Journal of Biomedical Optics最新文献

{"title":"Phantoms for use in optical coherence elastography.","authors":"Farzan Navaeipour, Jiayue Li, Shima Zamani, Lena Kranold, Rowan W Sanderson, Brendan F Kennedy","doi":"10.1117/1.JBO.31.8.086004","DOIUrl":"10.1117/1.JBO.31.8.086004","url":null,"abstract":"<p><strong>Significance: </strong>Optical coherence elastography (OCE) is an emerging biomedical imaging technique for mapping the micro-scale mechanical properties of tissue. Phantoms are vital for assessing OCE imaging performance in a controlled and systematic manner. Although the use of phantoms in OCE has been widely demonstrated, there is no consensus on suitable phantom materials or fabrication methods, limiting reproducibility and inter-laboratory comparison of OCE techniques.</p><p><strong>Aim: </strong>Our aim is to establish a unified framework for selecting, fabricating, and characterizing OCE phantoms by systematically evaluating the mechanical, optical, and structural properties of silicone, agar, and gelatin, the three most widely used OCE phantom materials.</p><p><strong>Approach: </strong>We conducted a literature review of phantom fabrication methods reported in OCE studies published between 1998 and 2025, comprising 223 papers, and identified silicone, agar, and gelatin as the most widely used OCE phantom materials. We experimentally characterized the elasticity, viscoelasticity, and attenuation coefficient of homogeneous phantoms fabricated from each material and investigated the effects of shelf life and optical scatterer concentration on mechanical properties. We further fabricated inclusion phantoms and tissue-mimicking surface roughness phantoms derived from optical coherence tomography (OCT) scans of human breast tissue using all three materials and evaluated their imaging performance using a compression OCE technique, quantitative micro-elastography (QME).</p><p><strong>Results: </strong>The elastic (tangent) modulus ranged from 7.2 to 175.9 kPa for silicone, 9.7 to 229.1 kPa for agar, and 3.5 to 29.4 kPa for gelatin, while OCT attenuation coefficients ranged from 0.2 to <math><mrow><mn>13.1</mn> <mtext>  </mtext> <msup><mrow><mi>mm</mi></mrow> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> </mrow> </math> across the three materials. Stress relaxation testing revealed distinct viscoelastic signatures, with relaxation time constants ranging from <math><mrow><mo>∼</mo> <mn>2</mn> <mtext>  </mtext> <mi>s</mi></mrow> </math> in silicone to over 1600 s in gelatin. We demonstrated that optical attenuation in these materials can be varied independently of mechanical properties. Inclusion and surface roughness phantoms were successfully fabricated from all three materials, with QME measurements revealing material-specific fabrication artifacts and demonstrating that surface topography can produce erroneous mechanical contrast in mechanically uniform materials.</p><p><strong>Conclusions: </strong>This study provides a framework to guide phantom material selection, fabrication, and characterization in OCE, identifying silicone as best suited for durable, predominantly elastic phantoms; agar for viscoelastic phantoms across a broad elasticity range; and gelatin for soft, highly viscoelastic phantoms. We believe that the results present","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"086004"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13452405/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148697716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of corneal phase and group refractive indices <i>in situ</i> and dispersion <i>ex vivo</i> using a hybrid spectral-domain OCT and confocal scanning system.","authors":"Jianli Ren, Xikai Wei, Cheng Lu, Qingyun Li, Kaixi Zheng, Dexi Zhu","doi":"10.1117/1.JBO.31.8.086003","DOIUrl":"10.1117/1.JBO.31.8.086003","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Significance: &lt;/strong&gt;Precise determination of corneal refractive indices is essential for accurate refractive power calculations, personalized refractive surgery planning, and glaucoma management. However, current clinical methods fail to distinguish between the group refractive index ( &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;n&lt;/mi&gt; &lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; ) for thickness quantification and the phase refractive index ( &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;n&lt;/mi&gt; &lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; ) for optical power calculations, often relying on population-averaged constants that mask individual heterogeneity.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Aim: &lt;/strong&gt;We aim to develop a multimodal measurement system integrating spectral-domain optical coherence tomography (SD-OCT) and confocal scanning for the precise extraction of the &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;n&lt;/mi&gt; &lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; , &lt;math&gt; &lt;mrow&gt; &lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; , and dispersion coefficients of corneal tissues.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Approach: &lt;/strong&gt;A dual-modality platform sharing an 860 nm source was constructed to jointly capture the optical path length (OPL) and confocal distance. A two-step progressive workflow was implemented: first, the &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;n&lt;/mi&gt; &lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; and thickness were independently determined via the OPL method to serve as target ground truths for extracting tissue-specific dispersion through iterative optimization; second, these quantified priors were utilized to jointly decouple the &lt;i&gt;in situ&lt;/i&gt; &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;n&lt;/mi&gt; &lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; , &lt;math&gt; &lt;mrow&gt; &lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;n&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; , and thickness of intact corneas.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;System validation using optical window plates yielded a relative error of only 0.01% to 0.09% for &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;n&lt;/mi&gt; &lt;mrow&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;/mrow&gt; &lt;/math&gt; and 0.17% to 5.74% for dispersion coefficients. For biological tissues, we report the first direct experimental measurement of phase dispersion for human lenticules ( &lt;math&gt;&lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;0.014468&lt;/mn&gt; &lt;mo&gt;±&lt;/mo&gt; &lt;mn&gt;0.004060&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;μ&lt;/mi&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; ) and porcine sections ( &lt;math&gt;&lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;0.010223&lt;/mn&gt; &lt;mo&gt;±&lt;/mo&gt; &lt;mn&gt;0.002811&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;μ&lt;/mi&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; ), where the human data showed high consistency with the theoretical Cauchy model ( &lt;math&gt;&lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;0.014186&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;μ&lt;/mi&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; ). Utilizing these priors, the system successfully decoupled the &lt;i&gt;in situ&lt;/i&gt; parameters of whole porcine eyes, yielding &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;n&lt;/m","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 8","pages":"086003"},"PeriodicalIF":3.3,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13452403/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148697660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Broad-linewidth sources result in a skin-tone bias in noninvasive optical measurement of oxygen saturation.","authors":"Giles Blaney, Sergio Fantini","doi":"10.1117/1.JBO.31.7.070501","DOIUrl":"10.1117/1.JBO.31.7.070501","url":null,"abstract":"<p><strong>Significance: </strong>Pulse oximeters overestimate arterial oxygen saturation in patients with darker skin tones, potentially increasing rates of occult hypoxemia. The emission of broad-linewidth light-emitting diodes (LEDs) has been proposed as a possible cause for this melanin-dependent bias.</p><p><strong>Aim: </strong>This letter utilizes a physics-based model to investigate if the spectral bandwidth of light sources contributes to melanin-dependent measurement biases.</p><p><strong>Approach: </strong>Pulse oximetry measurements were simulated across varying melanin concentrations and source bandwidths using a hybrid diffusion theory and Monte Carlo model. Epidermal melanin absorption was modeled with transmissive filters on the surfaces of an infinite slab representing bulk tissue.</p><p><strong>Results: </strong>Simulations demonstrate that pulse oximeter calibration curves depend on melanin concentration when broad-linewidth LEDs are utilized. Conversely, calibration curves remain independent of melanin when employing monochromatic laser diodes (LDs).</p><p><strong>Conclusion: </strong>Spectral coloring from broad-linewidth LEDs contributes to the skin-tone bias observed in pulse oximetry. Although updating calibration methods for different skin tones is a potential approach, adopting monochromatic LDs could alternatively eliminate this spectral-coloring contribution to the bias.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"070501"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13349327/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148421374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Depth-of-focus enhancement in optical coherence tomography via a cascaded image registration and fusion network for multi-focus imaging.","authors":"Yuhui Chu, Sicheng Li, Huabing Tan, Mai Dan, Yunpeng Zhao, Pengpeng Zhao","doi":"10.1117/1.JBO.31.7.076005","DOIUrl":"10.1117/1.JBO.31.7.076005","url":null,"abstract":"<p><strong>Significance: </strong>Optical coherence tomography (OCT) is widely used in biomedical imaging, but its ability to clearly resolve fine structures is limited to a narrow depth of focus (DOF). This constraint restricts reliable visualization of tissue microstructures across extended depth ranges, making strategies that extend the DOF while preserving fine structural fidelity and image sharpness highly desirable.</p><p><strong>Aim: </strong>We aim to enhance the effective DOF of OCT imaging while preserving fine structural details and image sharpness by developing a deep-learning-based reconstruction framework for multi-focus OCT data.</p><p><strong>Approach: </strong>We developed a cascaded image registration and fusion network (CRFN) to process multi-focus OCT images acquired using a swept-source OCT system with dynamic focal modulation enabled by an electrically tunable lens. The proposed network consists of a registration module for spatial alignment of multi-focus images and a fusion module for focus map-guided reconstruction. CRFN operates in an unsupervised, training-free manner, in which the network parameters are optimized directly on the acquired multi-focus OCT images, without relying on large-scale pre-collected training datasets.</p><p><strong>Results: </strong>Experiments conducted on <i>ex vivo</i> and <i>in vivo</i> specimens demonstrate that the proposed method improves image quality compared with unfused and conventional multi-focus fusion approaches. Quantitative evaluations on <i>ex vivo</i> specimens show maximum improvements of 8.29 dB in signal-to-noise ratio and 1.56 dB in contrast-to-noise ratio, compared with conventional methods. Moreover, the effective DOF is extended by a factor of <math><mrow><mo>∼</mo> <mn>2</mn></mrow> </math> , enabling clearer visualization of fine structural details across an enlarged depth range.</p><p><strong>Conclusions: </strong>The proposed CRFN improves multi-focus OCT reconstruction quality and extends the effective DOF without increasing hardware complexity or relying on extensive training data, highlighting its robustness and potential generalizability for biomedical OCT imaging applications.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076005"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13413486/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148620171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Halo-free quantitative phase imaging via physics-constrained self-supervised network.","authors":"Haobin Ye, Tianhe Wang, Lin Liu, Liangwei Li, Xiaohui Du, Ruqian Hao, Juanxiu Liu, Jing Zhang","doi":"10.1117/1.JBO.31.7.076503","DOIUrl":"10.1117/1.JBO.31.7.076503","url":null,"abstract":"<p><strong>Significance: </strong>The halo effect arising from limited spatial coherence and system noise severely compromises the accuracy of white-light diffraction phase microscopy, hindering its broader application in high-fidelity label-free biological observations.</p><p><strong>Aim: </strong>We propose and evaluate a physics-constrained halo-free self-supervised network (PC-HFSSN) designed to suppress the halo effect in partially coherent imaging systems without requiring experimentally inaccessible ground-truth phase labels.</p><p><strong>Approach: </strong>Our approach embeds a differentiable forward optical model directly into the network's loss function. By integrating the physical spatial smoothness constraints of halo fields with a Gaussian illumination approximation, our lightweight architecture was trained on multi-scale synthetic data to accurately isolate and remove halo fields from the acquired images.</p><p><strong>Results: </strong>Trained on diverse sample data, PC-HFSSN demonstrated robust \"simulation-to-reality\" generalization. Experimental validation of both simulations and dynamic live cells confirmed that the proposed method effectively eliminated the halo effect while preserving high-frequency phase accuracy and maintaining high computational efficiency.</p><p><strong>Conclusions: </strong>PC-HFSSN provides a robust, physically interpretable, and self-supervised solution for high-throughput quantitative phase imaging by balancing high fidelity and processing speed without the need for paired training data.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076503"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13340711/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148404751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperspectral imaging system for multiplexed cancer marker detection: design and clinical evaluation.","authors":"Oren Ben-Ami, Shmoolik Mangan, Tal Keidar Haran, Raz Ben-Uri, Efrat Ofek, Yuval Garini, Leeat Keren, Iris Barshack, Boaz Brill","doi":"10.1117/1.JBO.31.7.076504","DOIUrl":"10.1117/1.JBO.31.7.076504","url":null,"abstract":"<p><strong>Significance: </strong>Multiplexed biomarker assessment is increasingly required in oncologic diagnostics, yet tissue depletion from sequential immunohistochemistry (IHC) and molecular testing limits routine pathology. Many multiplex immunofluorescence platforms rely on iterative staining or complex instrumentation, restricting scalability and clinical adoption.</p><p><strong>Aim: </strong>The aim is to develop and clinically evaluate a hyperspectral multiplexed fluorescence imaging platform for simultaneous detection of multiple diagnostic biomarkers on a single formalin-fixed paraffin-embedded (FFPE) tissue section potentially compatible with routine workflows.</p><p><strong>Approach: </strong>A Fourier transform hyperspectral system incorporating a monolithic Sagnac interferometer was engineered for single-shot, full-spectrum acquisition without filter switching or iterative staining. A seven-biomarker lung cancer panel was applied in a single staining and imaging workflow, and custom spectral reconstruction and unmixing generated spatially resolved biomarker maps. Clinical performance was assessed retrospectively through blinded comparison with single-plex chromogenic IHC.</p><p><strong>Results: </strong>The system achieved submicron spatial resolution with minimal spectral cross-talk, enabling robust seven-channel imaging. Single-section analysis showed complete diagnostic concordance with reference IHC across the evaluated cohort of non-small cell lung cancer and other thoracic specimens and revealed biomarker co-localization, including tumor-associated PD-L1.</p><p><strong>Conclusions: </strong>This platform enables high-content diagnostic profiling from a single FFPE tissue section while conserving tissue and preserving spatial information, supporting further evaluation of its potential integration into routine clinical pathology workflows.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076504"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13349328/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148421334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Perioperative diffuse optical imaging of blood flow distributions for porcine skin flap viability assessment.","authors":"Samaneh Rabienia Haratbar, Fatemeh Hamedi, Mehrana Mohtasebi, Li Chen, Lesley Wong, Guoqiang Yu, Lei Chen","doi":"10.1117/1.JBO.31.7.076003","DOIUrl":"10.1117/1.JBO.31.7.076003","url":null,"abstract":"<p><strong>Significance: </strong>Mastectomy skin flap necrosis remains a major complication in implant-based breast reconstruction due to inadequate tissue blood flow. Existing diagnostic technologies are limited by shallow depth sensitivity, dye-related risks, contact requirements, and an inability to continuously assess blood flow.</p><p><strong>Aim: </strong>We aimed to translate a noncontact, dye-free, depth-sensitive speckle contrast diffuse correlation tomography (scDCT) technique to a clinically relevant porcine skin flap model for assessing flap blood flow and viability.</p><p><strong>Approach: </strong>The scDCT system was optimized to image blood flow over 7 days in four porcine skin flaps including sham, implant, half necrosis, and full necrosis (FN). Measurements were compared with indocyanine green angiography (ICG-A) as a reference standard.</p><p><strong>Results: </strong>scDCT enabled longitudinal monitoring of flap blood flow, revealing significant flow differences among flap types and over time. FN flaps consistently exhibited the most severe flow impairment, whereas other flap types showed partial or complete recovery over time, distinguishing nonviable from viable tissue. scDCT measurements demonstrated moderate to strong correlations with ICG-A across time points.</p><p><strong>Conclusions: </strong>The findings support scDCT as a promising perioperative imaging modality for improving flap necrosis risk stratification and surgical decision-making, with future work focused on large-scale validation and clinical translation.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076003"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13362226/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148436532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Panoramic hyperspectral optical mapping of cardiac membrane potential and tissue type.","authors":"Grant Kowalik, Rebekah Russo, Murray Loew, David Mendelowitz, Emilia Entcheva, Matthew W Kay","doi":"10.1117/1.JBO.31.7.076004","DOIUrl":"10.1117/1.JBO.31.7.076004","url":null,"abstract":"<p><strong>Significance: </strong>Cardiac panoramic optical mapping is a powerful approach for studying action potential dispersion and mapping arrhythmia triggers and propagation pathways over the entire surface of the heart. However, tissue type (muscle, connective tissue, and infarct scar) is also important for interpreting mapping data and is difficult to identify using optical mapping data alone.</p><p><strong>Aim: </strong>Panoramically map transmembrane potential and tissue type from the surface of infarcted hearts for correlative analysis of cardiac structure and function.</p><p><strong>Approach: </strong>We developed a multimodal panoramic imaging system to map epicardial tissue type (determined by collagen content) using a line-scan hyperspectral camera and a precision stage to translate and rotate the heart while illuminating the epicardial surface with UV light. Transmembrane potential was subsequently optically mapped by imaging a potentiometric probe with four high speed CMOS cameras position around the heart. The epicardial surface was reconstructed for each heart using images acquired every 3.6 deg of rotation, onto which hyperspectral and optical mapping data were texture mapped. All cameras were registered to one coordinate frame using a calibration procedure.</p><p><strong>Results: </strong>This system combines, for the first time, high-resolution hyperspectral imaging with optical mapping for quantitative correlative tissue structure-function analyses. It was used to study excitation wave propagation and action potentials across the surface of perfused rat hearts having a four-week-old infarct. The spectral band of collagen fluorescence (400 to 520 nm) revealed infarcted and border zone tissue. PVCs and reentrant activity were observed in 3 of 4 hearts at S1-S2 pacing intervals between 80 and 65 msec (S1 = 150 msec). PVCs originated near the infarct border and propagated around the infarct. Using the integral of spectral intensity from 400 to 435 nm, a k-means clustering algorithm classified each mapped site as either healthy, border zone, or infarcted tissue. Average action potential duration within those tissue types was longest for infarcted tissue, shorter for border zone tissue, and shortest for healthy tissue, a preliminary result that is consistent with the effect of an infarct on ventricular electrophysiology.</p><p><strong>Conclusions: </strong>This work demonstrates that panoramic hyperspectral mapping of tissue type and transmembrane potential is a powerful approach that enables functional mapping data to be analyzed within the context of local tissue type (healthy, infarct, and border) in living hearts.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076004"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13391206/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148562013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual SwinUNet architecture for enhanced photoacoustic imaging: a contrastive learning approach in image and sinogram domains.","authors":"Isha Munjal, Tekeshwar Hirwani, Jaya Prakash","doi":"10.1117/1.JBO.31.7.076002","DOIUrl":"10.1117/1.JBO.31.7.076002","url":null,"abstract":"<p><strong>Significance: </strong>Leveraging complementary information from multiple data representations enables richer feature extraction and greater robustness under challenging acquisition conditions. Such an approach enhances the accuracy, reliability, and generalizability of photoacoustic image reconstruction, ultimately leading to improved image quality and stronger performance across diverse photoacoustic imaging (PAI) scenarios.</p><p><strong>Aim: </strong>We propose a transformer-based dual SwinUNet architecture that learns features from both the image and sinogram domains to improve PAI within a contrastive learning framework.</p><p><strong>Approach: </strong>The developed dual SwinUNet architecture had multiple loss function-wherein noise-to-signal ratio was computed between the predicted output from each SwinUNet model and the ground truth, and the mean square error was estimated between the predicted outputs of both networks. The dual SwinUNet model was fed with two reconstructed images as inputs, generated using different reconstruction algorithms, i.e., backprojection and Tikhonov-regularized reconstruction. These input pairs can either be positive, meaning both inputs share the same ground truth, or negative, meaning they have different ground truths. The model was trained using a contrastive loss in the sinogram domain, enabling the model to learn distinctive features from both positive and negative pairs.</p><p><strong>Results: </strong>The performance of the different networks (ResNet, UNet, FDUNet, TNet, and the proposed network) was evaluated by varying the number of transducers, angular coverage, and noise levels. The data acquired with 100 transducers having a coverage angle of 135 deg have shown that the structural similarity index measure (SSIM) was improved by 7.5% and the universal image quality index improved by 18% compared with FDUNet. For <i>in vivo</i> mice data, SSIM improved by 6.8%, when using data from 100 transducers.</p><p><strong>Conclusions: </strong>The dual SwinUNet architecture demonstrates significant improvement in image quality for PAI by learning features from both the image and sinogram domains. The proposed framework can be extended using different DL architectures alongside different analytical/model-based reconstruction inputs.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076002"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13345084/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148411632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Method of spatial scanning of modulated laser radiation for outline imaging of interphalangeal joints.","authors":"Svetlana Shmavonyan, Aleksandr Khanbekyan, Marina Movsisyan, Valery Tuchin, Aram Papoyan","doi":"10.1117/1.JBO.31.7.076001","DOIUrl":"10.1117/1.JBO.31.7.076001","url":null,"abstract":"<p><strong>Significance: </strong>Optical transmission imaging is an inexpensive and noninvasive method of examining biological tissues and structures, but due to strong scattering, its applicability is limited to millimeter-thick samples, thus preventing <i>in vivo</i> studies of centimeter-thick biological organs.</p><p><strong>Aim: </strong>The development of a technique that overcomes the limitation imposed by scattering will significantly expand the scope of the application of transillumination imaging, allowing the examination or diagnosis of biological objects of centimeter thickness, in particular, interphalangeal joints.</p><p><strong>Approach: </strong>The approach used is based on a previously developed method of highly sensitive registration of predominantly ballistic and snake photons when scanning modulated laser radiation. In addition, to obtain a contour image, a technique of selective registration across the profile of a Gaussian laser beam was used, which made it possible to obtain high spatial resolution with a large diameter of a collimated laser beam. An optical clearing agent was used to mitigate the scattering imposed by the skin.</p><p><strong>Results: </strong>The method was tested on a model object and applied to obtain the contour of the interphalangeal joint. The resulting joint contour matches the actual shape, but its width in the image is larger than the actual width. Calculations show that the size of the structure in the image also depends on the intensity and diameter of the laser beam, as well as the extinction coefficient of the sample. It is shown that, given the other parameters, the extinction coefficient can be determined from the joint image space. The effect of the clearing agent on the clarity and contrast of the image is quantitatively analyzed, and a reduction in the scattering coefficient (by 9% to 14%) is estimated.</p><p><strong>Conclusions: </strong>The suggested method has been shown to be efficient for deep-tissue imaging of biological objects up to several centimeters thick, particularly joints, revealing the outline of structural features. We have shown that the use of an optical clearing agent allows reproducible images to be obtained with noticeably higher contrast and clarity, sufficient for preliminary express diagnostics of pathologies.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076001"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13319822/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148368028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}