PURPOSE: To demonstrate the plane of premacular hemorrhage in Valsalva retinopathy with optical coherence tomography.DESIGN: Observational case report METHODS: Two young men with Valsalva stress-related premacular hem...PURPOSE: To demonstrate the plane of premacular hemorrhage in Valsalva retinopathy with optical coherence tomography.DESIGN: Observational case report METHODS: Two young men with Valsalva stress-related premacular hemorrhage were evaluated by OCT scans, taken just above the level of sedimented blood. RESULTS: In both cases, OCT demonstrated two distinct membranes: a highly reflective band immediately above the premacular hemorrhage, corresponding to the internal limiting membrane, and an overlying patchy membrane with low optical reflectivity consistent with posterior hyaloid. CONCLUSION: OCT supported the clinical impression that the plane of premacular hemorrhage in Valsalva retinopathy is probably under ILM. Larger case studies are required to confirm this finding.展开更多
Receiver ghost reflections adversely affect variable-depth streamer （VDS） data acquisition. In addition, the frequency notches caused by the interference between receiver ghosts and primary waves strongly affect sei...Receiver ghost reflections adversely affect variable-depth streamer （VDS） data acquisition. In addition, the frequency notches caused by the interference between receiver ghosts and primary waves strongly affect seismic data processing and imaging. We developed a high-resolution Radon transform algorithm and used it to predict receiver ghosts from VDS data. The receiver ghost reflections are subtracted and removed from the raw data. We propose a forward Radon transform operator of VDS data in the frequency domain and, based on the ray paths of the receiver ghosts, we propose an inverse Radon transform operator. We apply the proposed methodology to model and field data with good results. We use matching and subtracting modules of commercially available seismic data processing software to remove the receiver ghosts. The frequency notches are compensated and the effective frequency bandwidth of the seismic data broadens.展开更多
Aims: To introduce new terminology and validate its reliability for the analys is of optical coherence tomography (OCT) scans, compare clinical detection of cy stoid macular oedema (CMO)and subretinal fluid (SRF) with...Aims: To introduce new terminology and validate its reliability for the analys is of optical coherence tomography (OCT) scans, compare clinical detection of cy stoid macular oedema (CMO)and subretinal fluid (SRF) with OCT findings, and to s tudy the effect of photodynamic therapy (PDT) on the foveal morphology. Methods: Patients with subfoveal, predominantly classic choroidal neovascularisation (CN V) secondary to age related macular degeneration (AMD) undergoing PDT were evalu ated with refraction protocol best corrected logMAR visual acuity (VA), slit lam p biomicroscopy, stereoscopic fluorescein angiography (FFA), and OCT. New termin ologies introduced to interpret the OCT scans were: neuroretinal foveal thicknes s (NFT), bilaminar foveal thickness (BFT), outer high reflectivity band thicknes s (OHRBT), intraretinal fluid (IRF), subretinal fluid (oSRF), and vitreomacular hyaloid attachment (VMHA). Results: Fifty six eyes of 53 patients were studied. VA was better in eyes with a thinner outer high reflectivity band (OHRBT) (p=0.0 2) and BFT (p=0.05). BFT was less in eyes that had undergone a greater number of PDT treatments (p=0.04). There was poor agreement between OCT and clinical exam ination in the detection of CMO and subretinal fluid (κ.=0.289 and κ.=0.165 re spectively). To validate the interpretation and measurements on OCT, two groups of 20 scans were analysed by two independent observers. There was good agreement between the observers in the detection of IRF,oSRF, and VMHA (p< 0.001). Measur ements of NFTand BFThad a high reproducibility, and of OHRBT reproducibility was low. Conclusions: New terminology has been introduced and tested. OCT appears t o be superior to clinical examination and FFAin the detection of CMO. In this st udy, better vision was associated with a thinner OHRBT and/or the absence of SRF giving insight into the biological effect of PDT.展开更多
文摘PURPOSE: To demonstrate the plane of premacular hemorrhage in Valsalva retinopathy with optical coherence tomography.DESIGN: Observational case report METHODS: Two young men with Valsalva stress-related premacular hemorrhage were evaluated by OCT scans, taken just above the level of sedimented blood. RESULTS: In both cases, OCT demonstrated two distinct membranes: a highly reflective band immediately above the premacular hemorrhage, corresponding to the internal limiting membrane, and an overlying patchy membrane with low optical reflectivity consistent with posterior hyaloid. CONCLUSION: OCT supported the clinical impression that the plane of premacular hemorrhage in Valsalva retinopathy is probably under ILM. Larger case studies are required to confirm this finding.
文摘Receiver ghost reflections adversely affect variable-depth streamer （VDS） data acquisition. In addition, the frequency notches caused by the interference between receiver ghosts and primary waves strongly affect seismic data processing and imaging. We developed a high-resolution Radon transform algorithm and used it to predict receiver ghosts from VDS data. The receiver ghost reflections are subtracted and removed from the raw data. We propose a forward Radon transform operator of VDS data in the frequency domain and, based on the ray paths of the receiver ghosts, we propose an inverse Radon transform operator. We apply the proposed methodology to model and field data with good results. We use matching and subtracting modules of commercially available seismic data processing software to remove the receiver ghosts. The frequency notches are compensated and the effective frequency bandwidth of the seismic data broadens.
文摘Aims: To introduce new terminology and validate its reliability for the analys is of optical coherence tomography (OCT) scans, compare clinical detection of cy stoid macular oedema (CMO)and subretinal fluid (SRF) with OCT findings, and to s tudy the effect of photodynamic therapy (PDT) on the foveal morphology. Methods: Patients with subfoveal, predominantly classic choroidal neovascularisation (CN V) secondary to age related macular degeneration (AMD) undergoing PDT were evalu ated with refraction protocol best corrected logMAR visual acuity (VA), slit lam p biomicroscopy, stereoscopic fluorescein angiography (FFA), and OCT. New termin ologies introduced to interpret the OCT scans were: neuroretinal foveal thicknes s (NFT), bilaminar foveal thickness (BFT), outer high reflectivity band thicknes s (OHRBT), intraretinal fluid (IRF), subretinal fluid (oSRF), and vitreomacular hyaloid attachment (VMHA). Results: Fifty six eyes of 53 patients were studied. VA was better in eyes with a thinner outer high reflectivity band (OHRBT) (p=0.0 2) and BFT (p=0.05). BFT was less in eyes that had undergone a greater number of PDT treatments (p=0.04). There was poor agreement between OCT and clinical exam ination in the detection of CMO and subretinal fluid (κ.=0.289 and κ.=0.165 re spectively). To validate the interpretation and measurements on OCT, two groups of 20 scans were analysed by two independent observers. There was good agreement between the observers in the detection of IRF,oSRF, and VMHA (p< 0.001). Measur ements of NFTand BFThad a high reproducibility, and of OHRBT reproducibility was low. Conclusions: New terminology has been introduced and tested. OCT appears t o be superior to clinical examination and FFAin the detection of CMO. In this st udy, better vision was associated with a thinner OHRBT and/or the absence of SRF giving insight into the biological effect of PDT.
