In this study,we propose a deep-learning-based method to correct motion artifacts in optical resolution photoacoustic microscopy(OR-PAM).The method is a convolutional neural network that establishes an end-to-end map ...In this study,we propose a deep-learning-based method to correct motion artifacts in optical resolution photoacoustic microscopy(OR-PAM).The method is a convolutional neural network that establishes an end-to-end map from input raw data with motion artifacts to output corrected images.First,we performed simulation studies to evaluate the feasibility and effectiveness of the proposed method.Second,we employed this method to process images of rat brain vessels with multiple motion artifacts to evaluate its performance for in vivo applications.The results demonstrate that this method works well for both large blood vessels and capillary networks.In comparison with traditional methods,the proposed method in this study can be easily modified to satisfy different scenarios of motion corrections in OR-PAM by revising the training sets.展开更多
Improving the spatial resolution of a fluorescence microscope has been an ongoing challenge in the imaging community.To address this challenge,a variety of approaches have been taken,ranging from instrumentation devel...Improving the spatial resolution of a fluorescence microscope has been an ongoing challenge in the imaging community.To address this challenge,a variety of approaches have been taken,ranging from instrumentation development to image postprocessing.An example of the latter is deconvolution,where images are numerically deblurred based on a knowledge of the microscope point spread function.However,deconvolution can easily lead to noise-amplification artifacts.Deblurring by postprocessing can also lead to negativities or fail to conserve local linearity between sample and image.We describe here a simple image deblurring algorithm based on pixel reassignment that inherently avoids such artifacts and can be applied to general microscope modalities and fluorophore types.Our algorithm helps distinguish nearby fluorophores,even when these are separated by distances smaller than the conventional resolution limit,helping facilitate,for example,the application of single-molecule localization microscopy in dense samples.We demonstrate the versatility and performance of our algorithm under a variety of imaging conditions.展开更多
Stimulated emission depletion(STED) microscopy is one of far-field optical microscopy techniques that can provide sub-diffraction spatial resolution. The spatial resolution of the STED microscopy is determined by the ...Stimulated emission depletion(STED) microscopy is one of far-field optical microscopy techniques that can provide sub-diffraction spatial resolution. The spatial resolution of the STED microscopy is determined by the specially engineered beam profile of the depletion beam and its power. However, the beam profile of the depletion beam may be distorted due to aberrations of optical systems and inhomogeneity of a specimen's optical properties, resulting in a compromised spatial resolution. The situation gets deteriorated when thick samples are imaged. In the worst case, the severe distortion of the depletion beam profile may cause complete loss of the superresolution effect no matter how much depletion power is applied to specimens. Previously several adaptive optics approaches have been explored to compensate aberrations of systems and specimens. However, it is difficult to correct the complicated high-order optical aberrations of specimens. In this report, we demonstrate that the complicated distorted wavefront from a thick phantom sample can be measured by using the coherent optical adaptive technique. The full correction can effectively maintain and improve spatial resolution in imaging thick samples.展开更多
Background:Conjunctival lymphoma,conjunctival amyloidosis and benign reactive lymphoid hyperplasia(BRLH)are conditions that often have a similar appearance on the ocular surface.The use of high resolution anterior seg...Background:Conjunctival lymphoma,conjunctival amyloidosis and benign reactive lymphoid hyperplasia(BRLH)are conditions that often have a similar appearance on the ocular surface.The use of high resolution anterior segment optical coherence tomography(HR-OCT)enables clinicians to evaluate distinctive differences in tissue morphology and cellular patterns in various ocular surface conditions.In this study,we characterize the morphological differences seen in conjunctival lymphoma,conjunctival amyloidosis and BRLH on HR-OCT imaging.Methods:A retrospective chart review was performed of patients with biopsy proven conjunctival lymphoma,conjunctival amyloidosis and BRLH between 2012 and 2019 at the Bascom Palmer Eye Institute.Patients were excluded if HR-OCT imaging was not performed on initial presentation.Results:Thirty-four total eyes of 27 patients were identified.Twenty eyes had conjunctival lymphoma(16 patients),8 eyes had conjunctival amyloidosis(6 patients)and 6 eyes had BRLH(5 patients).All conditions appeared clinically as pink,red or yellow subepithelial lesions but had different features on HR-OCT.In lymphoma,HR-OCT images typically showed homogenous,dark subepithelial lesions with smooth borders,containing monomorphic dot-like infiltrates.HR-OCT images of amyloidosis typically showed heterogeneous,dark lesions with irregular borders,often containing hyperreflective linear infiltrates.HR-OCT images of BRLH showed variable infiltration of the subepithelial tissue,at times with homogenous lesions containing dot-like infiltrates like lymphoma and other times with more hyperreflective,subepithelial tissue.Flow cytometry and gene rearrangement was needed for final differentiation between BRLH and lymphoma lesions.Conclusions:Distinctive features on HR-OCT of conjunctival lymphoma,conjunctival amyloidosis and BRLH can help characterize these lesions beyond what is apparent with the clinical examination.Future studies can further validate this technology’s use with more subtle and challenging lesions.展开更多
In optical scanning holography, one pupil produces a spherical wave and another produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object. The resolut...In optical scanning holography, one pupil produces a spherical wave and another produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object. The resolution of the hologram reconstruction is affected by the point spread function(PSF) of the optical system. In this paper, we modulate the PSF by a spiral phase plate, which significantly enhances the lateral and depth resolution. We explain the theory for such resolution enhancement and show simulation results to verify the efficacy of the approach.展开更多
Elasto-optical refractive index modulation due to photoacoustic initial pressure transients produced significant reflection of a probe beam when the absorbing interface had an appreciable refractive index difference.T...Elasto-optical refractive index modulation due to photoacoustic initial pressure transients produced significant reflection of a probe beam when the absorbing interface had an appreciable refractive index difference.This effect was harnessed in a new form of non-contact optical resolution photoacoustic microscopy called photoacoustic remote sensing microscopy.A noninterferometric system architecture with a low-coherence probe beam precludes detection of surface oscillations and other phase-modulation phenomenon.The probe beam was confocal with a scanned excitation beam to ensure detection of initial pressure-induced intensity reflections at the subsurface origin where pressures are largest.Phantom studies confirmed signal dependence on optical absorption,index contrast and excitation fluence.In vivo imaging of superficial microvasculature and melanoma tumors was demonstrated with~2.7±0.5μm lateral resolution.展开更多
Purpose:To develop an automated classification system using a machine learning classifier to distinguish clinically unaffected eyes in patients with keratoconus from a normal control population based on a combination ...Purpose:To develop an automated classification system using a machine learning classifier to distinguish clinically unaffected eyes in patients with keratoconus from a normal control population based on a combination of Scheimpflug camera images and ultra-high-resolution optical coherence tomography(UHR-OCT)imaging data.Methods:A total of 121 eyes from 121 participants were classified by 2 cornea experts into 3 groups:normal(50 eyes),with keratoconus(38 eyes)or with subclinical keratoconus(33 eyes).All eyes were imaged with a Scheimpflug camera and UHR-OCT.Corneal morphological features were extracted from the imaging data.A neural network was used to train a model based on these features to distinguish the eyes with subclinical keratoconus from normal eyes.Fisher’s score was used to rank the differentiable power of each feature.The receiver operating characteristic(ROC)curves were calculated to obtain the area under the ROC curves(AUCs).Results:The developed classification model used to combine all features from the Scheimpflug camera and UHR-OCT dramatically improved the differentiable power to discriminate between normal eyes and eyes with subclinical keratoconus(AUC=0.93).The variation in the thickness profile within each individual in the corneal epithelium extracted from UHR-OCT imaging ranked the highest in differentiating eyes with subclinical keratoconus from normal eyes.Conclusion:The automated classification system using machine learning based on the combination of Scheimpflug camera data and UHR-OCT imaging data showed excellent performance in discriminating eyes with subclinical keratoconus from normal eyes.The epithelial features extracted from the OCT images were the most valuable in the discrimination process.This classification system has the potential to improve the differentiable power of subclinical keratoconus and the efficiency of keratoconus screening.展开更多
Optical metamaterials have presented an innovative method of manipulating light.Hyperbolic metamaterials have an extremely high anisotropy with a hyperbolic dispersion relation.They are able to support high-k modes an...Optical metamaterials have presented an innovative method of manipulating light.Hyperbolic metamaterials have an extremely high anisotropy with a hyperbolic dispersion relation.They are able to support high-k modes and exhibit a high density of states which produce distinctive properties that have been exploited in various applications,such as super-resolution imaging,negative refraction,and enhanced emission control.Here,state-of-the-art hyperbolic metamaterials are reviewed,starting from the fundamental principles to applications of artificially structured hyperbolic media to suggest ways to fuse natural two-dimensional hyperbolic materials.The review concludes by indicating the current challenges and our vision for future applications of hyperbolic metamaterials.展开更多
Background:To report a case of bilateral benign reactive lymphoid hyperplasia(BRLH)of the conjunctiva treated with oral doxycycline and perform review of the literature evaluating the presentation,treatment and risk o...Background:To report a case of bilateral benign reactive lymphoid hyperplasia(BRLH)of the conjunctiva treated with oral doxycycline and perform review of the literature evaluating the presentation,treatment and risk of transformation to lymphoma.Case presentation:A case report is described and review of the literature from January 1975 to January 2019 was performed.A 30-year-old man presented with bilateral enlarging fleshy pink medial canthal conjunctival lesions.Incisional biopsy revealed BRLH.Oral doxycycline was initiated(100 mg two times a day)for a total of 2 months.Both lesions decreased in size significantly at the patient’s two-month follow up visit.The residual lesion in the right eye was excised along with an adjacent pterygium and the patient has been free of recurrence for the past 1.5 years.The lesion in the left eye has remained stable in size after cessation of the oral doxycycline.A total of 235 cases of conjunctival BRLH were identified in our literature search.The mean age at diagnosis was 35.2 years(range,5 to 91 years).BRLH lesions were unilateral in 75%of patients and bilateral in 25%of them.Seven patients(2.9%)had a concurrent Epstein-Barr virus(EBV)infection at the time of lesion appearance.The most common treatments were surgical excision(155/235 or 65.9%)and corticosteroids(30/235 or 12.7%),while 14%(33/235)of the patients were observed and 4.6%(11/235)received external beam radiotherapy alone.Recurrence occurred in ten patients(10/235 or 4.2%),of whom five had undergone surgical excision alone,two excision followed by external beam radiotherapy,one excision and oral corticosteroids,one radiotherapy alone and one had been treated with topical corticosteroids.Overall,only 2 of the 235 reported cases(0.8%)developed malignancy,one localized to the conjunctiva and one systemic.Conclusions:Benign reactive lymphoid hyperplasia is one of the lymphoproliferative disorders of the conjunctiva and ocular adnexa.Extensive literature review shows that most cases are treated with surgery,steroids or observation.Oral doxycycline may be considered an alternative non-invasive treatment of BRLH conjunctival lesions.BRLH lesions warrant careful follow up as they can rarely transform into conjunctival or systemic lymphoma.展开更多
基金This work was sponsored by National Natural Science Foundation of China,Nos.81571722,61775028 and 61528401.
文摘In this study,we propose a deep-learning-based method to correct motion artifacts in optical resolution photoacoustic microscopy(OR-PAM).The method is a convolutional neural network that establishes an end-to-end map from input raw data with motion artifacts to output corrected images.First,we performed simulation studies to evaluate the feasibility and effectiveness of the proposed method.Second,we employed this method to process images of rat brain vessels with multiple motion artifacts to evaluate its performance for in vivo applications.The results demonstrate that this method works well for both large blood vessels and capillary networks.In comparison with traditional methods,the proposed method in this study can be easily modified to satisfy different scenarios of motion corrections in OR-PAM by revising the training sets.
基金funded by the National Science Foundation(EEC-1647837,2215990)the National Institutes of Health(R01EB029171,R01NS116139).
文摘Improving the spatial resolution of a fluorescence microscope has been an ongoing challenge in the imaging community.To address this challenge,a variety of approaches have been taken,ranging from instrumentation development to image postprocessing.An example of the latter is deconvolution,where images are numerically deblurred based on a knowledge of the microscope point spread function.However,deconvolution can easily lead to noise-amplification artifacts.Deblurring by postprocessing can also lead to negativities or fail to conserve local linearity between sample and image.We describe here a simple image deblurring algorithm based on pixel reassignment that inherently avoids such artifacts and can be applied to general microscope modalities and fluorophore types.Our algorithm helps distinguish nearby fluorophores,even when these are separated by distances smaller than the conventional resolution limit,helping facilitate,for example,the application of single-molecule localization microscopy in dense samples.We demonstrate the versatility and performance of our algorithm under a variety of imaging conditions.
基金National Basic Research Program of China(2015CB352005)National Natural Science Foundation of China(NSFC)(61378091,61404123,61505118,61505121,61525503)+5 种基金China Postdoctoral Science Foundation(2014M55226)Natural Science Foundation of Guangdong Province(2014A030312008)Hong Kong,Macao and Taiwan cooperation innovation platform&major projects of international cooperation in Colleges and Universities in Guangdong Province(2015KGJHZ002)National Institute of General Medical Sciences(NIGMS)(P20GM103499,R21GM104683)National Science Foundation(NSF)(1539034)Shenzhen Basic Research Project(JCYJ20150930104948169,GJHZ20160226202139185,JCYJ20160328144746940)
文摘Stimulated emission depletion(STED) microscopy is one of far-field optical microscopy techniques that can provide sub-diffraction spatial resolution. The spatial resolution of the STED microscopy is determined by the specially engineered beam profile of the depletion beam and its power. However, the beam profile of the depletion beam may be distorted due to aberrations of optical systems and inhomogeneity of a specimen's optical properties, resulting in a compromised spatial resolution. The situation gets deteriorated when thick samples are imaged. In the worst case, the severe distortion of the depletion beam profile may cause complete loss of the superresolution effect no matter how much depletion power is applied to specimens. Previously several adaptive optics approaches have been explored to compensate aberrations of systems and specimens. However, it is difficult to correct the complicated high-order optical aberrations of specimens. In this report, we demonstrate that the complicated distorted wavefront from a thick phantom sample can be measured by using the coherent optical adaptive technique. The full correction can effectively maintain and improve spatial resolution in imaging thick samples.
基金Ronald and Alicia Lepke Grant,The Lee and Claire Hager Grant,The Jimmy and Gaye Bryan Grant,The H.Scott Huizenga Grant,The Grant and Diana Stanton-Thornbrough,The Robert Baer Family Grant,The Emilyn Page and Mark Feldberg Grant,The Gordon Charitable Foundation,The Jose Ferreira de Melo Grant,The Richard and Kathy Lesser Grant and The Richard Azar Family Grant(institutional grants),the Department of Veterans Affairs,Veterans Health Administration,Office of Research and Development,Clinical Sciences Research EPID-006-15S(Dr.Galor),R01EY026174(Dr.Galor)NIH Center Core Grant P30EY014801Research to Prevent Blindness Unrestricted Grant.
文摘Background:Conjunctival lymphoma,conjunctival amyloidosis and benign reactive lymphoid hyperplasia(BRLH)are conditions that often have a similar appearance on the ocular surface.The use of high resolution anterior segment optical coherence tomography(HR-OCT)enables clinicians to evaluate distinctive differences in tissue morphology and cellular patterns in various ocular surface conditions.In this study,we characterize the morphological differences seen in conjunctival lymphoma,conjunctival amyloidosis and BRLH on HR-OCT imaging.Methods:A retrospective chart review was performed of patients with biopsy proven conjunctival lymphoma,conjunctival amyloidosis and BRLH between 2012 and 2019 at the Bascom Palmer Eye Institute.Patients were excluded if HR-OCT imaging was not performed on initial presentation.Results:Thirty-four total eyes of 27 patients were identified.Twenty eyes had conjunctival lymphoma(16 patients),8 eyes had conjunctival amyloidosis(6 patients)and 6 eyes had BRLH(5 patients).All conditions appeared clinically as pink,red or yellow subepithelial lesions but had different features on HR-OCT.In lymphoma,HR-OCT images typically showed homogenous,dark subepithelial lesions with smooth borders,containing monomorphic dot-like infiltrates.HR-OCT images of amyloidosis typically showed heterogeneous,dark lesions with irregular borders,often containing hyperreflective linear infiltrates.HR-OCT images of BRLH showed variable infiltration of the subepithelial tissue,at times with homogenous lesions containing dot-like infiltrates like lymphoma and other times with more hyperreflective,subepithelial tissue.Flow cytometry and gene rearrangement was needed for final differentiation between BRLH and lymphoma lesions.Conclusions:Distinctive features on HR-OCT of conjunctival lymphoma,conjunctival amyloidosis and BRLH can help characterize these lesions beyond what is apparent with the clinical examination.Future studies can further validate this technology’s use with more subtle and challenging lesions.
基金supported in part by the Research Grants Council of the Hong Kong Special Administrative Region,China, under project 7131–12Ethe NSFC RGC grant under project N–HKU714–13
文摘In optical scanning holography, one pupil produces a spherical wave and another produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object. The resolution of the hologram reconstruction is affected by the point spread function(PSF) of the optical system. In this paper, we modulate the PSF by a spiral phase plate, which significantly enhances the lateral and depth resolution. We explain the theory for such resolution enhancement and show simulation results to verify the efficacy of the approach.
基金funding from the Killam Trust(Izaak Walton Killam Memorial Scholarship)Alberta Innovates Technology Futures+11 种基金Alberta Enterprise and Advanced Education(Graduate Student Scholarship)University of Alberta(Dissertation fellowship)Andrew Stewart Awards and SPIE(SPIE Scholarship in Optics and Photonics)funding from NSERC(355544-2008,375340-2009 and STPGP 396444)the Terry-Fox Foundationthe Canadian Cancer Society(TFF 019237,TFF 019240 and CCS 2011-700718)Alberta Innovates Health Solutions(AIHS CRIO Team Award#201201154)The Alberta Cancer Research Institute(ACB 23728)the Leaders Opportunity Fund of the Canada Foundation for Innovation(18472)Alberta Advanced Education and Technology,Small Equipment Grants Program(URSI09007SEG)Alberta Ingenuity/Alberta Innovates(scholarships for graduate and undergraduate students)the Alberta Innovates Technology Futures Postdoctoral Fellowship.
文摘Elasto-optical refractive index modulation due to photoacoustic initial pressure transients produced significant reflection of a probe beam when the absorbing interface had an appreciable refractive index difference.This effect was harnessed in a new form of non-contact optical resolution photoacoustic microscopy called photoacoustic remote sensing microscopy.A noninterferometric system architecture with a low-coherence probe beam precludes detection of surface oscillations and other phase-modulation phenomenon.The probe beam was confocal with a scanned excitation beam to ensure detection of initial pressure-induced intensity reflections at the subsurface origin where pressures are largest.Phantom studies confirmed signal dependence on optical absorption,index contrast and excitation fluence.In vivo imaging of superficial microvasculature and melanoma tumors was demonstrated with~2.7±0.5μm lateral resolution.
基金This study was supported by research grants from Key R&D Program Projects in Zhejiang Province(2019C03045)the National Major Equipment Program of China(2012YQ12008004)+1 种基金the National Key Research and Development Program of China(2016YFE0107000)the National Nature Science Foundation of China(Grant No.81570880).
文摘Purpose:To develop an automated classification system using a machine learning classifier to distinguish clinically unaffected eyes in patients with keratoconus from a normal control population based on a combination of Scheimpflug camera images and ultra-high-resolution optical coherence tomography(UHR-OCT)imaging data.Methods:A total of 121 eyes from 121 participants were classified by 2 cornea experts into 3 groups:normal(50 eyes),with keratoconus(38 eyes)or with subclinical keratoconus(33 eyes).All eyes were imaged with a Scheimpflug camera and UHR-OCT.Corneal morphological features were extracted from the imaging data.A neural network was used to train a model based on these features to distinguish the eyes with subclinical keratoconus from normal eyes.Fisher’s score was used to rank the differentiable power of each feature.The receiver operating characteristic(ROC)curves were calculated to obtain the area under the ROC curves(AUCs).Results:The developed classification model used to combine all features from the Scheimpflug camera and UHR-OCT dramatically improved the differentiable power to discriminate between normal eyes and eyes with subclinical keratoconus(AUC=0.93).The variation in the thickness profile within each individual in the corneal epithelium extracted from UHR-OCT imaging ranked the highest in differentiating eyes with subclinical keratoconus from normal eyes.Conclusion:The automated classification system using machine learning based on the combination of Scheimpflug camera data and UHR-OCT imaging data showed excellent performance in discriminating eyes with subclinical keratoconus from normal eyes.The epithelial features extracted from the OCT images were the most valuable in the discrimination process.This classification system has the potential to improve the differentiable power of subclinical keratoconus and the efficiency of keratoconus screening.
基金POSCO-POSTECH-RIST Convergence Research Center program funded by POSCOPOSTECH-Samsung Semiconductor Research Center(IO201215-08187-01)funded by Samsung ElectronicsNational Research Foundation(NRF)grant(NRF-2019R1A2C3003129)funded by the Ministry of Science and ICT,Republic of Korea.
文摘Optical metamaterials have presented an innovative method of manipulating light.Hyperbolic metamaterials have an extremely high anisotropy with a hyperbolic dispersion relation.They are able to support high-k modes and exhibit a high density of states which produce distinctive properties that have been exploited in various applications,such as super-resolution imaging,negative refraction,and enhanced emission control.Here,state-of-the-art hyperbolic metamaterials are reviewed,starting from the fundamental principles to applications of artificially structured hyperbolic media to suggest ways to fuse natural two-dimensional hyperbolic materials.The review concludes by indicating the current challenges and our vision for future applications of hyperbolic metamaterials.
文摘Background:To report a case of bilateral benign reactive lymphoid hyperplasia(BRLH)of the conjunctiva treated with oral doxycycline and perform review of the literature evaluating the presentation,treatment and risk of transformation to lymphoma.Case presentation:A case report is described and review of the literature from January 1975 to January 2019 was performed.A 30-year-old man presented with bilateral enlarging fleshy pink medial canthal conjunctival lesions.Incisional biopsy revealed BRLH.Oral doxycycline was initiated(100 mg two times a day)for a total of 2 months.Both lesions decreased in size significantly at the patient’s two-month follow up visit.The residual lesion in the right eye was excised along with an adjacent pterygium and the patient has been free of recurrence for the past 1.5 years.The lesion in the left eye has remained stable in size after cessation of the oral doxycycline.A total of 235 cases of conjunctival BRLH were identified in our literature search.The mean age at diagnosis was 35.2 years(range,5 to 91 years).BRLH lesions were unilateral in 75%of patients and bilateral in 25%of them.Seven patients(2.9%)had a concurrent Epstein-Barr virus(EBV)infection at the time of lesion appearance.The most common treatments were surgical excision(155/235 or 65.9%)and corticosteroids(30/235 or 12.7%),while 14%(33/235)of the patients were observed and 4.6%(11/235)received external beam radiotherapy alone.Recurrence occurred in ten patients(10/235 or 4.2%),of whom five had undergone surgical excision alone,two excision followed by external beam radiotherapy,one excision and oral corticosteroids,one radiotherapy alone and one had been treated with topical corticosteroids.Overall,only 2 of the 235 reported cases(0.8%)developed malignancy,one localized to the conjunctiva and one systemic.Conclusions:Benign reactive lymphoid hyperplasia is one of the lymphoproliferative disorders of the conjunctiva and ocular adnexa.Extensive literature review shows that most cases are treated with surgery,steroids or observation.Oral doxycycline may be considered an alternative non-invasive treatment of BRLH conjunctival lesions.BRLH lesions warrant careful follow up as they can rarely transform into conjunctival or systemic lymphoma.
