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Optical coherence tomography and computer-aided diagnosis of a murine model of chronic kidney disease
摘要： Chronic kidney disease (CKD) is characterized by a progressive loss of renal function over time. Histopathological analysis of the condition of glomeruli and the proximal convolutional tubules over time can provide valuable insights into the progression of CKD. Optical coherence tomography (OCT) is a technology that can analyze the microscopic structures of a kidney in a nondestructive manner. Recently, we have shown that OCT can provide real-time imaging of kidney microstructures in vivo without administering exogenous contrast agents. A murine model of CKD induced by intravenous Adriamycin (ADR) injection is evaluated by OCT. OCT images of the rat kidneys have been captured every week up to eight weeks. Tubular diameter and hypertrophic tubule population of the kidneys at multiple time points after ADR injection have been evaluated through a fully automated computer-vision system. Results revealed that mean tubular diameter and hypertrophic tubule population increase with time in post-ADR injection period. The results suggest that OCT images of the kidney contain abundant information about kidney histopathology. Fully automated computer-aided diagnosis based on OCT has the potential for clinical evaluation of CKD conditions.
关键词： chronic kidney disease,optical coherence tomography,medical image processing,proximal convolutional tubule
更新于2025-09-04 15:30:14
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Image reconstruction for frequency-domain diffuse optical tomography
摘要： The image reconstruction algorithm of diffuse optical tomography (DOT) is based on the diffusion equation and involves both the forward problem and inverse solution. The forward problem solves the diffusion equation using the finite element method for calculating the transmitted light distribution under the condition of presumed light source and optical coefficient. The inverse solution reconstructs the optical property coefficient distribution using Newton’s method. The work within this study develops an image reconstruction algorithm for frequency-domain DOT. A numerical simulations approach to light propagation in the tissue is conducted, while the optical property is reconstructed employing data around the boundary. We implement different designated simulation cases, including different contrast ratios of absorption and reduced scattering coefficient of inclusion with respect to the background used for verifying the results of the forward problem and the developed reconstruction algorithm. Reconstruction results indicate that the quality of reconstructed images can be effective for screening breast cancer.
关键词： frequency domain,Diffuse optical tomography,image reconstruction
更新于2025-09-04 15:30:14
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I'm Not Sure What Bothers Me in this Chest X-Ray but an HRCT May Help?
摘要： There are some inevitable risk factors of patient exposure to problems arising from human errors, including missed subtle radiological findings, early identification of which may alter the patient outcomes. Here we are discussing a patient who presented with a prior diagnosis of seasonal allergic rhinitis with symptoms assumed to be bronchial asthma. A second review of chest radiograph after discussion over an online platform (Tabula Rasa group on Facebook) revealed some subtle findings which we missed initially. Further work-up of the case revealed some astonishing findings. This case illustrates the importance of discussing unsolved cases on online platforms with peers and also to proceed for higher imaging to detect what has been missed on plain radiography.
关键词： chest X ray,high resolution computed tomography,subtle findings
更新于2025-09-04 15:30:14
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Diagnostic Performance of Peripapillary Retinal Nerve Fiber Layer Thickness for Detection of Glaucoma in an Elderly Population: The ALIENOR Study
摘要： PURPOSE. To assess diagnostic accuracy of spectral-domain optical coherence tomography (SD-OCT) to discriminate glaucoma and control subjects in an elderly population. METHODS. The antioxidants, essential lipids, nutrition and ocular maladies study (ALIENOR: ‘‘Antioxydants, Lipides Essentiels, Nutrition et Maladies Oculaires’’) is a population-based study. From 2009 to 2010, a total of 624 subjects, aged 74 years or older underwent a complete eye examination, including optic disc color photography and SD-OCT examination of the macula and the optic nerve head. Glaucoma diagnosis was made using retinophotography of the optic nerve head and International Society for Epidemiologic and Geographical Ophthalmology criteria. Average and sectorial peripapillary retinal nerve ?ber layer thicknesses (RNFLT) were compared between glaucoma and control subjects using area under the receiver operating characteristic curves (AUC), positive and negative likelihood ratios (LRt/LR(cid:2)), and diagnostic odds ratios (DOR). RESULTS. A total of 532 subjects had complete data, 492 were classi?ed as controls and 40 were classi?ed as glaucoma. Mean age was 82.1 6 4.2 years and average RNFLT was signi?cantly different between both groups (controls: 88.7 6 12.2 lm, glaucoma: 65.4 6 14.4 lm, P < 0.001). Highest AUC values were observed for average (0.895), temporal-inferior (0.874), and temporal-superior (0.868) RNFLT. Temporal-superior RNFLT had the highest DOR (25.31; LRt, 4.65; LR(cid:2), 0.18), followed by average RNFLT (DOR: 24.80; LRt, 6.36; LR(cid:2), 0.26). When using the normative database provided by the machine, DOR increased to 31.03 (LRt, 1.75; LR(cid:2), 0.06) if at least one parameter was considered abnormal (at P < 0.05). CONCLUSIONS. Parameters of SD-OCT RNFL may provide valuable information in a screening strategy to improve glaucoma detection in a general population of elderly people.
关键词： spectral-domain OCT,OCT,optical coherence tomography,glaucoma screening,likelihood ratios,aging
更新于2025-09-04 15:30:14
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Choroidal structural analysis in eyes with diabetic retinopathy and diabetic macular edema—A novel OCT based imaging biomarker
摘要： To evaluate structural changes in the choroid among patients with diabetic macular edema (DME), with varying grades of diabetic retinopathy (DR), using enhance depth imaging spectral domain optical coherence tomography (EDI SD-OCT) scans. A cross-sectional study was conducted on 82 eyes with DR and DME and 86 healthy control eyes. Eyes with DME were classified according to the severity of DR as per the international DR severity scale. Sub foveal choroidal thickness (SFCT)was obtained using EDI SD-OCT scans. These scans were binarized into luminal and stromal areas, to derive the choroidal vascularity index (CVI). CVI and SFCT were analyzed between the study and control group using paired-T test. Tukey’s test was used to correlate the differences in CVI and SFCT between different grades of DR. Further analysis was done to look for the effect of DR severity and type of DME on CVI as well as SFCT using correlation coefficient and linear regression analysis. SFCT was significantly increased in eyes with DME as compared to the controls (334.47 ±51.81μm vs 284.53±56.45μm, p<0.001), and showed an ascending trend with worsening of DR, though this difference was not statistically significant [mild non-proliferative diabetic retinopathy (NPDR) = 304.33±40.39μm, moderate NPDR = 327.81±47.39μm, severe NPDR = 357.72±62.65μm, proliferative DR (PDR) = 334.59±47.4μm, p-0.09]. CVI was significantly decreased in DME with DR eyes as compared to controls (63.89±1.89 vs 67.51 ±2.86, p<0.001). CVI was also significantly decreased with worsening DR (mild NPDR = 66.38±0.3, moderate NPDR = 65.28±0.37, severe NPDR = 63.50±0.47, PDR = 61.27±0.9, p<0.001). SFCT and CVI are dynamic parameters that are affected by DME. Unlike CVI, SFCT is also affected by ocular and systemic factors like edema and hypertension. CVI may be a more accurate surrogate marker for DME and DR and can potentially be used to monitor the progression of DR.
关键词： choroidal vascularity index,diabetic macular edema,subfoveal choroidal thickness,optical coherence tomography,diabetic retinopathy
更新于2025-09-04 15:30:14
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Optical coherence tomography of macular atrophy associated with microcephaly and presumed intrauterine Zika virus infection
摘要： This case report describes the retinal optical coherence tomography (OCT ) fin dings in a microcephalic infant with macular atrophy presumably caused by in trauterine Zika virus infection. OCT demonstrated atrophy of the outer retinal layers and choriocapillaris, including the outer nuclear layer and ellipsoid zone, associated with retinal pigment epithelium hyper-reflectivity and increased OCT penetration into deeper layers of the choroid and sclera. A major concern associated with this infection is the apparent increased incidence of microce- phaly in fetuses born to mothers infected with the Zika virus. It is becoming increasingly difficult to ignore the upsurge in congenital microcephaly observed in Brazil. Recently, ocular findings in infants with microcephaly associated with intrauterine Zika virus infection have been described. This is the first report of OCT imaging of macular atrophy in a child with presumed Zika virus infection-asso - ciated microcephaly.
关键词： Zika virus,Retina,Tomography, optical coherence,Microcephaly,Eye manifestations
更新于2025-09-04 15:30:14
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Optical coherence tomography in the evaluation of macular retinoblastoma
摘要： The retinoblastomais known as the most common intraocular malignancy of the childhood. In addition to other diagnostic methods theOptical Coherence Tomography (OCT) may be considered an important tool in the evaluation ofselective involvement of the retinaby small and medium sized tumors at the posterior pole of the eye.The authors present two cases of retinoblastoma in which the OCT was ableto demonstrate the morphological features of the tumor at diagnosis and the structural changes in tumor tissue and in adjacent retina that occurred, in each case, after different modalities of treatment.
关键词： Tomography, opticalcoherence,Case reports,Retinoblastoma/diagnosis,Retinal neoplasms/diagnosis
更新于2025-09-04 15:30:14
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Evaluation of systemic risk factors in different optical coherence tomographic patterns of diabetic macular edema
摘要： ● AIM: To elucidate the relationship between systemic risk factors and different patterns of diabetic macular edema (DME) determined with optical coherence tomography (OCT). ● METHODS: In this cross-sectional study, DME was classified by OCT as diffuse retinal thickness (DRT), cystoid macular edema (CME) and serous retinal detachment (SRD) and the relationship between the systemic risk factors and DME patterns was evaluated. ● RESULTS: Of the 57 patients with DME, 21 (36.8%) had DRT, 24 (42.1%) had CME and 12 (21.0%) had SRD. Micro- or macro-albuminuria was significantly higher in the DRT pattern (61.9%) compared with the SRD (50.0%) and CME patterns (25.0%; P=0.040). Hemoglobin A1c (HbA1c) level was significantly higher and patients were younger in the DRT pattern group (P=0.034, P=0.032). Best corrected visual acuity was the worst and central macular thickness was the thickest in the CME pattern group. ● CONCLUSION: Micro- or macro-albuminuria may be more frequent and HbA1c level may be higher in patients with DRT. These patients are also seen to be younger than patients with non-DRT.
关键词： diabetic macular edema,optical coherence tomography,serous retinal detachment,diffuse retinal thickness,cystoid macular edema
更新于2025-09-04 15:30:14
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Comparison study of OCT, HRT and VF findings among normal controls and patients with pseudoexfoliation, with or without increased IOP
摘要： Purpose: To compare and evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) measurements obtained with the optical coherence tomography (OCT) and the Heidelberg retina tomography (HRT) to visual field (VF) parameters in normal and in patients with pseudoexfoliation with or without increased intraocular pressure (IOP). Methods: A total of 96 subjects were included in our study aged between 65 years and 78 years. The normal group consisted of 28 subjects (14 men and 14 women). Out of the total number of patients, 68 patients who showed pseudoexfoliation (21 men and 47 women) were divided into two groups. Of these, the first group had pseudoexfoliation with increased IOP and the second group showed deposits of pseudoexfoliative material without an increase in IOP. The normal controls were randomly chosen and restricted to those without any glaucomatous optic disc damages, VF defects, and an IOP 15 mmHg. All subjects were prospectively included for repeated measurements of IOP, OCT, HRT, and VFs during the same visit by the same examiner and all measurements were repeated every 3 months. Results: Mean RNFL thickness measured by OCT was larger in the normal controls than in the other two groups (98.04 μm (first group) vs 75.42 μm and 97.02 μm (second group), P0.05). Four-quadrant RNFL thickness measurements were significantly different between the normal and the group 1 (P0.05) but not with the group 2 (P0.05). Rim area had a mean difference of -0.44, whereas cup-to-disc ratio (C/D) showed a mean difference of 0.31, thus being significantly different between the normal and the two groups (all P0.05). The median of the mean deviation parameter of VFs was -0.28 for the normal vs -0.32 and -0.18 for the other two groups, whereas pattern standard deviation median difference was 0.89 for the normal and 1.32 and 1.20 for the other two groups, respectively (P0.05). Conclusion: Both OCT and HRT showed early ONH and RNFL changes in their parameters and did not correlate with the normal findings of the automated perimetry.
关键词： retinal nerve fiber layer (RNFL),visual fields (VFs),pseudoexfoliation glaucoma,pseudoexfoliation syndrome,Heidelberg retina tomograph (HRT),optical coherence tomography (OCT)
更新于2025-09-04 15:30:14
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Evaluation of retinal nerve fiber layer thickness in Alzheimer disease usingspectral-domain optical coherence tomography
摘要： To evaluate the retinal nerve fiber layer (RNFL) thickness in patients with Alzheimer disease (AD) and to compare the results with those of healthy controls. Forty patients (mean age: 75.02 ± 6.34 years; 23 women) with untreated AD and 40 age-, sex-, and education-matched healthy patients were examined in this case-control prospective study. All patients underwent detailed ophthalmic and neurological examination. The Mini Mental State Examination (MMSE) was performed and RNFL thickness was measured using spectral-domain optical coherence tomography. The association between RNFL and MMSE score was also assessed. The average RNFL thickness was 84 ± 7.0 μm in AD patients and 107 ± 6.3 μm in healthy subjects (P < 0.001). The mean MMSE score was 21.9 ± 2.13 in AD patients. There was no significant correlation between the RNFL thickness and MMSE score. Patients with AD had reduced RNFL thickness in all quadrants compared with the control group. This finding suggests that RNFL thickness analysis may be useful in the early diagnosis of AD.
关键词： optical coherence tomography,retinal nerve fiber layer thickness,Alzheimer disease
更新于2025-09-04 15:30:14