorthi S, Thittai AK. Extending Imaging Depth in PLD-Based Photoacoustic Imaging: Moving Beyond Averaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:549-557. [PMID: 32784132 DOI: 10.1109/tuffc.2020.3015130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Pulsed laser diodes (PLDs) promise to be an attractive alternative to solid-state laser sources in photoacoustic tomography (PAT) due to their portability, high-pulse repetition frequency (PRF), and cost effectiveness. However, due to their lower energy per pulse, which, in turn, results in lower fluence required per photoacoustic signal generation, PLD-based photoacoustic systems generally have maximum imaging depth that is lower in comparison to solid-state lasers. Averaging of multiple frames is usually employed as a common practice in high PRF PLD systems to improve the signal-to-noise ratio of the PAT images. In this work, we demonstrate that by combining the recently described approach of subpitch translation on the receive-side ultrasound transducer alongside averaging of multiple frames, it is feasible to increase the depth sensitivity in a PLD-based PAT imaging system. Here, experiments on phantom containing diluted India ink targets were performed at two different laser energy level settings, that is, 21 and [Formula: see text]. Results obtained showed that the imaging depth improves by ~38.5% from 9.1 to 12.6 mm for 21- [Formula: see text] energy level setting and by ~33.3% from 10.8 to 14.4 mm for 27- [Formula: see text] energy level setting by using λ /4-pitch translation and average of 128 frames in comparison to λ -pitch data acquired with the average of 128 frames. However, the achievable frame rate is reduced by a factor of 2 and 4 for λ /2 and λ /4 subpitch translation, respectively.
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16
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Oxygen Saturation Imaging Using LED-Based Photoacoustic System. SENSORS 2021; 21:s21010283. [PMID: 33406653 PMCID: PMC7795655 DOI: 10.3390/s21010283] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 12/31/2020] [Accepted: 01/01/2021] [Indexed: 12/31/2022]
Abstract
Oxygen saturation imaging has potential in several preclinical and clinical applications. Dual-wavelength LED array-based photoacoustic oxygen saturation imaging can be an affordable solution in this case. For the translation of this technology, there is a need to improve its accuracy and validate it against ground truth methods. We propose a fluence compensated oxygen saturation imaging method, utilizing structural information from the ultrasound image, and prior knowledge of the optical properties of the tissue with a Monte-Carlo based light propagation model for the dual-wavelength LED array configuration. We then validate the proposed method with oximeter measurements in tissue-mimicking phantoms. Further, we demonstrate in vivo imaging on small animal and a human subject. We conclude that the proposed oxygen saturation imaging can be used to image tissue at a depth of 6–8 mm in both preclinical and clinical applications.
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17
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Chen J, Zhang Y, He L, Liang Y, Wang L. Wide-field polygon-scanning photoacoustic microscopy of oxygen saturation at 1-MHz A-line rate. PHOTOACOUSTICS 2020; 20:100195. [PMID: 32577378 PMCID: PMC7300162 DOI: 10.1016/j.pacs.2020.100195] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/25/2020] [Accepted: 06/03/2020] [Indexed: 05/06/2023]
Abstract
We report wide-field polygon-scanning functional OR-PAM that for the first time achieves 1-MHz A-line rate of oxygen saturation in vivo. We address two technical challenges. The first is a 1-MHz dual-wavelength pulsed laser that has sufficient pulse energy and ultrafast wavelength switching. The second is a polygon-scanning imaging probe that has a fast scanning speed, a large field of view, and great sensitivity. The OR-PAM system offers a B-scan rate of 477.5 Hz in a 12-mm range and a volumetric imaging rate of ∼1 Hz over a 12 × 5 mm2 scanning area. We image microvasculature and blood oxygen saturation in a 12 × 12 mm2 scanning area in 5 s. Dynamic imaging of oxygen saturation in the mouse ear is demonstrated to monitor fast response to epinephrine injection. The new wide-field fast functional imaging ability broadens the biomedical application of OR-PAM.
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Affiliation(s)
- Jiangbo Chen
- Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Ave, Kowloon, Hong Kong SAR, China
| | - Yachao Zhang
- Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Ave, Kowloon, Hong Kong SAR, China
| | - Linyun He
- Department of Hepatobiliary Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, 510282, China
| | - Yizhi Liang
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China
| | - Lidai Wang
- Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Ave, Kowloon, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Yuexing Yi Dao, Shenzhen, Guang Dong, 518057, China
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18
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Zhou X, Akhlaghi N, Wear KA, Garra BS, Pfefer TJ, Vogt WC. Evaluation of Fluence Correction Algorithms in Multispectral Photoacoustic Imaging. PHOTOACOUSTICS 2020; 19:100181. [PMID: 32405456 PMCID: PMC7210453 DOI: 10.1016/j.pacs.2020.100181] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 05/07/2023]
Abstract
Multispectral photoacoustic imaging (MPAI) is a promising emerging diagnostic technology, but fluence artifacts can degrade device performance. Our goal was to develop well-validated phantom-based test methods for evaluating and comparing MPAI fluence correction algorithms, including a heuristic diffusion approximation, Monte Carlo simulations, and an algorithm we developed based on novel application of the diffusion dipole model (DDM). Phantoms simulated a range of breast-mimicking optical properties and contained channels filled with chromophore solutions (ink, hemoglobin, or copper sulfate) or connected to a previously developed blood flow circuit providing tunable oxygen saturation (SO2). The DDM algorithm achieved similar spectral recovery and SO2 measurement accuracy to Monte Carlo-based corrections with lower computational cost, potentially providing an accurate, real-time correction approach. Algorithms were sensitive to optical property uncertainty, but error was minimized by matching phantom albedo. The developed test methods may provide a foundation for standardized assessment of MPAI fluence correction algorithm performance.
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Affiliation(s)
- Xuewen Zhou
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, 02742, United States
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Nima Akhlaghi
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Keith A. Wear
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, United States
| | - Brian S. Garra
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, United States
| | - T. Joshua Pfefer
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, United States
| | - William C. Vogt
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993, United States
- Corresponding author.
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Mahmoodkalayeh S, Zarei M, Ansari MA, Kratkiewicz K, Ranjbaran M, Manwar R, Avanaki K. Improving vascular imaging with co-planar mutually guided photoacoustic and diffuse optical tomography: a simulation study. BIOMEDICAL OPTICS EXPRESS 2020; 11:4333-4347. [PMID: 32923047 PMCID: PMC7449743 DOI: 10.1364/boe.385017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 07/01/2020] [Accepted: 07/01/2020] [Indexed: 05/04/2023]
Abstract
Diffuse optical tomography (DOT) and photoacoustic tomography (PAT) are functional imaging modalities that provide absorption coefficient maps of the tissue. Spatial resolution of DOT is relatively low due to light scattering characteristics of the tissue. On the other hand, although PAT can resolve regions of different absorptions with a high spatial resolution, measuring the absolute value of optical absorptions using PAT is challenging due to unknown light fluence distribution in the tissue. Development of image guidance techniques using a priori information of imaging target structure has been shown to increase the accuracy of DOT. PAT is one such method that can be used as a complementary modality to serve as a guide for DOT image reconstruction. On the other hand, estimated fluence map provided by DOT can be used to quantitatively correct PAT images. In this study we introduce a mutually-guided imaging system for fast and simultaneous optical and photoacoustic measurements of tissue absorption map, where DOT is guided by the PAT image and vice versa. Using the obtained absorption map of the tissue, we then estimate the tissue scattering map. We conducted this study using a series of simulations on digital phantoms and demonstrated the effectiveness of the proposed method.
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Affiliation(s)
| | - Mehrdad Zarei
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran 19839 69411, Iran
| | - Mohammad Ali Ansari
- Laser and Plasma Research Institute, Shahid Beheshti University, Tehran 19839 69411, Iran
| | - Karl Kratkiewicz
- Wayne State University, Bioengineering Department, Detroit, Michigan 48201, USA
| | - Mohsen Ranjbaran
- Department of Physics, University of Isfahan, Isfahan 81746-73441, Iran
| | - Rayyan Manwar
- Wayne State University, Bioengineering Department, Detroit, Michigan 48201, USA
| | - Kamran Avanaki
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA
- Department of Dermatology, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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20
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Bench C, Hauptmann A, Cox B. Toward accurate quantitative photoacoustic imaging: learning vascular blood oxygen saturation in three dimensions. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:jbo-200119R. [PMID: 32840068 PMCID: PMC7443711 DOI: 10.1117/1.jbo.25.8.085003] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/23/2020] [Indexed: 05/02/2023]
Abstract
SIGNIFICANCE Two-dimensional (2-D) fully convolutional neural networks have been shown capable of producing maps of sO2 from 2-D simulated images of simple tissue models. However, their potential to produce accurate estimates in vivo is uncertain as they are limited by the 2-D nature of the training data when the problem is inherently three-dimensional (3-D), and they have not been tested with realistic images. AIM To demonstrate the capability of deep neural networks to process whole 3-D images and output 3-D maps of vascular sO2 from realistic tissue models/images. APPROACH Two separate fully convolutional neural networks were trained to produce 3-D maps of vascular blood oxygen saturation and vessel positions from multiwavelength simulated images of tissue models. RESULTS The mean of the absolute difference between the true mean vessel sO2 and the network output for 40 examples was 4.4% and the standard deviation was 4.5%. CONCLUSIONS 3-D fully convolutional networks were shown capable of producing accurate sO2 maps using the full extent of spatial information contained within 3-D images generated under conditions mimicking real imaging scenarios. We demonstrate that networks can cope with some of the confounding effects present in real images such as limited-view artifacts and have the potential to produce accurate estimates in vivo.
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Affiliation(s)
- Ciaran Bench
- University College London, Department of Medical Physics and Biomedical Engineering, Gower Street, London, United Kingdom
- Address all correspondence to Ciaran Bench, E-mail:
| | - Andreas Hauptmann
- University of Oulu, Research Unit of Mathematical Sciences, Oulu, Finland
- University College London, Department of Computer Science, Gower Street, London, United Kingdom
| | - Ben Cox
- University College London, Department of Medical Physics and Biomedical Engineering, Gower Street, London, United Kingdom
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21
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Kanniyappan U, Wang B, Yang C, Ghassemi P, Litorja M, Suresh N, Wang Q, Chen Y, Pfefer TJ. Performance test methods for near-infrared fluorescence imaging. Med Phys 2020; 47:3389-3401. [PMID: 32304583 PMCID: PMC7496362 DOI: 10.1002/mp.14189] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 03/03/2020] [Accepted: 04/10/2020] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Near-infrared fluorescence (NIRF) imaging using exogenous contrast has gained much attention as a technique for enhancing visualization of vasculature using untargeted agents, as well as for the detection and localization of cancer with targeted agents. In order to address the emerging need for standardization of NIRF imaging technologies, it is necessary to identify the best practices suitable for objective, quantitative testing of key image quality characteristics. Toward the development of a battery of test methods that are rigorous yet applicable to a wide variety of devices, we have evaluated techniques for phantom design, measurement, and calculation of specific performance metrics. METHODS Using a NIRF imaging system for indocyanine green imaging, providing excitation at 780 nm and detection above 830 nm, we explored methods to evaluate uniformity, field of view, spectral crosstalk, spatial resolution, depth of field, sensitivity, linearity, and penetration depth. These measurements were performed using fluorophore-doped multiwell plate and high turbidity planar phantoms, as well as a 3D-printed multichannel phantom and a USAF 1951 resolution target. RESULTS AND CONCLUSIONS Based on a wide range of approaches described in medical and fluorescence imaging literature, we have developed and demonstrated a cohesive battery of test methods for evaluation of fluorescence image quality in wide-field imagers. We also propose a number of key metrics that can facilitate direct, quantitative comparison of device performance. These methods have the potential to facilitate more uniform evaluation and inter-comparison of clinical and preclinical imaging systems than is typically achieved, with the long-term goal of establishing international standards for fluorescence image quality assessment.
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Affiliation(s)
- Udayakumar Kanniyappan
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.,Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
| | - Bohan Wang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Charles Yang
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Pejhman Ghassemi
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
| | - Maritoni Litorja
- National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Nitin Suresh
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Quanzeng Wang
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
| | - Yu Chen
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA.,Department of Biomedical Engineering, University of Massachusetts Amherst, MA, USA
| | - T Joshua Pfefer
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, MD, USA
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22
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Zalev J, Richards LM, Clingman BA, Harris J, Cantu E, Menezes GLG, Avila C, Bertrand A, Saenz X, Miller S, Oraevsky AA, Kolios MC. Opto-acoustic imaging of relative blood oxygen saturation and total hemoglobin for breast cancer diagnosis. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-16. [PMID: 31849204 PMCID: PMC7005558 DOI: 10.1117/1.jbo.24.12.121915] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/22/2019] [Indexed: 05/14/2023]
Abstract
Opto-acoustic imaging involves using light to produce sound waves for visualizing blood in biological tissue. By using multiple optical wavelengths, diagnostic images of blood oxygen saturation and total hemoglobin are generated using endogenous optical contrast, without injection of any external contrast agent and without using any ionizing radiation. The technology has been used in recent clinical studies for diagnosis of breast cancer to help distinguish benign from malignant lesions, potentially reducing the need for biopsy through improved diagnostic imaging accuracy. To enable this application, techniques for mapping oxygen saturation differences within tissue are necessary. Using biologically relevant opto-acoustic phantoms, we analyze the ability of an opto-acoustic imaging system to display colorized parametric maps that are generated using a statistical mapping approach. To mimic breast tissue, a material with closely matching properties for optical absorption, optical scattering, acoustic attenuation, and speed of sound is used. The phantoms include two vessels filled with whole blood at oxygen saturation levels determined using a sensor-based approach. A flow system with gas-mixer and membrane oxygenator adjusts the oxygen saturation of each vessel independently. Datasets are collected with an investigational Imagio® breast imaging system. We examine the ability to distinguish vessels as the oxygen saturation level and imaging depth are varied. At depth of 15 mm and hematocrit of 42%, a sufficient level of contrast to distinguish between two 1.6-mm diameter vessels was measured for an oxygen saturation difference of ∼4.6 % . In addition, an oxygenated vessel was visible at a depth of 48 mm using an optical wavelength of 1064 nm, and a deoxygenated vessel was visible to a depth of 42 mm with 757 nm. The results provide insight toward using color mapped opto-acoustic images for diagnosing breast cancer.
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Affiliation(s)
- Jason Zalev
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
- Ryerson University, Department of Physics, Toronto, Ontario, Canada
- Address all correspondence to Jason Zalev, E-mail: ; Lisa M. Richards, E-mail: ; Bryan A. Clingman, E-mail:
| | - Lisa M. Richards
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
- Address all correspondence to Jason Zalev, E-mail: ; Lisa M. Richards, E-mail: ; Bryan A. Clingman, E-mail:
| | - Bryan A. Clingman
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
- Address all correspondence to Jason Zalev, E-mail: ; Lisa M. Richards, E-mail: ; Bryan A. Clingman, E-mail:
| | - Jeff Harris
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
| | - Edgar Cantu
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
| | | | - Carlos Avila
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
| | - Allison Bertrand
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
| | - Xavier Saenz
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
| | - Steve Miller
- Seno Medical Instruments, Inc., San Antonio, Texas, United States
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23
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Hochuli R, An L, Beard PC, Cox BT. Estimating blood oxygenation from photoacoustic images: can a simple linear spectroscopic inversion ever work? JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-13. [PMID: 31849203 PMCID: PMC7005536 DOI: 10.1117/1.jbo.24.12.121914] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 11/21/2019] [Indexed: 05/07/2023]
Abstract
Linear spectroscopic inversions, in which photoacoustic amplitudes are assumed to be directly proportional to absorption coefficients, are widely used in photoacoustic imaging to estimate blood oxygen saturation because of their simplicity. Unfortunately, they do not account for the spatially varying wavelength-dependence of the light fluence within the tissue, which introduces "spectral coloring," a potentially significant source of error. However, accurately correcting for spectral coloring is challenging, so we investigated whether there are conditions, e.g., sets of wavelengths, where it is possible to ignore the spectral coloring and still obtain accurate oxygenation measurements using linear inversions. Accurate estimates of oxygenation can be obtained when the wavelengths are chosen to (i) minimize spectral coloring, (ii) avoid ill-conditioning, and (iii) maintain a sufficiently high signal-to-noise ratio (SNR) for the estimates to be meaningful. It is not obvious which wavelengths will satisfy these conditions, and they are very likely to vary for different imaging scenarios, making it difficult to find general rules. Through the use of numerical simulations, we isolated the effect of spectral coloring from sources of experimental error. It was shown that using wavelengths between 500 nm and 1000 nm yields inaccurate estimates of oxygenation and that careful selection of wavelengths in the 620- to 920-nm range can yield more accurate oxygenation values. However, this is only achievable with a good prior estimate of the true oxygenation. Even in this idealized case, it was shown that considerable care must be exercised over the choice of wavelengths when using linear spectroscopic inversions to obtain accurate estimates of blood oxygenation. This suggests that for a particular imaging scenario, obtaining accurate and reliable oxygenation estimates using linear spectroscopic inversions requires careful modeling or experimental studies of that scenario, taking account of the instrumentation, tissue anatomy, likely sO2 range, and image formation process.
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Affiliation(s)
- Roman Hochuli
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Lu An
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Paul C. Beard
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Benjamin T. Cox
- University College London, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
- Address all correspondence to Benjamin T. Cox, E-mail:
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24
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Dantuma M, van Dommelen R, Manohar S. Semi-anthropomorphic photoacoustic breast phantom. BIOMEDICAL OPTICS EXPRESS 2019; 10:5921-5939. [PMID: 31799055 PMCID: PMC6865090 DOI: 10.1364/boe.10.005921] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 05/04/2023]
Abstract
Imaging parameters of photoacoustic breast imaging systems such as the spatial resolution and imaging depth are often characterized with phantoms. These objects usually contain simple structures in homogeneous media such as absorbing wires or spherical objects in scattering gels. While these kinds of basic phantoms are uncluttered and useful, they do not challenge the system as much as a breast does, and can thereby overestimate the system's performance. The female breast is a complex collection of tissue types, and the acoustic and optical attenuation of these tissues limit the imaging depth, the resolution and the ability to extract quantitative information. For testing and challenging photoacoustic breast imaging systems to the full extent before moving to in vivo studies, a complex breast phantom which simulates the breast's most prevalent tissues is required. In this work we present the first three dimensional multi-layered semi-anthropomorphic photoacoustic breast phantom. The phantom aims to simulate skin, fat, fibroglandular tissue and blood vessels. The latter three are made from custom polyvinyl chloride plastisol (PVCP) formulations and are appropriately doped with additives to obtain tissue realistic acoustic and optical properties. Two tumors are embedded, which are modeled as clusters of small blood vessels. The PVCP materials are surrounded by a silicon layer mimicking the skin. The tissue mimicking materials were cast into the shapes and sizes expected in the breast using 3D-printed moulds developed from a magnetic resonance imaging segmented numerical breast model. The various structures and layers were assembled to obtain a realistic breast morphology. We demonstrate the phantom's appearance in both ultrasound imaging as photoacoustic tomography and make a comparison with a photoacoustic image of a real breast. A good correspondence is observed, which confirms the phantom's usefulness.
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Affiliation(s)
- Maura Dantuma
- Multi-Modality Medical Imaging group, TechMed Centre, University of Twente, Enschede, The Netherlands
- Biomedical Photonic Imaging group, TechMed Centre, University of Twente, Enschede, The Netherlands
| | - Rianne van Dommelen
- Biomedical Photonic Imaging group, TechMed Centre, University of Twente, Enschede, The Netherlands
| | - Srirang Manohar
- Multi-Modality Medical Imaging group, TechMed Centre, University of Twente, Enschede, The Netherlands
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25
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Gehrung M, Bohndiek SE, Brunker J. Development of a blood oxygenation phantom for photoacoustic tomography combined with online pO2 detection and flow spectrometry. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-11. [PMID: 31625321 PMCID: PMC7005535 DOI: 10.1117/1.jbo.24.12.121908] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/09/2019] [Indexed: 05/07/2023]
Abstract
Photoacoustic tomography (PAT) is intrinsically sensitive to blood oxygen saturation (sO2) in vivo. However, making accurate sO2 measurements without knowledge of tissue- and instrumentation-related correction factors is extremely challenging. We have developed a low-cost flow phantom to facilitate validation of PAT systems. The phantom is composed of a flow circuit of tubing partially embedded within a tissue-mimicking material, with independent sensors providing online monitoring of the optical absorption spectrum and partial pressure of oxygen in the tube. We first test the flow phantom using two small molecule dyes that are frequently used for photoacoustic imaging: methylene blue and indocyanine green. We then demonstrate the potential of the phantom for evaluating sO2 using chemical oxygenation and deoxygenation of blood in the circuit. Using this dynamic assessment of the photoacoustic sO2 measurement in phantoms in relation to a ground truth, we explore the influence of multispectral processing and spectral coloring on accurate assessment of sO2. Future studies could exploit this low-cost dynamic flow phantom to validate fluence correction algorithms and explore additional blood parameters such as pH and also absorptive and other properties of different fluids.
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Affiliation(s)
- Marcel Gehrung
- Cancer Research UK Cambridge Institute, Li Ka-Shing Centre, Cambridge, United Kingdom
- University of Cambridge, Department of Physics, Cambridge, United Kingdom
| | - Sarah E. Bohndiek
- Cancer Research UK Cambridge Institute, Li Ka-Shing Centre, Cambridge, United Kingdom
- University of Cambridge, Department of Physics, Cambridge, United Kingdom
| | - Joanna Brunker
- Cancer Research UK Cambridge Institute, Li Ka-Shing Centre, Cambridge, United Kingdom
- University of Cambridge, Department of Physics, Cambridge, United Kingdom
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26
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Polacco MA, Hou H, Kuppusamy P, Chen EY. Measuring Flap Oxygen Using Electron Paramagnetic Resonance Oximetry. Laryngoscope 2019; 129:E415-E419. [PMID: 31034638 DOI: 10.1002/lary.28043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/03/2019] [Accepted: 04/15/2019] [Indexed: 12/18/2022]
Abstract
OBJECTIVES/HYPOTHESIS To determine if electron paramagnetic resonance (EPR) oximetry is a viable technology to aid in flap monitoring. STUDY DESIGN Prospective cohort. METHODS This was a cohort study assessing accuracy and speed of EPR oximetry in detecting ischemia of a saphenous artery-based flap in a rat model, using transcutaneous oximetry as a control. Measurements were obtained under both resting and ischemic conditions for nine Sprague Dawley rats (18 flaps), for 3 postoperative days following flap elevation. RESULTS The mean partial pressure of oxygen prior to tourniquet application was 66.9 ± 8.9 mm Hg with EPR oximetry and 64.7 ± 5.2 mm Hg with transcutaneous oximetry (P = .45). Mean partial pressures of oxygen during tourniquet application were 8.9 ± 3.2 mm Hg and 8.5 ± 2.9 mm Hg for EPR oximetry and transcutaneous oximetry, respectively (P = .48), and 67.2 ± 6.9 mm Hg and 65.3 ± 6.1 mm Hg after tourniquet release for EPR oximetry and transcutaneous oximetry, respectively (P = .44). The mean ischemia detection time of EPR oximetry was 49 ± 21 seconds. CONCLUSIONS Offering timely, accurate, and noninvasive tissue oxygen measurements, EPR oximetry is a promising adjunct in flap monitoring. LEVEL OF EVIDENCE NA Laryngoscope, 129:E415-E419, 2019.
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Affiliation(s)
- Marc A Polacco
- Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
| | - Huagang Hou
- Brigham and Women's Hospital, Boston, Massachusetts
| | | | - Eunice Y Chen
- Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire
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