A three-dimensional (3D) model of human anterior chamber is reconstructed to explore the effect of different corneal temperatures on the heat transfer in the chamber. Based on the optical coherence tomography imaging of the volunteers with normal anterior chamber, a 3D anterior chamber model was reconstructed by the method of UG parametric design. Numerical simulation of heat transfer and aqueous humor flow in the whole anterior chamber were analyzed by the finite volume methods at different corneal temperatures. The results showed that different corneal temperatures had obvious influence on the temperature distribution and the aqueous flow in the anterior chamber. The temperature distribution is linear and axial symmetrical around the pupillary axis. As the temperature difference increases, the symmetry becomes poorer. Aqueous floated along the warm side and sank along the cool side which forms a vortexing flow. Its velocity increased with the addition of temperature difference. Heat fluxes of cornea, lens andiris were mainly affected by the aqueous velocity. The higher the velocity, the bigger more absolute value of the above-mentioned heat fluxes became. It is practicable to perform the numerical simulation of anterior chamber by the optical coherence tomography imaging. The results are useful for studying the important effect of corneal temperature on the heat transfer and aqueous humor dynamics in the anterior chamber.
ObjectiveTo observe and analyze the correlations between aqueous humor cytokine concentrations and disorganization of retinal inner layers (DRIL), as well as postoperative visual acuity, in patients with idiopathic epiretinal membrane (iERM). MethodsA prospective clinical study. From November 2022 to October 2024, 40 eyes of 40 patients diagnosed with iERM at Ophthalmology Center of Zhejiang Provincial People's Hospital (Affiliated People's Hospital) underwent cataract surgery alone or combined with pars plana vitrectomy (iERM group) were enrolled; 19 eyes of 19 patients undergoing cataract surgery alone during the same period served as the control group. All eyes underwent best-corrected visual acuity (BCVA) testing and swept-source optical coherence tomography (SS-OCT). BCVA was assessed using a logarithmic visual acuity chart and converted to the logarithm of the minimum angle of resolution (logMAR) for statistical analysis. Central macular thickness (CMT) was measured using SS-OCT. The iERM group was further subdivided into DRIL-positive and DRIL-negative subgroups (21 eyes and 19 eyes, respectively), based on the presence or absence of DRIL. Aqueous humor samples were collected preoperatively from eyes in both the iERM and control groups. Concentrations of transforming growth factor (TGF)-β1, TGF-β2, TGF-β3, platelet-derived growth factor (PDGF)-AB, hepatocyte growth factor, fibroblast growth factor, vascular endothelial growth factor-A (VEGF-A), placental growth factor (PLGF), glial cell line-derived neurotrophic factor (GDNF), intercellular adhesion molecule-1 (ICAM-1), angiopoietin (Ang)-1, Ang-2, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were measured. Follow-up examinations using the same equipment and methods were performed at 1 month postoperatively. Aqueous cytokine levels were compared between the iERM group, control group, DRIL-positive subgroup, and DRIL-negative subgroup. Correlations between aqueous cytokine levels in the iERM group and BCVA or CMT were also analyzed. Intergroup comparisons utilized the Mann-Whitney U test; correlations between variables were assessed using Spearman's rank correlation analysis. ResultsCompared to the control group, the iERM group exhibited significantly higher aqueous concentrations of TGF-β1, TGF-β3, PDGF-AB, PLGF, GDNF, ICAM-1, Ang-1, and TNF-α (P＜0.05). Compared to the DRIL-negative subgroup, the DRIL-positive subgroup showed significantly elevated aqueous concentrations of TGF-β3, PDGF-AB, PLGF, GDNF, ICAM-1, Ang-1, Ang-2, TNF-α, and IL-6 (P＜0.05). Significant differences were observed in logMAR BCVA (P=0.028) and CMT (P＜0.001) within the iERM group between preoperative and 1-month postoperative measurements. LogMAR BCVA differed significantly between the DRIL-positive and DRIL-negative subgroups (P=0.048). Correlation analysis revealed that baseline aqueous levels of VEGF-A and IL-6 in eyes with DRIL were positively correlated with postoperative BCVA (r=0.324, 0.452; P=0.042, 0.003). No significant correlation was found between CMT and any cytokine (P＞0.05). ConclusionsAqueous humor cytokines are closely associated with DRIL in iERM patients. IL-6 and VEGF-A may serve as potential predictive biomarkers for early postoperative visual recovery.
Optical coherence tomography (OCT) is a new technique applied in cardiovascular system. It can detect vessel intimal, small structure of plaque surface and discover small lesions with its high axial resolution and quantification character. Especially with the application of OCT in characterization of coronary atherosclerotic plaque, diagnosis and treatment strategy making, optimizing percutaneous coronary intervention therapy and assessment after stent planting make the OCT become an efficient tool for cardiovascular disease diagnosis and treatment. This paper presents a novel coronary vessel intimal sequence extraction method based on prior boundary constraints in OCT image. On the basis of conventional Chan-Vese model, we modified the evolutionary weight function to control the evolutionary rate of boundary by adding local information of boundary curve. At the same time, we added the gradient energy term and intimal boundary constraint term based on priori boundary condition to further control the evolutionary of boundary curve. At last, coronary vessel intimal is extracted in a sequence way. The comparison with vessel intimal, manual segmented by clinical scientists (golden standard), indicates that our coronary vessel intimal extraction method is robust to intimal boundary blur, distortion, guide wire shadow and plaque disturbs. The results of this study can be applied to clinical aid diagnosis and precise diagnosis and treatment.
The aim of this study was to investigate the feasibility of anterior segment optical coherence tomography to assess the anterior segment morphology of hyperopia in school-aged children. 320 eyes of 160 school-aged children, 6-12 years of age, were examined with anterior segment optical coherence tomography and were divided into four groups according to the cycloplegic spherical equivalence of refractive error. The mentioned four groups were: emmetropia group, low hyperopia group, moderate hyperopia group and high hyperopia group. The measurements of central corneal thickness, anterior chamber depth, angle opening distance, trabecular iris space area and scleral angle were compared in pairs among objects in the four groups. The results showed that high hyperopia and moderate hyperopia had shallower anterior chamber depth and narrower anterior chamber angle compared to those in emmetropia group. The study also showed that anterior segment optical coherence tomography as a non-contact technology could become a new technology for accessing the anterior segment morphology of hyperopia in school-aged children.
Objective To explore the pathological diagnostic value of optical coherence tomography (OCT) in lung cancer. Methods This study selected patients who underwent general anesthesia and electronic bronchoscope biopsy at the Respiratory Endoscopy Center of Sichuan Provincial People’s Hospital from January 1, 2023, to December 1, 2023. White-light bronchoscopy (WLB), auto-fluorescence bronchoscopy (AFB), and OCT examinations were performed in all patients. Lesions were assessed for benign or malignant characteristics based on AFB and OCT before biopsy. The final pathological results were determined according to pathology report. Results A total of 124 patients were included in the study. The accuracy of OCT in differentiating the nature of lesions was 93.55%, significantly higher than AFB (accuracy 83.06%). The accuracy, sensitivity, and specificity of OCT were all higher than AFB. For squamous carcinoma, adenocarcinoma, and small cell lung cancer, the accuracy rates of OCT imaging characteristics were 91.94%, 94.35%, and 94.35%, respectively. Conclusion OCT can improve the accuracy of pre-bronchoscopic tissue pathology biopsy in determining the nature of lesions and provide rapid pathological typing basis, potentially further promoting the development of non-invasive histological biopsy.
Optical coherence tomography (OCT) is a non-invasive, rapid optical medical imaging modality and has become a hot topic in biomedical research. In recent years, several functional OCTs have emerged, including Doppler OCT, polarization-sensitive OCT, spectroscopic OCT, and optical coherence tomographic elastography, etc. These newer advances in functional OCT broaden the potential clinical application of OCT by providing novel ways to observe and understand tissue activity that cannot be accomplished by other current imaging methodologies.
Objective To observe the hemodynamic changes in the retina and choroid after scleral buckling surgery in eyes with rhegmatogenous retinal detachment (RRD). MethodsA prospective clinical observational study. A total of 25 eyes of 25 patients with RRD who underwent scleral buckling surgery in Tianjin Eye Hospital from February to April 2024 were included in the study. Among them, 10 were male and 15 were female. Age was 17-68 years old. All cases were monocular. The surgical eye and the contralateral healthy eye were divided into the affected eye group and the contralateral healthy eye group respectively. Best corrected visual acuity (BCVA), scanning source optical coherence tomography angiography (SS-OCTA), and axial length (AL) measurements were performed 3 months after surgery. SS-OCTA examination of macular area was performed by VG200 of Visual Microimaging (Henan) Technology Co., LTD. Scanning range 21 mm×26 mm. According to the partitioning method of the early treatment group of glycosuria retinopathy, the retina within 21 mm of the macular fovea was divided into concentric circles with the macular fovea as the center and diameters of 1-3, 3-6, 6-12, 12-21 mm, respectively. The built-in software of the device was used to record the central area (12 mm×12 mm in the fovea of the macula) and the peripheral area (12-21 mm range) retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), radial peripapillary capillaries (RPC) blood density and choroidal vascular index (CVI), choroidal vascular volume (CVV), and 1-3, 3-6, 6-12, 12-21 mm above concentric circles (S), nasal side (N), temporal side (T), and lower side (I) SCP, DCP, and RPC blood flow density. Quantitative data between the two groups were compared by independent sample t test or Wilcoxon signed rank test. The correlation between retinal and choroid blood flow parameters and postoperative BCVA was analyzed by Spearman correlation analysis. ResultsCompared with the opposite healthy eye group, SCP blood density in the central area (Z=?4.372), DCP blood density in the central area (Z=?2.829), and CVI in the peripheral area (Z=?2.138) were decreased in the affected eye group, and the differences were statistically significant (P＜0.05). SCP: in the affected eye group, the blood flow density in T3-6 mm, T6-12 mm, N6-12 mm and T12-21 mm regions decreased, while the blood flow density in I6-12 mm regions increased, with statistical significance (P＜0.05). DCP: blood flow density in S6-12 mm, I6-12 mm, S12-21 mm and I12-21 mm regions decreased significantly, and the differences were statistically significant (P＜0.05). RPC: blood flow density decreased significantly in T6-12 mm and I12-21 mm, and the differences were statistically significant (P＜0.05). CVI: T6-12 mm, S12-21 mm, T12-21 mm, I12-21 mm significantly decreased, and T1-3 mm, S12-21 mm significantly increased, the differences were statistically significant (P＜0.05). Correlation analysis showed that AL growth was positively correlated with CVV in central region (r=0.408, P=0.040) . The number of pad pressure was negatively correlated with the blood density of central DCP (r=?0.422, P=0.030). ConclusionsAfter scleral buckling operation, the blood flow density and choroidal blood flow parameters in RRD affected eyes are lower than those in contralateral healthy eyes in some areas. The increase of AL is positively correlated with CVV in the central region, and the wider the range of pad pressure, the worse the recovery of DCP blood density.
We aimed to establish an optical coherence tomography (OCT) system to measure the strain of blood vessels. A general OCT system was constructed firstly and its reliability was confirmed by comparing the OCT imaging of the porcine coronary and the corresponding histological slices. The strain of the porcine coronary was induced by static flow pressure and correlation algorithm was used to calculate the strain field of blood vessels within OCT images. The results suggest that bright-dark stratification of blood vessels displayed in OCT images is consistent with the intima and media layers of histological image. Furthermore, the strain of media layer is greater than that of the intima layer under the same static pressure. The optical coherence imaging system could not only measure the histological structure of the blood vessels, but also qualify the vessel strain under flow pressure.
The segmentation of the intracoronary optical coherence tomography (OCT) images is the basis of the plaque recognition, and it is important to the following plaque feature analysis, vulnerable plaque recognition and further coronary disease aided diagnosis. This paper proposes an algorithm about multi region plaque segmentation based on kernel graph cuts model that realizes accurate segmentation of fibrous, calcium and lipid pool plaques in coronary OCT image, while boundary information has been well reserved. We segmented 20 coronary images with typical plaques in our experiment, and compared the plaque regions segmented by this algorithm to the plaque regions obtained by doctor's manual segmentation. The results showed that our algorithm is accurate to segment the plaque regions. This work has demonstrated that it can be used for reducing doctors' working time on segmenting plaque significantly, reduce subjectivity and differences between different doctors, assist clinician's diagnosis and treatment of coronary artery disease.
Objective To observe the anastomotic status of the vortex veins in patients with central serous chorioretinopathy (CSC). MethodsA cross-sectional study of clinical practice. From July 2021 to July 2022, 50 cases (50 eyes) of monocular CSC patients diagnosed through ophthalmic examination at the First Affiliated Hospital of Zhengzhou University were included in the study. Among them, there were 37 males (74.0%, 37/50) and 13 females (26.0%, 13/50), with the mean age of (44.30±9.59) years old. The course of disease from the onset of symptoms to the time of treatment was less than 3 months. The affected eye and contralateral eye of CSC patients were divided into the affected eye group and contralateral eye group, respectively. Fifty healthy volunteers of the same age and gender were selected as the normal control group with 50 eyes. The macular area scanning source optical coherence tomography (OCT) vascular imaging examination was performed with Visual Microimaging (Henan) Technology Co., Ltd. VG200D. Horizontal watershed vortex veins anastomosis rate and asymmetric vortex-venous dilation rate were observed by en face OCT. The device comes with software to calculate the central foveal choroidal thickness (SFCT), mean choroidal thickness (MCT), and choroidal vascular index (CVI). One-way analysis of variance and χ2 test were used to compare the three groups. When variances were unequal between groups, nonparametric tests were performed. ResultsThe SFCT values of the affected eye group, contralateral eye group, and normal control group were (567.12±129.02), (513.26±133.17), (327.64±97.40) μm, respectively; MCT were (407.38±97.54), (388.24±94.13), (275.46±60.55) μm, respectively; CVI were 0.34±0.05, 0.32±0.04, and 0.27±0.04, respectively; anastomosis rates of vortex veins were 98% (49/50), 78% (39/50), and 40% (20/50), respectively; asymmetric dilation rates of vortex veins were 96% (48/50), 88% (44/50), and 48% (24/50), respectively. The differences of SFCT (F=53.974), MCT (Z=51.415), CVI (F=28.082), vortex vein anastomosis rate (χ2=43.056), asymmetric dilation rate of vortex veins (χ2=37.728) among three groups were statistically significant (P＜0.001). Compared with the contralateral eye group, the SFCT, MCT, CVI, vortex vein anastomosis rate, and vortex vein asymmetric dilation rate in the affected eye group were significantly higher than those in the contralateral eye group. Among them, the differences of SFCT (t=2.054), CVI (t=2.211), and vortex vein anastomosis rate (χ2=9.470) were statistically significant (P＜0.05); the differences of MCT (Z=7.490), asymmetric dilation rate of vortex veins（χ2=2.714) were not statistically significant (P=1.000, 0.140). ConclusionsSFCT, MCT, and CVI in the affected and contralateral eyes of monocular CSC patients significantly increase. The anastomotic rate and asymmetric dilation rate of the vortex vein in the opposite eye were lower than those in the affected eye.