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Swept source optical coherence tomography analysis of choroidal thickness in macular telangiectasia type 2: a case-control study
摘要： Purpose There has been a recent interest in the association of macular telangiectasia (MacTel) type 2 with central serous choroidopathy and other pachychoroid disorders. This study was performed to assess the subfoveal choroidal thickness (SFCT) in patients with MacTel type 2 and compare it with healthy controls using swept source optical coherence tomography (SS-OCT). Methods It was a retrospective case-control study performed at a tertiary eye care center. The cases constituted patients with MacTel type 2 detected over the last 2 years (April 2016 to March 2018). The controls were healthy adults with no posterior segment pathology. The patients were evaluated with color fundus photography, SS-OCT (Triton, Topcon Inc., Oakland, New Jersey, USA) and fundus fluorescein angiography. The cases were staged based on Gass and Blodi classification. SFCT was compared between the two groups. Results Sixty-five eyes of 33 patients with MacTel were included. The controls consisted of 61 eyes of 33 healthy age-matched (p = 0.81) and sex-matched (p = 0.31) adults. The mean SFCT in cases (353.0 ± 91.2 μm) was higher than controls (289.2 ± 69.0 μm), and this difference was statistically significant (p = 0.0001). The mean SFCT was different in various stages: 346.6 ± 86.3 μm (stage 2), 334.6 ± 90.2 μm (stage 3), 374.6 ± 94.0 μm (stage 4), and 294.8 ± 68.8 μm (stage 5), though this was not statistically significant (p = 0.28). Conclusions The choroid in MacTel type 2 patients was significantly thickened as compared to controls. SFCT may vary as the structural changes worsen over time.
关键词： Macular telangiectasia type 2,Swept source optical coherence tomography,Subfoveal choroidal thickness,Enhanced depth imaging
更新于2025-09-23 15:22:29
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Reproducibility and reliability of retinal and optic disc measurements obtained with swept-source optical coherence tomography in a healthy population
摘要： Purpose To analyze the reproducibility of macular and peripapillary thickness measurements, and optic nerve morphometric data obtained with Triton Optical coherence tomography (OCT) in a healthy population. Study design Observational cross sectional study. Material and methods A total of 108 eyes underwent evaluation using the Triton Swept Source-OCT. A wide protocol was used and measurements in each eye were repeated three times. Morphometric data of the optic nerve head, full macular thickness, ganglion cell layer (GCL) and retinal nerve fiber layer thickness (RNFL) were analyzed. For each parameter, the coefficient of variation (COV) and the intra-class (ICC) correlation values were calculated. Results Measurements were highly reproducible for all morphometric measurements of the optic disc, with a mean COV of 6.36%. Macular full thickness showed good COV and ICC coefficients, with a mean COV value of 1.00%. Macular GCL thickness showed a mean COV value of 3.06%, and ICC higher than 0.787. Peripapillary RNFL thickness showed good COV and ICC coefficients, with a mean COV value of 8.31% and ICC higher than 0.684. The inferotemporal sector showed the lowest ICC (0.685). Conclusions Triton OCT presents good reproducibility values in measurements corresponding to retinal parameters, with macular measurements showing the highest reproducibility rates. Peripapillary RNFL measurements should be evaluated with caution.
关键词： Reproducibility,Optical coherence tomography,Coefficient of variation,Swept source
更新于2025-09-23 15:22:29
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The Application of a New Model-Based Iterative Reconstruction in Low-Dose Upper Abdominal CT
摘要： Rationale and Objectives: To compare upper abdominal computed tomography (CT) image quality of new model-based iterative reconstruction (MBIR) with low-contrast resolution preference (MBIRNR40), conventional MBIR (MBIRc), and adaptive statistical iterative reconstruction (ASIR) at low dose with ASIR at routine-dose. Materials and Methods: Study included phantom and 60 patients who had initial and follow-up CT scans. For patients, the delay phase was acquired at routine-dose (noise index = 10 HU) for the initial scan and low dose (noise index = 20 HU) for the follow-up. The low-dose CT was reconstructed with 40% and 60% ASIR, MBIRc, and MBIRNR40, while routine-dose CT was reconstructed with 40% ASIR. CT value and noise measurements of the subcutaneous fat, back muscle, liver, and spleen parenchyma were compared using one-way ANOVA. Two radiologists used semiquantitative 7-scale (-3 to +3) to rate image quality and artifacts. Results: The phantom study revealed superior low-contrast resolution with MBIRNR40. For patient scans, the CT dose index for the low-dose CT was 3.00 ± 1.32 mGy, 75% lower than the 11.90 ± 4.75 mGy for the routine-dose CT. Image noise for the low-dose MBIRNR40 images was significantly lower than the low-dose MBIRc and ASIR images, and routine-dose ASIR images (p < 0.05). Subjective ratings showed higher image quality for low-dose MBIRNR40, with lower noise, better low-contrast resolution for abdominal structures, and finer lesion contours than those of low-dose MBIRc and ASIR images, and routine-dose ASIR images (p < 0.05). Conclusion: MBIRNR40 with low-contrast resolution preference provides significantly lower noise and better image quality than MBIRc and ASIR in low-dose abdominal CT; significantly better objective and subjective image quality than the routine-dose ASIR with 75% dose reduction.
关键词： Model-based iterative reconstruction,Abdominal CT.,X-ray computed tomography,Adaptive statistical iterative reconstruction,Radiation dose
更新于2025-09-23 15:22:29
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Radiation dose and image quality in intraoperative CT (iCT) angiography of the brain with stereotactic head frames
摘要： Objectives Intraoperative CT (iCT) angiography of the brain with stereotactic frames is an integral part of navigated neurosurgery. Validated data regarding radiation dose and image quality in these special examinations are not available. We therefore investigated two iCT protocols in this IRB-approved study. Methods Retrospective analysis of patients, who received a cerebral stereotactic iCT angiography on a 128 slice CT scanner between February 2016 and December 2017. In group A, automated tube current modulation (ATCM; reference value 410 mAs) and automated tube voltage selection (reference value 120 kV) were enabled, and only examinations with a selected voltage of 120 kV were included. In group B, fixed parameters were applied (300 mAs, 120 kV). Radiation dose was measured by assessing the volumetric CT dose index (CTDIvol), dose length product (DLP) and effective dose (ED). Signal-to-noise ratio (SNR) and image noise were assessed for objective image quality, visibility of arteries and grey-white differentiation for subjective image quality. Results Two hundred patients (n = 100 in each group) were included. In group A, median selected tube current was 643 mAs (group B, 300 mAs; p < 0.001). Median values of CTDIvol, DLP and ED were 91.54 mGy, 1561 mGy cm and 2.97 mSv in group A, and 43.15 mGy, 769 mGy cm and 1.46 mSv in group B (p < 0.001). Image quality did not significantly differ between groups (p > 0.05). Conclusions ATCM yielded disproportionally high radiation dose due to substantial tube current increase at the frame level, while image quality did not improve. Thus, ATCM should preferentially be disabled.
关键词： Neuronavigation,Brain,Computed tomography angiography,Radiation dosage
更新于2025-09-23 15:22:29
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Role of polysiloxanes in the synthesis of aligned porous silicon oxycarbide ceramics
摘要： The present work focuses on establishing the role of polysiloxane precursors in the synthesis of aligned porous polymer derived silicon oxycarbide ceramics. The precursors used for the synthesis are, polymethylhydrosiloxane, vinyl terminated polydimethylsiloxane and cyclic tetramethyl-tetravinlycyclotetrasiloxane. Hydrotalcite is used for attaining aligned macroporosity during the crosslinking stage itself. Subsequently, pyrolysis of the sample has been carried out to synthesize the ceramics. The evolution of pore structure in these PDCs during the crosslinking and pyrolysis is co-related to the thermal decomposition behaviour. The pore morphology, structure and the size were analyzed using SEM, X-ray computed tomography and BET. Our studies confirm the presence of bimodal porosity in these PDCs. These PDCs have a specific surface area ranging from 77 - 160 m2/g and a total pore volume ranging from 0.18 - 0.29 cm3/g. These results could be significant for achieving a controlled synthesis process of porous materials suitable for various applications like adsorption, filtering and electrochemical storage.
关键词： Mesoporous,X-Ray computed tomography,Pyrolysis,Polymer derived ceramics,Specific surface area
更新于2025-09-23 15:22:29
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PET Imaging of the P2X7 Ion Channel with a Novel Tracer [18F]JNJ-64413739 in a Rat Model of Neuroinflammation
摘要： Purpose: The P2X7 receptor, an adenosine triphosphate (ATP)-gated purinoreceptor, has emerged as one of the key players in neuroinflammatory processes. Therefore, developing a positron emission tomography (PET) tracer for imaging of P2X7 receptors in vivo presents a promising approach to diagnose, monitor, and study neuroinflammation in a variety of brain disorders. To fulfill the goal of developing a P2X7 PET ligand as a biomarker of neuroinflammation, [18F]JNJ-64413739 has been recently disclosed. Procedures: We evaluated [18F]JNJ-64413739 in a rat model of neuroinflammation induced by an intracerebral injection of lipopolysaccharide (LPS). In vivo brain uptake was determined by PET imaging. Upregulation of neuroinflammatory biomarkers was determined by quantitative polymerase chain reaction (qPCR). Distribution of the tracer in the brain was determined by ex vivo autoradiography (ARG). The specificity of [18F]JNJ-64413739 was confirmed by performing blocking experiments with the P2X7 antagonist JNJ-54175446. Results: Brain regions of rats injected with LPS had a significantly increased uptake (34 % ± 3 % s.e.m., p = 0.036, t test, standardized uptake value measured over the entire scanning period) of [18F]JNJ-64413739 relative to the corresponding brain regions of control animals injected with phosphate-buffered saline (PBS). The uptake in the contralateral regions and cerebellum was not significantly different between the groups of animals. The increase in uptake of [18F]JNJ-64413739 at the LPS-injected site observed by PET imaging was concordant with ex vivo ARG, upregulation of neuroinflammatory biomarkers, and elevated P2X7 expression levels. Conclusions: While further work is needed to study [18F]JNJ-64413739 in other types of neuroinflammation, the current results favorably characterize [18F]JNJ-64413739 as a potential PET tracer of central neuroinflammation.
关键词： Lipopolysaccharide,Rats,Positron emission tomography (PET),PET imaging,P2X7 receptor,LPS,[18F]JNJ-64413739,Neuroinflammation
更新于2025-09-23 15:22:29
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Haab striae: Optical coherence tomographic analysis
摘要： Purpose. — To study Haab striae in adults with primary congenital glaucoma and describe them by anterior segment optical coherence tomography, as well as analyze their evolution over the patient’s lifetime. Material and methods. — Three patients with primary congenital glaucoma were recruited, aged between 17 and 48 years old, with incidentally noted Haab striae on glaucoma consultation. They were studied by: slit lamp; anterior segment optical coherence tomography, Heidelberg Engineering Inc., Germany, (with anterior segment module) and Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, California, USA (with 3D reconstruction); and specular biomicroscopy. The results obtained were contrasted with other studies performed in children. Results. — Rounded excrescences protruding towards the anterior chamber were found, as well as dense, irregular tissue between them. In addition, endothelial abnormalities (polymegathism and polymorphism) were found. These findings fit the evolution of those obtained in pediatric studies and remain stable in adult life. Conclusions. — Through noninvasive methods such as optical coherence tomography and specular biomicroscopy, it is possible to make the diagnosis and follow up these patients. The findings suggest posterior corneal topographic changes; additional studies on this subject may be necessary.
关键词： Haab striae,Primary congenital glaucoma,Anterior segment optical coherence tomography,Corneal endothelium,Specular biomicroscopy
更新于2025-09-23 15:22:29
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Multimodal imaging based biomarkers predictive of early and late response to anti-VEGFs during the first year of treatment for neovascular age-related macular degeneration
摘要： Purpose. — To evaluate baseline predictive markers of early and late anatomical response to anti-vascular endothelial growth factor (anti-VEGF) treatment in patients with neovascular age-related macular degeneration (nAMD). Methods. — The records of the nAMD patients who underwent intravitreal ranibizumab or aflibercept treatment, received the 3 monthly loading doses, and completed a follow-up period of 12 months were included retrospectively. The anatomical treatment response at month 3 (early) and between month 3 and 12 (late) was classified as good, intermediate or poor. Baseline demographic, fluorescein angiography, and optical coherence tomography findings were compared among the three groups. Results. — One hundred and ten eyes (74.3%) showed good, 18 (12.2%) showed intermediate and 20 (13.5%) showed poor anatomical response at month 3, and 114 eyes (77.0%) showed good, 27 (18.2%) showed intermediate and 7 (4.7%) showed poor anatomical response between month 3 and month 12. Of the evaluated parameters, drug type (better in aflibercept), showed a statistically significant difference in regards to anatomical outcomes at both the early and late periods (P = 0.02 and P = 0.03). The greatest linear dimension of choroidal neovascularization (CNV) and presence of peaked pigment epithelial detachment (PED) were important factors for early anatomical anti-VEGF treatment response. Conclusion. — Larger CNV and the presence of a peaked PED appeared to be associated with a good early response, and the drug type seemed to be associated with both early and late poor anatomical response of anti-VEGF treatment in nAMD patients. Aflibercept appears to be more effective than ranibizumab in regards to the percentage of patients with better anatomical response in both the early and late treatment periods.
关键词： Optical coherence tomography,Ranibizumab,Age-related macular degeneration,Aflibercept,Fluorescein angiography
更新于2025-09-23 15:22:29
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Evaluation of calculus imaging on root surfaces by spectral-domain optical coherence tomography
摘要： Objective: The aim of this in vitro study was to evaluate the ability of optical coherence tomography (OCT) to display calculus on root surfaces. Material and Methods: Ten teeth with calculus on the root surface were embedded in resin, omitting the root surface. A region of interest (ROI) was marked by small drill holes coronally and apically of the calculus and imaged by spectral-domain optical coherence tomography ([SD OCT], Telesto SP5, centre wavelength 1310 nm) and light microscopy (LM). To evaluate the impact of different fluids on calculus visualisation, using OCT, root surfaces were covered by a layer of NaCl and blood and displayed by OCT. Subsequently, teeth were completely covered with resin and sectioned for histological evaluation. Within the ROI, lengths of root surface and calculus were measured by LM and OCT, and the ratio [%] was calculated. In addition, at three sites of each ROI, agreement of presence and length of calculus was evaluated. Both methods were compared using Pearson’s correlation. Results: Regarding the presence of calculus, agreement between LM and OCT was strong (κi = 0.783, p = 0.033), and measurements regarding the length of the calculus were strongly correlated (ri >0.906; pi <0.001). However, the values differed for dry (p = 0.023) and NaCl-covered root surfaces (p = 0.035). Conclusion: Calculus on the root surface can be displayed by SD-OCT, which therefore may be suited as imaging technology for subgingival calculus in periodontal pockets.
关键词： Optical coherence tomography Periodontitis Subgingival calculus Diagnosis SD-OCT
更新于2025-09-23 15:22:29
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The role of optical coherence tomography in the evaluation of compressive optic neuropathies
摘要： Purpose of review Optical coherence tomography (OCT) is a noninvasive imaging tool routinely used in ophthalmology that provides cross-sectional images of the retina. Compression of the anterior visual pathways results in progressive thinning of the retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) and this review will highlight the utility of OCT in evaluating patients with this condition. Recent findings The RNFL and macular GCC have been found to highly correlate with visual function in patients with compressive optic neuropathies. Preoperative RNFL and macular GCC thickness have emerged as the most reliable and consistent prognostic factors for visual recovery after surgery. Patients with an otherwise normal neuroophthalmic examination, including automated perimetry, may have macular GCC or RNFL thinning as the only manifestation of compression, enabling compressive optic neuropathies to be diagnosed at an earlier stage and managed accordingly. Summary Recent findings indicate that OCT is an important tool in the evaluation of patients with compressive optic neuropathies, particularly for prognosis in patients with visual field defects and diagnosis in patients with preserved or mildly reduced visual function. Anatomical changes detected by OCT may precede visual loss and allow for earlier diagnosis and presumably better visual outcomes.
关键词： optic neuropathy,anterior visual pathways,pituitary adenoma,optical coherence tomography
更新于2025-09-23 15:22:29