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Varadarajan D, Magnain C, Fogarty M, Boas DA, Fischl B, Wang H. A novel algorithm for multiplicative speckle noise reduction in ex vivo human brain OCT images. Neuroimage 2022; 257:119304. [PMID: 35568350 PMCID: PMC10018743 DOI: 10.1016/j.neuroimage.2022.119304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 10/18/2022] Open
Abstract
Optical coherence tomography (OCT) images of ex vivo human brain tissue are corrupted by multiplicative speckle noise that degrades the contrast to noise ratio (CNR) of microstructural compartments. This work proposes a novel algorithm to reduce noise corruption in OCT images that minimizes the penalized negative log likelihood of gamma distributed speckle noise. The proposed method is formulated as a majorize-minimize problem that reduces to solving an iterative regularized least squares optimization. We demonstrate the usefulness of the proposed method by removing speckle in simulated data, phantom data and real OCT images of human brain tissue. We compare the proposed method with state of the art filtering and non-local means based denoising methods. We demonstrate that our approach removes speckle accurately, improves CNR between different tissue types and better preserves small features and edges in human brain tissue.
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Affiliation(s)
- Divya Varadarajan
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA; Radiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Caroline Magnain
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA; Radiology, Harvard Medical School, Boston, MA 02115, USA
| | - Morgan Fogarty
- Imaging Science Program, Washington University McKelvey School of Engineering, St. Louis, MO 63130, USA; Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David A Boas
- Biomedical Engineering and Electrical and Computer Engineering, Boston University, Boston, MA 02215, USA
| | - Bruce Fischl
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA; Radiology, Harvard Medical School, Boston, MA 02115, USA; Harvard-MIT Health Science and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hui Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA; Radiology, Harvard Medical School, Boston, MA 02115, USA
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2
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Sommersperger M, Martin-Gomez A, Mach K, Gehlbach PL, Ali Nasseri M, Iordachita I, Navab N. Surgical scene generation and adversarial networks for physics-based iOCT synthesis. BIOMEDICAL OPTICS EXPRESS 2022; 13:2414-2430. [PMID: 35519277 PMCID: PMC9045909 DOI: 10.1364/boe.454286] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/17/2022] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
The development and integration of intraoperative optical coherence tomography (iOCT) into modern operating rooms has motivated novel procedures directed at improving the outcome of ophthalmic surgeries. Although computer-assisted algorithms could further advance such interventions, the limited availability and accessibility of iOCT systems constrains the generation of dedicated data sets. This paper introduces a novel framework combining a virtual setup and deep learning algorithms to generate synthetic iOCT data in a simulated environment. The virtual setup reproduces the geometry of retinal layers extracted from real data and allows the integration of virtual microsurgical instrument models. Our scene rendering approach extracts information from the environment and considers iOCT typical imaging artifacts to generate cross-sectional label maps, which in turn are used to synthesize iOCT B-scans via a generative adversarial network. In our experiments we investigate the similarity between real and synthetic images, show the relevance of using the generated data for image-guided interventions and demonstrate the potential of 3D iOCT data synthesis.
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Affiliation(s)
- Michael Sommersperger
- Chair for Computer Aided Medical Procedures and Augmented Reality, Informatics Department, Technical University of Munich, Munich, Bayern, Germany
- These authors contributed equally to this work
| | - Alejandro Martin-Gomez
- Chair for Computer Aided Medical Procedures and Augmented Reality, Informatics Department, Technical University of Munich, Munich, Bayern, Germany
- Laboratory for Computational Sensing and Robotics, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland, USA
- These authors contributed equally to this work
| | - Kristina Mach
- Chair for Computer Aided Medical Procedures and Augmented Reality, Informatics Department, Technical University of Munich, Munich, Bayern, Germany
| | - Peter Louis Gehlbach
- Wilmer Eye Institute Research, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - M Ali Nasseri
- Klinikum Rechts der Isar, Augenklinik, Munich, Bayern, Germany
| | - Iulian Iordachita
- Laboratory for Computational Sensing and Robotics, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Nassir Navab
- Chair for Computer Aided Medical Procedures and Augmented Reality, Informatics Department, Technical University of Munich, Munich, Bayern, Germany
- Laboratory for Computational Sensing and Robotics, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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Tan JL, Djayakarsana D, Wang H, Chan RW, Bailey C, Lau AZ. Deuterium MRS of early treatment-induced changes in tumour lactate in vitro. NMR IN BIOMEDICINE 2021; 34:e4599. [PMID: 34405471 DOI: 10.1002/nbm.4599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/20/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
Elevated production of lactate is a key characteristic of aberrant tumour cell metabolism and can be non-invasively measured as an early marker of tumour response using deuterium (2 H) MRS. Following treatment, changes in the 2 H-labelled lactate signal could identify tumour cell death or impaired metabolic function, which precede morphological changes conventionally used to assess tumour response. In this work, the association between apoptotic cell death, extracellular lactate concentration, and early treatment-induced changes in the 2 H-labelled lactate signal was established in an in vitro tumour model. Experiments were conducted at 7 T on acute myeloid leukaemia (AML) cells, which had been treated with 10 μg/mL of the chemotherapeutic agent cisplatin. At 24 and 48 h after cisplatin treatment the cells were supplied with 20 mM of [6,6'-2 H2 ]glucose and scanned over 2 h using a two-dimensional 2 H MR spectroscopic imaging sequence. The resulting signals from 2 H-labelled glucose, lactate, and water were quantified using a spectral fitting algorithm implemented on the Oxford Spectroscopy Analysis MATLAB toolbox. After scanning, the cells were processed for histological stains (terminal deoxynucleotidyl transferase UTP nick end labelling and haematoxylin and eosin) to assess apoptotic area fraction and cell morphology respectively, while a colorimetric assay was used to measure extracellular lactate concentrations in the supernatant. Significantly lower levels of 2 H-labelled lactate were observed in the 48 h treated cells compared with the untreated and 24 h treated cells, and these changes were significantly correlated with an increase in apoptotic fraction and a decrease in extracellular lactate. By establishing the biological processes associated with treatment-induced changes in the 2 H-labelled lactate signal, these findings suggest that 2 H MRS of lactate may be valuable in evaluating early tumour response.
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Affiliation(s)
- Josephine L Tan
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada
| | - Daniel Djayakarsana
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada
| | - Hanzhi Wang
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada
| | - Rachel W Chan
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada
| | - Colleen Bailey
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada
- Department of Physics, Ryerson University, Toronto, Canada
| | - Angus Z Lau
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Canada
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Demidov V, Demidova N, Pires L, Demidova O, Flueraru C, Wilson BC, Alex Vitkin I. Volumetric tumor delineation and assessment of its early response to radiotherapy with optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2021; 12:2952-2967. [PMID: 34123510 PMCID: PMC8176804 DOI: 10.1364/boe.424045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/05/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Texture analyses of optical coherence tomography (OCT) images have shown initial promise for differentiation of normal and tumor tissues. This work develops a fully automatic volumetric tumor delineation technique employing quantitative OCT image speckle analysis based on Gamma distribution fits. We test its performance in-vivo using immunodeficient mice with dorsal skin window chambers and subcutaneously grown tumor models. Tumor boundaries detection is confirmed using epi-fluorescence microscopy, combined photoacoustic-ultrasound imaging, and histology. Pilot animal study of tumor response to radiotherapy demonstrates high accuracy, objective nature, novelty of the proposed method in the volumetric separation of tumor and normal tissues, and the sensitivity of the fitting parameters to radiation-induced tissue changes. Overall, the developed methodology enables hitherto impossible longitudinal studies for detecting subtle tissue alterations stemming from therapeutic insult.
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Affiliation(s)
- Valentin Demidov
- University of Toronto, Faculty of Medicine, Department of Medical Biophysics, 101 College St., Toronto, M5G 1L7, Canada
- University Health Network, Princess Margaret Cancer Centre, 610 University Avenue, Toronto, M5G 2M9, Canada
- Authors contributed equally to this work
| | - Natalia Demidova
- University of Toronto at Mississauga, Department of Mathematical and Computational Sciences, 3359 Mississauga Road, Mississauga, L5L1C6, Canada
- Authors contributed equally to this work
| | - Layla Pires
- University Health Network, Princess Margaret Cancer Centre, 610 University Avenue, Toronto, M5G 2M9, Canada
| | - Olga Demidova
- Seneca College, Department of Arts and Science, 1750 Finch Ave. East, Toronto, M2J 2X5, Canada
| | - Costel Flueraru
- National Research Council Canada, Information Communication Technology, 1200 Montreal Road, Ottawa, K1A 0R6, Canada
| | - Brian C. Wilson
- University of Toronto, Faculty of Medicine, Department of Medical Biophysics, 101 College St., Toronto, M5G 1L7, Canada
- University Health Network, Princess Margaret Cancer Centre, 610 University Avenue, Toronto, M5G 2M9, Canada
| | - I. Alex Vitkin
- University of Toronto, Faculty of Medicine, Department of Medical Biophysics, 101 College St., Toronto, M5G 1L7, Canada
- University Health Network, Princess Margaret Cancer Centre, 610 University Avenue, Toronto, M5G 2M9, Canada
- University of Toronto, Faculty of Medicine, Department of Radiation Oncology, 149 College Street, Toronto, M5 T 1P5, Canada
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A Miniaturized Platform for Multiplexed Drug Response Imaging in Live Tumors. Cancers (Basel) 2021; 13:cancers13040653. [PMID: 33562152 PMCID: PMC7915324 DOI: 10.3390/cancers13040653] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary We have developed an implantable microdevice that is placed into a live tumor, and can directly image how effective various chemotherapy drugs are at inducing cell death, without having to remove or process the tumor tissue. Currently drug optimization is performed by assessing tumor shrinkage after treating a patient with systemic doses of a chemotherapy agent; this only evaluates a single treatment at a time and typically takes weeks-months before an optimal treatment strategy is found (if found at all) for a specific patient. In contrast, using the technology presented here, a personalized cancer treatment strategy can potentially be optimized and tailored to a specific patient’s tumor characteristics within several hours, without requiring surgical tissue removal or prolonged trials of potentially ineffective chemotherapies. Abstract By observing the activity of anti-cancer agents directly in tumors, there is potential to greatly expand our understanding of drug response and develop more personalized cancer treatments. Implantable microdevices (IMD) have been recently developed to deliver microdoses of chemotherapeutic agents locally into confined regions of live tumors; the tissue can be subsequently removed and analyzed to evaluate drug response. This method has the potential to rapidly screen multiple drugs, but requires surgical tissue removal and only evaluates drug response at a single timepoint when the tissue is excised. Here, we describe a “lab-in-a-tumor” implantable microdevice (LIT-IMD) platform to image cell-death drug response within a live tumor, without requiring surgical resection or tissue processing. The LIT-IMD is inserted into a live tumor and delivers multiple drug microdoses into spatially discrete locations. In parallel, it locally delivers microdose levels of a fluorescent cell-death assay, which diffuses into drug-exposed tissues and accumulates at sites of cell death. An integrated miniaturized fluorescence imaging probe images each region to evaluate drug-induced cell death. We demonstrate ability to evaluate multi-drug response over 8 h using murine tumor models and show correlation with gold-standard conventional fluorescence microscopy and histopathology. This is the first demonstration of a fully integrated platform for evaluating multiple chemotherapy responses in situ. This approach could enable a more complete understanding of drug activity in live tumors, and could expand the utility of drug-response measurements to a wide range of settings where surgery is not feasible.
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Wirtzfeld LA, Berndl ESL, Czarnota GJ, Kolios MC. Monitoring Quantitative Ultrasound Parameter Changes in a Cell Pellet Model of Cell Starvation. Biophys J 2017. [PMID: 28636919 DOI: 10.1016/j.bpj.2017.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Although it has previously been shown that the spectral analysis of ultrasound backscatter data is sensitive to the cellular changes caused by apoptosis, the sensitivity of spectral analysis to oncosis or ischemic cell death had not previously been studied. Whereas many anticancer treatments induce apoptosis, others induce cell starvation, or oncosis. HT-29 colon adenocarcinoma cells were formed into pellets and covered in phosphate-buffered saline at room temperature for 56 h. The pellets were imaged every 8 h with high-frequency (55 MHz) ultrasound and the raw radio-frequency data processed. The lack of nutrients available to the cells induced cell death due to oncosis. The attenuation slope, speed of sound, spectral slope, and midband fit were estimated at each of the eight time points to identify changes as the cells died due to starvation. The spectral slope decreased monotonically over the 56 h, whereas the attenuation slope showed an increase between 1 and 48 h, followed by a slight decrease between 48 and 56 h. The midband fit did not vary over time. The speed of sound increased from 1514 to 1532 m/s over the first 24 h, after which time it plateaued. These in vitro results indicate different trends in ultrasound parameter changes from those of in vitro apoptotic cells, suggesting that these different methods of cell death can be identified not only by morphological markers, but also by specific ultrasound signatures.
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Affiliation(s)
| | | | - Gregory J Czarnota
- Departments of Radiation Oncology and Imaging Research, Sunnybrook Health Sciences Centre, and the Departments of Radiation Oncology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Michael C Kolios
- Department of Physics, Ryerson University, Toronto, Ontario, Canada.
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Jesus DA, Majewska M, Krzyżanowska-Berkowska P, Iskander DR. Influence of eye biometrics and corneal micro-structure on noncontact tonometry. PLoS One 2017; 12:e0177180. [PMID: 28472178 PMCID: PMC5417684 DOI: 10.1371/journal.pone.0177180] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/23/2017] [Indexed: 02/07/2023] Open
Abstract
Purpose Tonometry is widely used as the main screening tool supporting glaucoma diagnosis. Still, its accuracy could be improved if full knowledge about the variation of the corneal biomechanical properties was available. In this study, Optical Coherence Tomography (OCT) speckle statistics are used to infer the organisation of the corneal micro-structure and hence, to analyse its influence on intraocular pressure (IOP) measurements. Methods Fifty-six subjects were recruited for this prospective study. Macro and micro-structural corneal parameters as well as subject age were considered. Macro-structural analysis included the parameters that are associated with the ocular anatomy, such as central corneal thickness (CCT), corneal radius, axial length, anterior chamber depth and white-to-white corneal diameter. Micro-structural parameters which included OCT speckle statistics were related to the internal organisation of the corneal tissue and its physiological changes during lifetime. The corneal speckle obtained from OCT was modelled with the Generalised Gamma (GG) distribution that is characterised with a scale parameter and two shape parameters. Results In macro-structure analysis, only CCT showed a statistically significant correlation with IOP (R2 = 0.25, p<0.001). The scale parameter and the ratio of the shape parameters of GG distribution showed statistically significant correlation with IOP (R2 = 0.19, p<0.001 and R2 = 0.17, p<0.001, respectively). For the studied group, a weak, although significant correlation was found between age and IOP (R2 = 0.053, p = 0.04). Forward stepwise regression showed that CCT and the scale parameter of the Generalised Gamma distribution can be combined in a regression model (R2 = 0.39, p<0.001) to study the role of the corneal structure on IOP. Conclusions We show, for the first time, that corneal micro-structure influences the IOP measurements obtained from noncontact tonometry. OCT speckle statistics can be employed to learn about the corneal micro-structure and hence, to further calibrate the IOP measurements.
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Affiliation(s)
- Danilo A. Jesus
- Department of Biomedical Engineering, Wroclaw University of Science & Technology, Wroclaw, Poland
- * E-mail:
| | - Małgorzata Majewska
- Department of Biomedical Engineering, Wroclaw University of Science & Technology, Wroclaw, Poland
| | | | - D. Robert Iskander
- Department of Biomedical Engineering, Wroclaw University of Science & Technology, Wroclaw, Poland
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Jesus DA, Iskander DR. Assessment of corneal properties based on statistical modeling of OCT speckle. BIOMEDICAL OPTICS EXPRESS 2017; 8:162-176. [PMID: 28101409 PMCID: PMC5231290 DOI: 10.1364/boe.8.000162] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/31/2016] [Accepted: 11/02/2016] [Indexed: 05/31/2023]
Abstract
A new approach to assess the properties of the corneal micro-structure in vivo based on the statistical modeling of speckle obtained from Optical Coherence Tomography (OCT) is presented. A number of statistical models were proposed to fit the corneal speckle data obtained from OCT raw image. Short-term changes in corneal properties were studied by inducing corneal swelling whereas age-related changes were observed analyzing data of sixty-five subjects aged between twenty-four and seventy-three years. Generalized Gamma distribution has shown to be the best model, in terms of the Akaike's Information Criterion, to fit the OCT corneal speckle. Its parameters have shown statistically significant differences (Kruskal-Wallis, p < 0.001) for short and age-related corneal changes. In addition, it was observed that age-related changes influence the corneal biomechanical behaviour when corneal swelling is induced. This study shows that Generalized Gamma distribution can be utilized to modeling corneal speckle in OCT in vivo providing complementary quantified information where micro-structure of corneal tissue is of essence.
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de Bruin DM, Broekgaarden M, van Gemert MJC, Heger M, de la Rosette JJ, Van Leeuwen TG, Faber DJ. Assesment of apoptosis induced changes in scattering using optical coherence tomography. JOURNAL OF BIOPHOTONICS 2016; 9:913-923. [PMID: 26564260 DOI: 10.1002/jbio.201500198] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/28/2015] [Accepted: 10/18/2015] [Indexed: 06/05/2023]
Abstract
The aim of this study is to identify changes in scattering with optical coherence tomography (OCT) and relate these measurements with mitochondrial changes during the initiation of apoptosis. Human retinal pigment epithelial cells were cultured and apoptosis was induced using 10% alcohol. Using the attenuation coefficient and backscattering, changes were measured during cell death in a cell-pellet and monolayer respectively. To confirm apoptosis, fluorescent activated cell sorting was used. Mitochondrial activity during apoptosis was assessed using an oxidative stress assay and fluorescent confocal microscopy. Pelleted apoptotic cells measured with OCT showed a clear rise while untreated cells showed a very small increase in attenuation coefficient. Monolayered apoptotic cells displayed a distinct increase, while untreated cells showed a small increase in the backscattering. Apoptosis was confirmed by FACS experiments. Mitochondrial changes during the onset of apoptosis were also measured. The results demonstrate that apoptotic cell death could be monitored in real-time by OCT. Changes in the scattering after induction of apoptosis are likely to be related to changes in the intracellular morphology. Oxidative stress-induced mitochondrial swelling could be responsible for the initial increase, while cell blebbing and secondary necrosis subsequently for the observed decrease in scattering.
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Affiliation(s)
- Daniel M de Bruin
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands.
- Urology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands.
| | - Mans Broekgaarden
- Experimental Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Martin J C van Gemert
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Michal Heger
- Experimental Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Jean J de la Rosette
- Urology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Ton G Van Leeuwen
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
| | - Dirk J Faber
- Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, Netherlands
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Weatherbee A, Sugita M, Bizheva K, Popov I, Vitkin A. Probability density function formalism for optical coherence tomography signal analysis: a controlled phantom study. OPTICS LETTERS 2016; 41:2727-30. [PMID: 27304274 DOI: 10.1364/ol.41.002727] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The distribution of backscattered intensities as described by the probability density function (PDF) of tissue-scattered light contains information that may be useful for tissue assessment and diagnosis, including characterization of its pathology. In this Letter, we examine the PDF description of the light scattering statistics in a well characterized tissue-like particulate medium using optical coherence tomography (OCT). It is shown that for low scatterer density, the governing statistics depart considerably from a Gaussian description and follow the K distribution for both OCT amplitude and intensity. The PDF formalism is shown to be independent of the scatterer flow conditions; this is expected from theory, and suggests robustness and motion independence of the OCT amplitude (and OCT intensity) PDF metrics in the context of potential biomedical applications.
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Jesus DA, Iskander DR. Age-related changes of the corneal speckle by Optical Coherence Tomography. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:5659-62. [PMID: 26737576 DOI: 10.1109/embc.2015.7319676] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ageing of the population has several consequences for the human visual system. The corneal tissue which is responsible for two thirds of the total optical power is not an exception, suffering structural and anatomical changes with the age. In this study, we have explored the usefulness of Optical Coherence Tomography (OCT) speckle to study the age-related changes in corneal stroma. The Generalized Gamma distribution has been suggested as a model for OCT corneal speckle and was used here to investigate OCT envelope statistics in three different age groups (65 subjects in total). The scaling and the two shape parameters have shown significant statistical differences (p <; 0.05) among the age groups, showing the possibility to track the corneal changes using envelope statistics. This study shows that Generalized Gamma distribution has a great potential to fit the corneal speckle and could be a helpful complement to evaluate the structure and elastic properties of the cornea in vivo.
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Farhat G, Giles A, Kolios MC, Czarnota GJ. Optical coherence tomography spectral analysis for detecting apoptosis in vitro and in vivo. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:126001. [PMID: 26641199 DOI: 10.1117/1.jbo.20.12.126001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 11/03/2015] [Indexed: 05/16/2023]
Abstract
Apoptosis is a form of programmed cell death characterized by a series of predictable morphological changes at the subcellular level, which modify the light-scattering properties of cells. We present a spectroscopic optical coherence tomography (OCT) technique to detect changes in subcellular morphology related to apoptosis in vitro and in vivo. OCT data were acquired from acute myeloid leukemia (AML) cells treated with cisplatin over a 48-h period. The backscatter spectrum of the OCT signal acquired from the cell samples was characterized by calculating its in vitro integrated backscatter (IB) and spectral slope (SS). The IB increased with treatment duration, while the SS decreased, with the most significant changes occurring after 24 to 48 h of treatment. These changes coincided with striking morphological transformations in the cells and their nuclei. Similar trends in the spectral parameter values were observed in vivo in solid tumors grown from AML cells in mice, which were treated with chemotherapy and radiation. Our results provide a strong foundation from which future experiments may be designed to further understand the effect of cellular morphology and kinetics of apoptosis on the OCT signal and demonstrate the feasibility of using this technique in vivo.
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Affiliation(s)
- Golnaz Farhat
- University of Toronto, Department of Medical Biophysics, Faculty of Medicine, 2075 Bayview Avenue, Toronto M4N 3M5, CanadabSunnybrook Health Sciences Centre, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto M4N 3M5, CanadacSunnybrook Health Sci
| | - Anoja Giles
- Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto M4N 3M5, CanadacSunnybrook Health Sciences Centre, Radiation Oncology, 2075 Bayview Avenue, Toronto M4N 3M5, Canada
| | - Michael C Kolios
- Ryerson University, Department of Physics, 350 Victoria Street, Toronto M5B 2K3, Canada
| | - Gregory J Czarnota
- University of Toronto, Department of Medical Biophysics, Faculty of Medicine, 2075 Bayview Avenue, Toronto M4N 3M5, CanadabSunnybrook Health Sciences Centre, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto M4N 3M5, CanadacSunnybrook Health Sci
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13
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Zhao Y, Marjanovic M, Chaney EJ, Graf BW, Mahmassani Z, Boppart MD, Boppart SA. Longitudinal label-free tracking of cell death dynamics in living engineered human skin tissue with a multimodal microscope. BIOMEDICAL OPTICS EXPRESS 2014; 5:3699-716. [PMID: 25360383 PMCID: PMC4206335 DOI: 10.1364/boe.5.003699] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/03/2014] [Accepted: 09/06/2014] [Indexed: 05/04/2023]
Abstract
We demonstrate real-time, longitudinal, label-free tracking of apoptotic and necrotic cells in living tissue using a multimodal microscope. The integrated imaging platform combines multi-photon microscopy (MPM, based on two-photon excitation fluorescence), optical coherence microscopy (OCM), and fluorescence lifetime imaging microscopy (FLIM). Three-dimensional (3-D) co-registered images are captured that carry comprehensive information of the sample, including structural, molecular, and metabolic properties, based on light scattering, autofluorescence intensity, and autofluorescence lifetime, respectively. Different cell death processes, namely, apoptosis and necrosis, of keratinocytes from different epidermal layers are longitudinally monitored and investigated. Differentiation of the two cell death processes in a complex living tissue environment is enabled by quantitative image analysis and high-confidence classification processing based on the multidimensional, cross-validating imaging data. These results suggest that despite the limitations of each individual label-free modality, this multimodal imaging approach holds the promise for studies of different cell death processes in living tissue and in vivo organs.
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Affiliation(s)
- Youbo Zhao
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Marina Marjanovic
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Eric J. Chaney
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Benedikt W. Graf
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Ziad Mahmassani
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Marni D. Boppart
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Stephen A. Boppart
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Internal Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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14
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Kirillin MY, Farhat G, Sergeeva EA, Kolios MC, Vitkin A. Speckle statistics in OCT images: Monte Carlo simulations and experimental studies. OPTICS LETTERS 2014; 39:3472-5. [PMID: 24978514 DOI: 10.1364/ol.39.003472] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The speckle pattern of an optical coherence tomography (OCT) image carries potentially useful sample information that may assist in tissue characterization. Recent biomedical results in vivo indicate that the distribution of signal intensities within an OCT tissue image is well described by a log-normal-like (Gamma) function. To fully understand and exploit this finding, an OCT Monte Carlo model that accounts for speckle effects was developed. The resultant Monte Carlo speckle statistics predictions agree well with experimental OCT results from a series of control phantoms with variable scattering properties; the Gamma distribution provides a good fit to the theoretical and experimental results. The ability to quantify subresolution tissue features via OCT speckle analysis may prove useful in diagnostic photomedicine.
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15
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Portnoy S, Fichtner ND, Dziegielewski C, Stanisz MP, Stanisz GJ. In vitro detection of apoptosis using oscillating and pulsed gradient diffusion magnetic resonance imaging. NMR IN BIOMEDICINE 2014; 27:371-380. [PMID: 24421173 DOI: 10.1002/nbm.3070] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/10/2013] [Accepted: 12/11/2013] [Indexed: 06/03/2023]
Abstract
Cellular apoptosis, a common pathway towards tumor regression, is induced by many radiotherapy and chemotherapy regimens. Imaging methods that can detect apoptosis may be able to assess treatment response earlier than typical tumor volume measurements. In this paper, a wide range of diffusion experiments and a simple model of diffusion in tissues were used to probe the microstructural effects of apoptosis. Experiments were conducted on acute myeloid leukemia cell pellets, where apoptosis was induced by treatment with the chemotherapeutic agent cisplatin. Seventy-two hours following cisplatin treatment, pulsed and oscillating gradient diffusion measurements were utilized to assess effects across a broad range of structural scales. The presence of apoptosis, which was histologically confirmed by TUNEL (terminal deoxynucleotidyl transferase UTP nick end labelling) staining, significantly changed diffusion properties. To describe these changes, the data were fit to the parallel plane model, which characterizes the effects of restricted diffusion in terms of three parameters: d, the restricted size, Dfree , the intrinsic, free diffusion coefficient of the solvent, and Drest , the long time or "restricted" diffusion coefficient. Apoptotic samples exhibited significant decreases in parameters d and Dfree and a significant increase in Drest . These changes appear consistent with the established morphological effects of apoptosis. In particular, the decrease in d may be a result of the combined effects of cell shrinkage, nuclear fragmentation and membrane blebbing, the decrease in Dfree may relate to cytosolic condensation, while the increase in Drest can be attributed to increased membrane permeability and extracellular volume fraction. By non-invasively detecting apoptosis, the methods reported in this study have the potential to improve upon current MRI methods for monitoring therapeutic response. Furthermore, these methods may offer sufficient specificity to differentiate between apoptosis and other modes of cell death, such as oncosis or necrosis.
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Affiliation(s)
- S Portnoy
- Department of Imaging Research, Sunnybrook Research Institute, Toronto, Canada
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16
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Lindenmaier AA, Conroy L, Farhat G, DaCosta RS, Flueraru C, Vitkin IA. Texture analysis of optical coherence tomography speckle for characterizing biological tissues in vivo. OPTICS LETTERS 2013; 38:1280-2. [PMID: 23595458 DOI: 10.1364/ol.38.001280] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We demonstrate a method for differentiating tissue disease states using the intrinsic texture properties of speckle in optical coherence tomography (OCT) images of normal and tumor tissues obtained in vivo. This approach fits a gamma distribution function to the nonlog-compressed OCT image intensities, thus allowing differentiation of normal and tumor tissues in an ME-180 human cervical cancer mouse xenograft model. Quantitative speckle intensity distribution analysis thus shows promise for identifying tissue pathologies, with potential for early cancer detection in vivo.
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Affiliation(s)
- Andras A Lindenmaier
- Department of Medical Biophysics, University of Toronto, 610 University Ave., Toronto, Ontario M5G 2M9, Canada
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17
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Blankenberg FG, Strauss HW. Recent Advances in the Molecular Imaging of Programmed Cell Death: Part II—Non–Probe-Based MRI, Ultrasound, and Optical Clinical Imaging Techniques. J Nucl Med 2012; 54:1-4. [DOI: 10.2967/jnumed.112.111740] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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18
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Li J, Tu Z, Shen Z, Xia Y, He Y, Liu S, Chen C. Quantitative measurement of optical attenuation coefficients of cell lines CNE1, CNE2, and NP69 using optical coherence tomography. Lasers Med Sci 2012; 28:621-5. [PMID: 22618158 DOI: 10.1007/s10103-012-1124-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 05/07/2012] [Indexed: 01/18/2023]
Abstract
The radiotherapy-related types of nasopharyngeal carcinoma (NPC) have been established, which give the most effective treatment for NPC patients using the individual therapy. To diagnose the types of NPC, we assess the general NPC cell lines CNE1, CNE2 and normal nasopharyngeal cell line NP69 using optical coherence tomography (OCT) in two steps: firstly, the OCT images of the three different types of cell pellets are captured. Secondly, by fitting Beer's law to the averaged A-scans in these OCT datasets, the attenuation coefficients (μ t ) of the cells can be extracted. The median attenuation coefficients (interquartile range) of CNE1, CNE2, and NP69 are 5.58 mm(-1) (IQR 5.55 to 5.65 mm(-1)), 5.91 mm(-1) (IQR 5.82 to 5.88 mm(-1)), and 8.96 mm(-1) (IQR 8.80 to 9.47 mm(-1)), respectively. The distinguishable quantitative OCT analysis (by μ t ) shows that the types of NPC could potentially be differentiated in real time and noninvasive.
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Affiliation(s)
- Jianghua Li
- School for Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, 510006, China
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19
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Abstract
OBJECTIVE The purposes of this review are to describe the signaling pathways of and the cellular changes that occur with apoptosis and other forms of cell death, summarize tracers and modalities used for imaging of apoptosis, delineate the relation between apoptosis and inhibition of protein translation, and describe spectroscopic technologies that entail high-frequency ultrasound and infrared and midinfrared light in characterizing the intracellular events of apoptosis. CONCLUSION Apoptosis is a highly orchestrated set of biochemical and morphologic cellular events. These events present many potential targets for the imaging of apoptosis in vivo. Imaging of apoptosis can facilitate early assessment of anticancer treatment before tumor shrinkage, which may increase the effectiveness of delivery of chemotherapy and radiation therapy and speed drug development.
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20
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Farhat G, Mariampillai A, Yang VXD, Czarnota GJ, Kolios MC. Detecting apoptosis using dynamic light scattering with optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2011; 16:070505. [PMID: 21806246 DOI: 10.1117/1.3600770] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A dynamic light scattering technique is implemented using optical coherence tomography (OCT) to measure the change in intracellular motion as cells undergo apoptosis. Acute myeloid leukemia cells were treated with cisplatin and imaged at a frame rate of 166 Hz using a 1300 nm swept-source OCT system at various times over a period of 48 h. Time correlation analysis of the speckle intensities indicated a significant increase in intracellular motion 24 h after treatment. This rise in intracellular motion correlated with histological findings of irregularly shaped and fragmented cells indicative of cell membrane blebbing and fragmentation.
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