1
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Zhang S, Miao J, Li LS. Challenges and advances in two-dimensional photoacoustic computed tomography: a review. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:070901. [PMID: 39006312 PMCID: PMC11245175 DOI: 10.1117/1.jbo.29.7.070901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 06/18/2024] [Accepted: 06/19/2024] [Indexed: 07/16/2024]
Abstract
Significance Photoacoustic computed tomography (PACT), a hybrid imaging modality combining optical excitation with acoustic detection, has rapidly emerged as a prominent biomedical imaging technique. Aim We review the challenges and advances of PACT, including (1) limited view, (2) anisotropy resolution, (3) spatial aliasing, (4) acoustic heterogeneity (speed of sound mismatch), and (5) fluence correction of spectral unmixing. Approach We performed a comprehensive literature review to summarize the key challenges in PACT toward practical applications and discuss various solutions. Results There is a wide range of contributions from both industry and academic spaces. Various approaches, including emerging deep learning methods, are proposed to improve the performance of PACT further. Conclusions We outline contemporary technologies aimed at tackling the challenges in PACT applications.
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Affiliation(s)
- Shunyao Zhang
- Rice University, Department of Electrical and Computer Engineering, Houston, Texas, United States
| | - Jingyi Miao
- Rice University, Department of Electrical and Computer Engineering, Houston, Texas, United States
| | - Lei S. Li
- Rice University, Department of Electrical and Computer Engineering, Houston, Texas, United States
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2
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Park H, Yao J, Jing Y. A frequency-domain model-based reconstruction method for transcranial photoacoustic imaging: A 2D numerical investigation. PHOTOACOUSTICS 2023; 33:100561. [PMID: 38021290 PMCID: PMC10658607 DOI: 10.1016/j.pacs.2023.100561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 12/01/2023]
Abstract
Phase aberration caused by the skull is a major barrier to achieving high quality photoacoustic images of human and non-human primates' brains. To address this issue, time-reversal methods have been used but they are computationally demanding and slow due to relying on solving the full-wave equation. The proposed approach is based on model-based image reconstruction in the frequency-domain to achieve near real-time image reconstruction. The relationship between an imaging region and transducer array elements can be mathematically described as a model matrix and the image reconstruction can be performed by pseudo-inverse of the model matrix. The model matrix is numerically calculated due to the lack of analytical solutions for transcranial ultrasound. However, this calculation only needs to be performed once for a given experimental setup and the same acoustic medium, and is an offline process not affecting the actual image reconstruction time. This non-iterative mode-based method demonstrates a substantial improvement in image reconstruction time, being approximately 18 times faster than the time-reversal method, all while maintaining comparable image quality.
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Affiliation(s)
- Hyungjoo Park
- The Graduate Program in Acoustics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Junjie Yao
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Yun Jing
- The Graduate Program in Acoustics, The Pennsylvania State University, University Park, PA 16802, USA
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3
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Alchera E, Monieri M, Maturi M, Locatelli I, Locatelli E, Tortorella S, Sacchi A, Corti A, Nebuloni M, Lucianò R, Pederzoli F, Montorsi F, Salonia A, Meyer S, Jose J, Giustetto P, Franchini MC, Curnis F, Alfano M. Early diagnosis of bladder cancer by photoacoustic imaging of tumor-targeted gold nanorods. PHOTOACOUSTICS 2022; 28:100400. [PMID: 36386292 PMCID: PMC9649962 DOI: 10.1016/j.pacs.2022.100400] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 06/30/2022] [Accepted: 08/29/2022] [Indexed: 06/16/2023]
Abstract
Detection and removal of bladder cancer lesions at an early stage is crucial for preventing tumor relapse and progression. This study aimed to develop a new technological platform for the visualization of small and flat urothelial lesions of high-grade bladder carcinoma in situ (CIS). We found that the integrin α5β1, overexpressed in bladder cancer cell lines, murine orthotopic bladder cancer and human bladder CIS, can be exploited as a receptor for targeted delivery of GNRs functionalized with the cyclic CphgisoDGRG peptide (Iso4). The GNRs@Chit-Iso4 was stable in urine and selectively recognized α5β1 positive neoplastic urothelium, while low frequency ultrasound-assisted shaking of intravesically instilled GNRs@Chit-Iso4 allowed the distribution of nanoparticles across the entire volume of the bladder. Photoacoustic imaging of GNRs@Chit-Iso4 bound to tumor cells allowed for the detection of neoplastic lesions smaller than 0.5 mm that were undetectable by ultrasound imaging and bioluminescence.
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Affiliation(s)
- Elisa Alchera
- Unit of Urology, URI, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Matteo Monieri
- Tumor Biology and Vascular Targeting Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Mirko Maturi
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, Bologna, Italy
| | - Irene Locatelli
- Unit of Urology, URI, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Erica Locatelli
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, Bologna, Italy
| | - Silvia Tortorella
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, Bologna, Italy
| | - Angelina Sacchi
- Tumor Biology and Vascular Targeting Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Angelo Corti
- Tumor Biology and Vascular Targeting Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Università Vita-Salute San Raffaele, Milan, Italy
| | - Manuela Nebuloni
- Pathology Unit, Department of Biomedical and Clinical Sciences, L. Sacco Hospital, Università degli Studi di Milano, Milan, Italy
| | - Roberta Lucianò
- Department of Pathology, IRCCS San Raffaele Hospital and Scientific Institute, Milan, Italy
| | - Filippo Pederzoli
- Unit of Urology, URI, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Università Vita-Salute San Raffaele, Milan, Italy
| | - Francesco Montorsi
- Unit of Urology, URI, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Università Vita-Salute San Raffaele, Milan, Italy
| | - Andrea Salonia
- Unit of Urology, URI, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Università Vita-Salute San Raffaele, Milan, Italy
| | - Sandra Meyer
- FUJIFILM Visualsonics Inc., Amsterdam, the Netherlands
| | - Jithin Jose
- FUJIFILM Visualsonics Inc., Amsterdam, the Netherlands
| | | | - Mauro Comes Franchini
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, Bologna, Italy
| | - Flavio Curnis
- Tumor Biology and Vascular Targeting Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Massimo Alfano
- Unit of Urology, URI, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy
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4
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Wen Y, Guo D, Zhang J, Liu X, Liu T, Li L, Jiang S, Wu D, Jiang H. Clinical photoacoustic/ultrasound dual-modal imaging: Current status and future trends. Front Physiol 2022; 13:1036621. [PMID: 36388111 PMCID: PMC9651137 DOI: 10.3389/fphys.2022.1036621] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 10/05/2022] [Indexed: 08/24/2023] Open
Abstract
Photoacoustic tomography (PAT) is an emerging biomedical imaging modality that combines optical and ultrasonic imaging, providing overlapping fields of view. This hybrid approach allows for a natural integration of PAT and ultrasound (US) imaging in a single platform. Due to the similarities in signal acquisition and processing, the combination of PAT and US imaging creates a new hybrid imaging for novel clinical applications. Over the recent years, particular attention is paid to the development of PAT/US dual-modal systems highlighting mutual benefits in clinical cases, with an aim of substantially improving the specificity and sensitivity for diagnosis of diseases. The demonstrated feasibility and accuracy in these efforts open an avenue of translating PAT/US imaging to practical clinical applications. In this review, the current PAT/US dual-modal imaging systems are discussed in detail, and their promising clinical applications are presented and compared systematically. Finally, this review describes the potential impacts of these combined systems in the coming future.
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Affiliation(s)
- Yanting Wen
- Department of Ultrasound Imaging, The Fifth People’s Hospital of Chengdu, Chengdu, China
- School of Computer Science and Technology, Chongqing University of Posts and Telecommunications, Chongqing, China
| | - Dan Guo
- Department of Ultrasound Imaging, The Fifth People’s Hospital of Chengdu, Chengdu, China
| | - Jing Zhang
- Department of Ultrasound Imaging, The Fifth People’s Hospital of Chengdu, Chengdu, China
- School of Computer Science and Technology, Chongqing University of Posts and Telecommunications, Chongqing, China
| | - Xiaotian Liu
- Department of Ultrasound Imaging, The Fifth People’s Hospital of Chengdu, Chengdu, China
| | - Ting Liu
- Department of Ultrasound Imaging, The Fifth People’s Hospital of Chengdu, Chengdu, China
| | - Lu Li
- Department of Ultrasound Imaging, The Fifth People’s Hospital of Chengdu, Chengdu, China
| | - Shixie Jiang
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, United States
| | - Dan Wu
- School of Computer Science and Technology, Chongqing University of Posts and Telecommunications, Chongqing, China
| | - Huabei Jiang
- Department of Medical Engineering, University of South Florida, Tampa, FL, United States
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5
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Abstract
Photoacoustic tomography (PAT) that integrates the molecular contrast of optical imaging with the high spatial resolution of ultrasound imaging in deep tissue has widespread applications in basic biological science, preclinical research, and clinical trials. Recently, tremendous progress has been made in PAT regarding technical innovations, preclinical applications, and clinical translations. Here, we selectively review the recent progresses and advances in PAT, including the development of advanced PAT systems for small-animal and human imaging, newly engineered optical probes for molecular imaging, broad-spectrum PAT for label-free imaging of biological tissues, high-throughput snapshot photoacoustic topography, and integration of machine learning for image reconstruction and processing. We envision that PAT will have further technical developments and more impactful applications in biomedicine.
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Affiliation(s)
- Lei Li
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, 1200 East California Boulevard, Mail Code 138-78, Pasadena, CA 91125, USA
| | - Lihong V. Wang
- Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, California Institute of Technology, 1200 East California Boulevard, Mail Code 138-78, Pasadena, CA 91125, USA
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6
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Wang Y, Xi L. Chronic cranial window for photoacoustic imaging: a mini review. Vis Comput Ind Biomed Art 2021; 4:15. [PMID: 34037873 PMCID: PMC8155166 DOI: 10.1186/s42492-021-00081-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 04/27/2021] [Indexed: 12/31/2022] Open
Abstract
Photoacoustic (PA) microscopy is being increasingly used to visualize the microcirculation of the brain cortex at the micron level in living rodents. By combining it with long-term cranial window techniques, vasculature can be monitored over a period of days extending to months through a field of view. To fulfill the requirements of long-term in vivo PA imaging, the cranial window must involve a simple and rapid surgical procedure, biological compatibility, and sufficient optical-acoustic transparency, which are major challenges. Recently, several cranial window techniques have been reported for longitudinal PA imaging. Here, the development of chronic cranial windows for PA imaging is reviewed and its technical details are discussed, including window installation, imaging quality, and longitudinal stability.
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Affiliation(s)
- Yongchao Wang
- School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, Sichuan, China.,Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China
| | - Lei Xi
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China.
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7
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Liang B, Wang S, Shen F, Liu QH, Gong Y, Yao J. Acoustic impact of the human skull on transcranial photoacoustic imaging. BIOMEDICAL OPTICS EXPRESS 2021; 12:1512-1528. [PMID: 33796369 PMCID: PMC7984784 DOI: 10.1364/boe.420084] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 05/03/2023]
Abstract
With balanced spatial resolution, imaging depth, and functional sensitivity, photoacoustic tomography (PAT) hold great promise for human brain imaging. However, the strong acoustic attenuation and aberration of the human skull (∼8 mm thick) are longstanding technical challenges for PAT of the human brain. In this work, we numerically investigated the impacts of the stratified human skull on photoacoustic wave propagation (i.e., the forward model) and PAT image formation (i.e., the inverse model). We simulated two representative transcranial PAT implementations: photoacoustic computed tomography (PACT) and photoacoustic macroscopy (PAMac). In the forward model, we simulated the detailed photoacoustic wave propagation from a point or line source through a digital human skull. The wave attenuation, refraction, mode conversation, and reverberation were thoroughly investigated. In the inverse model, we reconstructed the transcranial PACT and PAMac images of a point or line target enclosed by the human skull. Our results demonstrate that transcranial PAMac suffers mainly from wave reverberation within the skull, leading to prolonged signal duration and reduced axial resolution. Transcranial PACT is more susceptible to the skull's acoustic distortion, mode conversion, and reverberation, which collectively lead to strong image artifacts and deteriorated spatial resolutions. We also found that PACT with a ring-shaped transducer array shows more tolerance of the skull's adverse impacts and can provide more accurate image reconstruction. Our results suggest that incorporating the skull's geometry and acoustic properties can improve transcranial PAT image reconstruction. We expect that our results have provided a more comprehensive understanding of the acoustic impact of the human skull on transcranial PAT.
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Affiliation(s)
- Bingyang Liang
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan 523808, China
- National Key Laboratory on Vacuum Electronics, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China
| | - Shaomeng Wang
- National Key Laboratory on Vacuum Electronics, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China
| | - Fei Shen
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan 523808, China
| | - Qing Huo Liu
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA
| | - Yubin Gong
- School of Electrical Engineering and Intelligentization, Dongguan University of Technology, Dongguan 523808, China
- National Key Laboratory on Vacuum Electronics, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China
| | - Junjie Yao
- Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, USA
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8
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Photoacoustic Imaging of Human Vasculature Using LED versus Laser Illumination: A Comparison Study on Tissue Phantoms and In Vivo Humans. SENSORS 2021; 21:s21020424. [PMID: 33435375 PMCID: PMC7827532 DOI: 10.3390/s21020424] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/15/2022]
Abstract
Vascular diseases are becoming an epidemic with an increasing aging population and increases in obesity and type II diabetes. Point-of-care (POC) diagnosis and monitoring of vascular diseases is an unmet medical need. Photoacoustic imaging (PAI) provides label-free multiparametric information of deep vasculature based on strong absorption of light photons by hemoglobin molecules. However, conventional PAI systems use bulky nanosecond lasers which hinders POC applications. Recently, light-emitting diodes (LEDs) have emerged as cost-effective and portable optical sources for the PAI of living subjects. However, state-of-art LED arrays carry significantly lower optical energy (<0.5 mJ/pulse) and high pulse repetition frequencies (PRFs) (4 KHz) compared to the high-power laser sources (100 mJ/pulse) with low PRFs of 10 Hz. Given these tradeoffs between portability, cost, optical energy and frame rate, this work systematically studies the deep tissue PAI performance of LED and laser illuminations to help select a suitable source for a given biomedical application. To draw a fair comparison, we developed a fiberoptic array that delivers laser illumination similar to the LED array and uses the same ultrasound transducer and data acquisition platform for PAI with these two illuminations. Several controlled studies on tissue phantoms demonstrated that portable LED arrays with high frame averaging show higher signal-to-noise ratios (SNRs) of up to 30 mm depth, and the high-energy laser source was found to be more effective for imaging depths greater than 30 mm at similar frame rates. Label-free in vivo imaging of human hand vasculature studies further confirmed that the vascular contrast from LED-PAI is similar to laser-PAI for up to 2 cm depths. Therefore, LED-PAI systems have strong potential to be a mobile health care technology for diagnosing vascular diseases such as peripheral arterial disease and stroke in POC and resource poor settings.
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9
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Photoacoustic Molecular Imaging: Principles and Practice. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00016-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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10
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Balasundaram G, Krafft C, Zhang R, Dev K, Bi R, Moothanchery M, Popp J, Olivo M. Biophotonic technologies for assessment of breast tumor surgical margins-A review. JOURNAL OF BIOPHOTONICS 2021; 14:e202000280. [PMID: 32951321 DOI: 10.1002/jbio.202000280] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 06/11/2023]
Abstract
Breast conserving surgery (BCS) offering similar surgical outcomes as mastectomy while retaining breast cosmesis is becoming increasingly popular for the management of early stage breast cancers. However, its association with reoperation rates of 20% to 40% following incomplete tumor removal warrants the need for a fast and accurate intraoperative surgical margin assessment tool that offers cellular, structural and molecular information of the whole specimen surface to a clinically relevant depth. Biophotonic technologies are evolving to qualify as such an intraoperative tool for clinical assessment of breast cancer surgical margins at the microscopic and macroscopic scale. Herein, we review the current research in the application of biophotonic technologies such as photoacoustic imaging, Raman spectroscopy, multimodal multiphoton imaging, diffuse optical imaging and fluorescence imaging using medically approved dyes for breast cancer detection and/or tumor subtype differentiation toward intraoperative assessment of surgical margins in BCS specimens, and possible challenges in their route to clinical translation.
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Affiliation(s)
- Ghayathri Balasundaram
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | | | - Ruochong Zhang
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Kapil Dev
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Renzhe Bi
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Mohesh Moothanchery
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jürgen Popp
- Leibniz Institute of Photonic Technology, Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, University Jena, Jena, Germany
| | - Malini Olivo
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
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11
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Hosseinaee Z, Le M, Bell K, Reza PH. Towards non-contact photoacoustic imaging [review]. PHOTOACOUSTICS 2020; 20:100207. [PMID: 33024694 PMCID: PMC7530308 DOI: 10.1016/j.pacs.2020.100207] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/29/2020] [Accepted: 07/10/2020] [Indexed: 05/06/2023]
Abstract
Photoacoustic imaging (PAI) takes advantage of both optical and ultrasound imaging properties to visualize optical absorption with high resolution and contrast. Photoacoustic microscopy (PAM) is usually categorized with all-optical microscopy techniques such as optical coherence tomography or confocal microscopes. Despite offering high sensitivity, novel imaging contrast, and high resolution, PAM is not generally an all-optical imaging method unlike the other microscopy techniques. One of the significant limitations of photoacoustic microscopes arises from their need to be in physical contact with the sample through a coupling media. This physical contact, coupling, or immersion of the sample is undesirable or impractical for many clinical and pre-clinical applications. This also limits the flexibility of photoacoustic techniques to be integrated with other all-optical imaging microscopes for providing complementary imaging contrast. To overcome these limitations, several non-contact photoacoustic signal detection approaches have been proposed. This paper presents a brief overview of current non-contact photoacoustic detection techniques with an emphasis on all-optical detection methods and their associated physical mechanisms.
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Affiliation(s)
- Zohreh Hosseinaee
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, Ontario, N2L 3G1, Canada
| | - Martin Le
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, Ontario, N2L 3G1, Canada
| | - Kevan Bell
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, Ontario, N2L 3G1, Canada
- IllumiSonics Inc., Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Parsin Haji Reza
- PhotoMedicine Labs, Department of System Design Engineering, University of Waterloo, Ontario, N2L 3G1, Canada
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12
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Wang S, Larina IV, Larin KV. Label-free optical imaging in developmental biology [Invited]. BIOMEDICAL OPTICS EXPRESS 2020; 11:2017-2040. [PMID: 32341864 PMCID: PMC7173889 DOI: 10.1364/boe.381359] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/30/2020] [Accepted: 02/25/2020] [Indexed: 05/03/2023]
Abstract
Application of optical imaging in developmental biology marks an exciting frontier in biomedical optics. Optical resolution and imaging depth allow for investigation of growing embryos at subcellular, cellular, and whole organism levels, while the complexity and variety of embryonic processes set multiple challenges stimulating the development of various live dynamic embryonic imaging approaches. Among other optical methods, label-free optical techniques attract an increasing interest as they allow investigation of developmental mechanisms without application of exogenous markers or fluorescent reporters. There has been a boost in development of label-free optical imaging techniques for studying embryonic development in animal models over the last decade, which revealed new information about early development and created new areas for investigation. Here, we review the recent progress in label-free optical embryonic imaging, discuss specific applications, and comment on future developments at the interface of photonics, engineering, and developmental biology.
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Affiliation(s)
- Shang Wang
- Department of Biomedical Engineering, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, NJ 07030, USA
| | - Irina V. Larina
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Kirill V. Larin
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
- Department of Biomedical Engineering, University of Houston, 3605 Cullen Boulevard, Houston, TX 77204, USA
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13
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Poudel J, Na S, Wang LV, Anastasio MA. Iterative image reconstruction in transcranial photoacoustic tomography based on the elastic wave equation. Phys Med Biol 2020; 65:055009. [PMID: 31935694 PMCID: PMC7202377 DOI: 10.1088/1361-6560/ab6b46] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Photoacoustic computed tomography (PACT) is an emerging computed imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the photoacoustically induced initial pressure distribution within tissue. The PACT reconstruction problem corresponds to a time-domain inverse source problem, where the initial pressure distribution is recovered from the measurements recorded on an aperture outside the support of the source. A major challenge in transcranial PACT of the brain is to compensate for aberrations and attenuation in the measured data due to the propagation of the photoacoustic wavefields through the skull. To properly account for these effects, a wave equation-based inversion method can be employed that can model the heterogeneous elastic properties of the medium. In this study, an optimization-based image reconstruction method for 3D transcranial PACT is developed based on the elastic wave equation. To accomplish this, a forward-adjoint operator pair based on a finite-difference time-domain discretization of the 3D elastic wave equation is utilized to compute penalized least squares estimates of the initial pressure distribution. Computer-simulation and experimental studies are conducted to investigate the robustness of the reconstruction method to model mismatch and its ability to effectively resolve cortical and superficial brain structures.
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Affiliation(s)
- Joemini Poudel
- Department of Biomedical Engineering, Washington University in St. Louis, 1 Brookings Dr., St. Louis, MO 63130, United States of America
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14
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Cao R, Zhang C, Mitkin VV, Lankford MF, Li J, Zuo Z, Meyer CH, Goyne CP, Ahlers ST, Stone JR, Hu S. Comprehensive Characterization of Cerebrovascular Dysfunction in Blast Traumatic Brain Injury Using Photoacoustic Microscopy. J Neurotrauma 2019; 36:1526-1534. [PMID: 30501547 DOI: 10.1089/neu.2018.6062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Blast traumatic brain injury (bTBI) is a leading contributor to combat-related injuries and death. Although substantial emphasis has been placed on blast-induced neuronal and axonal injuries, co-existing dysfunctions in the cerebral vasculature, particularly the microvasculature, remain poorly understood. Here, we studied blast-induced cerebrovascular dysfunctions in a rat model of bTBI (blast overpressure: 187.8 ± 18.3 kPa). Using photoacoustic microscopy (PAM), we quantified changes in cerebral hemodynamics and metabolism-including blood perfusion, oxygenation, flow, oxygen extraction fraction, and the metabolic rate of oxygen-4 h post-injury. Moreover, we assessed the effect of blast exposure on cerebrovascular reactivity (CVR) to vasodilatory stimulation. With vessel segmentation, we extracted these changes at the single-vessel level, revealing their dependence on vessel type (i.e., artery vs. vein) and diameter. We found that bTBI at this pressure level did not induce pronounced baseline changes in cerebrovascular diameter, blood perfusion, oxygenation, flow, oxygen extraction, and metabolism, except for a slight sO2 increase in small veins (<45 μm) and blood flow increase in large veins (≥45 μm). In contrast, this blast exposure almost abolished CVR, including arterial dilation, flow upregulation, and venous sO2 increase. This study is the most comprehensive assessment of cerebrovascular structure and physiology in response to blast exposure to date. The observed impairment in CVR can potentially cause cognitive decline due to the mismatch between cognitive metabolic demands and vessel's ability to dynamically respond to meet the demands. Also, the impaired CVR can lead to increased vulnerability of the brain to metabolic insults, including hypoxia and ischemia.
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Affiliation(s)
- Rui Cao
- 1 Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Chenchu Zhang
- 1 Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Vladimir V Mitkin
- 2 Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia
| | - Miles F Lankford
- 3 Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia
| | - Jun Li
- 4 Department of Anesthesiology, University of Virginia, Charlottesville, Virginia
| | - Zhiyi Zuo
- 4 Department of Anesthesiology, University of Virginia, Charlottesville, Virginia
| | - Craig H Meyer
- 1 Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Christopher P Goyne
- 2 Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia
| | - Stephen T Ahlers
- 5 Operational and Undersea Medicine Directorate, Naval Medical Research Center, Silver Spring, Maryland
| | - James R Stone
- 3 Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia
| | - Song Hu
- 1 Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
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15
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Han SH. Review of Photoacoustic Imaging for Imaging-Guided Spinal Surgery. Neurospine 2018; 15:306-322. [PMID: 30531652 PMCID: PMC6347351 DOI: 10.14245/ns.1836206.103] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 11/10/2018] [Indexed: 12/23/2022] Open
Abstract
This review introduces the current technique of photoacoustic imaging as it is applied in imaging-guided surgery (IGS), which provides the surgeon with image visualization and analysis capabilities during surgery. Numerous imaging techniques have been developed to help surgeons perform complex operations more safely and quickly. Although surgeons typically use these kinds of images to visualize targets hidden by bone and other tissues, it is nonetheless more difficult to perform surgery with static reference images (e.g., computed tomography scans and magnetic resonance images) of internal structures. Photoacoustic imaging could enable real-time visualization of regions of interest during surgery. Several researchers have shown that photoacoustic imaging has potential for the noninvasive diagnosis of various types of tissues, including bone. Previous studies of the surgical application of photoacoustic imaging have focused on cancer surgery, but photoacoustic imaging has also recently attracted interest for spinal surgery, because it could be useful for avoiding pedicle breaches and for choosing an appropriate starting point before drilling or pedicle probe insertion. This review describes the current instruments and clinical applications of photoacoustic imaging. Its primary objective is to provide a comprehensive overview of photoacoustic IGS in spinal surgery.
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Affiliation(s)
- Seung Hee Han
- Division of Biophotonics, Princess Margaret Hospital, University Health Network, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
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16
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Samant P, Burt TA, Zhao ZJ, Xiang L. Nanoscale photoacoustic tomography for label-free super-resolution imaging: simulation study. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-10. [PMID: 30411552 DOI: 10.1117/1.jbo.23.11.116501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/12/2018] [Indexed: 06/08/2023]
Abstract
Resolutions higher than the optical diffraction limit are often desired in the context of cellular imaging and the study of disease progression at the cellular level. However, three-dimensional super-resolution imaging without reliance on exogenous contrast agents has so far not been achieved. We present nanoscale photoacoustic tomography (nPAT), an imaging modality based on the photoacoustic effect. nPAT can achieve a dramatic improvement in the axial resolution of the photoacoustic imaging. We derive the theoretical resolution and sensitivity of nPAT and demonstrate that nPAT can achieve a maximum axial resolution of 9.2 nm. We also demonstrate that nPAT can theoretically detect smaller numbers of molecules (∼273) than conventional photoacoustic microscopy due to its ability to detect acoustic signals very close to the photoacoustic source. We simulate nPAT imaging of malaria-infected red blood cells (RBCs) using digital phantoms generated from real biological samples, showing nPAT imaging of the RBC at different stages of infection. These simulations show the potential of nPAT to nondestructively image RBCs at the nanometer resolutions for in vivo samples without the use of exogenous contrast agents. Simulations of nPAT-enabled functional imaging show that nPAT can yield insight into malarial metabolism and biocrystallization processes. We believe that the experimental realization of nPAT has important applications in biomedicine.
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Affiliation(s)
- Pratik Samant
- University of Oklahoma, Stephenson School of Biomedical Engineering, Norman, Oklahoma, United States
| | - Timothy A Burt
- University of Oklahoma, Homer L. Dodge Department of Physics and Astronomy, Norman, Oklahoma, United States
| | - Zhizhuang Joe Zhao
- University of Oklahoma Health Sciences Center, Department of Pathology, Oklahoma City, Oklahoma, United States
| | - Liangzhong Xiang
- University of Oklahoma, School of Electric and Computer Engineering, Norman, Oklahoma, United States
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17
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Pushing the Boundaries of Neuroimaging with Optoacoustics. Neuron 2017; 96:966-988. [DOI: 10.1016/j.neuron.2017.10.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/22/2017] [Accepted: 10/16/2017] [Indexed: 02/07/2023]
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18
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Mitsuhashi K, Poudel J, Matthews TP, Garcia-Uribe A, Wang LV, Anastasio MA. A forward-adjoint operator pair based on the elastic wave equation for use in transcranial photoacoustic computed tomography. SIAM JOURNAL ON IMAGING SCIENCES 2017; 10:2022-2048. [PMID: 29387291 PMCID: PMC5788322 DOI: 10.1137/16m1107619] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Photoacoustic computed tomography (PACT) is an emerging imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the photoacoustically induced initial pressure distribution within tissue. The PACT reconstruction problem corresponds to an inverse source problem in which the initial pressure distribution is recovered from measurements of the radiated wavefield. A major challenge in transcranial PACT brain imaging is compensation for aberrations in the measured data due to the presence of the skull. Ultrasonic waves undergo absorption, scattering and longitudinal-to-shear wave mode conversion as they propagate through the skull. To properly account for these effects, a wave-equation-based inversion method should be employed that can model the heterogeneous elastic properties of the skull. In this work, a forward model based on a finite-difference time-domain discretization of the three-dimensional elastic wave equation is established and a procedure for computing the corresponding adjoint of the forward operator is presented. Massively parallel implementations of these operators employing multiple graphics processing units (GPUs) are also developed. The developed numerical framework is validated and investigated in computer19 simulation and experimental phantom studies whose designs are motivated by transcranial PACT applications.
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Affiliation(s)
- Kenji Mitsuhashi
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
| | - Joemini Poudel
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
| | - Thomas P Matthews
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
| | - Alejandro Garcia-Uribe
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
| | - Lihong V Wang
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
| | - Mark A Anastasio
- Department of Biomedical Engineering, Washington University in St.Louis, St.Louis, MO USA
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19
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Poudel J, Matthews TP, Li L, Anastasio MA, Wang LV. Mitigation of artifacts due to isolated acoustic heterogeneities in photoacoustic computed tomography using a variable data truncation-based reconstruction method. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:41018. [PMID: 28267192 PMCID: PMC5340213 DOI: 10.1117/1.jbo.22.4.041018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 02/17/2017] [Indexed: 05/04/2023]
Abstract
Photoacoustic computed tomography (PACT) is an emerging computed imaging modality that exploits optical contrast and ultrasonic detection principles to form images of the absorbed optical energy density within tissue. If the object possesses spatially variant acoustic properties that are unaccounted for by the reconstruction method, the estimated image can contain distortions. While reconstruction methods have recently been developed to compensate for this effect, they generally require the object’s acoustic properties to be known a priori. To circumvent the need for detailed information regarding an object’s acoustic properties, we previously proposed a half-time reconstruction method for PACT. A half-time reconstruction method estimates the PACT image from a data set that has been temporally truncated to exclude the data components that have been strongly aberrated. However, this method can be improved upon when the approximate sizes and locations of isolated heterogeneous structures, such as bones or gas pockets, are known. To address this, we investigate PACT reconstruction methods that are based on a variable data truncation (VDT) approach. The VDT approach represents a generalization of the half-time approach, in which the degree of temporal truncation for each measurement is determined by the distance between the corresponding ultrasonic transducer location and the nearest known bone or gas void location. Computer-simulated and experimental data are employed to demonstrate the effectiveness of the approach in mitigating artifacts due to acoustic heterogeneities.
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Affiliation(s)
- Joemini Poudel
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Thomas P. Matthews
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Lei Li
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Mark A. Anastasio
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
- Address all correspondence to: Mark A. Anastasio, E-mail:
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri, United States
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20
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Abstract
OBJECTIVE Photoacoustic (PA) imaging emerges as a unique tool to study biological samples based on optical absorption contrast. In PA imaging, piezoelectric transducers are commonly used to detect laser-induced ultrasonic waves. However, they typically lack adequate broadband sensitivity at ultrasonic frequency higher than 100 MHz, whereas their bulky size and optically opaque nature cause technical difficulties in integrating PA imaging with conventional optical imaging modalities. To overcome these limitations, optical methods of ultrasound detection were developed and shown their unique applications in PA imaging. METHODS We provide an overview of recent technological advances in optical methods of ultrasound detection and their applications in PA imaging. A general theoretical framework describing sensitivity, bandwidth, and angular responses of optical ultrasound detection is also introduced. RESULTS Optical methods of ultrasound detection can provide improved detection angle and sensitivity over significantly extended bandwidth. In addition, its versatile variants also offer additional advantages, such as device miniaturization, optical transparency, mechanical flexibility, minimal electrical/mechanical crosstalk, and potential noncontact PA imaging. CONCLUSION The optical ultrasound detection methods discussed in this review and their future evolution may play an important role in PA imaging for biomedical study and clinical diagnosis.
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21
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Laviña B. Brain Vascular Imaging Techniques. Int J Mol Sci 2016; 18:ijms18010070. [PMID: 28042833 PMCID: PMC5297705 DOI: 10.3390/ijms18010070] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 12/13/2016] [Accepted: 12/26/2016] [Indexed: 12/13/2022] Open
Abstract
Recent major improvements in a number of imaging techniques now allow for the study of the brain in ways that could not be considered previously. Researchers today have well-developed tools to specifically examine the dynamic nature of the blood vessels in the brain during development and adulthood; as well as to observe the vascular responses in disease situations in vivo. This review offers a concise summary and brief historical reference of different imaging techniques and how these tools can be applied to study the brain vasculature and the blood-brain barrier integrity in both healthy and disease states. Moreover, it offers an overview on available transgenic animal models to study vascular biology and a description of useful online brain atlases.
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Affiliation(s)
- Bàrbara Laviña
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, 75185 Uppsala, Sweden.
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22
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Gagnon L, Smith AF, Boas DA, Devor A, Secomb TW, Sakadžić S. Modeling of Cerebral Oxygen Transport Based on In vivo Microscopic Imaging of Microvascular Network Structure, Blood Flow, and Oxygenation. Front Comput Neurosci 2016; 10:82. [PMID: 27630556 PMCID: PMC5006088 DOI: 10.3389/fncom.2016.00082] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 07/25/2016] [Indexed: 01/09/2023] Open
Abstract
Oxygen is delivered to brain tissue by a dense network of microvessels, which actively control cerebral blood flow (CBF) through vasodilation and contraction in response to changing levels of neural activity. Understanding these network-level processes is immediately relevant for (1) interpretation of functional Magnetic Resonance Imaging (fMRI) signals, and (2) investigation of neurological diseases in which a deterioration of neurovascular and neuro-metabolic physiology contributes to motor and cognitive decline. Experimental data on the structure, flow and oxygen levels of microvascular networks are needed, together with theoretical methods to integrate this information and predict physiologically relevant properties that are not directly measurable. Recent progress in optical imaging technologies for high-resolution in vivo measurement of the cerebral microvascular architecture, blood flow, and oxygenation enables construction of detailed computational models of cerebral hemodynamics and oxygen transport based on realistic three-dimensional microvascular networks. In this article, we review state-of-the-art optical microscopy technologies for quantitative in vivo imaging of cerebral microvascular structure, blood flow and oxygenation, and theoretical methods that utilize such data to generate spatially resolved models for blood flow and oxygen transport. These “bottom-up” models are essential for the understanding of the processes governing brain oxygenation in normal and disease states and for eventual translation of the lessons learned from animal studies to humans.
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Affiliation(s)
- Louis Gagnon
- Optics Division, Department of Radiology, MHG/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School Charlestown, MA, USA
| | - Amy F Smith
- Institut de Mécanique des Fluides de ToulouseToulouse, France; Department of Physiology, University of ArizonaTucson, AZ, USA
| | - David A Boas
- Optics Division, Department of Radiology, MHG/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School Charlestown, MA, USA
| | - Anna Devor
- Optics Division, Department of Radiology, MHG/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical SchoolCharlestown, MA, USA; Departments of Neurosciences and Radiology, University of California, San DiegoLa Jolla, CA, USA
| | | | - Sava Sakadžić
- Optics Division, Department of Radiology, MHG/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School Charlestown, MA, USA
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23
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Wang LV, Yao J. A practical guide to photoacoustic tomography in the life sciences. Nat Methods 2016; 13:627-38. [PMID: 27467726 PMCID: PMC4980387 DOI: 10.1038/nmeth.3925] [Citation(s) in RCA: 710] [Impact Index Per Article: 88.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/20/2016] [Indexed: 12/21/2022]
Abstract
The life sciences can benefit greatly from imaging technologies that connect microscopic discoveries with macroscopic observations. One technology uniquely positioned to provide such benefits is photoacoustic tomography (PAT), a sensitive modality for imaging optical absorption contrast over a range of spatial scales at high speed. In PAT, endogenous contrast reveals a tissue's anatomical, functional, metabolic, and histologic properties, and exogenous contrast provides molecular and cellular specificity. The spatial scale of PAT covers organelles, cells, tissues, organs, and small animals. Consequently, PAT is complementary to other imaging modalities in contrast mechanism, penetration, spatial resolution, and temporal resolution. We review the fundamentals of PAT and provide practical guidelines for matching PAT systems with research needs. We also summarize the most promising biomedical applications of PAT, discuss related challenges, and envision PAT's potential to lead to further breakthroughs.
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Affiliation(s)
- Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Junjie Yao
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
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24
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Weber J, Beard PC, Bohndiek SE. Contrast agents for molecular photoacoustic imaging. Nat Methods 2016; 13:639-50. [PMID: 27467727 DOI: 10.1038/nmeth.3929] [Citation(s) in RCA: 771] [Impact Index Per Article: 96.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 06/25/2016] [Indexed: 02/07/2023]
Abstract
Photoacoustic imaging (PAI) is an emerging tool that bridges the traditional depth limits of ballistic optical imaging and the resolution limits of diffuse optical imaging. Using the acoustic waves generated in response to the absorption of pulsed laser light, it provides noninvasive images of absorbed optical energy density at depths of several centimeters with a resolution of ∼100 μm. This versatile and scalable imaging modality has now shown potential for molecular imaging, which enables visualization of biological processes with systemically introduced contrast agents. Understanding the relative merits of the vast range of contrast agents available, from small-molecule dyes to gold and carbon nanostructures to liposome encapsulations, is a considerable challenge. Here we critically review the physical, chemical and biochemical characteristics of the existing photoacoustic contrast agents, highlighting key applications and present challenges for molecular PAI.
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Affiliation(s)
- Judith Weber
- Department of Physics, University of Cambridge, Cambridge, UK
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Paul C Beard
- Department of Medical Physics and Biomedical Engineering, University College London, London, UK
| | - Sarah E Bohndiek
- Department of Physics, University of Cambridge, Cambridge, UK
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
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25
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Li L, Xia J, Li G, Garcia-Uribe A, Sheng Q, Anastasio MA, Wang LV. Label-free photoacoustic tomography of whole mouse brain structures ex vivo. NEUROPHOTONICS 2016; 3:035001. [PMID: 29181425 PMCID: PMC5696384 DOI: 10.1117/1.nph.3.3.035001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/06/2016] [Indexed: 05/03/2023]
Abstract
Capitalizing on endogenous hemoglobin contrast, photoacoustic-computed tomography (PACT), a deep-tissue high-resolution imaging modality, has drawn increasing interest in neuroimaging. However, most existing studies are limited to functional imaging on the cortical surface and the deep brain structural imaging capability of PACT has never been demonstrated. Here, we explicitly studied the limiting factors of deep brain PACT imaging. We found that the skull distorted the acoustic signal and blood suppressed the structural contrast from other chromophores. When the two effects are mitigated, PACT can potentially provide high-resolution label-free imaging of structures in the entire mouse brain. With [Formula: see text] in-plane resolution, we can clearly identify major structures of the brain, which complements magnetic resonance microscopy for imaging small-animal brain structures. Spectral PACT studies indicate that structural contrasts mainly originate from cytochrome distribution and that the presence of lipid sharpens the image contrast; brain histology results provide further validation. The feasibility of imaging the structure of the brain in vivo is also discussed. Our results demonstrate that PACT is a promising modality for both structural and functional brain imaging.
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Affiliation(s)
- Lei Li
- Washington University in St. Louis, Department of Electrical and System Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
- Washington University in St. Louis, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Jun Xia
- University at Buffalo, The State University of New York, Department of Biomedical Engineering, 332 Bonner Hall, Buffalo, New York 14260, United States
| | - Guo Li
- Washington University in St. Louis, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Alejandro Garcia-Uribe
- Washington University in St. Louis, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Qiwei Sheng
- Washington University in St. Louis, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Mark A. Anastasio
- Washington University in St. Louis, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Electrical and System Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
- Washington University in St. Louis, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
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26
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Attia ABE, Ho CJH, Chandrasekharan P, Balasundaram G, Tay HC, Burton NC, Chuang KH, Ntziachristos V, Olivo M. Multispectral optoacoustic and MRI coregistration for molecular imaging of orthotopic model of human glioblastoma. JOURNAL OF BIOPHOTONICS 2016; 9:701-8. [PMID: 27091626 DOI: 10.1002/jbio.201500321] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/29/2016] [Accepted: 03/29/2016] [Indexed: 05/24/2023]
Abstract
Multi-modality imaging methods are of great importance in oncologic studies for acquiring complementary information, enhancing the efficacy in tumor detection and characterization. We hereby demonstrate a hybrid non-invasive in vivo imaging approach of utilizing magnetic resonance imaging (MRI) and Multispectral Optoacoustic Tomography (MSOT) for molecular imaging of glucose uptake in an orthotopic glioblastoma in mouse. The molecular and functional information from MSOT can be overlaid on MRI anatomy via image coregistration to provide insights into probe uptake in the brain, which is verified by ex vivo fluorescence imaging and histological validation. In vivo MSOT and MRI imaging of an orthotopic glioma mouse model injected with IRDye800-2DG. Image coregistration between MSOT and MRI enables multifaceted (anatomical, functional, molecular) information from MSOT to be overlaid on MRI anatomy images to derive tumor physiological parameters such as perfusion, haemoglobin and oxygenation.
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Affiliation(s)
| | - Chris Jun Hui Ho
- Singapore Bioimaging Consortium, 11 Biopolis Way, Helios #01-02, Singapore, 138667
| | | | | | - Hui Chien Tay
- Singapore Bioimaging Consortium, 11 Biopolis Way, Helios #01-02, Singapore, 138667
| | | | - Kai-Hsiang Chuang
- Queensland Brain Institute, University of Queensland, Brisbane, 4072, Australia.
| | - Vasilis Ntziachristos
- Institute for Biological and Medical Imaging, Technische Universität München and Helmholtz Zentrum München, Neuherberg, Germany
| | - Malini Olivo
- Singapore Bioimaging Consortium, 11 Biopolis Way, Helios #01-02, Singapore, 138667.
- School of Physics, National University of Ireland, Galway, Ireland.
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27
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Zhou Y, Yao J, Wang LV. Tutorial on photoacoustic tomography. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:61007. [PMID: 27086868 PMCID: PMC4834026 DOI: 10.1117/1.jbo.21.6.061007] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/22/2016] [Indexed: 05/18/2023]
Abstract
Photoacoustic tomography (PAT) has become one of the fastest growing fields in biomedical optics. Unlike pure optical imaging, such as confocal microscopy and two-photon microscopy, PAT employs acoustic detection to image optical absorption contrast with high-resolution deep into scattering tissue. So far, PAT has been widely used for multiscale anatomical, functional, and molecular imaging of biological tissues. We focus on PAT’s basic principles, major implementations, imaging contrasts, and recent applications.
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Affiliation(s)
- Yong Zhou
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, Campus Box 1097, St. Louis, Missouri 63130, United States
| | - Junjie Yao
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, Campus Box 1097, St. Louis, Missouri 63130, United States
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, Campus Box 1097, St. Louis, Missouri 63130, United States
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28
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Emerging concepts in functional and molecular photoacoustic imaging. Curr Opin Chem Biol 2016; 33:25-31. [PMID: 27111279 DOI: 10.1016/j.cbpa.2016.04.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 04/03/2016] [Indexed: 01/21/2023]
Abstract
Providing the specific imaging contrast of optical absorption and excellent spatial scalability across the optical and ultrasonic dimensions, photoacoustic imaging has been rapidly emerging and expanding in the past two decades. In this review, I focus on a few latest advances in this enabling technology that hold the potential to transform in vivo functional and molecular imaging at multiple length scales. Specifically, multi-parametric photoacoustic microscopy enables simultaneous high-resolution mapping of hemoglobin concentration, oxygen saturation and blood flow-opening up the possibility of quantifying the metabolic rate of oxygen at the microscopic level. The pump-probe approach harnesses a variety of photoinduced transient optical absorption as novel contrast mechanisms for high-specificity molecular imaging at depth and as nonlinear excitation strategies for high-resolution volumetric microscopy beyond the conventional limit. Novel magneto-optical and photochromic probes lead to contrast-enhanced molecular photoacoustic imaging through differential detection.
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29
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Sakadžić S, Lee J, Boas DA, Ayata C. High-resolution in vivo optical imaging of stroke injury and repair. Brain Res 2015; 1623:174-92. [PMID: 25960347 PMCID: PMC4569527 DOI: 10.1016/j.brainres.2015.04.044] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 12/15/2022]
Abstract
Central nervous system (CNS) function and dysfunction are best understood within a framework of interactions between neuronal, glial and vascular compartments comprising the neurovascular unit (NVU), all of which contribute to stroke-induced CNS injury, plasticity, repair, and recovery. Recent advances in in vivo optical microscopy have enabled us to observe and interrogate cells and their processes with high spatial resolution in real time and in their natural environment deep in the brain tissue. Here, we review some of these state-of-the-art imaging techniques with an emphasis on imaging the interactions among the constituents of the NVU during ischemic injury and repair in small animal models. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.
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Affiliation(s)
- Sava Sakadžić
- Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
| | - Jonghwan Lee
- Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - David A Boas
- Optics Division, MHG/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Cenk Ayata
- Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA; Stroke Service and Neuroscience Intensive Care Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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30
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Yao J, Wang LV. Photoacoustic Brain Imaging: from Microscopic to Macroscopic Scales. NEUROPHOTONICS 2014; 1:1877516. [PMID: 25401121 PMCID: PMC4232215 DOI: 10.1117/1.nph.1.1.011003] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/28/2014] [Accepted: 03/31/2014] [Indexed: 05/12/2023]
Abstract
Human brain mapping has become one of the most exciting contemporary research areas, with major breakthroughs expected in the following decades. Modern brain imaging techniques have allowed neuroscientists to gather a wealth of anatomic and functional information about the brain. Among these techniques, by virtue of its rich optical absorption contrast, high spatial and temporal resolutions, and deep penetration, photoacoustic tomography (PAT) has attracted more and more attention, and is playing an increasingly important role in brain studies. In particular, PAT complements other brain imaging modalities by providing high-resolution functional and metabolic imaging. More importantly, PAT's unique scalability enables scrutinizing the brain at both microscopic and macroscopic scales, using the same imaging contrast. In this Review, we present the state-of-the-art PAT techniques for brain imaging, summarize representative neuroscience applications, outline the technical challenges in translating PAT to human brain imaging, and envision potential technological deliverables.
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Affiliation(s)
- Junjie Yao
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
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Li H, Dong B, Zhang Z, Zhang HF, Sun C. A transparent broadband ultrasonic detector based on an optical micro-ring resonator for photoacoustic microscopy. Sci Rep 2014; 4:4496. [PMID: 24675547 PMCID: PMC3968454 DOI: 10.1038/srep04496] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 02/25/2014] [Indexed: 11/29/2022] Open
Abstract
Photoacoustic microscopy (PAM) does not rely on contrast agent to image the optical absorption contrast in biological tissue. It is uniquely suited for measuring several tissue physiological parameters, such as hemoglobin oxygen saturation, that would otherwise remain challenging. Researchers are designing new clinical diagnostic tools and multimodal microscopic systems around PAM to fully unleash its potential. However, the sizeable and opaque piezoelectric ultrasonic detectors commonly used in PAM impose a serious constraint. Our solution is a coverslip-style optically transparent ultrasound detector based on a polymeric optical micro-ring resonator (MRR) with a total thickness of 250 μm. It enables highly-sensitive ultrasound detection over a wide receiving angle with a bandwidth of 140 MHz, which corresponds to a photoacoustic saturation limit of 287 cm−1, at an estimated noise-equivalent pressure (NEP) of 6.8 Pa. We also established a theoretical framework for designing and optimizing the MRR for PAM.
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Affiliation(s)
- Hao Li
- 1] Department of Biomedical Engineering, Northwestern University, Evanston IL 60208 [2]
| | - Biqin Dong
- 1] Department of Biomedical Engineering, Northwestern University, Evanston IL 60208 [2] Department of Mechanical Engineering, Northwestern University, Evanston IL 60208 [3]
| | - Zhen Zhang
- Department of Mechanical Engineering, Northwestern University, Evanston IL 60208
| | - Hao F Zhang
- 1] Department of Biomedical Engineering, Northwestern University, Evanston IL 60208 [2] Department of Ophthalmology, Northwestern University, Chicago IL 60611
| | - Cheng Sun
- Department of Mechanical Engineering, Northwestern University, Evanston IL 60208
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Tsunoi Y, Sato S, Kawauchi S, Ashida H, Saitoh D, Terakawa M. In vivo photoacoustic molecular imaging of the distribution of serum albumin in rat burned skin. Burns 2013; 39:1403-8. [DOI: 10.1016/j.burns.2013.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Revised: 03/09/2013] [Accepted: 03/15/2013] [Indexed: 10/27/2022]
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Wang K, Huang C, Kao YJ, Chou CY, Oraevsky AA, Anastasio MA. Accelerating image reconstruction in three-dimensional optoacoustic tomography on graphics processing units. Med Phys 2013; 40:023301. [PMID: 23387778 DOI: 10.1118/1.4774361] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Optoacoustic tomography (OAT) is inherently a three-dimensional (3D) inverse problem. However, most studies of OAT image reconstruction still employ two-dimensional imaging models. One important reason is because 3D image reconstruction is computationally burdensome. The aim of this work is to accelerate existing image reconstruction algorithms for 3D OAT by use of parallel programming techniques. METHODS Parallelization strategies are proposed to accelerate a filtered backprojection (FBP) algorithm and two different pairs of projection/backprojection operations that correspond to two different numerical imaging models. The algorithms are designed to fully exploit the parallel computing power of graphics processing units (GPUs). In order to evaluate the parallelization strategies for the projection/backprojection pairs, an iterative image reconstruction algorithm is implemented. Computer simulation and experimental studies are conducted to investigate the computational efficiency and numerical accuracy of the developed algorithms. RESULTS The GPU implementations improve the computational efficiency by factors of 1000, 125, and 250 for the FBP algorithm and the two pairs of projection/backprojection operators, respectively. Accurate images are reconstructed by use of the FBP and iterative image reconstruction algorithms from both computer-simulated and experimental data. CONCLUSIONS Parallelization strategies for 3D OAT image reconstruction are proposed for the first time. These GPU-based implementations significantly reduce the computational time for 3D image reconstruction, complementing our earlier work on 3D OAT iterative image reconstruction.
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Affiliation(s)
- Kun Wang
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA
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Hu S, Wang L. Optical-resolution photoacoustic microscopy: auscultation of biological systems at the cellular level. Biophys J 2013; 105:841-7. [PMID: 23972836 PMCID: PMC3752103 DOI: 10.1016/j.bpj.2013.07.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 06/16/2013] [Accepted: 07/12/2013] [Indexed: 11/19/2022] Open
Abstract
Photoacoustic microscopy (PAM) offers unprecedented sensitivity to optical absorption and opens a new window to study biological systems at multiple length- and timescales. In particular, optical-resolution PAM (OR-PAM) has pushed the technical envelope to submicron length scales and millisecond timescales. Here, we review the state of the art of OR-PAM in biophysical research. With properly chosen optical wavelengths, OR-PAM can spectrally differentiate a variety of endogenous and exogenous chromophores, unveiling the anatomical, functional, metabolic, and molecular information of biological systems. Newly uncovered contrast mechanisms of linear dichroism and Förster resonance energy transfer further distinguish OR-PAM. Integrating multiple contrasts and advanced scanning mechanisms has capacitated OR-PAM to comprehensively interrogate biological systems at the cellular level in real time. Two future directions are discussed, where OR-PAM holds the potential to translate basic biophysical research into clinical healthcare.
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Affiliation(s)
- Song Hu
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Lihong V. Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
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Huang C, Wang K, Nie L, Wang LV, Anastasio MA. Full-wave iterative image reconstruction in photoacoustic tomography with acoustically inhomogeneous media. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:1097-110. [PMID: 23529196 PMCID: PMC4114232 DOI: 10.1109/tmi.2013.2254496] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Existing approaches to image reconstruction in photoacoustic computed tomography (PACT) with acoustically heterogeneous media are limited to weakly varying media, are computationally burdensome, and/or cannot effectively mitigate the effects of measurement data incompleteness and noise. In this work, we develop and investigate a discrete imaging model for PACT that is based on the exact photoacoustic (PA) wave equation and facilitates the circumvention of these limitations. A key contribution of the work is the establishment of a procedure to implement a matched forward and backprojection operator pair associated with the discrete imaging model, which permits application of a wide-range of modern image reconstruction algorithms that can mitigate the effects of data incompleteness and noise. The forward and backprojection operators are based on the k-space pseudospectral method for computing numerical solutions to the PA wave equation in the time domain. The developed reconstruction methodology is investigated by use of both computer-simulated and experimental PACT measurement data.
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Affiliation(s)
- Chao Huang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Kun Wang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Liming Nie
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
| | - Lihong V. Wang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130 USA
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Wang K, Anastasio MA. A simple Fourier transform-based reconstruction formula for photoacoustic computed tomography with a circular or spherical measurement geometry. Phys Med Biol 2013; 57:N493-9. [PMID: 23165199 DOI: 10.1088/0031-9155/57/23/n493] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Photoacoustic computed tomography (PACT), also known as optoacoustic tomography, is an emerging imaging modality that has great potential for a wide range of biomedical imaging applications. In this note, we derive a hybrid reconstruction formula that is mathematically exact and operates on a data function that is expressed in the temporal frequency and spatial domains. This formula explicitly reveals new insights into how the spatial frequency components of the sought-after object function are determined by the temporal frequency components of the data function measured with a circular or spherical measurement geometry in two- and three-dimensional implementations of PACT, respectively. The structure of the reconstruction formula is surprisingly simple compared with existing Fourier-domain reconstruction formulae. It also yields a straightforward numerical implementation that is robust and two orders of magnitude more computationally efficient than filtered backprojection algorithms.
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Affiliation(s)
- Kun Wang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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Zhang C, Zhang YS, Yao DK, Xia Y, Wang LV. Label-free photoacoustic microscopy of cytochromes. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:20504. [PMID: 23370407 PMCID: PMC3560837 DOI: 10.1117/1.jbo.18.2.020504] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/15/2013] [Accepted: 01/16/2013] [Indexed: 05/18/2023]
Abstract
Photoacoustic microscopy (PAM) has achieved submicron lateral resolution in showing subcellular structures; however, relatively few endogenous subcellular contrasts have so far been imaged. Given that the hemeprotein, mostly cytochromes in general cells, is optically absorbing around the Soret peak (~420 nm), we implemented label-free PAM of cytochromes in cytoplasm for the first time. By measuring the photoacoustic spectra of the oxidized and reduced states of fibroblast lysate and fitting the difference spectrum with three types of cytochromes, we found that the three cytochromes account for more than half the optical absorption in the cell lysate at 420 nm wavelength. Fixed fibroblasts on slides were imaged by PAM at 422 and 250 nm wavelengths to reveal cytoplasms and nuclei, respectively, as confirmed by standard staining histology. PAM was also applied to label-free histology of mouse ear sections by showing cytoplasms and nuclei of various cells. PAM of cytochromes in cytoplasm is expected to be a high-throughput, label-free technique for studying live cell functions, which cannot be accomplished by conventional histology.
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Affiliation(s)
- Chi Zhang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
| | - Yu Shrike Zhang
- Georgia Institute of Technology and Emory University, The Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia 30332
| | - Da-Kang Yao
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
| | - Younan Xia
- Georgia Institute of Technology and Emory University, The Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia 30332
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
- Address all correspondence to: Lihong V. Wang, Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130. Tel: +(314) 935-6152; Fax: +(314) 935-7448; E-mail:
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Zhang C, Maslov K, Yao J, Wang LV. In vivo photoacoustic microscopy with 7.6-µm axial resolution using a commercial 125-MHz ultrasonic transducer. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:116016. [PMID: 23123975 PMCID: PMC3487171 DOI: 10.1117/1.jbo.17.11.116016] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Photoacoustic microscopy has achieved submicron lateral resolution, but its axial resolution is much lower. Here an axial resolution of 7.6 μm, the highest axial resolution validated by experimental data, has been achieved by using a commercial 125 MHz ultrasonic transducer for signal detection followed by the Wiener deconvolution for signal processing. Limited by the working distance, the high-frequency ultrasonic transducer can penetrate 1.2 mm into biological tissue from the ultrasound detection side. At this depth, the signal-to-noise ratio decreases by 11 dB, and the axial resolution degrades by 36%. The new system was demonstrated in imaging melanoma cells ex vivo and mouse ears in vivo.
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Affiliation(s)
- Chi Zhang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
| | - Konstantin Maslov
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
| | - Junjie Yao
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130
- Address all correspondence to: Lihong V. Wang, Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130. Tel: (314) 935-6152; Fax: (314) 935-7448; E-mail:
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Wang K, Su R, Oraevsky AA, Anastasio MA. Investigation of iterative image reconstruction in three-dimensional optoacoustic tomography. Phys Med Biol 2012; 57:5399-423. [PMID: 22864062 DOI: 10.1088/0031-9155/57/17/5399] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Iterative image reconstruction algorithms for optoacoustic tomography (OAT), also known as photoacoustic tomography, have the ability to improve image quality over analytic algorithms due to their ability to incorporate accurate models of the imaging physics, instrument response and measurement noise. However, to date, there have been few reported attempts to employ advanced iterative image reconstruction algorithms for improving image quality in three-dimensional (3D) OAT. In this work, we implement and investigate two iterative image reconstruction methods for use with a 3D OAT small animal imager: namely a penalized least-squares (PLS) method employing a quadratic smoothness penalty and a PLS method employing a total variation norm penalty. The reconstruction algorithms employ accurate models of the ultrasonic transducer impulse responses. Experimental data sets are employed to compare the performances of the iterative reconstruction algorithms to that of a 3D filtered backprojection (FBP) algorithm. By the use of quantitative measures of image quality, we demonstrate that the iterative reconstruction algorithms can mitigate image artifacts and preserve spatial resolution more effectively than FBP algorithms. These features suggest that the use of advanced image reconstruction algorithms can improve the effectiveness of 3D OAT while reducing the amount of data required for biomedical applications.
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Affiliation(s)
- Kun Wang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
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Huang C, Nie L, Schoonover RW, Guo Z, Schirra CO, Anastasio MA, Wang LV. Aberration correction for transcranial photoacoustic tomography of primates employing adjunct image data. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:066016. [PMID: 22734772 PMCID: PMC3381039 DOI: 10.1117/1.jbo.17.6.066016] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 04/09/2012] [Accepted: 04/12/2012] [Indexed: 05/18/2023]
Abstract
A challenge in photoacoustic tomography (PAT) brain imaging is to compensate for aberrations in the measured photoacoustic data due to their propagation through the skull. By use of information regarding the skull morphology and composition obtained from adjunct x-ray computed tomography image data, we developed a subject-specific imaging model that accounts for such aberrations. A time-reversal-based reconstruction algorithm was employed with this model for image reconstruction. The image reconstruction methodology was evaluated in experimental studies involving phantoms and monkey heads. The results establish that our reconstruction methodology can effectively compensate for skull-induced acoustic aberrations and improve image fidelity in transcranial PAT.
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Affiliation(s)
- Chao Huang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri
| | - Liming Nie
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri
| | - Robert W. Schoonover
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri
| | - Zijian Guo
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri
| | | | - Mark A. Anastasio
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri
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Huang C, Nie L, Schoonover RW, Wang LV, Anastasio MA. Photoacoustic computed tomography correcting for heterogeneity and attenuation. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:061211. [PMID: 22734741 PMCID: PMC3380947 DOI: 10.1117/1.jbo.17.6.061211] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 01/20/2012] [Accepted: 01/20/2012] [Indexed: 05/19/2023]
Abstract
We report an investigation of image reconstruction in photoacoustic tomography for objects that possess heterogeneous material and acoustic attenuation distributions. When the object contains materials, such as bone and soft-tissue, that are modeled using power law attenuation models with distinct exponents, we demonstrate that the effects of acoustic attenuation due to the most strongly attenuating material can be compensated for if the attenuation of the other less attenuating material(s) are neglected. Experiments with phantom objects are presented to validated our findings.
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Affiliation(s)
- Chao Huang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
| | - Liming Nie
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
| | - Robert W. Schoonover
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
| | - Lihong V. Wang
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
| | - Mark A. Anastasio
- Washington University in St. Louis, Department of Biomedical Engineering, St. Louis, Missouri 63130
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Abstract
Photoacoustic tomography (PAT) can create multiscale multicontrast images of living biological structures ranging from organelles to organs. This emerging technology overcomes the high degree of scattering of optical photons in biological tissue by making use of the photoacoustic effect. Light absorption by molecules creates a thermally induced pressure jump that launches ultrasonic waves, which are received by acoustic detectors to form images. Different implementations of PAT allow the spatial resolution to be scaled with the desired imaging depth in tissue while a high depth-to-resolution ratio is maintained. As a rule of thumb, the achievable spatial resolution is on the order of 1/200 of the desired imaging depth, which can reach up to 7 centimeters. PAT provides anatomical, functional, metabolic, molecular, and genetic contrasts of vasculature, hemodynamics, oxygen metabolism, biomarkers, and gene expression. We review the state of the art of PAT for both biological and clinical studies and discuss future prospects.
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Affiliation(s)
- Lihong V Wang
- Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University, St. Louis, MO 63130, USA.
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Gratt S, Passler K, Nuster R, Paltauf G. Photoacoustic section imaging with an integrating cylindrical detector. BIOMEDICAL OPTICS EXPRESS 2011; 2:2973-81. [PMID: 22076260 PMCID: PMC3207368 DOI: 10.1364/boe.2.002973] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 09/19/2011] [Accepted: 09/20/2011] [Indexed: 05/20/2023]
Abstract
A piezoelectric detector with a cylindrical shape is investigated for photoacoustic section imaging. Images are acquired by rotating a sample in front of the cylindrical detector. With its length exceeding the size of the imaging object, it works as an integrating sensor and therefore allows reconstructing section images with the inverse Radon transform. Prior to the reconstruction the Abel transform is applied to the measured signals to improve the accuracy of the image. A resolution of about 100 µm within a section and of 500 µm between sections is obtained. Additionally, a series of images of a zebra fish is shown.
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