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Paul A, Mallidi S. U-Net enhanced real-time LED-based photoacoustic imaging. JOURNAL OF BIOPHOTONICS 2024; 17:e202300465. [PMID: 38622811 PMCID: PMC11164633 DOI: 10.1002/jbio.202300465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 02/18/2024] [Accepted: 03/17/2024] [Indexed: 04/17/2024]
Abstract
Photoacoustic (PA) imaging is hybrid imaging modality with good optical contrast and spatial resolution. Portable, cost-effective, smaller footprint light emitting diodes (LEDs) are rapidly becoming important PA optical sources. However, the key challenge faced by the LED-based systems is the low light fluence that is generally compensated by high frame averaging, consequently reducing acquisition frame-rate. In this study, we present a simple deep learning U-Net framework that enhances the signal-to-noise ratio (SNR) and contrast of PA image obtained by averaging low number of frames. The SNR increased by approximately four-fold for both in-class in vitro phantoms (4.39 ± 2.55) and out-of-class in vivo models (4.27 ± 0.87). We also demonstrate the noise invariancy of the network and discuss the downsides (blurry outcome and failure to reduce the salt & pepper noise). Overall, the developed U-Net framework can provide a real-time image enhancement platform for clinically translatable low-cost and low-energy light source-based PA imaging systems.
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Affiliation(s)
- Avijit Paul
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
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Nguyen CD, Chen Y, Kaplan DL, Mallidi S. Multi-spectral photoacoustic imaging combined with acoustic radiation force impulse imaging for applications in tissue engineering. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.23.590806. [PMID: 38712117 PMCID: PMC11071356 DOI: 10.1101/2024.04.23.590806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Tissue engineering is a dynamic field focusing on the creation of advanced scaffolds for tissue and organ regeneration. These scaffolds are customized to their specific applications and are often designed to be complex, large structures to mimic tissues and organs. This study addresses the critical challenge of effectively characterizing these thick, optically opaque scaffolds that traditional imaging methods fail to fully image due to their optical limitations. We introduce a novel multi-modal imaging approach combining ultrasound, photoacoustic, and acoustic radiation force impulse imaging. This combination leverages its acoustic-based detection to overcome the limitations posed by optical imaging techniques. Ultrasound imaging is employed to monitor the scaffold structure, photoacoustic imaging is employed to monitor cell proliferation, and acoustic radiation force impulse imaging is employed to evaluate the homogeneity of scaffold stiffness. We applied this integrated imaging system to analyze melanoma cell growth within silk fibroin protein scaffolds with varying pore sizes and therefore stiffness over different cell incubation periods. Among various materials, silk fibroin was chosen for its unique combination of features including biocompatibility, tunable mechanical properties, and structural porosity which supports extensive cell proliferation. The results provide a detailed mesoscale view of the scaffolds' internal structure, including cell penetration depth and biomechanical properties. Our findings demonstrate that the developed multimodal imaging technique offers comprehensive insights into the physical and biological dynamics of tissue-engineered scaffolds. As the field of tissue engineering continues to advance, the importance of non-ionizing and non-invasive imaging systems becomes increasingly evident, and by facilitating a deeper understanding and better characterization of scaffold architectures, such imaging systems are pivotal in driving the success of future tissue-engineering solutions.
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Fakhoury JW, Lara JB, Manwar R, Zafar M, Xu Q, Engel R, Tsoukas MM, Daveluy S, Mehregan D, Avanaki K. Photoacoustic imaging for cutaneous melanoma assessment: a comprehensive review. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:S11518. [PMID: 38223680 PMCID: PMC10785699 DOI: 10.1117/1.jbo.29.s1.s11518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/07/2023] [Accepted: 12/21/2023] [Indexed: 01/16/2024]
Abstract
Significance Cutaneous melanoma (CM) has a high morbidity and mortality rate, but it can be cured if the primary lesion is detected and treated at an early stage. Imaging techniques such as photoacoustic (PA) imaging (PAI) have been studied and implemented to aid in the detection and diagnosis of CM. Aim Provide an overview of different PAI systems and applications for the study of CM, including the determination of tumor depth/thickness, cancer-related angiogenesis, metastases to lymph nodes, circulating tumor cells (CTCs), virtual histology, and studies using exogenous contrast agents. Approach A systematic review and classification of different PAI configurations was conducted based on their specific applications for melanoma detection. This review encompasses animal and preclinical studies, offering insights into the future potential of PAI in melanoma diagnosis in the clinic. Results PAI holds great clinical potential as a noninvasive technique for melanoma detection and disease management. PA microscopy has predominantly been used to image and study angiogenesis surrounding tumors and provide information on tumor characteristics. Additionally, PA tomography, with its increased penetration depth, has demonstrated its ability to assess melanoma thickness. Both modalities have shown promise in detecting metastases to lymph nodes and CTCs, and an all-optical implementation has been developed to perform virtual histology analyses. Animal and human studies have successfully shown the capability of PAI to detect, visualize, classify, and stage CM. Conclusions PAI is a promising technique for assessing the status of the skin without a surgical procedure. The capability of the modality to image microvasculature, visualize tumor boundaries, detect metastases in lymph nodes, perform fast and label-free histology, and identify CTCs could aid in the early diagnosis and classification of CM, including determination of metastatic status. In addition, it could be useful for monitoring treatment efficacy noninvasively.
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Affiliation(s)
- Joseph W. Fakhoury
- Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Juliana Benavides Lara
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, Chicago, Illinois, United States
| | - Rayyan Manwar
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, Chicago, Illinois, United States
| | - Mohsin Zafar
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, Chicago, Illinois, United States
| | - Qiuyun Xu
- Wayne State University, Department of Biomedical Engineering, Detroit, Michigan, United States
| | - Ricardo Engel
- Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Maria M. Tsoukas
- University of Illinois at Chicago, Department of Dermatology, Chicago, Illinois, United States
| | - Steven Daveluy
- Wayne State University School of Medicine, Department of Dermatology, Detroit, Michigan, United States
| | - Darius Mehregan
- Wayne State University School of Medicine, Department of Dermatology, Detroit, Michigan, United States
| | - Kamran Avanaki
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, Chicago, Illinois, United States
- University of Illinois at Chicago, Department of Dermatology, Chicago, Illinois, United States
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Paul S, Mulani S, Singh MKA, Singh MS. Improvement of LED-based photoacoustic imaging using lag-coherence factor (LCF) beamforming. Med Phys 2023; 50:7525-7538. [PMID: 37843980 DOI: 10.1002/mp.16780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 10/18/2023] Open
Abstract
BACKGROUND Owing to its portability, affordability, and energy-efficiency, LED-based photoacoustic (PA) imaging is increasingly becoming popular when compared to its laser-based alternative, mainly for superficial vascular imaging applications. However, this technique suffers from low SNR and thereby limited imaging depth. As a result, visual image quality of LED-based PA imaging is not optimal, especially in sub-surface vascular imaging applications. PURPOSE Combination of linear ultrasound (US) probes and LED arrays are the most common implementation in LED-based PA imaging, which is currently being explored for different clinical imaging applications. Traditional delay-and-sum (DAS) is the most common beamforming algorithm in linear array-based PA detection. Side-lobes and reconstruction-related artifacts make the DAS performance unsatisfactory and poor for a clinical-implementation. In this work, we explored a new weighting-based image processing technique for LED-based PAs to yield improved image quality when compared to the traditional methods. METHODS We are proposing a lag-coherence factor (LCF), which is fundamentally based on the combination of the spatial auto-correlation of the detected PA signals. In LCF, the numerator contains lag-delay-multiply-and-sum (DMAS) beamformer instead of a conventional DAS beamformer. A spatial auto-correlation operation is performed between the detected US array signals before using DMAS beamformer. We evaluated the new method on both tissue-mimicking phantom (2D) and human volunteer imaging (3D) data acquired using a commercial LED-based PA imaging system. RESULTS Our novel correlation-based weighting technique showed LED-based PA image quality improvement when it is combined with conventional DAS beamformer. Both phantom and human volunteer imaging results gave a direct confirmation that by introducing LCF, image quality was improved and this method could reduce side-lobes and artifacts when compared to the DAS and coherence-factor (CF) approaches. Signal-to-noise ratio, generalized contrast-to-noise ratio, contrast ratio and spatial resolution were evaluated and compared with conventional beamformers to assess the reconstruction performance in a quantitative way. Results show that our approach offered image quality enhancement with an average signal-to-noise ratio and spatial resolution improvement of around 20% and 25% respectively, when compared with conventional CF based DAS algorithm. CONCLUSIONS Our results demonstrate that the proposed LCF based algorithm performs better than the conventional DAS and CF algorithms by improving signal-to-noise ratio and spatial resolution. Therefore, our new weighting technique could be a promising tool to improve the performance of LED-based PA imaging and thus accelerate its clinical translation.
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Affiliation(s)
- Souradip Paul
- School of physics, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
| | - Sufayan Mulani
- School of physics, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, India
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Kim M, Pelivanov I, O'Donnell M. Review of Deep Learning Approaches for Interleaved Photoacoustic and Ultrasound (PAUS) Imaging. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2023; 70:1591-1606. [PMID: 37910419 PMCID: PMC10788151 DOI: 10.1109/tuffc.2023.3329119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Photoacoustic (PA) imaging provides optical contrast at relatively large depths within the human body, compared to other optical methods, at ultrasound (US) spatial resolution. By integrating real-time PA and US (PAUS) modalities, PAUS imaging has the potential to become a routine clinical modality bringing the molecular sensitivity of optics to medical US imaging. For applications where the full capabilities of clinical US scanners must be maintained in PAUS, conventional limited view and bandwidth transducers must be used. This approach, however, cannot provide high-quality maps of PA sources, especially vascular structures. Deep learning (DL) using data-driven modeling with minimal human design has been very effective in medical imaging, medical data analysis, and disease diagnosis, and has the potential to overcome many of the technical limitations of current PAUS imaging systems. The primary purpose of this article is to summarize the background and current status of DL applications in PAUS imaging. It also looks beyond current approaches to identify remaining challenges and opportunities for robust translation of PAUS technologies to the clinic.
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Manwar R, Li X, Kratkiewicz K, Zhu D, Avanaki K. Adaptive coherent weighted averaging algorithm for enhancement of photoacoustic tomography images of brain. JOURNAL OF BIOPHOTONICS 2023; 16:e202300103. [PMID: 37468445 DOI: 10.1002/jbio.202300103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/15/2023] [Accepted: 07/03/2023] [Indexed: 07/21/2023]
Abstract
One common method to improve the low signal-to-noise ratio of the photoacoustic (PA) signal generated from weak absorbers or absorbers located in deep tissue is to acquire signal multiple times from the same region and perform averaging. However, pulse-to-pulse laser fluctuations together with differences in the beam profile of the pulses create undeterministic multiple scattering processes in the tissue. This phenomenon consequently induces a spatiotemporal displacement in the PA signal samples which in turn deteriorates the effectiveness of signal averaging. Here, we present an adaptive coherent weighted averaging algorithm to adjust the locations and values of PA signal samples for more efficient signal averaging. The proposed method is evaluated in a linear array-based PA imaging setup of ex vivo sheep brain.
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Affiliation(s)
- Rayyan Manwar
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Xin Li
- Department of Computer Science, Wayne State University, Detroit, Michigan, USA
| | - Karl Kratkiewicz
- Department of Biomedical Engineering, Wayne State University, Detroit, Michigan, USA
| | - Dongxiao Zhu
- Department of Computer Science, Wayne State University, Detroit, Michigan, USA
| | - Kamran Avanaki
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
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Lopez L, Pichon P, Loiseau P, Viana B, Mahiou R, Druon F, Georges P, Balembois F. Ce:LYSO, from scintillator to solid-state lighting as a blue luminescent concentrator. Sci Rep 2023; 13:7199. [PMID: 37137933 PMCID: PMC10156901 DOI: 10.1038/s41598-023-32689-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/31/2023] [Indexed: 05/05/2023] Open
Abstract
Cerium-doped lutetium-yttrium oxyorthosilicate (Ce:LYSO) is a well-known single crystal scintillator used in medical imaging and security scanners. Recent development of high power UV LED, matching its absorption band, questions the possibility to use Ce:LYSO in a new way: as LED-pumped solid-state light source. Since Ce:LYSO is available in large size crystals, we investigate its potential as a luminescent concentrator. This paper reports an extensive study of the performance in close relation to the spectroscopic properties of this crystal. It gives the reasons why the Ce:LYSO crystal tested in this study is less efficient than Ce:YAG for luminescent concentration: limited quantum efficiency and high losses coming from self-absorption and from excited-state absorption are playing key roles. However, we demonstrate that a Ce:LYSO luminescent concentrator is an innovative source for solid-state lighting. Pumped by a peak power of 3400 W in quasi-continuous wave regime (40 µs, 10 Hz), a rectangular (1 × 22 × 105 mm3) Ce:LYSO crystal delivers a broadband spectrum (60 nm FWHM) centered at 430 nm. At full output aperture (20 × 1 mm2), it emits a peak power of 116 W. On a squared output surface (1 × 1 mm2) it emits 16 W corresponding to a brightness of 509 W cm-2 sr-1. This combination of spectrum power and brightness is higher than blue LEDs and opens perspectives for Ce:LYSO in the field of illumination namely for imaging.
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Affiliation(s)
- Lisa Lopez
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France.
| | - Pierre Pichon
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France
| | - Pascal Loiseau
- Université PSL, Chimie ParisTech, CNRS, Institut de Recherche de Chimie Paris, 75005, Paris, France
| | - Bruno Viana
- Université PSL, Chimie ParisTech, CNRS, Institut de Recherche de Chimie Paris, 75005, Paris, France
| | - Rachid Mahiou
- Université Clermont Auvergne, CNRS, Clermont Auvergne INP, ICCF, 63000, Clermont-Ferrand, France
| | - Frederic Druon
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France
| | - Patrick Georges
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France
| | - François Balembois
- Université Paris-Saclay, Institut d'Optique Graduate School, CNRS, Laboratoire Charles Fabry, 91127, Palaiseau, France
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Wang Z, Yang F, Zhang W, Xiong K, Yang S. Towards in vivo photoacoustic human imaging: shining a new light on clinical diagnostics. FUNDAMENTAL RESEARCH 2023. [DOI: 10.1016/j.fmre.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
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9
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Van Heumen S, Riksen JJ, Singh MKA, Van Soest G, Vasilic D. LED-based photoacoustic imaging for preoperative visualization of lymphatic vessels in patients with secondary limb lymphedema. PHOTOACOUSTICS 2023; 29:100446. [PMID: 36632606 PMCID: PMC9826814 DOI: 10.1016/j.pacs.2022.100446] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/16/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
Lymphedema is the accumulation of protein-rich fluid in the interstitium (i.e., dermal backflow (DBF)). Preoperative imaging of the lymphatic vessels is a prerequisite for lymphovenous bypass surgical planning. We investigated the visualization of lymphatic vessels and veins using light-emitting diode (LED)-based photoacoustic imaging (PAI). Indocyanine-green mediated near-infrared fluorescence lymphography (NIRF-L) was done in fifteen patients with secondary limb lymphedema. Photoacoustic images were acquired in locations where lymphatic vessels and DBF were observed with NIRF-L. We demonstrated that LED-based PAI can visualize and differentiate lymphatic vessels and veins even in the presence of DBF. We observed lymphatic and blood vessels up to depths of 8.3 and 8.6 mm, respectively. Superficial lymphatic vessels and veins can be visualized using LED-based PAI even in the presence of DBF showing the potential for pre-operative assessment. Further development of the technique is needed to improve its usability in clinical settings.
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Affiliation(s)
- Saskia Van Heumen
- Department of Plastic and Reconstructive Surgery, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
- Department of Cardiology, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
| | - Jonas J.M. Riksen
- Department of Cardiology, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
| | | | - Gijs Van Soest
- Department of Cardiology, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
| | - Dalibor Vasilic
- Department of Plastic and Reconstructive Surgery, Erasmus MC, University Medical Center, Rotterdam, the Netherlands
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Shi M, Vercauteren T, Xia W. Spatiotemporal singular value decomposition for denoising in photoacoustic imaging with a low-energy excitation light source. BIOMEDICAL OPTICS EXPRESS 2022; 13:6416-6430. [PMID: 36589568 PMCID: PMC9774869 DOI: 10.1364/boe.471198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 05/12/2023]
Abstract
Photoacoustic (PA) imaging is an emerging hybrid imaging modality that combines rich optical spectroscopic contrast and high ultrasonic resolution, and thus holds tremendous promise for a wide range of pre-clinical and clinical applications. Compact and affordable light sources such as light-emitting diodes (LEDs) and laser diodes (LDs) are promising alternatives to bulky and expensive solid-state laser systems that are commonly used as PA light sources. These could accelerate the clinical translation of PA technology. However, PA signals generated with these light sources are readily degraded by noise due to the low optical fluence, leading to decreased signal-to-noise ratio (SNR) in PA images. In this work, a spatiotemporal singular value decomposition (SVD) based PA denoising method was investigated for these light sources that usually have low fluence and high repetition rates. The proposed method leverages both spatial and temporal correlations between radiofrequency (RF) data frames. Validation was performed on simulations and in vivo PA data acquired from human fingers (2D) and forearm (3D) using a LED-based system. Spatiotemporal SVD greatly enhanced the PA signals of blood vessels corrupted by noise while preserving a high temporal resolution to slow motions, improving the SNR of in vivo PA images by 90.3%, 56.0%, and 187.4% compared to single frame-based wavelet denoising, averaging across 200 frames, and single frame without denoising, respectively. With a fast processing time of SVD (∼50 µs per frame), the proposed method is well suited to PA imaging systems with low-energy excitation light sources for real-time in vivo applications.
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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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Rajasekar B, Nirmala P, Bhuvaneswari P, Radhika R, Asha S, Kavitha KR, Belay SS. A Feasible Multimodal Photoacoustic Imaging Approach for Evaluating the Clinical Symptoms of Inflammatory Arthritis. BIOMED RESEARCH INTERNATIONAL 2022; 2022:7358575. [PMID: 36046441 PMCID: PMC9420593 DOI: 10.1155/2022/7358575] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/27/2022] [Accepted: 08/09/2022] [Indexed: 12/03/2022]
Abstract
Numerous traditional medical imaging methods, including computed tomography with X-rays, positron emission tomography (PET), and magnetic resonance imaging (MRI), are utilized frequently in medical settings to screen for illnesses, diagnose patients, and track the effectiveness of treatments. When examining bone protrusions, CT is preferred over MRI for scanning connective tissue. Although the picture quality of PET is inferior to that of CT and MR, it is outstanding for detecting the molecular markers and metabolic functions of illnesses. To give high-resolution structural pictures and improved ailment sensitivity and specificity within another image, multimodal data and substantial therapeutic influence on advanced diagnostics and therapeutics have been used. The goal was to evaluate the clinical significance of multimodal photoacoustic/ultrasound (PA/US) articular imaging scoring, a cutting-edge image technique that may show the microvessels and oxygen levels of rheumatoid arthritis-related inflamed joints (RA). The PA/US imaging technology analyzed seven tiny joints. The PA and power Doppler (PD) impulses were semiquantified using a 0-3 grading scale, and the averages of the PA and PD scores for the seven joints are computed. Three PA+SO2 types were found determined by the relative oxygen levels (SO2) measurements of the affected joints. Researchers evaluated the relationships between the disease activity ratings and the PA/US imaging ratings. The PA scores and medical ratings that reflect the extent of the pain have strong relationships with each other, as do the PA+SO2 combinations. PA may be clinically useful in assessing RA. Thus, the research evaluated the clinical symptoms of inflammatory arthritis using a multimodal photoacoustic image process.
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Affiliation(s)
- B. Rajasekar
- Department of Electronics and Communication Engineering, Sathyabama Institute of Science and Technology, Chennai, 600119 Tamil Nadu, India
| | - P. Nirmala
- Department of Electronics and Communication Engineering, Saveetha School of Engineering, SIMATS, Chennai, 602 105 Tamil Nadu, India
| | - P. Bhuvaneswari
- Department of Electronics and Communication Engineering, Sri Venkateswara College of Engineering and Technology, Chittoor, Andhra Pradesh 517127, India
| | - R. Radhika
- Department of Electronics and Communication Engineering, S.A Engineering College, Chennai, 600077 Tamil Nadu, India
| | - S. Asha
- Department of Electronics and Communication Engineering, Saveetha Engineering College, Chennai, 602105 Tamil Nadu, India
| | - K. R. Kavitha
- Department of Electronics and Communication Engineering, Sona College of Technology, Salem, 636005 Tamil Nadu, India
| | - Semagn Shifere Belay
- School of Computing, Woldia Institute of Technology, Woldia University, Ethiopia
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Feng T, Ge Y, Xie Y, Xie W, Liu C, Li L, Ta D, Jiang Q, Cheng Q. Detection of collagen by multi-wavelength photoacoustic analysis as a biomarker for bone health assessment. PHOTOACOUSTICS 2021; 24:100296. [PMID: 34522607 PMCID: PMC8426564 DOI: 10.1016/j.pacs.2021.100296] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/06/2021] [Accepted: 08/24/2021] [Indexed: 05/26/2023]
Abstract
Collagen is an important biomarker of osteoporosis progression. Noninvasive, multispectral, photoacoustic (PA) techniques use pulsed laser light to induce PA signals to facilitate the visualization of chemical components that are strongly related to tissue health. In this study, the feasibility of multi-wavelength PA (MWPA) measurement of the collagen in bone, using the wavelength range of 1300-1800 nm, was investigated. First, the feasibility of this approach for detecting the collagen content of bone was demonstrated by means of numerical simulation. Then, ex vivo experiments were conducted on both animal and human bone specimens with different bone densities using the MWPA method. The relative collagen content was extracted and compared with the results of micro-computed tomography (micro-CT) and histology. The results showed that the "relative collagen content" parameter obtained using the MWPA approach correlated well with the bone volume ratio obtained from micro-CT images and histological analysis results. This study highlights the potential of the proposed PA technique for determining the collagen content of bones as a biomarker for bone health assessment.
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Affiliation(s)
- Ting Feng
- School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Yuxiang Ge
- Department of Sports Medicine and Adult Reconstructive Surgery, Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing 210008, Jiangsu, China
- Department of Orthopedic Surgery, Minhang Hospital, Fudan University, Shanghai, 201100, China
| | - Yejing Xie
- School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Weiya Xie
- Institute of Acoustics, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Chengcheng Liu
- Academy for Engineering and Technology, Fudan University, Shanghai, 200433, China
| | - Lan Li
- Department of Sports Medicine and Adult Reconstructive Surgery, Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing 210008, Jiangsu, China
| | - Dean Ta
- Department of Electronic Engineering, Fudan University, Shanghai 200433, China
| | - Qing Jiang
- Department of Sports Medicine and Adult Reconstructive Surgery, Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing 210008, Jiangsu, China
| | - Qian Cheng
- Institute of Acoustics, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
- The Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration, Ministry of Education, Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China
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14
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Orfanakis M, Tserevelakis GJ, Zacharakis G. A Cost-Efficient Multiwavelength LED-Based System for Quantitative Photoacoustic Measurements. SENSORS 2021; 21:s21144888. [PMID: 34300627 PMCID: PMC8309896 DOI: 10.3390/s21144888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/30/2021] [Accepted: 07/15/2021] [Indexed: 01/13/2023]
Abstract
The unique ability of photoacoustic (PA) sensing to provide optical absorption information of biomolecules deep inside turbid tissues with high sensitivity has recently enabled the development of various novel diagnostic systems for biomedical applications. In many cases, PA setups can be bulky, complex, and costly, as they typically require the integration of expensive Q-switched nanosecond lasers, and also presents limited wavelength availability. This article presents a compact, cost-efficient, multiwavelength PA sensing system for quantitative measurements, by utilizing two high-power LED sources emitting at central wavelengths of 444 and 628 nm, respectively, and a single-element ultrasonic transducer at 3.5 MHz for signal detection. We investigate the performance of LEDs in pulsed mode and explore the dependence of PA responses on absorber's concentration and applied energy fluence using tissue-mimicking phantoms demonstrating both optical absorption and scattering properties. Finally, we apply the developed system on the spectral unmixing of two absorbers contained at various relative concentrations in the phantoms, to provide accurate estimations with absolute deviations ranging between 0.4 and 12.3%. An upgraded version of the PA system may provide valuable in-vivo multiparametric measurements of important biomarkers, such as hemoglobin oxygenation, melanin concentration, local lipid content, and glucose levels.
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Affiliation(s)
- Michalis Orfanakis
- Foundation for Research and Technology Hellas, Institute of Electronic Structure and Laser, N. Plastira 100, GR-70013 Heraklion, Greece; (M.O.); (G.J.T.)
- School of Medicine, University of Crete, GR-71003 Heraklion, Greece
| | - George J. Tserevelakis
- Foundation for Research and Technology Hellas, Institute of Electronic Structure and Laser, N. Plastira 100, GR-70013 Heraklion, Greece; (M.O.); (G.J.T.)
| | - Giannis Zacharakis
- Foundation for Research and Technology Hellas, Institute of Electronic Structure and Laser, N. Plastira 100, GR-70013 Heraklion, Greece; (M.O.); (G.J.T.)
- Correspondence:
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15
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Hassan HW, Grasso V, Korostynska O, Khan H, Jose J, Mirtaheri P. An overview of assessment tools for determination of biological Magnesium implant degradation. Med Eng Phys 2021; 93:49-58. [PMID: 34154775 DOI: 10.1016/j.medengphy.2021.05.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 04/22/2021] [Accepted: 05/19/2021] [Indexed: 12/14/2022]
Abstract
Medical implants made of biodegradable materials are advantageous for short-term applications as fracture fixation and mechanical support during bone healing. After completing the healing process, the implant biodegrades without any long-term side effects nor any need for surgical removal. In particular, Magnesium (Mg) implants, while degrading, can cause physiological changes in the tissues surrounding the implant. The evaluation of structural remodeling is relevant, however, the functional assessment is crucial to provide information about physiological changes in tissues, which can be applied as an early marker during the healing process. Hence, non-invasive monitoring of structural and functional changes in the surrounding tissue during the healing process is essential, and the need for new assessing methods is emerging. This paper provides an assessment of Mg based implants, and an extensive review of the literature is presented with the focus on the imaging techniques for investigation of the Mg implants' biodegradation. The potential of a hybrid analysis, including Near-Infrared Spectroscopy (NIRS) and photoacoustic imaging (PAI) technology, is further discussed. A hybrid solution may play a significant role in monitoring implants and have several advantages for monitoring tissue oxygenation in addition to tissue's acidity, which is directly connected to the Mg implants degradation process. Such a hybrid assessment system can be a simple, ambulant, and less costly technology with the potential for clinically monitoring of Mg implants at site.
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Affiliation(s)
- Hafiz Wajahat Hassan
- Oslo Metropolitan University, Faculty of Technology, Art and Design, Department of Mechanical, Electronic and Chemical Engineering, Oslo, Norway
| | | | - Olga Korostynska
- Oslo Metropolitan University, Faculty of Technology, Art and Design, Department of Mechanical, Electronic and Chemical Engineering, Oslo, Norway
| | - Haroon Khan
- Oslo Metropolitan University, Faculty of Technology, Art and Design, Department of Mechanical, Electronic and Chemical Engineering, Oslo, Norway
| | - Jithin Jose
- FUJIFILM VisualSonics, Amsterdam, The Netherlands
| | - Peyman Mirtaheri
- Oslo Metropolitan University, Faculty of Technology, Art and Design, Department of Mechanical, Electronic and Chemical Engineering, Oslo, Norway.
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16
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In Vivo Assessment of Hypoxia Levels in Pancreatic Tumors Using a Dual-Modality Ultrasound/Photoacoustic Imaging System. MICROMACHINES 2021; 12:mi12060668. [PMID: 34200388 PMCID: PMC8229757 DOI: 10.3390/mi12060668] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 12/12/2022]
Abstract
Noninvasive anatomical and functional imaging has become an essential tool to evaluate tissue oxygen saturation dynamics in preclinical or clinical studies of hypoxia. Our dual-wavelength technique for photoacoustic (PA) imaging based on the differential absorbance spectrum of oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb) can quantify tissue oxygen saturation using the intrinsic contrast property. PA imaging of tissue oxygen saturation can be used to monitor tumor-related hypoxia, which is a particularly relevant functional parameter of the tumor microenvironment that has a strong influence on tumor aggressiveness. The simultaneous acquisition of anatomical and functional information using dual-modality ultrasound (US) and PA imaging technology enhances the preclinical applicability of the method. Here, the developed dual-modality US/PA system was used to measure relative tissue oxygenation using the dual-wavelength technique. Tissue oxygen saturation was quantified in a pancreatic tumor mouse model. The differences in tissue oxygenation were detected by comparing pancreatic samples from normal and tumor-bearing mice at various time points after implantation. The use of an in vivo pancreatic tumor model revealed changes in hypoxia at various stages of tumor growth. The US/PA imaging data positively correlated with the results of immunohistochemical staining for hypoxia. Thus, our dual-modality US/PA imaging system can be used to reliably assess and monitor hypoxia in pancreatic tumor mouse models. These findings enable the use of a combination of US and PA imaging to acquire anatomical and functional information on tumor growth and to evaluate treatment responses in longitudinal preclinical studies.
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17
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Yao J, Wang LV. Perspective on fast-evolving photoacoustic tomography. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-210105-PERR. [PMID: 34196136 PMCID: PMC8244998 DOI: 10.1117/1.jbo.26.6.060602] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 06/17/2021] [Indexed: 05/19/2023]
Abstract
SIGNIFICANCE Acoustically detecting the rich optical absorption contrast in biological tissues, photoacoustic tomography (PAT) seamlessly bridges the functional and molecular sensitivity of optical excitation with the deep penetration and high scalability of ultrasound detection. As a result of continuous technological innovations and commercial development, PAT has been playing an increasingly important role in life sciences and patient care, including functional brain imaging, smart drug delivery, early cancer diagnosis, and interventional therapy guidance. AIM Built on our 2016 tutorial article that focused on the principles and implementations of PAT, this perspective aims to provide an update on the exciting technical advances in PAT. APPROACH This perspective focuses on the recent PAT innovations in volumetric deep-tissue imaging, high-speed wide-field microscopic imaging, high-sensitivity optical ultrasound detection, and machine-learning enhanced image reconstruction and data processing. Representative applications are introduced to demonstrate these enabling technical breakthroughs in biomedical research. CONCLUSIONS We conclude the perspective by discussing the future development of PAT technologies.
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Affiliation(s)
- Junjie Yao
- Duke University, Department of Biomedical Engineering, Durham, North Carolina, United States
| | - Lihong V. Wang
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Department of Electrical Engineering, Pasadena, California, United States
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18
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Biomedical Photoacoustic Imaging and Sensing Using Affordable Resources. SENSORS 2021; 21:s21072572. [PMID: 33917611 PMCID: PMC8038837 DOI: 10.3390/s21072572] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 04/02/2021] [Indexed: 12/20/2022]
Abstract
The photoacoustic (PA) effect, also called the optoacoustic effect, was discovered in the 1880s by Alexander Graham Bell and has been utilized for biomedical imaging and sensing applications since the early 1990s [...].
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19
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Huang Q, Garrett A, Bose S, Blocker S, Rios AC, Clevers H, Shen X. The frontier of live tissue imaging across space and time. Cell Stem Cell 2021; 28:603-622. [PMID: 33798422 PMCID: PMC8034393 DOI: 10.1016/j.stem.2021.02.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
What you see is what you get-imaging techniques have long been essential for visualization and understanding of tissue development, homeostasis, and regeneration, which are driven by stem cell self-renewal and differentiation. Advances in molecular and tissue modeling techniques in the last decade are providing new imaging modalities to explore tissue heterogeneity and plasticity. Here we describe current state-of-the-art imaging modalities for tissue research at multiple scales, with a focus on explaining key tradeoffs such as spatial resolution, penetration depth, capture time/frequency, and moieties. We explore emerging tissue modeling and molecular tools that improve resolution, specificity, and throughput.
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Affiliation(s)
- Qiang Huang
- Department of Pediatric Surgery, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710004 Shaanxi, China; Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA
| | - Aliesha Garrett
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA
| | - Shree Bose
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA
| | - Stephanie Blocker
- Center for In Vitro Microscopy, Duke University, Durham, NC 27708, USA
| | - Anne C Rios
- Princess Máxima Center for Pediatric Oncology, Utrecht 3584, the Netherlands; Department of Cancer Research, Oncode Institute, Hubrecht Institute-KNAW Utrecht, Utrecht 3584, the Netherlands
| | - Hans Clevers
- Princess Máxima Center for Pediatric Oncology, Utrecht 3584, the Netherlands; Department of Cancer Research, Oncode Institute, Hubrecht Institute-KNAW Utrecht, Utrecht 3584, the Netherlands; Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and University Medical Center (UMC) Utrecht, Utrecht 3584, the Netherlands
| | - Xiling Shen
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA.
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20
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Thomas A, Paul S, Mitra J, Singh MS. Enhancement of Photoacoustic Signal Strength with Continuous Wave Optical Pre-Illumination: A Non-Invasive Technique. SENSORS (BASEL, SWITZERLAND) 2021; 21:1190. [PMID: 33567650 PMCID: PMC7914629 DOI: 10.3390/s21041190] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 11/16/2022]
Abstract
Use of portable and affordable pulse light sources (light emitting diodes (LED) and laser diodes) for tissue illumination offers an opportunity to accelerate the clinical translation of photoacoustic imaging (PAI) technology. However, imaging depth in this case is limited because of low output (optical) power of these light sources. In this work, we developed a noninvasive technique for enhancing strength (amplitude) of photoacoustic (PA) signal. This is a photothermal-based technique in which a continuous wave (CW) optical beam, in addition to short-pulse ~ nsec laser beam, is employed to irradiate and, thus, raise the temperature of sample material selectively over a pre-specified region of interest (we call the process as pre-illumination). The increase in temperature, in turn enhances the PA-signal strength. Experiments were conducted in methylene blue, which is one of the commonly used contrast agents in laboratory research studies, to validate change in temperature and subsequent enhancement of PA-signal strength for the following cases: (1) concentration or optical absorption coefficient of sample, (2) optical power of CW-optical beam, and (3) time duration of pre-illumination. A theoretical hypothesis, being validated by numerical simulation, is presented. To validate the proposed technique for clinical and/or pre-clinical applications (diagnosis and treatments of cancer, pressure ulcers, and minimally invasive procedures including vascular access and fetal surgery), experiments were conducted in tissue-mimicking Agar phantom and ex-vivo animal tissue (chicken breast). Results demonstrate that pre-illumination significantly enhances PA-signal strength (up to ~70% (methylene blue), ~48% (Agar phantom), and ~40% (chicken tissue)). The proposed technique addresses one of the primary challenges in the clinical translation of LED-based PAI systems (more specifically, to obtain a detectable PA-signal from deep-seated tissue targets).
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Affiliation(s)
- Anjali Thomas
- Biomedical Instrumentation and Imaging Laboratory (BIIL), School of Physics (SoP), Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Thiruvananthapuram 695551, India; (A.T.); (S.P.)
| | - Souradip Paul
- Biomedical Instrumentation and Imaging Laboratory (BIIL), School of Physics (SoP), Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Thiruvananthapuram 695551, India; (A.T.); (S.P.)
| | - Joy Mitra
- Scanning Probe Microscopy and Plasmonics Lab, School of Physics (SoP), Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Thiruvananthapuram 695551, India;
| | - Mayanglambam Suheshkumar Singh
- Biomedical Instrumentation and Imaging Laboratory (BIIL), School of Physics (SoP), Indian Institute of Science Education and Research Thiruvananthapuram (IISER-TVM), Thiruvananthapuram 695551, India; (A.T.); (S.P.)
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21
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Abstract
Lymphedema occurs when interstitial fluid and fibroadipose tissues accumulate abnormally because of decreased drainage of lymphatic fluid as a result of injury, infection, or congenital abnormalities of the lymphatic system drainage pathway. An accurate anatomical map of the lymphatic vasculature is needed not only for understanding the pathophysiology of lymphedema but also for surgical planning. However, because of their limited spatial resolution, no imaging modalities are currently able to noninvasively provide a clear visualization of the lymphatic vessels. Photoacoustic imaging is an emerging medical imaging technique that provides unique scalability of optical resolution and acoustic depth of penetration. Moreover, light-absorbing biomolecules, including oxy- and deoxyhemoglobin, lipids, water, and melanin, can be imaged. Using exogenous contrast agents that are taken up by lymphatic vessels, e.g., indocyanine green, photoacoustic lymphangiography, which has a higher spatial resolution than previous imaging modalities, is possible. Using a new prototype of a photoacoustic imaging system with a wide field of view developed by a Japanese research group, high-resolution three-dimensional structural information of the vasculatures was successfully obtained over a large area in both healthy and lymphedematous extremities. Anatomical information on the lymphatic vessels and adjacent veins provided by photoacoustic lymphangiography is helpful for the management of lymphedema. In particular, such knowledge will facilitate the planning of microsurgical lymphaticovenular anastomoses to bypass the excess fluid component by joining with the circulatory system peripherally. Although challenges remain to establish its implementation in clinical practice, photoacoustic lymphangiography may contribute to improved treatments for lymphedema patients in the near future.
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22
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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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23
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Oxygen Saturation Imaging Using LED-Based Photoacoustic System. SENSORS 2021; 21:s21010283. [PMID: 33406653 PMCID: PMC7795655 DOI: 10.3390/s21010283] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 12/31/2020] [Accepted: 01/01/2021] [Indexed: 12/31/2022]
Abstract
Oxygen saturation imaging has potential in several preclinical and clinical applications. Dual-wavelength LED array-based photoacoustic oxygen saturation imaging can be an affordable solution in this case. For the translation of this technology, there is a need to improve its accuracy and validate it against ground truth methods. We propose a fluence compensated oxygen saturation imaging method, utilizing structural information from the ultrasound image, and prior knowledge of the optical properties of the tissue with a Monte-Carlo based light propagation model for the dual-wavelength LED array configuration. We then validate the proposed method with oximeter measurements in tissue-mimicking phantoms. Further, we demonstrate in vivo imaging on small animal and a human subject. We conclude that the proposed oxygen saturation imaging can be used to image tissue at a depth of 6–8 mm in both preclinical and clinical applications.
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24
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Kuniyil Ajith Singh M, Xia W. Portable and Affordable Light Source-Based Photoacoustic Tomography. SENSORS (BASEL, SWITZERLAND) 2020; 20:E6173. [PMID: 33138296 PMCID: PMC7663770 DOI: 10.3390/s20216173] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/27/2022]
Abstract
Photoacoustic imaging is a hybrid imaging modality that offers the advantages of optical (spectroscopic contrast) and ultrasound imaging (scalable spatial resolution and imaging depth). This promising modality has shown excellent potential in a wide range of preclinical and clinical imaging and sensing applications. Even though photoacoustic imaging technology has matured in research settings, its clinical translation is not happening at the expected pace. One of the main reasons for this is the requirement of bulky and expensive pulsed lasers for excitation. To accelerate the clinical translation of photoacoustic imaging and explore its potential in resource-limited settings, it is of paramount importance to develop portable and affordable light sources that can be used as the excitation light source. In this review, we focus on the following aspects: (1) the basic theory of photoacoustic imaging; (2) inexpensive light sources and different implementations; and (3) important preclinical and clinical applications, demonstrated using affordable light source-based photoacoustics. The main focus will be on laser diodes and light-emitting diodes as they have demonstrated promise in photoacoustic tomography-the key technological developments in these areas will be thoroughly reviewed. We believe that this review will be a useful opus for both the beginners and experts in the field of biomedical photoacoustic imaging.
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Affiliation(s)
- Mithun Kuniyil Ajith Singh
- Research and Business Development Division, CYBERDYNE INC., Stationsplein 45, A4.004, 3013 AK Rotterdam, The Netherlands;
| | - Wenfeng Xia
- School of Biomedical Engineering& Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, UK
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25
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Xavierselvan M, Singh MKA, Mallidi S. In Vivo Tumor Vascular Imaging with Light Emitting Diode-Based Photoacoustic Imaging System. SENSORS (BASEL, SWITZERLAND) 2020; 20:E4503. [PMID: 32806575 PMCID: PMC7472236 DOI: 10.3390/s20164503] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/07/2020] [Accepted: 08/08/2020] [Indexed: 12/13/2022]
Abstract
Photoacoustic (PA) imaging has shown tremendous promise for imaging tumor vasculature and its function at deeper penetration depths without the use of exogenous contrast agents. Traditional PA imaging systems employ expensive and bulky class IV lasers with low pulse repetition rate, due to which its availability for preclinical cancer research is hampered. In this study, we evaluated the capability of a Light-Emitting Diode (LED)-based PA and ultrasound (US) imaging system for monitoring heterogeneous microvasculature in tumors (up to 10 mm in depth) and quantitatively compared the PA images with gold standard histology images. We used a combination of a 7 MHz linear array US transducer and 850 nm excitation wavelength LED arrays to image blood vessels in a subcutaneous tumor model. After imaging, the tumors were sectioned and stained for endothelial cells to correlate with PA images across similar cross-sections. Analysis of 30 regions of interest in tumors from different mice showed a statistically significant R-value of 0.84 where the areas with high blood vessel density had high PA response while low blood vessel density regions had low PA response. Our results confirm that LED-based PA and US imaging can provide 2D and 3D images of tumor vasculature and the potential it has as a valuable tool for preclinical cancer research.
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Affiliation(s)
- Marvin Xavierselvan
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA;
| | - Mithun Kuniyil Ajith Singh
- Research & Business Development Division, Cyberdyne INC, Cambridge Innovation Center, 3013 Rotterdam, The Netherlands;
| | - Srivalleesha Mallidi
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA;
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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26
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Multiangle Long-Axis Lateral Illumination Photoacoustic Imaging Using Linear Array Transducer. SENSORS 2020; 20:s20144052. [PMID: 32708170 PMCID: PMC7411732 DOI: 10.3390/s20144052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/18/2020] [Accepted: 07/19/2020] [Indexed: 12/23/2022]
Abstract
Photoacoustic imaging (PAI) combines optical contrast with ultrasound spatial resolution and can be obtained up to a depth of a few centimeters. Hand-held PAI systems using linear array usually operate in reflection mode using a dark-field illumination scheme, where the optical fiber output is attached to both sides of the elevation plane (short-axis) of the transducer. More recently, bright-field strategies where the optical illumination is coaxial with acoustic detection have been proposed to overcome some limitations of the standard dark-field approach. In this paper, a novel multiangle long-axis lateral illumination is proposed. Monte Carlo simulations were conducted to evaluate light delivery for three different illumination schemes: bright-field, standard dark-field, and long-axis lateral illumination. Long-axis lateral illumination showed remarkable improvement in light delivery for targets with a width smaller than the transducer lateral dimension. A prototype was developed to experimentally demonstrate the feasibility of the proposed approach. In this device, the fiber bundle terminal ends are attached to both sides of the transducer’s long-axis and the illumination angle of each fiber bundle can be independently controlled. The final PA image is obtained by the coherent sum of subframes acquired using different angles. The prototype was experimentally evaluated by taking images from a phantom, a mouse abdomen, forearm, and index finger of a volunteer. The system provided light delivery enhancement taking advantage of the geometry of the target, achieving sufficient signal-to-noise ratio at clinically relevant depths.
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27
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Kuriakose M, Nguyen CD, Kuniyil Ajith Singh M, Mallidi S. Optimizing Irradiation Geometry in LED-Based Photoacoustic Imaging with 3D Printed Flexible and Modular Light Delivery System. SENSORS 2020; 20:s20133789. [PMID: 32640683 PMCID: PMC7374354 DOI: 10.3390/s20133789] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 01/04/2023]
Abstract
Photoacoustic (PA) imaging–a technique combining the ability of optical imaging to probe functional properties of the tissue and deep structural imaging ability of ultrasound–has gained significant popularity in the past two decades for its utility in several biomedical applications. More recently, light-emitting diodes (LED) are being explored as an alternative to bulky and expensive laser systems used in PA imaging for their portability and low-cost. Due to the large beam divergence of LEDs compared to traditional laser beams, it is imperative to quantify the angular dependence of LED-based illumination and optimize its performance for imaging superficial or deep-seated lesions. A custom-built modular 3-D printed hinge system and tissue-mimicking phantoms with various absorption and scattering properties were used in this study to quantify the angular dependence of LED-based illumination. We also experimentally calculated the source divergence of the pulsed-LED arrays to be 58° ± 8°. Our results from point sources (pencil lead phantom) in non-scattering medium obey the cotangential relationship between the angle of irradiation and maximum PA intensity obtained at various imaging depths, as expected. Strong dependence on the angle of illumination at superficial depths (−5°/mm at 10 mm) was observed that becomes weaker at intermediate depths (−2.5°/mm at 20 mm) and negligible at deeper locations (−1.1°/mm at 30 mm). The results from the tissue-mimicking phantom in scattering media indicate that angles between 30–75° could be used for imaging lesions at various depths (12 mm–28 mm) where lower LED illumination angles (closer to being parallel to the imaging plane) are preferable for deep tissue imaging and superficial lesion imaging is possible with higher LED illumination angles (closer to being perpendicular to the imaging plane). Our results can serve as a priori knowledge for the future LED-based PA system designs employed for both preclinical and clinical applications.
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Affiliation(s)
- Maju Kuriakose
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA; (M.K.); (C.D.N.)
| | - Christopher D. Nguyen
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA; (M.K.); (C.D.N.)
| | | | - Srivalleesha Mallidi
- Department of Biomedical Engineering, Tufts University, Medford, MA 02155, USA; (M.K.); (C.D.N.)
- Correspondence:
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Tomographic Ultrasound and LED-Based Photoacoustic System for Preclinical Imaging. SENSORS 2020; 20:s20102793. [PMID: 32422995 PMCID: PMC7294432 DOI: 10.3390/s20102793] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 01/19/2023]
Abstract
Small animals are widely used as disease models in medical research. Noninvasive imaging modalities with functional capability play an important role in studying the disease state and treatment progress. Photoacoustics, being a noninvasive and functional modality, has the potential for small-animal imaging. However, the conventional photoacoustic tomographic systems use pulsed lasers, making it expensive, bulky, and require long acquisition time. In this work, we propose the use of photoacoustic and ultrasound tomographic imaging with LEDs as the light source and acoustic detection using a linear transducer array. We have demonstrated full-view tomographic imaging of a euthanized mouse and a potential application in liver fibrosis research.
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