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.
Intravascular optical coherence tomography (IVOCT) has emerged as a high-resolution and minimal-invasive imaging technique that provides high-speed visualization of coronary arterial vessel walls and clearly displays the vessel lumen and lesions under the intima. However, morphological gray-scale images cannot provide enough information about the tissue components to accurately characterize the plaque tissues including calcified, fibrous, lipidic and mixed plaques. Quantitative IVOCT (qIVOCT) is necessary to provide the physiological contrast mechanisms and obtain the characteristic parameters of tissues with clinical diagnostic value. In this paper, the progress of qIVOCT is reviewed. The current methods for quantitatively measuring optical, elastic and hemodynamic parameters of vessel wall and plaque tissues using IVOCT gray-scale images and raw backscattered signals are introduced and potential development is forecast.
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.
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.
ObjectiveTo observe the histopathological changes in peripheral retinal lesions under intraoperative optical coherence tomography (iOCT). Methods A retrospective case series study. Eighty-eight patients (194 eyes) who underwent vitreoretinal surgery in the Department of Ophthalmology at the East Ward of the First Affiliated Hospital of Zhengzhou University from October 2021 to May 2022 in 94 eyes were included in the study. Among them, 49 cases were male and 39 cases were female, with the mean age of (50.93±17.55) years. Ninety-four eyes included 32 eyes with retinal detachment, 6 eyes with proliferative diabetic retinopathy, 28 eyes with vitreous hemorrhage, 8 eyes with ocular trauma, 14 eyes with the macular lesion, 1 eye with uveitis, 1 eye with family exudative vitreoretinopathy (FEVR), 1 eye with acute retinal necrosis (ARN), and 3 eyes with lens dislocation. All affected eyes were examined with iOCT during vitreoretinal surgery. The iOCT scanning of the peripheral retina was performed with the help of episcleral pressure. The pre-equatorial and serrated edge anterior and posterior of retinas were scanned according to the characteristics of different fundus diseases. Various abnormal fundus manifestations were recorded. Results In 94 eyes, 53 eyes (56.38%, 53/94) have different types of retinopathy in the peripheral retina. Of these, 7 eyes (7.45%) have retinal cystoid degeneration; 19 eyes (20.21%) have lattice degeneration; and 8 eyes (8.51%) have pigment degeneration; 9 eyes (9.57%) have pavement-like degeneration; 7 eyes (7.45%) have small occult holes; 1 eye (1.06%) has familial exudative vitreoretinopathy (FEVR) serrated edge "dyke-like" proliferative degeneration; 4 eyes (4.26%) have vitreous and retinopathy adhesions; and one eye (1.06%) has ARN. Conclusion With clear refractive media, iOCT can provide clear scans of different peripheral retinal lesions.
Objective To observe the curative effect of a personalized surgical scheme based on scanning source optical coherence tomography (SS-OCT) image features in the treatment of congenital optic disc pit (ODP) with maculopathy (ODP-M). MethodsA prospective interventional cohort study. From September 2019 to May 2024, 15 patients with 15 eyes who were diagnosed with ODP-M by ophthalmology examination in Department of Ophthalmonogy of The First Affiliated Hospital of Zhengzhou University were included in the study. Best corrected visual acuity (BCVA) and SS-OCT were performed in all affected eyes. Standard E word visual acuity chart was used for BCVA examination, which was converted into logarithm of the minimum angle of resolution (logMAR) BCVA for record. The center retinal thickness (CRT) was measured by SS-OCT examination of macular area using VG200D of Henan SVision Imaging Technology Co., LTD. According to the morphological characteristics of ODP and the splitting, edema and detachment of macular region, combined with the degree of pulling of the boundary membrane between the posterior vitreous cortex and macular region, a personalized surgical method was designed. Class I: pars plana vitrectomy combined with macular boundary film stripping, ODP boundary film packing and vitreous cavity gas filling. Class Ⅱ: pars plana vitrectomy combined with non-retained macular boundary film stripping or ODP inner boundary film packing, vitreous cavity gas filling. Class Ⅰ and Class Ⅱ operations were performed in 10 and 5 eyes of 15 eyes, respectively. The postoperative follow-up time was ＞6 months. Follow-up time was performed with the same equipment before surgery. BCVA changes, CRT reduction rate and complications were observed. BCVA and CRT were compared before and after operation by paired sample t test. ResultsThere were 15 eyes in 15 cases, 4 eyes in 4 males and 11 eyes in 11 females. The age was (28.87±16.5) years. logMAR BCVA of the affected eye was 0.94±0.51. CRT was (697.80±301.80) μm. At the last follow-up, the logMAR BCVA was 0.53±0.49. CRT was (392.53±167.55) μm. Compared with before operation, BCVA and CRT were significantly improved, and the difference was statistically significant (t=3.23, 3.25; P=0.006, 0.006). After surgery, transient intraocular hypertension occurred in 2 eyes, and the intraocular pressure returned to normal level after 3 to 7 days without special treatment. Two eyes underwent an unexpected second operation. Among them, one eye underwent Class Ⅰ surgery, the tunnel at ODP was closed after surgery, and there was a small amount of subretinal fluid in the macular area. Class Ⅱ surgery was performed in 1 eye with retinal reattachment. ConclusionPersonalized surgical treatment of ODP-M based on SS-OCT image features can reduce CRT and improve visual acuity.
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.
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.
ObjectiveTo examine the postoperative morphological changes in outer retinal wave-like changes (ORC) in eyes with rhegmatogenous retinal detachment (RRD). MethodsA retrospective clinical study. From March 2020 to March 2024, 64 eyes of 64 RRD patients diagnosed at The Second Affiliated Hospital of Zunyi Medical University were included. The cohort included 39 males (39 eyes) and 25 females (25 eyes), with a mean age of (45.3±15.7) years and a mean retinal detachment duration of (16.6±13.5) days. Macular involvement was observed in 51 eyes. Scleral buckling surgery (SB), pars plana vitrectomy (PPV), and SB+PPV were performed in 17, 44, and 3 eyes respectively. Best corrected visual acuity (BCVA) and spectral domain optical coherence tomography examinations were performed in all affected eyes. BCVA examination was performed using the standard logarithmic visual acuity chart, and the visual acuity was converted to logarithm of the minimum angle of resolution (logMAR) during statistics. Combined with the ORC situation before the operation, the morphological repositioning of outer retinal folds (ORF) after the operation was classified into types Ⅰ, Ⅱ and Ⅲ. One week and one and three months after the operation, relevant examinations were performed using the same equipment and methods as before the operation. The structural characteristics of ORC and the morphology of ORF after surgery were observed. The comparison between groups was conducted using the independent sample t test or the Mann-Whitney U test. ResultsAmong the 64 eyes, preoperative ORC was present in 46 eyes (71.9%, 46/64) and absent in 18 eyes (28.1%, 18/64). The 18 eyes without ORC had retinal detachment durations of either ≤4 days or ≥42 days. Postoperatively, ORF was observed in 51 eyes (79.7%, 51/64) and absent in 13 eyes (20.3%, 13/64). Among the 51 eyes with macular holes involved, 24 eyes (47.1%, 24/51) had ORF after the operation and 27 eyes (52.9%, 27/51) had no ORF. Among the 46 and 18 eyes with and without ORC, the ORF after surgery was 28 (60.9%, 28/46) and 1 (5.6%, 1/18) eyes, respectively. There was a statistically significant difference in the reduction rate of ORF after surgery between eyes with and without ORC (χ2=15.974, P＜0.001). Among the 46 eyes with ORC, the proportions of ORF to types Ⅰ, Ⅱ and Ⅲ after surgery were 24 (52.2%, 24/46), 20 (43.5%, 20/46), and 2 (4.3%, 2/46) eyes, respectively. There was no statistically significant difference in the incidence of ORF after different surgical methods in eyes with ORC (P＞0.05). One week and one month after the surgery, the logMAR BCVA of the affected eyes with and without ORF was 0.97±0.47, 0.69±0.34 and 0.85±0.32, 0.54±0.21, respectively. The BCVA of those without ORF was better than that of those with ORF, but the differences were not statistically significant (t=0.237, 0.408; P＞0.05). ConclusionsThe occurrence of ORC in RRD eyes has a certain relationship with the time of retinal detachment. For RRD eyes with ORC before the operation, the repositioning morphology after the operation is more likely to show changes in ORF. The transformation from ORC to ORF after ORC surgery has no correlation with the surgical method.
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.