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.
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.
Objective To evaluate the application value of optical coherence tomography angiography (OCTA) in obstructive sleep apnea syndrome (OSAS). Methods A comprehensive search of both domestic and international databases was conducted to identify clinical studies on the use of OCTA in OSAS, from the establishment of the databases to May 2024. A meta-analysis was performed using Revman 5.4 software. Results A total of 134 studies were initially identified, with 14 studies meeting the inclusion criteria, encompassing 999 subjects (739 in the OSAS group and 260 in the healthy group). Meta-analysis results indicated that the superficial capillary plexus (SCP) density in the fovea (MD=–2.05, 95%CI –3.75 to –0.35, P=0.02) and parafovea (MD=–1.56, 95%CI –2.44 to –0.68, P=0.000 5) was significantly lower in the OSAS group compared with the healthy group. In the mild to moderate OSAS group, SCP density was significantly lower in the fovea (MD=–2.41, 95%CI –4.32 to –0.49, P=0.01), parafovea (MD=–1.17, 95%CI –2.01 to –0.32, P=0.007), and perifovea (MD=–1.73, 95%CI –2.69 to –0.77, P=0.000 4) compared with the healthy group. In the severe OSAS group, SCP density in the perifovea (MD=–1.33, 95%CI –2.53 to –0.13, P=0.03) was significantly lower than that of the healthy group. SCP density in the whole area (MD=0.36, 95%CI 0.05 to 0.68, P=0.02) was significantly higher in the mild to moderate OSAS group compared with the severe OSAS group. In the deep capillary plexus (DCP) density, the OSAS group showed significantly lower densities in the whole area (MD=–2.16, 95%CI –3.51 to –0.81, P=0.002), fovea (MD=–2.38, 95%CI –4.38 to –0.37, P=0.02), and parafovea (MD=–2.33, 95%CI –3.93 to –0.73, P=0.004) compared with the healthy group. The mild to moderate OSAS group also showed significantly lower densities in the whole area (MD=–2.02, 95%CI –3.33 to –0.72, P=0.002) and parafovea (MD=–1.65, 95%CI –3.04 to –0.26, P=0.02) compared with the healthy group. The severe OSAS group had significantly lower DCP density in the whole area (MD=–2.26, 95%CI –3.85 to –0.66, P=0.006) and parafovea (MD=–1.47, 95%CI –2.31 to –0.62, P=0.000 7) compared with the healthy group. DCP density in the whole area (MD=0.54, 95%CI 0.02 to 1.07, P=0.04) was significantly higher in the mild to moderate OSAS group compared with the severe OSAS group. Regarding the retinal nerve fiber layer (RNFL) thickness, the inferior quadrant (MD=4.01, 95%CI 0.69 to 7.32, P=0.02) and temporal quadrant (MD=4.35, 95%CI 1.88 to 6.82, P=0.000 6) were significantly thicker in the mild to moderate OSAS group compared with the severe OSAS group. In terms of the foveal avascular zone (FAZ) area, the severe OSAS group showed a significantly larger FAZ area (MD=0.06, 95%CI 0.03 to 0.08, P<0.000 01) compared with the healthy group. Conclusion OCTA-related ocular biomarkers may be associated with the occurrence and progression of OSAS and have potential applications in the diagnosis and treatment of OSAS.
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 the changes of chorioidal thickness (ChT) in patients with central serous chorioretinopathy (CSC) in different mode of vortic venous dilation. MethodsA prospective cross-sectional observational study. A total of 80 patients with 89 eyes (CSC group) diagnosed in Department of Ophthalmology, General Hospital of Central Theater Command from April to October 2023 were included in the study. Among them, 64 males had 71 eyes and 17 females had 18 eyes. A total of 15 healthy volunteers matched in age and sex were selected as the control group. Among them, 14 men had 26 eyes and one woman had two eyes. The macular region was examined by ultra-wide-angle scanning frequency source optical coherence tomography (OCTA) with BM400K BMizar made by TowardPi (Beijing) Medical Technology Co., LTD. Scanning rate 1 536 A scanning×1 280 B scanning, scanning range 24 mm×20 mm. The accompanying software delineated nine subfields (superotemporal, upper, superonasal, temporal, central, nasal, inferotemporal, lower, inferonasal regions) to record ChT. En-face OCTA mode was utilized to observe the anatomy and functional anastomosis of the vortex veins above and below the choroidal blood layer. Eyes in the CSC group were further categorized into upper-dominant, symmetrical, and lower-dominant groups based on the difference in vortex vein expansion shown in the choroidal layer of the en-face image, with 36, 35, and 18 eyes respectively. Statistical analysis included the use of independent samples t-test or Mann-Whitney test for comparison between two groups, one-way analysis of variance or Kruskal-Wallis H test for comparison between multiple groups, and the χ test or Fisher test for categorical variables. ResultsCompared with the control group, ChT in the CSC group was thickened in the foveal area and different areas of the macula, with the greatest difference in the fovea, and the differences were statistically significant (t=3.345, 5.018, 2.902, 4.667, 7.276, 3.307, 3.868, 4.795, 2.583; P＜0.05). Compared with the ChT of the control group, there was no statistically significant difference in the superotemporal, region of the upper-dominant group (t=1.510, P＞0.05); in other regions, the differences were statistically significant (t=3.207, 5.163, 2.526, 4.310, 6.285, 2.656, 3.812, 2.173; P＜0.05). The differences in the foveal area and other areas in the symmetrical group were statistically significant (t=4.488, 5.554, 3.457, 5.314, 7.256, 3.507, 5.584, 6.019, 2.994; P＜0.05). In the superotemporal, and superonasal, regions of the lower dominant group, the differences were not statistically significant (t=1.150, 1.465; P＜0.05); in other regions, the differences were statistically significant (t=2.278, 4.168, 5.244, 2.783, 5.040, 3.432, 2.095; P＜0.05). ConclusionThe dilated distribution of vortex veins on en-face ultra-wide-angle OCTA has a corresponding relationship with ChT. In eyes with CSC, the superior vortex vein drainage system may be the primary route for choroidal drainage.
ObjectiveTo observe the correlation between retinal capillary density and retinal thickness in the macula and spherical equivalent (SE) in school-age children. MethodsA cross-sectional study. From May to December 2022, 182 school-age children who visited the ophthalmology department of the First Affiliated Hospital of Zhengzhou University were included . There were 95 males and 87 females. The age ranged from 6 to 12 years, and the spherical equivalent (SE) was +0.50 to －6.00 D. They were divided into three groups based on the SE of the right eyes: 54 eyes in emmetropia group (+0.50≤SE＜－0.50 D), 71 eyes in low myopia group (－0.50≤SE＜－3.00 D), and 57 eyes in moderate myopia group (－3.00≤SE≤－6.00 D). The macular area of 6 mm×6 mm was scanned using swept-source optical coherence tomography angiography and was divided into three concentric rings centered on the fovea, including the macular central fovea (0-1 mm diameter), inner ring (1-3 mm diameter) and outer ring (3-6 mm diameter). The retinal thickness and blood flow density of superficial vascular plexus (SVP) and deep vascular plexus (DVP) in different zones within 6 mm of the macular area were measured. The relationships between SE and SVP, DVP and retinal thickness in each ring region were investigated by univariate and multivariate linear regression analyses, smooth curve fitting, and threshold effects. ResultsThere were significant differences in the SVP (F=6.64, 26.06, 22.69) and DVP (F=7.97, 25.01, 5.09) of macular central fovea, inner ring and outer ring among the emmetropia, low myopia and moderate myopia groups (P＜0.05). Univariate linear regression analysis showed that the SVP (β=－0.56, －1.17, －0.79) and DVP (β=－1.03, －0.93, －0.45) of the three regions were positively correlated with SE (P＜0.05). After smooth curve fitting, threshold effect analysis and multivariate linear regression analysis, the SVP and DVP in the macular central fovea were linearly positively correlated with SE (β=－0.91, －1.40; P＜0.05), and SVP and DVP in the inner ring and outer ring showed an inverted U-shaped curve relationship with SE with the inflection (＜3.00 D). When the SE was less than ＜3.00 D, the SVP and DVP in the inner ring and outer ring were positively correlated with SE (P＜0.05). When the SE was higher than －3.00 D, except for the DVP in the inner ring region, the other parameters were negatively correlated with SE (P＜0.05). There were significant differences in retinal thickness of the inner ring and outer ring (F=5.47, 16.36; P＜0.05), and no significant difference in the macular central fovea among the emmetropia, low and moderate myopia groups (F=2.16, P＞0.05). By using univariate and multivariate linear regression analyses, the retinal thickness in the inner ring and outer ring were negatively correlated with SE (β =1.99, 3.05; P＜0.05). However, no correlation was found between retinal thickness and SE in the macular central fovea (β=－1.65, P＞0.05). ConclusionsIn school-age children with SE between +0.50 D and －6.00 D, the retinal capillaries density of the macular central fovea gradually increase, and increase first and then decrease in the inner ring and outer ring with increasing SE. The retinal thickness of inner ring and outer ring gradually decrease and not change significantly in the macular central fovea.
In recent years, optical coherence tomography (OCT) has developed into a popular coronary imaging technology at home and abroad. The segmentation of plaque regions in coronary OCT images has great significance for vulnerable plaque recognition and research. In this paper, a new algorithm based on K-means clustering and improved random walk is proposed and Semi-automated segmentation of calcified plaque, fibrotic plaque and lipid pool was achieved. And the weight function of random walk is improved. The distance between the edges of pixels in the image and the seed points is added to the definition of the weight function. It increases the weak edge weights and prevent over-segmentation. Based on the above methods, the OCT images of 9 coronary atherosclerotic patients were selected for plaque segmentation. By contrasting the doctor’s manual segmentation results with this method, it was proved that this method had good robustness and accuracy. It is hoped that this method can be helpful for the clinical diagnosis of coronary heart disease.
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.
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.
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.
