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Combination of High-Resolution Optical Coherence Tomography and Raman Spectroscopy for Improved Staging and Grading in Bladder Cancer
摘要： We present a combination of optical coherence tomography (OCT) and Raman spectroscopy (RS) for improved diagnosis and discrimination of different stages and grades of bladder cancer ex vivo by linking the complementary information provided by these two techniques. Bladder samples were obtained from biopsies dissected via transurethral resection of the bladder tumor (TURBT). As OCT provides structural information rapidly, it was used as a red-flag technology to scan the bladder wall for suspicious lesions with the ability to discriminate malignant tissue from healthy urothelium. Upon identification of degenerated tissue via OCT, RS was implemented to determine the molecular characteristics via point measurements at suspicious sites. Combining the complementary information of both modalities allows not only for staging, but also for differentiation of low-grade and high-grade cancer based on a multivariate statistical analysis. OCT was able to clearly differentiate between healthy and malignant tissue by tomogram inspection and achieved an accuracy of 71% in the staging of the tumor, from pTa to pT2, through texture analysis followed by k-nearest neighbor classification. RS yielded an accuracy of 93% in discriminating low-grade from high-grade lesions via principal component analysis followed by k-nearest neighbor classification. In this study, we show the potential of a multi-modal approach with OCT for fast pre-screening and staging of cancerous lesions followed by RS for enhanced discrimination of low-grade and high-grade bladder cancer in a non-destructive, label-free and non-invasive way.
关键词： principal component analysis (PCA),Raman spectroscopy (RS),k-nearest neighbor classification (kNN),bladder cancer,optical coherence tomography (OCT)
更新于2025-09-10 09:29:36
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[IEEE 2018 24th International Conference on Pattern Recognition (ICPR) - Beijing, China (2018.8.20-2018.8.24)] 2018 24th International Conference on Pattern Recognition (ICPR) - Fully convolutional network and graph-based method for co-segmentation of retinal layer on macular OCT images
摘要： Retinal layer segmentation in optical coherence tomography (OCT) images is crucial for the diagnosis and study of retinal diseases. Graph-based methods are commonly used in layer segmentation. However, most of these methods require a lot of human efforts for determining an appropriate model to compute good edge weights. In this paper, we propose a novel automatic method for segmenting retinal layers in macular OCT images. Specially, we propose a new fully convolutional deep learning architecture with a side output layer to directly learn optimal graph-edge weights from raw pixels. The architecture can automatically learn multi-scale and multi-level features to generate accurate boundary probabilities as good edge weights without hand-crafted appropriate models. The boundaries are finalized by using graph segmentation method. The proposed method is evaluated on a dataset with 130 OCT B-scans. The experimental results show the mean absolute boundary positioning differences are 1.48±0.34 pixel.
关键词： fully convolutional network,retinal layer segmentation,graph-based framework,Optical coherence tomography (OCT)
更新于2025-09-09 09:28:46
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Current OCT Approaches Do Not Reliably Identify TCFAs
摘要： It is now clearly established that Thin-Capped Fibroatheromas (TCFAs) lead to most Acute Coronary Syndromes (ACSs). The ability to selectively intervene on TCFAs predisposed to rupture and ACSs would dramatically alter the practice of cardiology. While the ability of OCT to identify thin walled plaques at micron scale resolutions has represented a major advance, it is a misconception that it can reliably identify TCFAs. One major reason is that the ‘diffuse border’ criteria currently used to determine ‘lipid plaque’ is almost undoubtedly from high scattering in the intima and not because of core composition (necrotic core). A second reason is that, rather than looking at lipid collections, studies need to be focused on identifying necrotic cores with OCT. Necrotic cores are characteristic of TCFAs and not lipid collections. Numerous other OCT approaches are available which can potentially accurately assess TCFAs, but these have not been aggressively pursed which we believe likely stems in part from the misconceptions over the efficacy of ‘diffuse borders’.
关键词： Myocardial infarction,Optical coherence tomography: OCT,Macrophages,Plaque rupture,Acute coronary syndrome: ACS,Thin capped fibroatheroma: TCFA,Lipid,Massachusetts General Hospital Lightlab
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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Retinal and Choroidal Imaging With 870-nm Spectral-Domain OCT Compared With 1050-nm Spectral-Domain OCT, With and Without Enhanced Depth Imaging
摘要： The purpose of this study was to compare images of the retina and choroid obtained with Spectralis 1050-nm spectral-domain optical coherence tomography (SD-OCT) with and without enhanced depth imaging (EDI) to the commercially available 870-nm SD-OCT with and without EDI. Methods: Full-length 308 line scans were obtained with both 870- and 1050-nm Spectralis OCT instruments, with and without EDI. Two trained retina physicians masked to wavelength and EDI status assessed the ability to visualize the vitreoretinal interface and full-thickness choroid, and subfoveal choroidal thickness (SFCT) was measured. Results: Included in the study were 21 eyes. The vitreoretinal interface was visualized best with 870-nm OCT without EDI and was diminished with 1050-nm OCT. Graders preferred 1050 nm with EDI over 870 nm with EDI in qualitative comparisons of the choroid; 1050 nm without EDI was slightly preferred over 870 nm with EDI but was not statistically significant. SFCT measurements correlated well among the imaging modalities except for 870 nm without EDI. Conclusions: SD-OCT with EDI at 870 nm provides good visualization of both the vitreoretinal interface and choroid, whereas 1050-nm SD-OCT with or without EDI provides more choroidal detail at the expense of visualization of the vitreoretinal interface.
关键词： longer wavelength,optical coherence tomography (OCT),choroid,retina
更新于2025-09-04 15:30:14
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Optical coherence tomography imaging of the basal ganglia: feasibility and brief review
摘要： Optical coherence tomography (OCT) is a promising medical imaging technique that uses light to capture real-time cross-sectional images from biological tissues in micrometer resolution. Commercially available optical coherence tomography systems are employed in diverse applications, including art conservation and diagnostic medicine, notably in cardiology and ophthalmology. Application of this technology in the brain may enable distinction between white matter and gray matter, and obtainment of detailed images from within the encephalon. We present, herein, the in vivo implementation of OCT imaging in the rat brain striatum. For this, two male 60-day-old rats (Rattus norvegicus, Albinus variation, Wistar) were stereotactically implanted with guide cannulas into the striatum to guide a 2.7-French diameter high-definition OCT imaging catheter (Dragonfly, St. Jude Medical, USA). Obtained images were compared with corresponding histologically stained sections to collect imaging samples. A brief analysis of OCT technology and its current applications is also reported, as well as intra-cerebral OCT feasibility on brain mapping during neurosurgical procedures.
关键词： Basal ganglia,Optical coherence tomography (OCT),Rat brain,Histology,Thalamus,Brain imaging
更新于2025-09-04 15:30:14
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Comparison study of OCT, HRT and VF findings among normal controls and patients with pseudoexfoliation, with or without increased IOP
摘要： Purpose: To compare and evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) measurements obtained with the optical coherence tomography (OCT) and the Heidelberg retina tomography (HRT) to visual field (VF) parameters in normal and in patients with pseudoexfoliation with or without increased intraocular pressure (IOP). Methods: A total of 96 subjects were included in our study aged between 65 years and 78 years. The normal group consisted of 28 subjects (14 men and 14 women). Out of the total number of patients, 68 patients who showed pseudoexfoliation (21 men and 47 women) were divided into two groups. Of these, the first group had pseudoexfoliation with increased IOP and the second group showed deposits of pseudoexfoliative material without an increase in IOP. The normal controls were randomly chosen and restricted to those without any glaucomatous optic disc damages, VF defects, and an IOP 15 mmHg. All subjects were prospectively included for repeated measurements of IOP, OCT, HRT, and VFs during the same visit by the same examiner and all measurements were repeated every 3 months. Results: Mean RNFL thickness measured by OCT was larger in the normal controls than in the other two groups (98.04 μm (first group) vs 75.42 μm and 97.02 μm (second group), P0.05). Four-quadrant RNFL thickness measurements were significantly different between the normal and the group 1 (P0.05) but not with the group 2 (P0.05). Rim area had a mean difference of -0.44, whereas cup-to-disc ratio (C/D) showed a mean difference of 0.31, thus being significantly different between the normal and the two groups (all P0.05). The median of the mean deviation parameter of VFs was -0.28 for the normal vs -0.32 and -0.18 for the other two groups, whereas pattern standard deviation median difference was 0.89 for the normal and 1.32 and 1.20 for the other two groups, respectively (P0.05). Conclusion: Both OCT and HRT showed early ONH and RNFL changes in their parameters and did not correlate with the normal findings of the automated perimetry.
关键词： retinal nerve fiber layer (RNFL),visual fields (VFs),pseudoexfoliation glaucoma,pseudoexfoliation syndrome,Heidelberg retina tomograph (HRT),optical coherence tomography (OCT)
更新于2025-09-04 15:30:14
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A two-year study of diffused retinal pigment epitheliopathy treated with half-dose photodynamic therapy guided by simultaneous angiography and optical coherence tomography
摘要： Objectives Diffused retinal pigment epitheliopathy (DRPE) is not necessarily the same as chronic central serous chorioretinopathy (CSC), but a severe subgroup under the umbrella of chronic CSC. This study was to evaluate the efficacy and safety of half-dose PDT treating DRPE. Methods A retrospective case series design was used. Forty-eight consecutive patients (48 eyes) with DRPE treated with half-dose PDT underwent follow-up at baseline, 3 months, 6 months, 12 months and 24 months. Simultaneous FA, ICGA and OCT were used for the treatment and follow-up. The primary outcomes were the subretinal fluid and best-corrected visual acuity in optical coherence tomography. Results Complete fluid absorption was achieved in 95.8% of eyes at 3 months and 100.0% of eyes at 24 months. The baseline logarithm of the minimum angle of resolution (logMAR) BCVA, which was 0.51 ± 0.36, significantly improved to 0.43 ± 0.38 (p < 0.001) at 6 months. The boost continued to 0.29 ± 0.37 (p < 0.001) at 12 months and 0.19 ± 0.39 (p < 0.001) at 24 months. The integrities of the ellipsoid zone (EZ) and interdigitation zone (IZ) improved throughout. Regression analyses showed the BCVA in logMAR was inversely correlated with the EZ (p < 0.01) and IZ (p < 0.01). The recurrence rate was 6.3%. No severe complications were witnessed. Conclusions In 48 eyes with DRPE, simultaneous angiography and OCT facilitated a more comprehensive guidance for half-dose PDT treatment and follow-up. The BCVA improvement occurred at 6 months, which may be attributed to the restoration of the outer retinal structure.
关键词： chronic central serous chorioretinopathy,half-dose photodynamic therapy,Diffused retinal pigment epitheliopathy,angiography,CSC,optical coherence tomography,OCT,DRPE,PDT
更新于2025-09-04 15:30:14