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Correlation between optic nerve head structural parameters and glaucomatous visual field indices
摘要： We examined associations between optic nerve head structural parameters and glaucomatous visual field indices. The study population included patients with glaucomatous optic neuropathy who were evaluated at Aichi Medical University, Nagakute, Aichi, Japan, from October 2010 to January 2011. A total of 57 eyes from 33 patients were assessed. We measured visual field using a Humphrey field analyzer, peripapillary retinal nerve fiber layer thickness (RNFL-T), and Bruch’s membrane opening-minimum rim width (BMO-MRW) using spectral domain optical coherence tomography, and rim area with referring three-dimensional photography. Spearman’s rank correlation coefficients were calculated between the threshold of visual sensitivity or total deviation of visual field and the following five optic nerve head structural parameters: RNFL-T length, BMO-MRW length, rim area, and calculated RNFL-T and BMO-MRW volumes (each length multiplied by rim area). The Akaike information criterion was calculated to determine which structural parameter was the best predictor of each visual field index. Threshold of visual sensitivity had correlation coefficients of 0.23 with global sector of RNFL-T, 0.32 with BMO-MRW, 0.14 with rim area, 0.21 with RNFL-T volume, and 0.26 with BMO-MRW volume. The correlation coefficients for each parameter with total deviation of visual field were 0.22, 0.33, 0.28, 0.36, and 0.37, respectively. The Akaike information criterion of BMO-MRW showed the smallest values in analyses of both threshold of visual sensitivity and total deviation. The present results show that RNFL-T volume and BMO-MRW volume were more strongly correlated with total deviation than BMO-MRW, but BMO-MRW appeared to be the best predictor of the two glaucomatous visual field indices.
关键词： retinal nerve fiber layer thickness,rim area,visual field,glaucoma,spectral domain optical coherence tomography,Bruch’s membrane opening-minimum rim width
更新于2025-09-04 15:30:14
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Resistive Index of Ophthalmic Artery as a Bioimaging Biomarker for the Severity of Diabetic Retinopathy
摘要： Objective: To assess the resistive index (RI) of ophthalmic artery (OA) and central retinal artery (CRA) as a bioimaging biomarker for the severity of diabetic retinopathy, for the first time. Design: Tertiary care center based cross sectional study. Setting: RI in OA and CRA was studied using color Doppler and gray scale sonography. Central Subfield Thickness (CST), Cube Average Thickness (CAT), retinal photoreceptor ellipsoid zone (EZ) disruption, and Retinal Nerve Fiber Layer (RNFL) thickness were studied using SD-OCT. Participants: Sample size was calculated using 95% confidence interval. 69 consecutive cases of type 2 diabetes mellitus between the ages of 40 and 70 years were included after informed consent. According to Early Treatment Diabetic Retinopathy Study (ETDRS) classification cases were grouped as: diabetes mellitus with no retinopathy (No DR) (n=22); non-proliferative diabetic retinopathy (NPDR) (n=25); and Proliferative Diabetic Retinopathy (PDR) (n=22). Healthy control subjects of similar age were included (n=22). Main outcome measures: RI in OA and CRA. Results: A significant increase in RI of OA and CRA was observed with increased severity of DR. A significant positive correlation of RI of OA and CRA with CST, CAT and grades of EZ disruption and a negative correlation with RNFL thickness was observed. RI of OA was found to be a significant independent predictor of severity of DR [multivariate analysis OR=0.00, p<0.001; area under receiver operating characteristic curve analysis=0.941-1.000, p<0.001]. Conclusions: Resistive index of OA is a bio imaging biomarker for the severity of DR.
关键词： Retinal nerve fiber layer,Ophthalmic artery,Central retinal artery,Optical coherence tomography,Biomarkers,Resistive index,Diabetic retinopathy
更新于2025-09-04 15:30:14
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PET imaging in adaptive radiotherapy of gastrointestinal tumors
摘要： radiotherapy is a cornerstone in the multimodality treatment of several gastrointestinal (gi) tumors. Positron-emission tomography (PeT) has an established role in the diagnosis, response assessment and (re-)staging of these tumors. Nevertheless, the value of PeT in adaptive radiotherapy remains unclear. This review focuses on the role of PeT in adaptive radiotherapy, i.e. during the treatment course and in the delineation process.
关键词： gastrointestinal tract,Positron-emission tomography,radiotherapy
更新于2025-09-04 15:30:14
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Evaluation of the Structure–Function Relationship in Glaucoma Using a Novel Method for Estimating the Number of Retinal Ganglion Cells in the Human Retina
摘要： PURPOSE. We developed a simple method for estimating the number of retinal ganglion cells (RGCs) in the human retina using optical coherence tomography (OCT), compared it to a previous approach, and demonstrated its potential for furthering our understanding of the structure–function relationship in glaucoma. METHODS. Swept-source (ss) OCT data and 10-2 visual ?elds (VFs) were obtained from 43 eyes of 36 healthy controls, and 50 eyes of 50 glaucoma patients and suspects. Using estimates of RGC density from the literature and relatively few assumptions, estimates of the number of RGCs in the macula were obtained based on ssOCT-derived RGC layer thickness measurements. RESULTS. The RGC estimates were in general agreement with previously published values derived from histology, whereas a prior method based on VF sensitivity did not agree as well with histological data and had signi?cantly higher (P ? 0.001) and more variable (P < 0.001) RGC estimates than the new method based on ssOCT. However, the RGC estimates of the new approach were not zero for extreme VF losses, suggesting that a residual, non-RGC contribution needs to be added. Finally, the new ssOCT-derived RGC estimates were signi?cantly (P < 0.001 to P ? 0.018) related to VF sensitivity (Spearman’s q ? 0.26–0.47), and, in contrast to claims made in prior studies, statistically signi?cant RGC loss did not occur more often than statistically signi?cant visual loss. CONCLUSIONS. The novel method for estimating RGCs yields values that are closer to histological estimates than prior methods, while relying on considerably fewer assumptions. Although the value added for clinical applications is yet to be determined, this approach is useful for assessing the structure–function relationship in glaucoma.
关键词： visual ?elds,glaucoma,retinal ganglion cells,structure versus function,macula,optical coherence tomography
更新于2025-09-04 15:30:14
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Ultra–Short-Term Reproducibility of Speckle-Noise Freed Fluid and Tissue Compartmentalization of the Choroid Analyzed by Standard OCT
摘要： Purpose: We measured reproducibility of speckle-noise freed fluid and tissue compartmentalization of the choroid (choroidal angiography and tissue characterization). Methods: This study included 26 eyes of 13 healthy females: 13 were used for repeated measurements and 13 were used for side comparison. A semiautomated algorithm removed speckle-noise with structure preservation. Results: Intraclass correlation (ICC), with respect to reproducibility of the method, showed an ICC for choroidal fluid inner space analysis (FISA) of 95.15% (90.01–98.24). The ICC of tissue inner space analysis (TISA) was 99.75% (99.47–99.91). The total choroid ratio (TCR), calculated from volumes of tissue to vessels, showed an ICC of 88.84% (78.28–95.82). Comparison of eyes (left to right) showed a difference for FISA of 0.033 (95% confidence interval [CI] (cid:2)0.0018–0.0680, P ? 0.063), TISA (cid:2)0.118 (CI (cid:2)0.2373–0.0023, P ? 0.055), and TCR (cid:2)0.590 (CI (cid:2)0.9047 to (cid:2)0.2754, P ? 0.004). The ICC for FISA and TISA showed a trend in the difference comparing left and right eyes; however, TCR showed a significant difference between the eyes in the measured area (P , 0.001). Mean overall FISA was 0.58 mm3 (range, 0.25–0.98 mm3, SD ? 0.14). Mean TISA was 3.45 mm3 (range, 2.38–5.0 mm3, SD 0.072). Mean TCR was 6.13 (overall range, 3.93–10.2, SD ? 1.34). Conclusions: Differences in choroidal layers between subjects were found mainly due to alterations in choroidal tissue. Reproducibility of speckle-noise freed choroidal angiography appeared excellent.
关键词： choroid,imaging,speckle noise,angiography,optical coherence tomography,tissue
更新于2025-09-04 15:30:14
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European Microscopy Congress 2016: Proceedings || Factors limiting the doping efficiency in atomic layer deposited ZnO:Al thin films: a dopant distribution study by transmission electron microscopy and atom probe tomography
摘要： Transparent conducting oxides (TCOs), such as indium tin oxide (ITO), are commonly used as transparent electrodes in a wide variety of devices, such as in displays and solar cells. ZnO has been reported to be a promising alternative TCO for ITO, because of its lower cost. As the conductivity of intrinsic ZnO films is too low for the applications in mind, doping the ZnO film is essential, the most common dopant being Al. Atomic layer deposition (ALD) is an emerging technique for the deposition of doped ZnO thin films, allowing for accurate thickness control and excellent conformality on high aspect ratio topologies. Due to the self-limiting half-reactions and cyclic nature of the ALD process, not only the aforementioned characteristics can be met, but also the amount and distribution of dopants can be controlled by selecting the precursors (i.e. the Zn or Al precursors) for each individual half-cycle. However, thus far, the maximum conductivity that can be obtained in Al-doped ZnO (ZnO:Al) thin films prepared by ALD appears to be limited by the low doping efficiency of Al. To better understand the origin of this limitation, the 3-dimensional distribution of Al atoms in ZnO films has been examined using a combination of Transmission Electron Microscopy (TEM) and Atom Probe Tomography (APT). For this study, three ZnO:Al films with different Al:Zn ratios were grown sequentially in one film stack, and capped and separated by intrinsic ZnO films. A diagram of the stack is shown in Fig. 1a. This geometry allowed a single APT or TEM measurement to collect data on all three doped films, keeping the analytical conditions identical. BFTEM studies (Fig 1b) showed that for high Al concentrations the ZnO grains are interrupted, while they continue across the lower doped layers. Scanning TEM – High Angle Annular Dark Field (HAADF) imaging and 2-D EDX mappings allows for revealing the aluminum distribution as a function of film depth, showing that the Al-doped layers follow the surface topography of the ZnO grains during growth Fig. 1c,d. However, TEM is limited in providing 3-D dopant distributions, on the one hand because of the limited sensitivity of EDX, on the other hand because of the projection of rough interfaces in a 2-D image. The latter is illustrated in Fig. 2a: individual Al-doped layers can clearly be discerned for larger interspacings, but are poorly recognizable in layer ‘AZO-3’. One-dimensional depth profiles extracted from cylindrical sub-volumes of the 3D APT data (Fig. 2 b) are presented in Fig. 2c. These 1D profiles show that the peaks in Al concentration are no δ-functions, as might be expected from the binary nature of the ALD process. Instead, the peaks have a full width at half maximum (FWHM) of ~2 nm. The 3-dimensional dopant distribution can be used to explain the dependencies of resistivity and doping efficiency on growth recipes used. When the local Al density is too high, the doping efficiency is limited by two proposed limiting factors: the solid solubility limit of Al atoms in a ZnO matrix and the disorder-induced carrier localization.
关键词： atom probe tomography,atomic layer deposition,transparent conducting oxides
更新于2025-09-04 15:30:14
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VALIDATION OF A CONVOLUTION INTEGRAL FOR CONDUCTIVITY IMAGING
摘要： Magnetic induction tomography has been under consideration for imaging electrical conductivity distributions within the human body. Multi-coil systems are most commonly employed for this task, requiring a numerical solution of Maxwell’s equations at each position of the coil array. An alternative uses a single coil placed near the conductive target while measuring coil self-impedance changes at a number of unique locations. Recently, a closed-form solution of Maxwell’s equations, in the form of a 3D convolution integral, was found for a single coil consisting of concentric circular loops that relates impedance change (loss) to an arbitrary conductivity. Its development required spatially uniform permittivity and permeability, yet showed quantitative agreement with experiment. Here, we provide a much more rigorous test of the convolution integral in experiments that allow large permittivity changes across coil dimensions. Loss is measured while the coil is placed at known positions relative to plastic columns of variable diameter which are ?lled with salt solutions of varying conductivity. In all cases, coil loss varies linearly with conductivity and with zero intercept. Quantitative agreement is observed only when column diameter is greater than or equal to coil diameter. Because of linearity, the convolution integral is useful for image reconstruction, though contrast could be either reduced or enhanced in those circumstances when relative permittivity change exceeds ～ 70.
关键词： single-coil system,conductivity imaging,convolution integral,Maxwell’s equations,Magnetic induction tomography
更新于2025-09-04 15:30:14
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Transient spectral domain optical coherence tomography findings in classic MEWDS: a case report
摘要： The purpose of this study was to describe a patient with multiple evanescent white dot syndrome (MEWDS) who presented with classic retinal findings and transient changes in outer retinal anatomy. A 20-year-old man presented with mild blurred vision in the left eye, reporting flu-like symptoms 1 week before the visual symptoms started. Fundus examination of the left eye revealed foveal granularity and multiple scattered spots deep to the retina in the posterior pole. Fluorescein angiography and indocyanine green angiography showed typical MEWDS findings. Spectral Domain Optical Coherence Tomography has shown transient changes in outer retinal anatomy with disappearance of inner segment-outer segment junction and mild attenuation of external limiting membrane. Six months later, Spectral Domain Optical Coherence Tomography has shown complete resolution with recovery of normal outer retinal aspect.
关键词： Case reports,Tomography, optical coherence,Syndrome/diagnosis,Retinal diseases/diagnosis
更新于2025-09-04 15:30:14
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Synthesis of gadolinium-based Bi<sub>2</sub>S<sub>3</sub> nanoparticles as cancer theranostics for dual-modality computed tomography /magnetic resonance imaging-guided photothermal therapy
摘要： Development of a safe, efficient and inexpensive multifunctional nanoplatform using a facile approach for multimodal imaging and therapeutic functions becomes more and more practically relevant but challenging. In this work, we demonstrated a novel nanocomposites (Bi2S3-Gd) for computed tomography (CT)/magnetic resonance (MR) imaging-guided photothermal therapy for cancer in vitro. It was achieved by modification of hydrophobic Bi2S3 with a smart amphiphilic gadolinium-chelated ligand. The as-prepared nanocomposites composed of low cost Bi2S3 and gadolinium complexes, showed high stability, excellent biocompatibility and good photostability. It was observed that Bi2S3-Gd nanocomposites can efficiently convert the NIR light into heat, and then suppressed the growth of tumor cells under NIR laser irradiation. Apart from serving as an effective photothermal agent, the as-prepared nanomaterials could induce an efficient contrast enhancement for both CT and MRI imaging at low concentrations of Bi and Gd, rendering more accurate diagnosis. This work suggests the potential of Bi2S3-Gd nanomaterials as a novel multifunctional nanoplatform for CT/MRI imaging-guided photothermal therapy for cancer.
关键词： photothermal therapy,magnetic resonance imaging,Bismuth sulfide,amphiphilic ligand,computed tomography imaging
更新于2025-09-04 15:30:14
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A Comparison of Progressive Loss of the Ellipsoid Zone (EZ) Band in Autosomal Dominant and X-Linked Retinitis Pigmentosa
摘要： PURPOSE. In patients with retinitis pigmentosa (RP), the inner segment ellipsoid zone (EZ; also known as the inner segment/outer segment [IS/OS] border) is a marker of the usable visual ?eld at a given point in time and of the progression of the disease over time. Here we compare the change in the width per year of the EZ band in patients with autosomal dominant (ad) and x-linked (xl) RP. METHODS. Using optical coherence tomography (OCT), 9-mm horizontal and vertical line scans through the fovea were obtained for one eye of 26 xlRP patients and 33 adRP patients. Scans were repeated on average 2.0 years later (range, 0.6–4.8 years). Using a manual segmentation procedure, the EZ band was delineated and its horizontal width (HW) and vertical width (VW) were determined. RESULTS. The adRP and xlRP patients had similar initial EZ HW (xlRP: 11.8 6 5.48, adRP: 12.4 6 6.38, P ? 0.69) and VW (xlRP: 8.5 6 4.98, adRP: 11.4 6 7.18, P ? 0.09). However, between visits the absolute loss and percent loss of the EZ width per year was signi?cantly greater for xlRP than adRP for both HW (xlRP: 1.0 6 0.68/y, 9.6 6 5.6%/y; adRP: 0.4 6 0.58/y, 3.4 6 5.4%/y; P < 0.001) and VW (xlRP: 0.8 6 0.88/y, 9.2 6 8.9%/y; adRP: 0.3 6 0.58/y, 4.2 6 6.4%/y; P < 0.01). There was a weak correlation between the loss of EZ width per year and the initial width for xlRP (r2 ? 0.17, P ? 0.036), but no correlation for adRP (r2 ? 0.004, P ? 0.73). The test–retest difference of EZ HW was 0.2 6 0.58. CONCLUSIONS. The OCT data here support a faster rate of loss per year in the case of xlRP. (ClinicalTrials.gov number, NCT00100230.)
关键词： optical coherence tomography,retinitis pigmentosa,progression
更新于2025-09-04 15:30:14