Optical Coherence Tomography Study Research Articles

Neuroretinal Alterations in Schizophrenia and Bipolar Disorder: An Updated Meta-analysis.

Schizophrenia (SZ) and bipolar disorder (BD) are characterized by major symptomatic, cognitive, and neuroanatomical changes. Recent studies have used optical coherence tomography (OCT) to investigate retinal changes in SZ and BD, but their unique and shared changes require further evaluation. Articles were identified using PubMed and Google Scholar. 39 studies met the inclusion criteria. Diagnostic groups were proband (SZ/BD combined), SZ, BD, and healthy control (HC) eyes. Meta-analyses utilized fixed and random effects models when appropriate, and publication bias was corrected using trim-and-fill analysis ("meta" package in R). Results are reported as standardized mean differences with 95% CIs. Data from 3145 patient eyes (1956 SZ, 1189 BD) and 3135 HC eyes were included. Studies identified thinning of the peripapillary retinal nerve fiber layer (pRNFL, overall and in 2 subregions), m-Retina (overall and all subregions), mGCL-IPL, mIPL, and mRPE in SZ patients. BD showed thinning of the pRNFL (overall and in each subregion), pGCC, and macular Retina (in 5 subregions), but no changes in thickness or volume for the total retina. Neither SZ nor BD patients demonstrated significant changes in the fovea, mRNFL, mGCL, mGCC, mINL, mOPL, mONL, or choroid thicknesses. Moderating effects of age, illness duration, and smoking on retinal structures were identified. This meta-analysis builds upon previous literature in this field by incorporating recent OCT studies and examining both peripapillary and macular retinal regions with respect to psychotic disorders. Overall, this meta-analysis demonstrated both peripapillary and macular structural retinal abnormalities in people with SZ or BD compared with HCs.

A spectral domain optical coherence tomography (SD-OCT) study of intraretinal hyperreflective foci and its relationship with visual acuity and grades of retinopathy among patients of diabetes mellitus in Indian population

BackgroundHyperreflective foci (HRF) are biomarkers in detection of diabetic retinopathy (DR). Presence of HRF on spectral domain optical coherence tomography (SD-OCT) can give a correlation with visual acuity change and grades of DR. Purpose of this study is to determine the presence, location, and role of HRF in the retina of DM patients with and without retinopathy. MethodsA total of 192 eyes of patients suffering from type II DM were evaluated. Patients were divided into 2 groups, with Group A having diabetes without retinopathy (20 patients) and group B (76 patients) having diabetes and various grades of retinopathy. SD-OCT was performed in all patients, passing through the center of fovea. On OCT, presence and absence of HRF were noted. Characteristics of the hyper-reflective spots were evaluated: location, shape, size, back shadowing and association with central macular thickness (CMT), visual acuity, and grades of retinopathy. ResultsHRF were present in 169 eyes (88%) out of 192 eyes. The shape and location of HRF tend to change with disease progression. HRF were significantly associated with increasing grades of retinopathy (χ2 = 57.586, p < 0.01) Association of macular edema was significant with both retinopathy (χ2 = 8.895, p < 0.05) and HRF (χ2 = 34.720, p < 0.01). Association of best-corrected visual acuity with HRF (χ2 = 21.232, p < 0.01), macular edema (χ2 = 86.960, p < 0.01), and CMT (χ2 = 47.959, p< 0 .01) was significant. ConclusionHRF is a great indicator for early diagnosis of subclinical retinopathy and can be used to monitor the progression of disease and development of macular edema. Significant difference is present in HRF distribution and morphology.

Characterizing Retinal Sensitivity and Structure in Congenital Stationary Night Blindness: A Combined Microperimetry and OCT Study.

To investigate the characteristics of microperimetry and optical coherence tomography (OCT) in congenital stationary night blindness (CSNB), as well as their structure-function association. This cross-sectional study included 32 eyes from 32 participants with CSNB, comprising 18 with complete CSNB and 14 with incomplete CSNB, along with 36 eyes from 36 CSNB-unaffected controls matched for age, sex, and spherical equivalent. Using MP-3 microperimetry, central retinal sensitivity was assessed within a 20° field, distributed across six concentric rings (0°, 2°, 4°, 6°, 8°, and 10°). OCT was used to analyze retinal and choroidal thickness. The study aimed to assess the overall and ring-wise retinal sensitivity, as well as choroidal and retinal thickness in CSNB and CSNB-unaffected controls, with a secondary focus on the relationship between retinal sensitivity and microstructural features on OCT. In comparison with CSNB-unaffected subjects, the overall and ring-wise retinal sensitivity as well as choroidal thickness were reduced in patients with CSNB (P < 0.001). Moreover, the central sensitivity in incomplete CSNB group was lower than in complete CSNB group (25.72 ± 3.93 dB vs. 21.92 ± 4.10dB; P < 0.001). The retinal thickness in the CSNB group was thinner outside the fovea compared with the CSNB-unaffected group. Multiple mixed regression analyses revealed that point-to-point retinal sensitivity was significantly correlated with BCVA (P = 0.002) and the corresponding retinal thickness (P = 0.004). Examination of retinal sensitivity and OCT revealed different spatial distribution profiles in CSNB and its subtypes. In CSNB eyes, retinal sensitivity on microperimetry was associated with retinal thickness on OCT.

Maculopapillary Bundle Degeneration in Optic Neuropathies.

Degeneration of the maculopapillary bundle (MPB) is a prominent feature in a spectrum of optic neuropathies. MPB-selective degeneration is seen in specific conditions, such as nutritional and toxic optic neuropathies, Leber hereditary optic neuropathy (LHON), and dominant optic atrophy (DOA). Despite their distinct etiologies and clinical presentations, which encompass variations in age of incidence and monocular or binocular onset, these disorders share a core molecular mechanism: compromised mitochondrial homeostasis. This disruption is characterized by dysfunctions in mitochondrial metabolism, biogenesis, and protein synthesis. This article provides a comprehensive understanding of the MPB's role in optic neuropathies, emphasizing the importance of mitochondrial mechanisms in the pathogenesis of these conditions. Optical coherence tomography studies have characterized the retinal nerve fiber layer changes accompanying mitochondrial-affiliated optic neuropathies. Selective thinning of the temporal optic nerve head is preceded by thickening in early stages of these disorders which correlates with reductions in macular ganglion cell layer thinning and vascular atrophy. A recently proposed mechanism underpinning the selective atrophy of the MPB involves the positive feedback of reactive oxygen species generation as a common consequence of mitochondrial dysfunction. Additionally, new research has revealed that the MPB can undergo degeneration in the early stages of glaucoma, challenging the historically held belief that this area was not involved in this common optic neuropathy. A variety of anatomical risk factors influence the propensity of glaucomatous MPB degeneration, and cases present distinct patterns of ganglion cell degeneration that are distinct from those observed in mitochondria-associated diseases. This review synthesizes clinical and molecular research on primary MPB disorders, highlighting the commonalities and differences in their pathogenesis. 1.Temporal degeneration of optic nerve fibers accompanied by cecocentral scotoma is a hallmark of maculopapillary bundle (MPB) degeneration. 2.Mechanisms of MPB degeneration commonly implicate mitochondrial dysfunction. 3.Recent research challenges the traditional belief that the MPB is uninvolved in glaucoma by showing degeneration in the early stages of this common optic neuropathy, yet with features distinct from other MPB-selective neuropathies. 4.Reactive oxygen species generation is a mechanism linking mitochondrial mechanisms of MPB-selective optic neuropathies, but in-vivo and in-vitro studies are needed to validate this hypothesis.

Longitudinal evaluation of macular vascular density alterations in unilateral amblyopic children undergoing therapy: An optical coherence tomographic angiography study

ImportanceUnderstanding the pathophysiology of the macula in amblyopic eyes is an active research area. ObjectiveTo correlate macular retinal vascular density changes with best-corrected visual acuity changes following occlusion therapy for amblyopia in children. DesignA prospective cohort study of children visiting the Pediatric Ophthalmology Division of our institution between January 2020 and January 2022 was conducted. SettingA specialist eye hospital in Saudi Arabia. ParticipantsThirty children with unilateral amblyopia. ExposureOcclusion therapy for amblyopia.Main Outcome and Measures: Best corrected visual acuity (logMAR) before and at each of the four optical coherence tomographic angiographies was compared in amblyopic and fellow eyes. The effect of pretreatment determinants on the correlation between best-corrected visual acuity and retinal vascular density changes was reviewed. ResultsIn this cohort of 30 amblyopic and 30 fellow eyes from 30 children (mean age 8.7 ± 1.4 years; male: female 18:12. The best-corrected visual acuity improved from a median of 0.6 (interquartile range 0.5; 1.1) pretreatment to a median of 0.4 (interquartile range 0.2; 0.6) posttreatment in amblyopic eyes, and from a median of 0.1 to 0.05 in the fellow eyes. The total percentage change in retinal vascular density in the amblyopic eye was significantly higher than that in the fellow eye (Z = −1.92, P = 0.05). The change in best-corrected visual acuity in the amblyopic eye after a median of 98 months (interquartile range, 69–126 months) of intervention was significantly correlated with the refraction-adjusted change in retinal vascular density (B = −0.03, 95 % confidence interval −0.04, −0.02, P < 0.001) and was influenced by strabismus (B = −0.46, 95 % confidence interval −0.59, −0.34, P < 0.001), type of amblyopia (B = 0.24, 95 % confidence interval 0.12, 0.36, P < 0.001), duration of occlusion (B = −0.43, 95 % confidence interval −0.65, −0.22, P < 0.001), and occlusion compliance (B = 0.24, 95 % confidence interval 0.11, 0.36, P < 0.001). Conclusionsand Relevance: The RVD in amblyopic eyes in the first six months of therapy was significantly lower than that in fellow eyes, but not in subsequent assessments.

Repeatability, interocular correlation and agreement of optic nerve head vessel density in healthy eyes: a swept-source optical coherence tomographic angiography study.

To assess the repeatability, interocular correlation, and agreement of quantitative swept-source optical coherence tomography angiography (OCTA) optic nerve head (ONH) parameters in healthy subjects. Thirty-three healthy subjects were enrolled. The ONH of both eyes were imaged four times by a swept-source-OCTA using a 3 mm ×3 mm scanning protocol. Images of the radial peripapillary capillary were analyzed by a customized Matlab program, and the vessel density, fractal dimension, and vessel diameter index were measured. The repeatability of the four scans was determined by the intraclass correlation coefficient (ICC). The most well-centered optic disc from the four repeated scans was then selected for the interocular correlation and agreement analysis using the Pearson correlation coefficient, ICC and Bland-Altman plots. All swept-source-OCTA ONH parameters exhibited certain repeatability, with ICC>0.760 and coefficient of variation (CoV)≤7.301%. The obvious interocular correlation was observed for papillary vessel density (ICC=0.857), vessel diameter index (ICC=0.857) and fractal dimension (ICC=0.906), while circumpapillary vessel density exhibited moderate interocular correlation (ICC=0.687). Bland-Altman plots revealed an agreement range of -5.26% to 6.21% for circumpapillary vessel density. OCTA ONH parameters demonstrate good repeatability in healthy subjects. The interocular correlations of papillary vessel density, fractal dimension and vessel diameter index are high, but the correlation for circumpapillary vessel density is moderate.

Angular Integral Autocorrelation for Speed Estimation in Shear-Wave Elastography

The utilization of a reverberant shear-wave field in shear-wave elastography has emerged as a promising technique for achieving robust shear-wave speed (SWS) estimation. However, many types of estimators cannot accurately measure SWS within such a complicated 3D wave field. This study introduces an advanced autocorrelation estimator based on angular integration known as the angular integral autocorrelation (AIA) approach to address this issue. The AIA approach incorporates all the autocorrelation data from various angles during measurements, resulting in enhanced robustness to both noise and imperfect distributions in SWS estimation. The effectiveness of the AIA estimator for SWS estimation is first validated using a k-Wave simulation of a stiff branching tube in a uniform background. Furthermore, the AIA estimator is applied to ultrasound elastography experiments, magnetic resonance imaging (MRI) experiments, and optical coherence tomography (OCT) studies across a range of different excitation frequencies on tissues and phantoms, including in vivo scans. The results verify the capacity of the AIA approach to enhance the accuracy of SWS estimation and the signal-to-noise ratio (SNR), even within an imperfect reverberant shear-wave field. Compared to simple autocorrelation approaches, the AIA approach can also successfully visualize and define lesions while significantly improving the estimated SWS and SNR in homogeneous background materials and providing improved elastic contrast between structures within the scans. These findings demonstrate the robustness and effectiveness of the AIA approach across a wide range of applications, including ultrasound elastography, magnetic resonance elastography (MRE), and optical coherence elastography (OCE), for accurately identifying the elastic properties of biological tissues in diverse excitation scenarios.

Reduced macular thickness and vascular density in abnormal glucose metabolism patients: A meta-analysis of optical coherence tomography (OCT) and OCT angiography studies.

Alterations in macular thickness and vascular density before clinically visible diabetic retinopathy (DR) remain inconclusive. This study aimed to determine whether retinal manifestations in abnormal glucose metabolism (AGM) patients differ from those in the healthy individuals. PubMed, Embase, and Web of Science were searched between 2000 and 2021. The eligibility criteria were AGM patients without DR. Primary and secondary outcomes measured by optical coherence tomography (OCT) and OCT angiography (OCTA) were analyzed and expressed as standardized mean differences (SMDs) with 95% confidence intervals (CIs). A random-effects model was used in the data synthesis. The potential publication bias for the variables was evaluated using Egger's test. A total of 86 observational studies involving 13,773 participants and 15,416 eyes were included. OCT revealed that compared to healthy controls, the total macular thickness of AGM patients was thinner, including the thickness of fovea (-0.24, 95% CI [-0.39, -0.08]; P =0.002, I2 =87.7%), all regions of parafovea (-0.32, 95% CI [-0.54, -0.11]; P =0.003; I2 =71.7%) and the four quadrants of perifovea; the thickness of peripapillary retinal nerve fiber layer (pRNFL), macular retinal nerve fiber layer (mRNFL), and ganglion cell layer (GCL) also decreased. OCTA indicated that the superficial and deep vascular density decreased, the foveal avascular zone (FAZ) area enlarged, and the acircularity index (AI) reduced in AGM individuals. Retinal thinning and microvascular lesions have occurred before the advent of clinically detectable DR; OCT and OCTA may have the potential to detect these preclinical changes. PROSPERO; http://www.crd.york.ac.uk/prospero/ ; No. CRD42021269885.

Assessment of Macular Thickness in Different Grades of Myopia: An Optical Coherence Tomography Study in a Rural Tertiary Care Hospital

Abstract Background: Myopia is a condition related to the refractive error that causes visual disability. Due to its high prevalence, it can contribute to complicated cataracts and related conditions such as primary open-angle glaucoma. The risks of retinal detachment, chorioretinal atrophy, pigmentary degeneration, vitreous degeneration and retinal breaks may increase with an increase in axial length and severity of myopia, among other long-term effects of high myopia. The aim of this study was to assess the role of macular thickness and myopia in non-invasive optical coherence tomography (OCT). Materials and Methods: This was a prospective, hospital-based observational study conducted for 18 months in a tertiary care centre in Karnataka. A total of 155 consecutive myopia patients aged ≥10 years attending the outpatient Department of Ophthalmology were included in the study. The data were analysed using the Statistical Package for Social Sciences (SPSS) for Windows, version 22.0 (SPSS Inc., Chicago). Result: The participants aged from 10 to 75 years with a female preponderance of 60%. The mean age of participants is 31.95 yrs. The majority of the patients had mild myopia (91.6%), compared with moderate (5.8%) and high (2.6%) myopia. The mean value of best-corrected visual acuity improved from 0.67 to 0.08 in high, 0.94 to 0.22 in mild and 0.71 to 0.26 in moderate myopia patients. The mean maximum retinal thickness was 472 micrometres, and the mean minimum retinal thickness was 178 micrometres. Conclusion: There is a high prevalence of mild myopia cases, especially at extremes of age. Myopia was more common among females. There was a significant difference among different classes of myopia with respect to uncorrected and best-corrected visual acuity. The parafovea was thinner and the fovea thicker among myopia.

Importance of Short-Term Neointimal Coverage of Drug-Eluting Stents in the Duration of Dual Antiplatelet Therapy.

Dual antiplatelet therapy (DAPT) is mandatory after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) implantation, but optimal DAPT duration remains a topic of intense discussion. The shorter regimen of DAPT might be especially beneficial for high-bleeding-risk (HBR) patients. Novel stent platforms have been designed with innovations that should facilitate vessel healing following stent implantation and enable short DAPT. This review aimed to summarize evidence of the neointimal coverage of short-term stents and their implications for DAPT duration. Results from histological and optical coherence tomography (OCT) studies confirm the significant role of uncovered struts after the implantation of a stent in patients presenting with late stent thrombosis. Several studies have shown favorable vessel healing at one month (with 83.2% of covered struts, on average) and three months following stent implantation (with 93.3% of covered struts, on average). Solely HBR patient trials have proven that one month of DAPT can be applicable and safe in this population. Three-month DAPT was tested in a more diverse population and remains effective and safe in comparison to a longer DAPT regimen. That evidence proves that short-term DAPT might be applicable, especially for HBR patients.

Morphological characteristics of in-stent restenosis with different degrees of area stenosis: an optical coherence tomography study.

The morphological characteristics of in-stent restenosis (ISR) in relation to varying degrees of area stenosis have not been comprehensively examined. This study aimed to explore the tissue characteristics of patients experiencing ISR with different degrees of area stenosis through the utilization of optical coherence tomography (OCT). In total, 230 patients with ISR who underwent OCT were divided into the following three groups: area stenosis (AS) < 70% (n = 26); 70-80% (n = 119) and AS ≥ 80% (n = 85). Among the 230 patients, the clinical presentation as stable angina was 61.5% in AS < 70%, followed by 47.2% in 70% < AS ≤ 80%, and 31.8% in AS ≥ 80% (P = 0.010). The OCT findings showed that heterogeneous neointima, ISNA, LRP, neointima rupture, TCFA-like pattern, macrophage infiltration, red and white thrombus was more common with AS increased. Ordinal logistic regression analysis showed that higher AS was associated with previous dyslipidemia (odds ratio [OR], 4.754; 95% confidence interval [CI], 1.419-15.927, P = 0.011), neointimal rupture (OR: 3.640; 95% CI, 1.169-11.325, P = 0.026), red thrombus (OR: 4.482; 95% CI, 1.269-15.816, P = 0.020) and white thrombus (OR: 5.259; 95% CI, 1.660-16.659, P = 0.005). Patients with higher degrees of area stenosis in the context of ISR exhibited a greater number of discernible morphological characteristics as identified through OCT analysis. Furthermore, previous dyslipidemia, neointimal rupture, white thrombus and red thrombus were highly associated with and the progression of ISR lesions.

The impact of statins treatments for plaque characteristics in stable angina pectoris patients with very low and high low-density lipoprotein cholesterol levels: an intracoronary optical coherence tomography study.

Low-density lipoprotein cholesterol (LDL-C) levels are recommended according to the patient's risk factors based on guidelines. In patients achieving low LDL-C levels, the need for statins is uncertain, and the plaque characteristics of patients not treated with statins are unclear. In addition, the difference in plaque characteristics with and without statins is unclear in similarly high LDL levels. We evaluate the impact of statins on plaque characteristics on optical coherence tomography (OCT) in patients with very low LDL-C levels and high LDL-C levels. A total of 173 stable angina pectoris patients with 173 lesions undergoing OCT before percutaneous coronary intervention were evaluated. We divided the LDL-C levels into three groups: < 70mg/dL (n = 48), 70mg/dL ≤ LDL-C < 100mg/dL (n = 71), and ≥ 100mg/dL (n = 54). Among patients with LDL-C < 70mg/dL, patients not treated with statins showed a significantly higher C-reactive protein level (0.27 ± 0.22mg/dL vs. 0.15 ± 0.19mg/dL, p = 0.049), and higher incidence of thin-cap fibroatheromas (TCFAs; 44% [7/16] vs. 13% [4/32], p = 0.021) than those treated with statins. Among patients with LDL-C level ≥ 100mg/dL, patients treated with statins showed a significantly higher prevalence of familial hypercholesterolemia (FH) (38% [6/16] vs. 5% [2/38], p = 0.004), lower incidence of TCFAs (6% [1/16] vs. 39% [15/38], p = 0.013), healed plaques (13% [2/16] vs. 47% [18/38], p = 0.015), and higher incidence of fibrous plaques (75% [12/16] vs. 42% [16/38], p = 0.027) than patients not treated with statins. While patients achieved a low LDL-C, patients not treated with statins had high plaque vulnerability and high systemic inflammation. While patients had a high LDL-C level with a high prevalence of FH, patients treated with statins had stable plaque characteristics.

Association between periprocedural myocardial injury and neointimal characteristics in patients with in-stent restenosis: an optical coherence tomography study.

The relationship between neointimal characteristics of in-stent restenosis (ISR) and periprocedural myocardial injury (PMI) remains unclear. Therefore, this study aimed to investigate the relationship between PMI and neointimal characteristics of ISR by using optical coherence tomography (OCT). This was a retrospective study. We enrolled 140 patients diagnosed with ISR with normal baseline high-sensitivity troponin T (hs-cTnT) levels who underwent OCT and subsequent revascularization by means of drug-coated balloon (DCB) or drug-eluting stent (DES) between October 2018 and October 2022 in the Affiliated Hospital of Zunyi Medical University. Based on the 4th universal definition of myocardial infarction, patients whose hs-cTnT were increased five times above the upper reference limit (URL) after percutaneous coronary interventions (PCI) were deemed to PMI. The patients were subdivided into PMI (n=53) and non-PMI (n=87) groups. In the univariable analysis, variables in the baselines, angiography characteristics and OCT findings were analyzed with binary logistic regression. A P value of <0.2 was included in the multivariable model. Multivariable logistic regression analysis was used to identify the independent predictors of PMI. The prevalence of intra-intimal microvessels in patients with PMI was higher than in those without PMI (58.5% vs. 32.2%, P=0.003). The ratio of intra-stent plaque rupture (PR) was also higher in patients with PMI (60.4% vs. 40.2%, P=0.021). Multivariable logistic regression analysis showed that intra-intimal microvessels [odds ratio (OR): 3.193, 95% confidence interval (CI): 1.280-7.966; P=0.013] and intra-stent PR (OR: 2.124, 95% CI: 1.153-4.732; P=0.035) were independently associated with PMI. Intra-intimal microvessels and intra-stent PR were independently associated with PMI. Accurate identification and recognition of intra-intimal microvessels and intra-stent PR may be helpful in preventing PMI.

Quantitative assessments of retinal macular structure among rural-dwelling older adults in China: a population-based, cross-sectional, optical coherence tomography study

ObjectivesTo quantitatively assess and compare retinal macular structures of rural-dwelling older adults in China using two different optical coherence tomography (OCT) scanners and to examine their associations with demographic, lifestyle,...

Pancoronary plaque characteristics in STEMI patients with rapid plaque progression: An optical coherence tomography study

BackgroundNon-culprit plaque progression is associated with recurrent cardiac ischemic events and worse clinical outcomes. Given that atherosclerosis is a systemic disease, the pancoronary characteristics of patients with rapid plaque progression are unknown. This study aims to identify pancoronary plaque features in patients with ST-segment elevation myocardial infarction (STEMI) with and without rapid plaque progression, focused on the patient level. Methods and resultsFrom January 2017 to July 2019, 291 patients underwent 3-vessel optical coherence tomography imaging at the time of the primary procedure and a follow-up angiography interval of 12 months. The final analysis included 237 patients. Overall, 308 non-culprit lesions were found in 78 STEMI patients with rapid plaque progression, and 465 non-culprit plaques were found in 159 STEMI patients without rapid plaque progression. These patients had a higher pancoronary vulnerability (CLIMA-defined high-risk plaque: 47.4% vs. 33.3%; non-culprit plaque rupture: 25.6% vs. 14.5%) and a significantly higher prevalence of other vulnerable plaque characteristics (i.e., lipid-rich plaque, cholesterol crystal, microchannels, calcification, spotty calcification, and thrombus) at baseline versus those without rapid plaque progression. Lesions with rapid progression were highly distributed at the LAD, tending to be near the bifurcation. In multivariate analysis, age ≥ 65 years was an independent predictor of subsequent rapid lesion progression at the patient level, whereas microchannel, spotty calcification, and cholesterol crystal were independent predictors for STEMI patients ≥65 years old. ConclusionsSTEMI patients with subsequent rapid plaque progression had higher pancoronary vulnerability and commonly presented vulnerable plaque morphology. Aging was the only predictor of subsequent rapid plaque progression.

Detection of acute and early-delayed radiation-induced changes in the white matter of the rat brain based on numerical processing of optical coherence tomography data.

Detection of radiation-induced changes of the brain white matter is important for brain neoplasms repeated surgery. We investigated the influence of irradiation on the scattering properties of the white matter using optical coherence tomography (OCT). Healthy Wistar rats undergone the irradiation of the brain right hemisphere. At seven time points from the irradiation procedure (2-14 weeks), an ex vivo OCT study was performed with subsequent calculation of attenuation coefficient values in the corpus callosum followed by immunohistochemical analysis. As a result, we discovered acute and early-delayed changes characterized by the edema of different severity, accompanied by a statistically significant decrease in attenuation coefficient values. In particular, these changes were found at 2 weeks after irradiation in the irradiated hemisphere, while at 6- and 12-week time points they affected both irradiated and contralateral hemisphere. Thus, radiation-induced changes occurring in white matter during the first 3 months after irradiation can be detected by OCT.

Association of Metabolic Syndrome with Macular Thickness and Volume in Older Adults: A Population-Based Optical Coherence Tomography Study.

Background: To explore the associations of the metabolic syndrome (MetS) and individual components with macular thickness and volume among rural-dwelling Chinese older adults. Methods: This population-based cross-sectional study included 705 participants (age ≥60 years) derived from the MIND-China study. In 2018-2019, we collected data through face-to-face interview, clinical examination, optical coherence tomography (OCT) examination, and blood test. We measured macular thickness and volume using spectral-domain OCT. MetS was defined following the International Diabetes Federation (IDF) criteria, the IDF/American Heart Association (AHA) criteria, the National Cholesterol Education Program-Adult Treatment Panel III criteria, and the Chinese Diabetes Society (CDS) criteria. Data were analyzed with multivariable general linear models. Results: MetS was significantly associated with thinner macula in central (multivariable-adjusted β = -5.29; 95% confidence interval: -9.31 to -1.26), parafoveal (-2.85; -5.73 to 0.04) and perifoveal regions (-4.37; -6.79 to -1.95) when using the IDF criteria, in the perifoveal regions (-3.82; -6.18 to -1.47) when using the IDF/AHA criteria, and in the central region (-5.63; -10.25 to -1.02) when using the CDS criteria, and with reduced macular volume when using the IDF (-0.16; -0.26 to -0.07) and IDF/AHA (-0.13; -0.22 to -0.04) criteria. In the parafoveal region, the IDF-defined MetS was significantly associated with thinner retina in men (β = -6.25; -10.94 to -1.56) but not in women. Abdominal obesity (-2.83; -5.41 to -0.25) and elevated fasting blood glucose (-2.65; -5.08 to -0.21) were associated with thinner macular thickness in the perifoveal region. Conclusion: MetS is associated with macular thinning and reduced macular volume among rural-dwelling older adults, and the associations vary by the defining criteria of MetS.

Clinical Impact of In-Stent Calcification in Coronary Arteries: Optical Coherence Tomography Study

In-stent restenosis with neoatherosclerosis has been known as the predictor of target lesion revascularization (TLR) after percutaneous coronary intervention (PCI). However, impact of in-stent calcification (ISC) alone on clinical outcomes remains unknown since neoatherosclerosis by optical coherence tomography (OCT) includes both in-stent lipid and calcification. We aimed to assess an effect of ISC on clinical outcomes and clinical differences among different types of ISC. We included 126 lesions that underwent OCT-guided PCI and divided those into the ISC group (n=38) and the non-ISC group (n=88) according to the presence of ISC. The cumulative incidence of clinically-driven TLR (CD-TLR) was compared between the ISC and non-ISC groups. Impact of in-stent calcified nodule and nodular calcification on CD-TLR was evaluated in the Cox hazard model. The incidence of CD-TLR was significantly higher in the ISC group than in the non-ISC group (p=0.004). In the multivariate Cox hazard model, ISC was significantly associated with CD-TLR [hazard ratio (HR): 3.58; 95% confidence interval (CI): 1.33-9.65; p=0.01]. In-stent calcified nodule/nodular calcification and in-stent nodular calcification alone were also the factors significantly associated with CD-TLR (HR: 3.34; 95%CI: 1.15-9.65; p=0.03 and HR: 5.21; 95%CI: 1.82-14.91; p=0.002, respectively). ISC without in-stent calcified nodule/nodular calcification, which was defined as in-stent smooth calcification, was not associated with CD-TLR. In conclusion, ISC was associated with the higher rate of CD-TLR. Types of calcifications that led to the high rate of CD-TLR were in-stent calcified nodule/nodular calcification and in-stent nodular calcification alone but not in-stent smooth calcification. In-stent calcified nodule and nodular calcification should be paid more attention.

Normative retinal nerve fiber layer thickness in a healthy pediatric South Asian cohort: a spectral-domain optical coherence tomography study.

Currently, the normative values for retinal nerve fiber layer (RNFL) thickness in our population have not been widely studied. Our study aimed to assess the peripapillary RNFL thickness (RNFLT) with Optopol Copernicus REVO80® spectral-domain optical coherence tomography (SD-OCT) amongst healthy children and its associations. One hundred eighty-two eyes of 91 consecutive healthy children 3 to 16 years of age with a refractive error ≤ ± 5 D were included after a thorough eye exam including visual acuity, refraction, tonometry, pachymetry, axial length estimation, and slit lamp exam including fundus assessment. RNFLT was measured via Optopol Copernicus REVO80® high resolution SD-OCT by a single experienced observer with 3D disc mode within a circular area of diameter 3.45 mm and the ring further divided into four quadrants: inferior, superior, nasal, and temporal. The mean age was 11.12 ± 3.12 years (range, 3-16). The average RNFLT was 120.13 ± 12.6 μm. The mean superior RNFL was the thickest at 138.21 ± 16.6 μm, next was the mean inferior RNFLT at 137.62 ± 17.2 μm, followed by the nasal 91.61 ± 18.5 μm and then the temporalat 74.58 ± 11.7 μm. No significant differences in RNFLT were noted between the two eyes. The mean RNFLT was significantly higher in males as compared to females, in vertical quadrants and at an average (p < 0.05). No significant relationship was found between the average RNFLT and factors such as age, axial length, corneal thickness, cup-to-disc ratio, intraocular pressure, or refractive error. This study establishes normative values of RNFLT for this subgroup of Pakistani children for the Optopol Copernicus REVO80® SD-OCT device.

Prediction and Detection of Glaucomatous Visual Field Progression Using Deep Learning on Macular Optical Coherence Tomography.

A deep learning model trained on macular OCT imaging studies detected clinically significant functional glaucoma progression and was also able to predict future progression. To use macular optical coherence tomography (OCT) imaging to predict the future and detect concurrent visual field progression, respectively, using deep learning. A retrospective cohort study. A pretraining data set was comprised of 7,702,201 B-scan images from 151,389 macular OCT studies. The progression detection task included 3902 macular OCT imaging studies from 1534 eyes of 828 patients with glaucoma, and the progression prediction task included 1346 macular OCT studies from 1205 eyes of 784. A novel deep learning method was developed to detect glaucoma progression and predict future progression using macular OCT, based on self-supervised pretraining of a vision transformer (ViT) model on a large, unlabeled data set of OCT images. Glaucoma progression was defined as a mean deviation (MD) rate of change of ≤ -0.5 dB/year over 5 consecutive Humphrey visual field tests, and rapid progression was defined as MD change ≤ -1 dB/year. Diagnostic performance of the ViT model for prediction of future visual field progression and detection of concurrent visual field progression using area under the receiver operating characteristic curve (AUC), sensitivity, and specificity. The model distinguished stable eyes from progressing eyes, achieving an AUC of 0.90 (95% CI, 0.88-0.91). Rapid progression was detected with an AUC of 0.92 (95% CI, 0.91-0.93). The model also demonstrated high predictive ability for forecasting future glaucoma progression, with an AUC of 0.85 (95% CI 0.83-0.87). Rapid progression was predicted with an AUC of 0.84 (95% CI 0.81-0.86). A deep learning model detected clinically significant functional glaucoma progression using macular OCT imaging studies and was also able to predict future progression. Early identification of patients undergoing glaucoma progression or at high risk for future progression may aid in clinical decision-making.