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Integrating Handcrafted and Deep Features for Optical Coherence Tomography Based Retinal Disease Classification
摘要： Deep Neural Networks (DNNs) have been widely applied to automatic analysis of medical images for disease diagnosis, and to help human experts by efficiently processing immense amounts of images. While handcrafted feature has been used for eye disease detection or classification since the 1990s, DNN was recently adopted in this area and showed very promising performance. Since handcrafted and deep feature can extract complementary information, we propose in this paper three different integration frameworks to combine handcrafted and deep feature for optical coherence tomography (OCT) image based eye disease classification. In addition, to integrate the handcrafted feature at Input and Fully Connection (FC) layers using existing networks like VGG, DenseNet and Xception, a novel ribcage network (RC Net) is also proposed for feature integration at middle layers. For RC Net, two “rib” channels are designed to independently process deep and handcrafted features, and another so called “spine” channel is designed for the integration. While dense blocks are the main components of the three channels, sum operation is proposed for the feature map integration. Our experimental results showed that the deep networks achieved better classification accuracy after integration of the handcrafted features e.g. SIFT and Gabor. The RC Net showed the best performance among all proposed feature integration methods.
关键词： feature integration,deep learning,Artificial intelligence,optical coherence tomography
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - High Intensity Focused Ultrasound (HIFU) Combines Optical Coherence Tomography(OCT) for Biological Tissue Treatment and Evaluation
摘要： Light intensity focused ultrasound (LIFU) is an early stage medical technology that is in various stages of development to treat a range of disorders including super?cial diseases. Optical coherence tomography (OCT) is a rapid development imaging technique in recent ten years, which is a good way to monitor the tissue structure of super?cial diseases. In this study, OCT system is used to monitor the tissue structure of super?cial diseases during LIFU treatment. During the treatment, LIFU was performed on the lesion area of the sample with different energy levels for different times: 5s, 10s, 15s, 20s, 25s, 30s, respectively. During the treatment, the OCT system was working to monitor the tissue structure. The results showed that the light intensity of the lesion area increased with the treatment time, and the structure of the tissue changed. This study provides a new method for monitoring the treatment of super?cial diseases with LIFU.
关键词： Monitoring,Optical coherence tomography,Tissue structure,Super?cial diseases,Light intensity focused ultrasound
更新于2025-09-23 15:22:29
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[IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Numerical Simulation of Low-Coherence Radiation Propagation in Turbid Media and Structural Image Reconstruction in Endoscopic Optical Coherence Tomography with Allowance for Speckle Fluctuations
摘要： A method of Monte Carlo simulation of low-coherence radiation propagation in turbid media with consideration of speckle noise (the result of mutual interference of secondary spherical waves) is described. The process of photon propagation within investigated object, such as biological tissue, includes the following steps: the photon injection, mean free path determination, the verification of the fulfillment of the boundary condition, the absorption and scattering. Structural image reconstruction in optical coherence tomography (OCT) with consideration of speckle fluctuations is made by summation the statistical weight of the beam coming out of the investigated object inside the detector area with the intensity of a series of pixels of the current A-scan. The key feature of the presented method is the description of the investigated object geometry. Three-dimensional array of voxels combined into parallelograms, and the border cross checking is carried out by using an improved Smith algorithm. The described method can be used to obtain high-quality endoscopic structural OCT images of body cavities and tracts (diagnosis of the respiratory tract, cardiovascular system, gastrointestinal tract, genitourinary system, etc.).
关键词： coherence probing depth,Monte Carlo simulation,optical coherence tomography,voxel based model,speckle fluctuations,structural image
更新于2025-09-23 15:22:29
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<sup>18</sup> F-Sodium Fluoride Positron Emission Tomography and Plaque Calcification
摘要： 18F-sodium fluoride (18F-NaF) was introduced as a tracer for imaging skeletal diseases in 1962 and was approved by the Food and Drug Administration in 1972.1 Recently, with the increased availability of positron emission tomography (PET) scanners there has been a surge in clinical utilization of 18F-NaF imaging for oncological applications. The incidental observation, nearly a decade ago, of 18F-NaF uptake in the vasculature in patients undergoing PET imaging for cancer has led to a growing number of investigations exploring the potential role of this tracer in atherosclerosis.2–4 However, the biological correlates of 18F-NaF imaging in the vasculature, and its potential role in risk stratification of patients and prospective identification of vulnerable plaques remain incompletely characterized. In this issue of the Journal, Creager et al5 address some of these gaps by exploring the relationship between 18F-NaF binding and the size of microcalcifications using a 3-dimensional hydrogel platform.6 In agreement with a previous publication,2 their study finds that smaller and more numerous microcalcifications (ie, higher surface areas of calcifications) are associated with higher 18F-NaF binding when compared with fewer larger calcifications.5 The study also provides ex vivo proof-of-concept evidence for the correlation between 18F-NaF binding and foci of ongoing calcification in mouse and human atherosclerotic plaques.5
关键词： Editorials,sodium fluoride,atherosclerosis,inflammation,positron emission tomography
更新于2025-09-23 15:22:29
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A Comprehensive Model for Correcting RNFL Readings of Varying Signal Strengths in Cirrus Optical Coherence Tomography
摘要： PURPOSE. To develop a model for the Cirrus HD-OCT that allows for the comparison of retinal nerve fiber layer (RNFL) thickness measurements with dissimilar signal strengths (SS) and accounts for test–retest variability. METHODS. Retinal nerve fiber layers were obtained in normals using the Cirrus optic disc cube 200 3 200 protocol during a single encounter. Five RNFL scans were obtained with a SS of 9 or 10. Diffusion lens filters were used to degrade SS to obtain five scans at each SS group of 7 or 8, 5 or 6, and 3 or 4. The relationship between average RNFL thickness and SS was established, and an equation was developed to allow for adjustment of an RNFL measurement had it been a SS of 7. Intravisit interclass correlation coefficient (ICC) and coefficient of variation (CV) parameter estimates for each SS group were calculated. Repeatability and upper tolerance limit were calculated as 1.96 3 =2 3 within-subject standard deviation (Sw) and 1.645 3 =2 3 Sw, respectively. RESULTS. There was a linear relationship between average RNFL and SS. RNFLadj ? RNFL (cid:2) 1.03*SS t 7.21 allows for the adjustment of RNFL readings to the same SS. Interclass correlation coefficients and CVs were good for all measurements down to SS of 3 or 4. Repeatability and upper tolerance limit were 5.24 and 4.40 lm, respectively. CONCLUSIONS. Our model adjusts RNFL readings based on SS and includes an upper tolerance limit of 5 lm. If validated, this model could improve the detection of real RNFL changes. Further study to validate this model should be performed before widespread use is adopted.
关键词： glaucoma anterior segment,Cirrus OCT,signal strength,optical coherence tomography
更新于2025-09-23 15:22:29
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Cell Motility as Contrast Agent in Retinal Explant Imaging With Full-Field Optical Coherence Tomography
摘要： PURPOSE. To use cell motility as a contrast agent in retinal explants. METHODS. Macaque and mouse retinal explants were imaged with high resolution full field optical coherence tomography (FFOCT) and dynamic FFOCT, coupled with fluorescence imaging. RESULTS. Static and dynamic FFOCT create complementary contrast from different structures within a cell. When imaging in vitro samples, static FFOCT detects steep refractive index gradients to reveal stationary structures including fibers, vessels, collagen, and cell contours, while dynamic FFOCT emphasizes metabolic activity of moving structures that are mainly intracellular, thus creating or enhancing contrast in cells that were previously hidden in noise. Dynamic FFOCT enables detection of most of the retinal cell types in the ganglion cell, inner and outer nuclear layers, where static FFOCT contrast is too low in relation to the noise background. CONCLUSIONS. Composite static and dynamic FFOCT provides a new kind of FFOCT image containing valuable information for imaging of retinal explants. It provides label-free en face images of living retinas, with a subcellular resolution. Dynamic FFOCT adds information about cell activity, which is of interest in longitudinal explant studies.
关键词： explant,motility,optical coherence tomography
更新于2025-09-23 15:22:29
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A Label-free Multicolor Optical Surface Tomography (ALMOST) imaging method for nontransparent 3D samples
摘要： Background: Current mesoscale 3D imaging techniques are limited to transparent or cleared samples or require the use of X-rays. This is a severe limitation for many research areas, as the 3D color surface morphology of opaque samples—for example, intact adult Drosophila, Xenopus embryos, and other non-transparent samples—cannot be assessed. We have developed “ALMOST,” a novel optical method for 3D surface imaging of reflective opaque objects utilizing an optical projection tomography device in combination with oblique illumination and optical filters. Results: As well as demonstrating image formation, we provide background information and explain the reconstruction—and consequent rendering—using a standard filtered back projection algorithm and 3D software. We expanded our approach to fluorescence and multi-channel spectral imaging, validating our results with micro-computed tomography. Different biological and inorganic test samples were used to highlight the versatility of our approach. To further demonstrate the applicability of ALMOST, we explored the muscle-induced form change of the Drosophila larva, imaged adult Drosophila, dynamically visualized the closure of neural folds during neurulation of live Xenopus embryos, and showed the complementarity of our approach by comparison with transmitted light and fluorescence OPT imaging of a Xenopus tadpole. Conclusion: Thus, our new modality for spectral/color, macro/mesoscopic 3D imaging can be applied to a variety of model organisms and enables the longitudinal surface dynamics during development to be revealed.
关键词： Tomography,Opaque samples,Real color,Label-free,3D imaging,Mesoscale,Morphology
更新于2025-09-23 15:22:29
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Maximum entropy based non-negative optoacoustic tomographic image reconstruction
摘要： Objective: Optoacoustic (photoacoustic) tomography is aimed at reconstructing maps of the initial pressure rise induced by the absorption of light pulses in tissue. In practice, due to inaccurate assumptions in the forward model, noise and other experimental factors, the images are often afflicted by artifacts, occasionally manifested as negative values. The aim of the work is to develop an inversion method which reduces the occurrence of negative values and improves the quantitative performance of optoacoustic imaging. Methods: We present a novel method for optoacoustic tomography based on an entropy maximization algorithm, which uses logarithmic regularization for attaining non-negative reconstructions. The reconstruction image quality is further improved using structural prior based fluence correction. Results: We report the performance achieved by the entropy maximization scheme on numerical simulation, experimental phantoms and in-vivo samples. Conclusion: The proposed algorithm demonstrates superior reconstruction performance by delivering non-negative pixel values with no visible distortion of anatomical structures. Significance: Our method can enable quantitative optoacoustic imaging, and has the potential to improve pre-clinical and translational imaging applications.
关键词： inverse problems,image reconstruction,Optical parameters,regularization theory,photoacoustic tomography
更新于2025-09-23 15:22:29
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Performance of Cone Beam Computed Tomography Systems in Visualizing the Cortical Plate in 3D Image Reconstruction: An Study
摘要： Introduction: Cortical bone is an important anatomical structure and its thickness needs to be determined prior to many dental procedures to ensure treatment success. Imaging modalities are necessarily used in dentistry for treatment planning and dental procedures. Three-dimensional image reconstruction not only provides visual information but also enables accurate measurement of anatomical structures; thus, it is necessarily required for maxillofacial examination and in case of skeletal problems in this region. Aims: This study aimed to assess the ability of three Cone Beam Computed Tomography (CBCT) systems including Cranex 3D, NewTom 3G and 3D Promax for Three-Dimensional (3D) image reconstruction of the cortical plate with variable thicknesses. Methods: Depending on the cortical bone thickness, samples were evaluated in three groups of ≤ 0.5 mm, 0.6 -1 mm and 1.1-1.5 mm cortical bone thickness. The CBCT scans were obtained from each sample using three systems, their respective FOVs, and 3D scans were reconstructed using their software programs. Two observers viewed the images twice with a two-week interval. The ability of each system in the 3D reconstruction of different thicknesses of cortical bone was determined based on its visualization on the scans. The data were analyzed using SPSS and Kappa test. Results: The three systems showed the greatest difference in the 3D reconstruction of cortical bone with < 0.5 mm thickness. Cranex 3D with 4×6 cm2 FOV had the highest and 3D Promax with 8×8 cm2 FOV had the lowest efficacy for 3D reconstruction of cortical bone. Cranex 3D with 4×6 cm2 and 6×8 cm2 FOVs and NewTom 3G with 5×5 cm2 and 8×5 cm2 FOVs showed significantly higher efficacy for 3D reconstruction of cortical bone with 0.6-1mm thickness while 3D Promax followed by NewTom 3G with 8×8 cm2 FOV had the lowest efficacy for this purpose. Conclusion: Most CBCT systems have high efficacy for 3D image reconstruction of cortical bone with thicknesses over 1 mm while they have poor efficacy for image reconstruction of cortical bone with less than 0.5 mm thickness. Thus, for accurate visualization of anatomical structures on CBCT scans, systems with smaller FOVs and consequently smaller voxel size are preferred.
关键词： Cone-Beam Computed Tomography (CBCT),Imaging,Computer-assisted,Image processing,Three-dimensional,Cortical bone
更新于2025-09-23 15:22:29
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Cone-beam CT reconstruction along any orientation of interest
摘要： We present a novel method which provides X-ray CT users the flexibility to reconstruct an object along any of its internal flat features. This internal feature, which is generally not parallel to the object’s external surface, can be either an interface between two materials or one surface of an internal layer. This method is developed based on our existing CT differential reconstruction algorithm that is achieved by modifying the popular Feldkamp-Davis-Kress cone-beam reconstruction technique. The theory of this technology is described. One case-study demonstrates that this method is independent of the surface selection of several parallel features. Another case-study shows its capability to reconstruct any individual plate along the plate’s own orientation with a three-plate object.
关键词： differential CT reconstruction,cone-beam reconstruction,Computed tomography,orientation-preferred reconstruction
更新于2025-09-23 15:22:29