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[Lecture Notes in Computer Science] Intravascular Imaging and Computer Assisted Stenting and Large-Scale Annotation of Biomedical Data and Expert Label Synthesis Volume 11043 (7th Joint International Workshop, CVII-STENT 2018 and Third International Workshop, LABELS 2018, Held in Conjunction with MICCAI 2018, Granada, Spain, September 16, 2018, Proceedings) || Deep Learning-Based Detection and Segmentation for BVS Struts in IVOCT Images
摘要： Bioresorbable Vascular Sca?old (BVS) is the latest stent type for the treatment of coronary artery disease. A major challenge of BVS is that once it is malapposed during implantation, it may potentially increase the risks of late stent thrombosis. Therefore it is important to analyze struts malapposition during implantation. This paper presents an automatic method for BVS malapposition analysis in intravascular optical coherence tomography images. Struts are ?rstly detected by a detector trained through deep learning. Then, struts boundaries are segmented using dynamic programming. Based on the segmentation, apposed and malapposed struts are discriminated automatically. Experimental results show that the proposed method successfully detected 97.7% of 4029 BVS struts with 2.41% false positives. The average Dice coe?cient between the segmented struts and ground truth was 0.809. It concludes that the proposed method is accurate and e?cient for BVS struts detection and segmentation, and enables automatic malapposition analysis.
关键词： Bioresorbable vascular sca?old,Deep learning,Intravascular optical coherence tomography,Detection and segmentation
更新于2025-09-04 15:30:14
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Voltage Noise and Jitter Analysis for Swept Source Optical Coherence Tomography using KTa1-xNbxO3 Deflector
摘要： This paper describes voltage noise and jitter analysis for the depth deviation of a point spread function in a swept source optical coherence tomography system using a KTa1-xNbxO3 deflector. An interference waveform with voltage noise and jitter was simulated according to a previous report. Typical values for the voltage noise ΔVTYP and jitter ΔtTYP were also obtained from a previous report and experiment. It was determined that the depth deviation is limited by the ΔtTYP of the system. Therefore, the quality of the tomographic image can be efficiently improved by reducing jitter.
关键词： Interference waveform,Jitter,Simulation,Swept source optical coherence tomography,Signal-to-noise ratio,Voltage noise
更新于2025-09-04 15:30:14
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Vitrectomy for diabetic macular edema: optical coherence tomography criteria and pathology of the vitreomacular interface
摘要： Purpose: To correlate spectral-domain optical coherence tomography (SD-OCT) criteria and clinical data with pathology of the vitreomacular interface (VMI) in eyes with diabetic macular edema (DME). Design: Retrospective cross-sectional study and laboratory investigation. Methods: We included specimens of 27 eyes of 26 patients with center-involved DME that underwent vitrectomy with peeling of the internal limiting membrane (ILM). Selection of specimens was consecutive and in retrospect using our register of the Vitreoretinal Pathology Unit. Clinical data and SD-OCT examinations were correlated to immunocytochemistry and transmission electron microscopy. Classification of DME comprised sponge-like diffuse retinal thickening, cystoid macular edema, and serous retinal detachment. VMI was evaluated for presence of epiretinal membrane (ERM) and thickened vitreous cortex (tVC). Results: ERMs and tVC were found in all DME types. Diffuse DME showed more often tVC than cystoid DME. Hyalocytes, contractile myofibroblasts, glial cells, matrix metalloproteinases-2 and -9, and collagen type I, II and III were positive tested irrespective of DME type. There were no significant cell fragments at the retinal side of ILM. Visual acuity improved in the majority of cases and macular thickness decreased significantly during mean follow-up of 17 ± 10 months. Conclusions: All eyes presented pathologic VMI changes irrespective of the OCT classification of DME type or presence of ERM. Composition of fibrocellular membranes at the VMI indicated remodelling of vitreous cortex and transdifferentiation of hyalocytes into myofibroblasts. Our findings might argue for an early surgical intervention in eyes with DME irrespective of the presence of traction formation imaged by SD-OCT.
关键词： optical coherence tomography,diabetic macular edema,vitrectomy,pathology,vitreomacular interface
更新于2025-09-04 15:30:14
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Imaging and visualization of the polarization state of the probing beam in polarization-sensitive optical coherence tomography
摘要： We propose a simple and ef?cient method of color-encoded Stokes parameters to visualize the polarization states for polarization-sensitive optical coherence tomography (PS-OCT) of biological tissue. In this method, polarization states of the probing light are detected and described in the Stokes domain. Three primary colors of red, green, and blue are used to code Stokes parameters of Q, U, and V, respectively, which can be used to represent and visualize each unique polarization state. A strategy that uses the polarization state as the PS-OCT imaging parameter is ?rst introduced to obtain high contrast images of the birefringent samples. Then, color-based automatic segmentation of birefringent components from 3D scanned tissue volume is proposed to isolate the network of the 3D nerve bundles in a mouse brain without cutting the brain into slices. Experimental validation and demonstrations are given by imaging ex vivo mouse tail and brain tissues to show the usefulness of proposed polarization state imaging and segmentation methods.
关键词： automatic segmentation,Stokes parameters,birefringent tissue,polarization-sensitive optical coherence tomography,polarization state imaging
更新于2025-09-04 15:30:14
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Synthesis and evaluation of 4-(2-fluoro-4-[11C]methoxyphenyl)-5-((2-methylpyridin-4-yl)methoxy)picolinamide for PET imaging of the metabotropic glutamate receptor 2 in the rat brain
摘要： Metabotropic glutamate receptor 2 (mGluR2) has been suggested as a therapeutic target for treating schizophrenia-like symptoms arising from increased glutamate transmission in the human forebrain. However, no reliable positron emission tomography (PET) radiotracer allowing for in vivo visualization of mGluR2 in the human brain is currently available. In this study, we synthesized 4-(2-fluoro-4-[11C]methoxyphenyl)-5-((2-methylpyridin-4-yl)methoxy)picolinamide ([11C]1) and evaluated its potential as a PET tracer for imaging mGluR2 in the rodent brain. Compound 1, a negative allosteric modulator (NAM) of mGluR2, showed high in vitro binding affinity (IC50: 26 nM) for mGluR2 overexpressed in human cells. [11C]1 was synthesized by O-[11C]methylation of the phenol precursor 2 with [11C]methyl iodide. After the reaction, HPLC purification and formulation, [11C]1 of 7.4 ± 2.8 GBq (n = 8) was obtained from [11C]carbon dioxide of 22.5 ± 4.8 GBq (n = 8) with >99% radiochemical purity and 70 ± 32 GBq/μmol (n = 8) molar activity at the end of synthesis. In vitro autoradiography for rat brains showed that [11C]1 binding was heterogeneously distributed in the cerebral cortex, striatum, hippocampus, and cerebellum. This pattern is consistent with the regional distribution pattern of mGluR2 in the rodent brain. The radioactivity was significantly reduced by self- or MNI-137 (a mGluR2 NAM) blocking. Small-animal PET studies indicated a low in vivo specific binding of [11C]1 in the rat brain. The brain uptake was increased in a P-glycoprotein and breast cancer resistant protein double knockout mouse, when compared to a wild-type mouse. While [11C]1 presented limited potential as an in vivo PET tracer for mGluR2, we suggested that it can be used as a lead compound for developing new radiotracers with improved in vivo brain properties.
关键词： positron emission tomography,radiotracer,schizophrenia,metabotropic glutamate receptor 2,in vitro autoradiography
更新于2025-09-04 15:30:14
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Optic nerve head width and retinal nerve fiber layer changes are good indexes for validating the successful induction of experimental anterior ischemic optic neuropathy
摘要： Reproducible skills are essential for successful induction of a rat model of anterior ischemic optic neuropathy (rAION). We established an in vivo validation index by measuring the natural course of optic nerve head (ONH) width and retinal nerve fiber layer (RNFL) thickness in the rAION model using optical coherence tomography (OCT). The rAION model was induced by photodynamic operations. We measured the ONH width and RNFL thickness in the acute stage (<3 days), subacute stage (day 7 and day 14) and later stage (day 28) post-infarct by OCT. RNFL were measured by hematoxylin and eosin stain (HE) to confirm the OCT findings. The RGCs survival rate was determined by retrograde Fluoro-gold labeling, and the visual function was assessed with flash visual-evoked potentials (FVEPs) 4 weeks post-infarct. The ONH showed significant swelling in the acute stage, which also correlated with RNFL swelling. The swelling was reduced to normal within one-week post-infarct. The rAION group (0.51± 0.12 mm2) showed a significant RNFL thinning when compared with sham groups (0.92±0.15 mm2, p<0.05) on day-28 post-infarct. And HE-stained retina cross sections also showed RNFL thinning, which further confirmed our OCT Findings. The RGC density and P1-N2 amplitude were significantly reduced in rAION. Swelling, reduction of swelling, and atrophy of RNFL in acute, sub-acute, and later stage, respectively, are important events for confirming the successful induction of rAION. They suggest that the longitudinal OCT data provides a reliable index for validating the reproducibility and correct order of rAION.
关键词： optic nerve head (ONH),retinal ganglion cells (RGCs),optical coherence tomography (OCT),anterior ischemic optic neuropathy in rats (rAION),retina nerve fiber layer (RNFL)
更新于2025-09-04 15:30:14
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Reflectivity and thickness analysis of epiretinal membranes using spectral-domain optical coherence tomography
摘要： · AIM: To compare thickness and reflectivity spectral domain optical coherence tomography (SD-OCT) findings in patients with idiopathic epiretinal membranes (ERMs), before and after ERM peeling surgery, with normal controls. · METHODS: A retrospective study analyzing SD-OCTs of eyes with ERMs undergoing ERM peeling surgery by one surgeon from 2008 to 2010 and normal control eyes. SD-OCTs were analyzed using a customized algorithm to measure reflectivity and thickness. The relationship between the SD-OCT findings and best corrected visual acuity (BCVA) outcomes was also studied. · RESULTS: Thirty-four ERM eyes and 12 normal eyes were identified. Preoperative eyes had high reflectivity and thickness of the group of layers from the internal limiting membrane (ILM) to the retinal pigment epithelium (RPE) and the group of layers from the ILM to the external limiting membrane (ELM). The reflectivity of these two groups of layers decreased postoperatively, but were still higher than normal eyes. In contrast, preoperative eyes had lower reflectivity of two 10 × 15 pixel regions of interest (ROIs) incorporating: 1) ELM + outer nuclear layer (ONL) and 2) photoreceptor layer (PRL) + RPE, compared to controls. The values of reflectivity of these ROIs increased postoperatively, but were still lower than normal. A larger improvement in BCVA postoperatively was correlated with a greater degree of abnormal preoperative reflectivity and thickness findings. · CONCLUSION: Quantitative differences in reflectivity and thickness between preoperative, postoperative, and normal SD-OCTs allow assessment of changes in the retina secondary to ERM. Our study identified hyperreflective inner retinal changes and hyporeflective outer retinal changes in patients with ERMs. SD-OCT quantitative measures of reflectivity and/or thickness of specific groups of retinal layers and/or ROIs correlate with improvement in BCVA.
关键词： epiretinal membranes,retina,imaging,reflectivity,optical coherence tomography,vitrectomy
更新于2025-09-04 15:30:14
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Evaluation of Each Retinal Layer Thickness According to Preoperative OCT Patterns after Idiopathic ERM Removal
摘要： ??: ??? ???????? ? ? ????????? ???? ??? ?? ?? ?? ???? ????? ??? ??? ????, ?????? ????? ????? ???. ??? ??: ??? ?????? ??? ?? 6?? ?? ????? ???? ?? 63? 63?? ???? ????? ?????. ? ? ???????? ?? ????? ??? ???, ???, ????? ???? ?? ?? ???? ????? ??? ??? ????, ?????? ????? ??? ???. ??: ? ? ??? ???, ???, ??? ????, ?????? ??? ????? ???. ???? ?? ? ? ? ??????+????, ????, ?????? ???, ???, ??? ??? ??? ????? ???, ? ? ??????+????? ?????? ???, ???, ??? ??? ????? ??? ??? ???. ? ? ??? ???? ??? ? ? ???? ???, ????? ????? ? ? ??????+????? ?????, ?????? ????? ????? ?? ??? ????. ??: ??? ???????? ????????? ???? ??? ?? ? ? ???? ??? ??? ???. ?? ???? ??? ?? ? ? ??? ???? ?? ? ????? ???? ??? ????? ??? ???? ??? ? ???.
关键词： Epiretinal membrane,Retinal layer thickness,Optical coherence tomography
更新于2025-09-04 15:30:14
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The Evaluation of Prognostic Factors after Vitrectomy for Lamellar Macular Hole Using Optical Coherence Tomography
摘要： Purpose: To evaluate the prognostic factors that predict visual outcome after vitrectomy for lamellar macular hole using optical coherence tomography (OCT). Methods: This study included 26 eyes that underwent pars plana vitrectomy, epiretinal membrane removal, and internal limiting membrane peeling for lamellar macular hole. The maximum parafoveal thickness, maximum height and diameter of lamellar macular hole, maximum height and diameter of intraretinal splitting, thinnest foveal floor thickness, and inner segment/outer segment disruption length on preoperative OCT image were investigated for prognostic factors that predict visual outcome. Results: The mean follow-up period was 32.2 months and the mean best corrected visual acuity improved significantly after vitrectomy from log MAR 0.47 ± 0.32 to log MAR 0.23 ± 0.23. The postoperative visual acuity correlated significantly with preoperative visual acuity, thinnest foveal floor thickness and inner segment/outer segment disruption length, but not with maximum parafoveal thickness, maximum height and diameter of lamellar macular hole and maximum height and diameter of intraretinal splitting. Conclusions: The thinnest foveal floor thickness and inner segment/outer segment disruption length on preoperative OCT image were significant prognostic factors.
关键词： Lamellar macular hole,Optical coherence tomography,Prognostic factors
更新于2025-09-04 15:30:14
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Label-Free Identification of Lymphocyte Subtypes Using Three-Dimensional Quantitative Phase Imaging and Machine Learning
摘要： We describe here a protocol for the label-free identification of lymphocyte subtypes using quantitative phase imaging and machine learning. Identification of lymphocyte subtypes is important for the study of immunology as well as diagnosis and treatment of various diseases. Currently, standard methods for classifying lymphocyte types rely on labeling specific membrane proteins via antigen-antibody reactions. However, these labeling techniques carry the potential risks of altering cellular functions. The protocol described here overcomes these challenges by exploiting intrinsic optical contrasts measured by 3D quantitative phase imaging and a machine learning algorithm. Measurement of 3D refractive index (RI) tomograms of lymphocytes provides quantitative information about 3D morphology and phenotypes of individual cells. The biophysical parameters extracted from the measured 3D RI tomograms are then quantitatively analyzed with a machine learning algorithm, enabling label-free identification of lymphocyte types at a single-cell level. We measure the 3D RI tomograms of B, CD4+ T, and CD8+ T lymphocytes and identified their cell types with over 80% accuracy. In this protocol, we describe the detailed steps for lymphocyte isolation, 3D quantitative phase imaging, and machine learning for identifying lymphocyte types.
关键词： lymphocyte identification,machine learning,holotomography,immune cell,immunology,Immunology and Infection,Quantitative phase imaging,optical diffraction tomography,holographic microscopy,label-free imaging
更新于2025-09-04 15:30:14