Journal of Biomedical Optics最新文献

{"title":"Dual optical elastography detects TGF - β -induced alterations in the biomechanical properties of skin scaffolds.","authors":"Taye T Mekonnen,Yogeshwari S Ambekar,Christian Zevallos-Delgado,Achuth Nair,Fernando Zvietcovich,Hoda Zarkoob,Manmohan Singh,Yi Wei Lim,Marc Ferrer,Salavat R Aglyamov,Giuliano Scarcelli,Min Jae Song,Kirill V Larin","doi":"10.1117/1.jbo.29.9.095002","DOIUrl":"https://doi.org/10.1117/1.jbo.29.9.095002","url":null,"abstract":"SignificanceThe skin's mechanical properties are tightly regulated. Various pathologies can affect skin stiffness, and understanding these changes is a focus in tissue engineering. Ex vivo skin scaffolds are a robust platform for evaluating the effects of various genetic and molecular interactions on the skin. Transforming growth factor-beta ( TGF - β ) is a critical signaling molecule in the skin that can regulate the amount of collagen and elastin in the skin and, consequently, its mechanical properties.AimThis study investigates the biomechanical properties of bio-engineered skin scaffolds, focusing on the influence of TGF - β , a signaling molecule with diverse cellular functions.ApproachThe TGF - β receptor I inhibitor, galunisertib, was employed to assess the mechanical changes resulting from dysregulation of TGF - β . Skin scaffold samples, grouped into three categories (control, TGF - β -treated, and TGF - β + galunisertib-treated), were prepared in two distinct culture media-one with aprotinin (AP) and another without. Two optical elastography techniques, namely wave-based optical coherence elastography (OCE) and Brillouin microscopy, were utilized to quantify the biomechanical properties of the tissues.ResultsResults showed significantly higher wave speed (with AP, p < 0.001 ; without AP, p < 0.001 ) and Brillouin frequency shift (with AP, p < 0.001 ; without AP, p = 0.01 ) in TGF - β -treated group compared with the control group. The difference in wave speed between the control and TGF - β + galunisertib with ( p = 0.10 ) and without AP ( p = 0.36 ) was not significant. Moreover, the TGF - β + galunisertib-treated group exhibited lower wave speed without and with AP and reduced Brillouin frequency shift than the TGF - β -treated group without AP, further strengthening the potential role of TGF - β in regulating the mechanical properties of the samples.ConclusionsThese findings offer valuable insights into TGF - β -induced biomechanical alterations in bio-engineered skin scaffolds, highlighting the potential of OCE and Brillouin microscopy in the development of targeted therapies in conditions involving abnormal tissue remodeling and fibrosis.","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"9 1","pages":"095002"},"PeriodicalIF":3.5,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PoLambRimetry: a multispectral polarimetric atlas of lamb brain.","authors":"Verónica Mieites,Giulio Anichini,Ji Qi,Kevin O'Neill,Olga M Conde,Daniel S Elson","doi":"10.1117/1.jbo.29.9.096002","DOIUrl":"https://doi.org/10.1117/1.jbo.29.9.096002","url":null,"abstract":"SignificanceMueller matrix imaging (MMI) is a comprehensive form of polarization imaging useful for assessing structural changes. However, there is limited literature on the polarimetric properties of brain specimens, especially with multispectral analysis.AimWe aim to employ multispectral MMI for an exhaustive polarimetric analysis of brain structures, providing a reference dataset for future studies and enhancing the understanding of brain anatomy for clinicians and researchers.ApproachA multispectral wide-field MMI system was used to measure six fresh lamb brain specimens. Multiple decomposition methods (forward polar, symmetric, and differential) and polarization invariants (indices of polarimetric purity and anisotropy coefficients) have been calculated to obtain a complete polarimetric description of the samples. A total of 16 labels based on major brain structures, including grey matter (GM) and white matter (WM), were identified. K -nearest neighbors classification was used to distinguish between GM and WM and validate the feasibility of MMI for WM identification.ResultsAs the wavelength increases, both depolarization and retardance increase, suggesting enhanced tissue penetration into deeper layers. Moreover, utilizing multiple wavelengths allowed us to track dynamic shifts in the optical axis of retardance within the brain tissue, providing insights into morphological changes in WM beneath the cortical surface. The use of multispectral data for classification outperformed all results obtained with single-wavelength data and provided over 95% accuracy for the test dataset.ConclusionsThe consistency of these observations highlights the potential of multispectral wide-field MMI as a non-invasive and effective technique for investigating the brain's architecture.","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"18 1","pages":"096002"},"PeriodicalIF":3.5,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monte Carlo simulation of spatial frequency domain imaging for breast tumors during compression.","authors":"Constance M Robbins,Kuanren Qian,Yongjie Jessica Zhang,Jana M Kainerstorfer","doi":"10.1117/1.jbo.29.9.096001","DOIUrl":"https://doi.org/10.1117/1.jbo.29.9.096001","url":null,"abstract":"SignificanceNear-infrared optical imaging methods have shown promise for monitoring response to neoadjuvant chemotherapy (NAC) for breast cancer, with endogenous contrast coming from oxy- and deoxyhemoglobin. Spatial frequency domain imaging (SFDI) could be used to detect this contrast in a low-cost and portable format, but it has limited imaging depth. It is possible that local tissue compression could be used to reduce the effective tumor depth.AimTo evaluate the potential of SFDI for therapy response prediction, we aim to predict how changes to tumor size, stiffness, and hemoglobin concentration would be reflected in contrast measured by SFDI under tissue compression.ApproachFinite element analysis of compression on an inclusion-containing soft material is combined with Monte Carlo simulation to predict the measured optical contrast.ResultsWhen the effect of compression on blood volume is not considered, contrast gain from compression increases with the size and stiffness of the inclusion and decreases with the inclusion depth. With a model of reduction of blood volume from compression, compression reduces imaging contrast, an effect that is greater for larger inclusions and stiffer inclusions at shallower depths.ConclusionsThis computational modeling study represents a first step toward tracking tumor changes induced by NAC using SFDI and local compression.","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"7 1","pages":"096001"},"PeriodicalIF":3.5,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142258333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transportable hyperspectral imaging setup based on fast, high-density spectral scanning for <i>in situ</i> quantitative biochemical mapping of fresh tissue biopsies.","authors":"Luca Giannoni, Marta Marradi, Kevin Scibilia, Ivan Ezhov, Camilla Bonaudo, Angelos Artemiou, Anam Toaha, Frédéric Lange, Charly Caredda, Bruno Montcel, Alessandro Della Puppa, Ilias Tachtsidis, Daniel Rückert, Francesco Saverio Pavone","doi":"10.1117/1.JBO.29.9.093508","DOIUrl":"10.1117/1.JBO.29.9.093508","url":null,"abstract":"<p><strong>Significance: </strong>Histopathological examination of surgical biopsies, such as in glioma and glioblastoma resection, is hindered in current clinical practice by the long time required for the laboratory analysis and pathological screening, typically taking several days or even weeks to be completed.</p><p><strong>Aim: </strong>We propose here a transportable, high-density, spectral scanning-based hyperspectral imaging (HSI) setup, named HyperProbe1, that can provide <i>in situ</i>, fast biochemical analysis, and mapping of fresh surgical tissue samples, right after excision, and without the need for fixing, staining nor compromising the integrity of the tissue properties.</p><p><strong>Approach: </strong>HyperProbe1 is based on spectral scanning via supercontinuum laser illumination filtered with acousto-optic tunable filters. Such methodology allows the user to select any number and type of wavelength bands in the visible and near-infrared range between 510 and 900 nm (up to a maximum of 79) and to reconstruct 3D hypercubes composed of high-resolution (4 to <math><mrow><mn>5</mn> <mtext>  </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> ), widefield images ( <math><mrow><mn>0.9</mn> <mo>×</mo> <mn>0.9</mn> <mtext>  </mtext> <msup><mrow><mi>mm</mi></mrow> <mrow><mn>2</mn></mrow> </msup> </mrow> </math> ) of the surgical samples, where each pixel is associated with a complete spectrum.</p><p><strong>Results: </strong>The HyperProbe1 setup is here presented and characterized. The system is applied to 11 fresh surgical biopsies of glioma from routine patients, including different grades of tumor classification. Quantitative analysis of the composition of the tissue is performed via fast spectral unmixing to reconstruct the mapping of major biomarkers, such as oxy-( <math> <mrow> <msub><mrow><mi>HbO</mi></mrow> <mrow><mn>2</mn></mrow> </msub> </mrow> </math> ) and deoxyhemoglobin (HHb), as well as cytochrome-c-oxidase (CCO). We also provided a preliminary attempt to infer tumor classification based on differences in composition in the samples, suggesting the possibility of using lipid content and differential CCO concentrations to distinguish between lower and higher-grade gliomas.</p><p><strong>Conclusions: </strong>A proof of concept of the performances of HyperProbe1 for quantitative, biochemical mapping of surgical biopsies is demonstrated, paving the way for improving current post-surgical, histopathological practice via non-destructive, <i>in situ</i> streamlined screening of fresh tissue samples in a matter of minutes after excision.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"29 9","pages":"093508"},"PeriodicalIF":3.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11384341/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142288118","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 dark-field microscopy of human breast lumpectomy samples for tumor margin detection in breast-conserving surgery.","authors":"Jeeseong Hwang, Philip Cheney, Stephen C Kanick, Hanh N D Le, David M McClatchy, Helen Zhang, Nian Liu, Zhan-Qian John Lu, Tae Joon Cho, Kimberly Briggman, David W Allen, Wendy A Wells, Brian W Pogue","doi":"10.1117/1.JBO.29.9.093503","DOIUrl":"10.1117/1.JBO.29.9.093503","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Significance: &lt;/strong&gt;Hyperspectral dark-field microscopy (HSDFM) and data cube analysis algorithms demonstrate successful detection and classification of various tissue types, including carcinoma regions in human post-lumpectomy breast tissues excised during breast-conserving surgeries.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Aim: &lt;/strong&gt;We expand the application of HSDFM to the classification of tissue types and tumor subtypes in pre-histopathology human breast lumpectomy samples.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Approach: &lt;/strong&gt;Breast tissues excised during breast-conserving surgeries were imaged by the HSDFM and analyzed. The performance of the HSDFM is evaluated by comparing the backscattering intensity spectra of polystyrene microbead solutions with the Monte Carlo simulation of the experimental data. For classification algorithms, two analysis approaches, a supervised technique based on the spectral angle mapper (SAM) algorithm and an unsupervised technique based on the &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;K&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;-means algorithm are applied to classify various tissue types including carcinoma subtypes. In the supervised technique, the SAM algorithm with manually extracted endmembers guided by H&E annotations is used as reference spectra, allowing for segmentation maps with classified tissue types including carcinoma subtypes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;The manually extracted endmembers of known tissue types and their corresponding threshold spectral correlation angles for classification make a good reference library that validates endmembers computed by the unsupervised &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;K&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;-means algorithm. The unsupervised &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;K&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;-means algorithm, with no &lt;i&gt;a priori&lt;/i&gt; information, produces abundance maps with dominant endmembers of various tissue types, including carcinoma subtypes of invasive ductal carcinoma and invasive mucinous carcinoma. The two carcinomas' unique endmembers produced by the two methods agree with each other within &lt;math&gt;&lt;mrow&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;%&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt; residual error margin.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;Our report demonstrates a robust procedure for the validation of an unsupervised algorithm with the essential set of parameters based on the ground truth, histopathological information. We have demonstrated that a trained library of the histopathology-guided endmembers and associated threshold spectral correlation angles computed against well-defined reference data cubes serve such parameters. Two classification algorithms, supervised and unsupervised algorithms, are employed to identify regions with carcinoma subtypes of invasive ductal carcinoma and invasive mucinous carcinoma present in the tissues. The two carcinomas' unique endmembers used by the two methods agree to &lt;math&gt;&lt;mrow&gt;&lt;mo&gt;&lt;&lt;/mo&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;mo&gt;%&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt; residual error margin. This library of high quality and collected under an environment with no ambient background may be instrumental to develop or va","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"29 9","pages":"093503"},"PeriodicalIF":3.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11075096/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140876462","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 of 4T1 mammary carcinomas grown in dorsal skinfold window chambers: spectral renormalization and fluorescence modeling.","authors":"Tadej Tomanic, Tim Bozic, Bostjan Markelc, Jost Stergar, Gregor Sersa, Matija Milanic","doi":"10.1117/1.JBO.29.9.093504","DOIUrl":"10.1117/1.JBO.29.9.093504","url":null,"abstract":"<p><strong>Significance: </strong>Hyperspectral imaging (HSI) of murine tumor models grown in dorsal skinfold window chambers (DSWCs) offers invaluable insight into the tumor microenvironment. However, light loss in a glass coverslip is often overlooked, and particular tissue characteristics are improperly modeled, leading to errors in tissue properties extracted from hyperspectral images.</p><p><strong>Aim: </strong>We highlight the significance of spectral renormalization in HSI of DSWC models and demonstrate the benefit of incorporating enhanced green fluorescent protein (EGFP) excitation and emission in the skin tissue model for tumors expressing genes to produce EGFP.</p><p><strong>Approach: </strong>We employed an HSI system for intravital imaging of mice with 4T1 mammary carcinoma in a DSWC over 14 days. We performed spectral renormalization of hyperspectral images based on the measured reflectance spectra of glass coverslips and utilized an inverse adding-doubling (IAD) algorithm with a two-layer murine skin model, to extract tissue parameters, such as total hemoglobin concentration and tissue oxygenation ( <math> <mrow><msub><mi>StO</mi> <mn>2</mn></msub> </mrow> </math> ). The model was upgraded to consider EGFP fluorescence excitation and emission. Moreover, we conducted additional experiments involving tissue phantoms, human forearm skin imaging, and numerical simulations.</p><p><strong>Results: </strong>Hyperspectral image renormalization and the addition of EGFP fluorescence in the murine skin model reduced the mean absolute percentage errors (MAPEs) of fitted and measured spectra by up to 10% in tissue phantoms, 0.55% to 1.5% in the human forearm experiment and numerical simulations, and up to 0.7% in 4T1 tumors. Similarly, the MAPEs for tissue parameters extracted by IAD were reduced by up to 3% in human forearms and numerical simulations. For some parameters, statistically significant differences ( <math><mrow><mi>p</mi> <mo><</mo> <mn>0.05</mn></mrow> </math> ) were observed in 4T1 tumors. Ultimately, we have shown that fluorescence emission could be helpful for 4T1 tumor segmentation.</p><p><strong>Conclusions: </strong>The results contribute to improving intravital monitoring of DWSC models using HSI and pave the way for more accurate and precise quantitative imaging.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"29 9","pages":"093504"},"PeriodicalIF":3.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11262746/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141748313","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":"Detection and margin assessment of thyroid carcinoma with microscopic hyperspectral imaging using transformer networks.","authors":"Minh Ha Tran, Ling Ma, Hasan Mubarak, Ofelia Gomez, James Yu, Michelle Bryarly, Baowei Fei","doi":"10.1117/1.JBO.29.9.093505","DOIUrl":"10.1117/1.JBO.29.9.093505","url":null,"abstract":"<p><strong>Significance: </strong>Hyperspectral imaging (HSI) is an emerging imaging modality for oncological applications and can improve cancer detection with digital pathology.</p><p><strong>Aim: </strong>The study aims to highlight the increased accuracy and sensitivity of detecting the margin of thyroid carcinoma in hematoxylin and eosin (H&E)-stained histological slides using HSI and data augmentation methods.</p><p><strong>Approach: </strong>Using an automated microscopic imaging system, we captured 2599 hyperspectral images from 65 H&E-stained human thyroid slides. Images were then preprocessed into 153,906 image patches of dimension <math><mrow><mn>250</mn> <mo>×</mo> <mn>250</mn> <mo>×</mo> <mn>84</mn> <mtext>  pixels</mtext></mrow> </math> . We modified the TimeSformer network architecture, which used alternating spectral attention and spatial attention layers. We implemented several data augmentation methods for HSI based on the RandAugment algorithm. We compared the performances of TimeSformer on HSI against the performances of pretrained ConvNext and pretrained vision transformers (ViT) networks on red, green, and blue (RGB) images. Finally, we applied attention unrolling techniques on the trained TimeSformer network to identify the biological features to which the network paid attention.</p><p><strong>Results: </strong>In the testing dataset, TimeSformer achieved an accuracy of 90.87%, a weighted <math> <mrow><msub><mi>F</mi> <mn>1</mn></msub> </mrow> </math> score of 89.79%, a sensitivity of 91.50%, and an area under the receiving operator characteristic curve (AU-ROC) score of 97.04%. Additionally, TimeSformer produced thyroid carcinoma tumor margins with an average Jaccard score of 0.76 mm. Without data augmentation, TimeSformer achieved an accuracy of 88.23%, a weighted <math> <mrow><msub><mi>F</mi> <mn>1</mn></msub> </mrow> </math> score of 86.46%, a sensitivity of 85.53%, and an AU-ROC score of 94.94%. In comparison, the ViT network achieved an 89.98% accuracy, an 88.14% weighted <math> <mrow><msub><mi>F</mi> <mn>1</mn></msub> </mrow> </math> score, an 84.77% sensitivity, and a 96.17% AU-ROC. Our visualization results showed that the network paid attention to biological features.</p><p><strong>Conclusions: </strong>The TimeSformer model trained with hyperspectral histological data consistently outperformed conventional RGB-based models, highlighting the superiority of HSI in this context. Our proposed augmentation methods improved the accuracy, the <math> <mrow><msub><mi>F</mi> <mn>1</mn></msub> </mrow> </math> score, and the sensitivity score.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"29 9","pages":"093505"},"PeriodicalIF":3.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11268383/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141758976","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 with deep learning for quantification of tissue hemoglobin, melanin, and scattering.","authors":"Thomas T Livecchi, Steven L Jacques, Hrebesh M Subhash, Mark C Pierce","doi":"10.1117/1.JBO.29.9.093507","DOIUrl":"10.1117/1.JBO.29.9.093507","url":null,"abstract":"<p><strong>Significance: </strong>Hyperspectral cameras capture spectral information at each pixel in an image. Acquired spectra can be analyzed to estimate quantities of absorbing and scattering components, but the use of traditional fitting algorithms over megapixel images can be computationally intensive. Deep learning algorithms can be trained to rapidly analyze spectral data and can potentially process hyperspectral camera data in real time.</p><p><strong>Aim: </strong>A hyperspectral camera was used to capture <math><mrow><mn>1216</mn> <mo>×</mo> <mn>1936</mn> <mtext>  pixel</mtext></mrow> </math> wide-field reflectance images of <i>in vivo</i> human tissue at 205 wavelength bands from 420 to 830 nm.</p><p><strong>Approach: </strong>The optical properties of oxyhemoglobin, deoxyhemoglobin, melanin, and scattering were used with multi-layer Monte Carlo models to generate simulated diffuse reflectance spectra for 24,000 random combinations of physiologically relevant tissue components. These spectra were then used to train an artificial neural network (ANN) to predict tissue component concentrations from an input reflectance spectrum.</p><p><strong>Results: </strong>The ANN achieved low root mean square errors in a test set of 6000 independent simulated diffuse reflectance spectra while calculating concentration values more than 4000× faster than a conventional iterative least squares approach.</p><p><strong>Conclusions: </strong><i>In vivo</i> finger occlusion and gingival abrasion studies demonstrate the ability of this approach to rapidly generate high-resolution images of tissue component concentrations from a hyperspectral dataset acquired from human subjects.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"29 9","pages":"093507"},"PeriodicalIF":3.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11378079/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142154206","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":"Relationship between depth-wise refractive index and biomechanical properties of human articular cartilage.","authors":"Bilour Khan, Ervin Nippolainen, Fatemeh Shahini, Nonappa, Alexey Popov, Juha Töyräs, Isaac O Afara","doi":"10.1117/1.JBO.29.9.095003","DOIUrl":"10.1117/1.JBO.29.9.095003","url":null,"abstract":"<p><strong>Significance: </strong>Optical properties of biological tissues, such as refractive index (RI), are fundamental properties, intrinsically linked to the tissue's composition and structure. We hypothesize that, as the RI and the functional properties of articular cartilage (AC) are dependent on the tissue's structure and composition, the RI of AC is related to its biomechanical properties.</p><p><strong>Aim: </strong>This study aims to investigate the relationship between RI of human AC and its biomechanical properties.</p><p><strong>Approach: </strong>Human cartilage samples ( <math><mrow><mi>n</mi> <mo>=</mo> <mn>22</mn></mrow> </math> ) were extracted from the right knee joint of three cadaver donors (one female, aged 47 years, and two males, aged 64 and 68 years) obtained from a commercial biobank (Science Care, Phoenix, Arizona, United States). The samples were initially subjected to mechanical indentation testing to determine elastic [equilibrium modulus (EM) and instantaneous modulus (IM)] and dynamic [dynamic modulus (DM)] viscoelastic properties. An Abbemat 3200 automatic one-wavelength refractometer operating at 600 nm was used to measure the RI of the extracted sections. Similarly, Spearman's and Pearson's correlation coefficients were employed for non-normal and normal datasets, respectively, to determine the correlation between the depth-wise RI and biomechanical properties of the cartilage samples as a function of the collagen fibril orientation.</p><p><strong>Results: </strong>A positive correlation with statistically significant relations ( <math><mrow><mi>p</mi> <mo>-</mo> <mtext>values</mtext> <mo><</mo> <mn>0.05</mn></mrow> </math> ) was observed between the RI and the biomechanical properties (EM, IM, and DM) along the tissue depth for each zone, e.g., superficial, middle, and deep zones. Likewise, a lower positive correlation with statistically significant relations ( <math><mrow><mi>p</mi> <mo>-</mo> <mtext>values</mtext> <mo><</mo> <mn>0.05</mn></mrow> </math> ) was also observed for collagen fibril orientation of all zones with the biomechanical properties.</p><p><strong>Conclusions: </strong>The results indicate that, although the RI exhibits different levels of correlation with different biomechanical properties, the relationship varies as a function of the tissue depth. This knowledge paves the way for optically monitoring changes in AC biomechanical properties nondestructively via changes in the RI. Thus, the RI could be a potential biomarker for assessing the mechanical competency of AC, particularly in degenerative diseases, such as osteoarthritis.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"29 9","pages":"095003"},"PeriodicalIF":3.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11413650/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142288117","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":"Spectral analysis comparison of pushbroom and snapshot hyperspectral cameras for <i>in vivo</i> brain tissues and chromophore identification.","authors":"Alberto Martín-Pérez, Alejandro Martinez de Ternero, Alfonso Lagares, Eduardo Juarez, César Sanz","doi":"10.1117/1.JBO.29.9.093510","DOIUrl":"https://doi.org/10.1117/1.JBO.29.9.093510","url":null,"abstract":"<p><strong>Significance: </strong>Hyperspectral imaging sensors have rapidly advanced, aiding in tumor diagnostics for <i>in vivo</i> brain tumors. Linescan cameras effectively distinguish between pathological and healthy tissue, whereas snapshot cameras offer a potential alternative to reduce acquisition time.</p><p><strong>Aim: </strong>Our research compares linescan and snapshot hyperspectral cameras for <i>in vivo</i> brain tissues and chromophore identification.</p><p><strong>Approach: </strong>We compared a linescan pushbroom camera and a snapshot camera using images from 10 patients with various pathologies. Objective comparisons were made using unnormalized and normalized data for healthy and pathological tissues. We utilized the interquartile range (IQR) for the spectral angle mapping (SAM), the goodness-of-fit coefficient (GFC), and the root mean square error (RMSE) within the 659.95 to 951.42 nm range. In addition, we assessed the ability of both cameras to capture tissue chromophores by analyzing absorbance from reflectance information.</p><p><strong>Results: </strong>The SAM metric indicates reduced dispersion and high similarity between cameras for pathological samples, with a 9.68% IQR for normalized data compared with 2.38% for unnormalized data. This pattern is consistent across GFC and RMSE metrics, regardless of tissue type. Moreover, both cameras could identify absorption peaks of certain chromophores. For instance, using the absorbance measurements of the linescan camera, we obtained SAM values below 0.235 for four peaks, regardless of the tissue and type of data under inspection. These peaks are one for cytochrome b in its oxidized form at <math><mrow><mi>λ</mi> <mo>=</mo> <mn>422</mn> <mtext>  </mtext> <mi>nm</mi></mrow> </math> , two for <math> <mrow> <msub><mrow><mi>HbO</mi></mrow> <mrow><mn>2</mn></mrow> </msub> </mrow> </math> at <math><mrow><mi>λ</mi> <mo>=</mo> <mn>542</mn> <mtext>  </mtext> <mi>nm</mi></mrow> </math> and <math><mrow><mi>λ</mi> <mo>=</mo> <mn>576</mn> <mtext>  </mtext> <mi>nm</mi></mrow> </math> , and one for water at <math><mrow><mi>λ</mi> <mo>=</mo> <mn>976</mn> <mtext>  </mtext> <mi>nm</mi></mrow> </math> .</p><p><strong>Conclusion: </strong>The spectral signatures of the cameras show more similarity with unnormalized data, likely due to snapshot sensor noise, resulting in noisier signatures post-normalization. Comparisons in this study suggest that snapshot cameras might be viable alternatives to linescan cameras for real-time brain tissue identification.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"29 9","pages":"093510"},"PeriodicalIF":3.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11420787/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142347391","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}