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1.
Foods ; 9(12)2020 Dec 13.
Article in English | MEDLINE | ID: mdl-33322182

ABSTRACT

The prices of walnuts vary according to their geographical origin and, therefore, offer a financial incentive for adulteration. A reliable analysis method is required to quickly detect possible misdeclarations and thus prevent food fraud. In this study, a method to distinguish between seven geographical origins of walnuts using Fourier transform near-infrared (FT-NIR) spectroscopy combined with chemometrics as a fast, versatile, and easy to handle analytical tool was developed. NIR spectra of 212 ground and afterwards freeze-dried walnut samples, harvested in three consecutive years (2017-2019), were collected. We optimized the data pre-processing by applying and evaluating 50,545 different pre-processing combinations, followed by linear discriminant analysis (LDA) which was confirmed by nested cross-validation. The results show that in the scope of our research minimal pre-processing led to the best results: By applying just multiplicative scatter correction (MSC) and median centering, a classification accuracy of 77.00% ± 1.60% was achieved. Consequently, this complex model can be used to answer economically relevant questions e.g., to distinguish between European and Chinese walnuts. Furthermore, the great influence of the applied pre-processing methods, e.g., the selected wavenumber range, on the achieved classification accuracy is shown which underlines the importance of optimization of the pre-processing strategy.

2.
Foods ; 9(7)2020 Jul 13.
Article in English | MEDLINE | ID: mdl-32668805

ABSTRACT

Truffles are certainly the most expensive mushrooms; the price depends primarily on the species and secondly on the origin. Because of the price differences for the truffle species, food fraud is likely to occur, and the visual differentiation is difficult within the group of white and within the group of black truffles. Thus, the aim of this study was to develop a reliable method for the authentication of five commercially relevant truffle species via Fourier transform near-infrared (FT-NIR) spectroscopy as an easy to handle approach combined with chemometrics. NIR-data from 75 freeze-dried fruiting bodies were recorded. Various spectra pre-processing techniques and classification methods were compared and validated using nested cross-validation. For the white truffle species, the most expensive Tuber magnatum could be differentiated with an accuracy of 100% from Tuber borchii. Regarding the black truffle species, the relatively expensive Tuber melanosporum could be distinguished from Tuber aestivum and the Chinese truffles with an accuracy of 99%. Since the most expensive Italian Tuber magnatum is highly prone to fraud, the origin was investigated and Italian T. magnatum truffles could be differentiated from non-Italian T. magnatum truffles by 83%. Our results demonstrate the potential of FT-NIR spectroscopy for the authentication of truffle species.

3.
Retina ; 32(2): 256-64, 2012 Feb.
Article in English | MEDLINE | ID: mdl-21926940

ABSTRACT

PURPOSE: Idiopathic juxtafoveal telangiectasia (IJT) is characteristically associated with pigmentary changes. Polarization-sensitive spectral-domain optical coherence tomography (PS-SD-OCT) enables imaging of the retinal pigment epithelium (RPE) and similar melanin-containing structures based on specific polarization properties. This study examined IJT with the latest-generation SD-OCT and PS-SD-OCT, identifying pathophysiologically relevant characteristics of the retinal layers and RPE. METHODS: Twenty-two eyes of 12 patients with IJT were examined by PS-SD-OCT, with special focus on RPE detection and segmentation. Furthermore, SD-OCT technology (Cirrus, Spectralis, and 3D-OCT-1000) was applied. Characteristics of the retinal layers and RPE were evaluated. A classification system based on OCT characteristics of IJT was suggested. RESULTS: Polarization-sensitive spectral-domain optical coherence tomography together with SD-OCT identified characteristic patterns of IJT, used to classify eyes into three distinct groups. Group 1 (5 eyes) revealed discrete alterations in the inner retinal layers; group 2 (12 eyes) showed irregularities of the junction between the inner and outer photoreceptor segments with outer retinal atrophy but an intact RPE. Group 3 (5 eyes) revealed RPE irregularities and loss in addition to intraretinal alterations and photoreceptor abnormalities. CONCLUSION: This study described characteristic morphologic changes in IJT based on PS-SD-OCT and SD-OCT. Morphologic changes were classified, possibly leading to an OCT-based grading scheme. The intensity images of SD-OCT verified intraretinal and photoreceptor irregularities in great detail, whereas PS-SD-OCT additionally showed RPE alterations.


Subject(s)
Retinal Pigment Epithelium/pathology , Retinal Telangiectasis/pathology , Tomography, Optical Coherence , Female , Humans , Male , Middle Aged , Retinal Telangiectasis/classification , Visual Acuity/physiology
4.
Biomed Opt Express ; 2(5): 1159-68, 2011 Apr 12.
Article in English | MEDLINE | ID: mdl-21559128

ABSTRACT

Using a spectral domain OCT system, equipped with a broadband Ti:sapphire laser, we imaged the human retina with 5 µm x 1.3 µm transverse and axial resolution at acquisition rate of 100 kHz. Such imaging speed significantly reduces motion artifacts. Combined with the ultra-high resolution, this allows observing microscopic retinal details with high axial definition without the help of adaptive optics. In this work we apply our system to image the parafoveal capillary network. We demonstrate how already on the intensity level the parafoveal capillaries can be segmented by a simple structural high pass filtering algorithm. This data is then used to quantitatively characterize the capillary network of healthy and diseased eyes. We propose to use the fractal dimension as index for capillary integrity of pathologic disorders.

5.
Invest Ophthalmol Vis Sci ; 52(7): 4571-9, 2011 Jun 28.
Article in English | MEDLINE | ID: mdl-21474772

ABSTRACT

PURPOSE: To estimate the potential of polarization-sensitive optical coherence tomography (PS-OCT) for quantitative assessment of drusen in patients with early age-related macular degeneration (AMD). METHODS: Fifteen eyes from 13 patients presenting drusen consistent with Age-Related Eye Disease Study classifications (grades 2 and 3) were examined ophthalmoscopically, followed by fundus photography, autofluorescence imaging, and three-dimensional scanning using a PS-OCT. For the automated evaluation of drusen location, area, and volume, a novel segmentation algorithm was developed based on the polarization scrambling characteristics of the retinal pigment epithelium (RPE) and applied to each complete data set. Subsequently, the drusen in each individual B-scan were identified by two independent expert graders. Concordance between manual and automated segmentation results was analyzed. Errors in the automated segmentation performance were classified as nonsignificant, moderate, or severe. RESULTS. In all, 2355 individual drusen, with a mean of 157 drusen per eye, were analyzed. Of drusen seen in the individual B-scans, 91.4% were detected manually by both expert graders. The automated segmentation algorithm identified 96.5% of all drusen without significant error. The mean difference in manual and automated drusen area (mean, 4.65 mm(2)) was 0.150. The number of detected drusen was significantly higher with automated than that with manual segmentation. PS-OCT segmentation was generally superior to fundus photography (P < 0.001). Particularly in nondetected drusen, a large variability in drusen morphology was noted. CONCLUSIONS: Automated drusen detection based on PS-OCT technology allows a fast and accurate determination of drusen location, number, and total area.


Subject(s)
Automation , Early Diagnosis , Macular Degeneration/complications , Optic Disk Drusen/diagnosis , Tomography, Optical Coherence/methods , Aged , Diagnosis, Differential , Female , Humans , Imaging, Three-Dimensional , Macular Degeneration/diagnosis , Male , Middle Aged , Optic Disk Drusen/etiology , Reproducibility of Results
6.
Retina ; 31(3): 453-63, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21221050

ABSTRACT

PURPOSE: The purpose of this study was to evaluate standardized automated segmentation procedures of spectral domain optical coherence tomography (SD-OCT) in imaging of age-related macular degeneration. METHODS: Twenty-nine eyes of 29 patients with neovascular age-related macular degeneration were included. Three groups were assigned, according to the predominant localization of extravasated fluid in the intra-, subretinal, and subretinal pigment epithelium (RPE) compartment. Automated segmentation procedures were evaluated in B scans of 512 × 128 × 1024 and 200 × 200 × 1024 scan patterns using SD-OCT (Cirrus). Alignment errors at the internal limiting membrane, actual RPE, and extrapolation of the physiologic RPE (RPE fit) were graded using a standardized classification system. RESULTS: The rate of severe alignment failures was 56% and 41% for the 512 × 128 and the 200 × 200 raster pattern, respectively. Internal limiting membrane and actual RPE boundaries were most correctly delineated in the 200 × 200 raster pattern. Retinal pigment epithelium fit alignment was generally poor in 50% of scans. Retinal thickness values defined by internal limiting membrane and actual RPE segmentation were 90% accurate and not compromised by RPE fit misalignment. Subretinal fluid was demarcated most reliably. Alignment errors may occur together with a large spectrum of morphologic alterations. CONCLUSION: Automated algorithms of SD-OCT demonstrate a substantial rate of alignment failures in the assessment of exudative age-related macular degeneration pathologies, which are usually associated with misinterpretation of boundaries at the (sub) RPE level.


Subject(s)
Tomography, Optical Coherence/instrumentation , Wet Macular Degeneration/diagnosis , Aged , Algorithms , Basement Membrane/pathology , Exudates and Transudates , Female , Humans , Male , Retina/pathology , Retinal Pigment Epithelium/pathology , Tomography, Optical Coherence/methods , Visual Acuity
7.
Acta Ophthalmol ; 89(4): 369-75, 2011 Jun.
Article in English | MEDLINE | ID: mdl-19878107

ABSTRACT

PURPOSE: To investigate the physiological retinal response to uneventful cataract surgery using conventional time-domain (TD-OCT) and current spectral-domain optical coherence tomography (SD-OCT) in combination with an assessment of the anterior chamber inflammatory reaction by laser flare/cell meter (LCFM). METHODS: Thirty-four patients scheduled for cataract surgery were included in this prospective pilot study. Retinal parameters were examined according to a standardized examination procedure using TD-OCT (Stratus; Carl Zeiss Meditec, Dublin, California, USA) and SD-OCT (Cirrus; Carl Zeiss Meditec) devices. The inflammatory reaction of the anterior chamber was measured by LFCM (Kowa FC-1000, Kowa Co. Ltd, Tokyo, Japan). Examinations were carried out preoperatively and at day 2, week 1 and week 4 postoperatively. RESULTS: A slight decrease of central retinal thickness values was identified at day 2 postoperatively followed by an increase of these parameters at week 4. LFCM showed peak values in all patients at day 2 postoperatively with a constant decrease at the following visits. No visible pathological retinal changes were seen after surgery. CONCLUSION: A biphasic retinal response after surgery could be shown with SD-OCT and TD-OCT technology. By using the advantages of rasterscanning mode, SD-OCT technology is superior to TD-OCT imaging in the investigation of the physiological retinal response to cataract surgery.


Subject(s)
Anterior Eye Segment/pathology , Phacoemulsification , Postoperative Complications , Retina/pathology , Uveitis, Anterior/diagnosis , Aged , Aged, 80 and over , Capsulorhexis , Diagnostic Techniques, Ophthalmological , Female , Humans , Inflammation/pathology , Lens Implantation, Intraocular , Male , Middle Aged , Pilot Projects , Prospective Studies , Tomography, Optical Coherence
8.
Acta Ophthalmol ; 89(2): 185-9, 2011 Mar.
Article in English | MEDLINE | ID: mdl-19764914

ABSTRACT

PURPOSE: This study compared automatic- and manual segmentation modalities in the retina of healthy eyes using high-definition optical coherence tomography (HD-OCT). METHODS: Twenty retinas in 20 healthy individuals were examined using an HD-OCT system (Carl Zeiss Meditec, Inc.). Three-dimensional imaging was performed with an axial resolution of 6 µm at a maximum scanning speed of 25,000 A-scans/second. Volumes of 6 × 6 × 2 mm were scanned. Scans were analysed using a matlab-based algorithm and a manual segmentation software system (3D-Doctor). The volume values calculated by the two methods were compared. RESULTS: Statistical analysis revealed a high correlation between automatic and manual modes of segmentation. The automatic mode of measuring retinal volume and the corresponding three-dimensional images provided similar results to the manual segmentation procedure. Both methods were able to visualize retinal and subretinal features accurately. CONCLUSIONS: This study compared two methods of assessing retinal volume using HD-OCT scans in healthy retinas. Both methods were able to provide realistic volumetric data when applied to raster scan sets. Manual segmentation methods represent an adequate tool with which to control automated processes and to identify clinically relevant structures, whereas automatic procedures will be needed to obtain data in larger patient populations.


Subject(s)
Retina/anatomy & histology , Tomography, Optical Coherence , Adult , Algorithms , Automation , Female , Humans , Imaging, Three-Dimensional , Male , Reference Values , Visual Acuity/physiology , Young Adult
9.
Invest Ophthalmol Vis Sci ; 52(3): 1599-605, 2011 Mar 01.
Article in English | MEDLINE | ID: mdl-21051733

ABSTRACT

PURPOSE: To analyze the functional and morphologic effects of different ranibizumab treatment regimens on retinal and subretinal as well as sub-RPE compartments in neovascular age-related macular degeneration (nAMD) using spectral-domain optical coherence tomography (SD-OCT) and manual segmentation software. METHODS: Twenty-seven eyes of 27 patients with nAMD were examined over a 12-month period. Two treatment arms received either monthly or quarterly administered intravitreal ranibizumab. Intraretinal, subretinal, and sub-RPE volume equivalents were delineated using manual segmentation software over a defined series of B-scans obtained by SD-OCT. The mean area in pixels was calculated for each compartment at each time interval. RESULTS: SD-OCT and manual segmentation allowed for exact identification of intraretinal, subretinal and sub-RPE compartments and their responses to different treatment regimens. The loading dose demonstrated a corresponding treatment effect on all anatomic parameters. In contrast to the sub-RPE compartment, intraretinal fluid accumulation and subretinal fluid accumulation (SRFA) demonstrated an immediate response to ranibizumab therapy. The overall plasticity of the morphologic response declined over time. In general, SRFA demonstrated greater sensitivity for therapeutic effects and was more frequently associated with recurrent disease. CONCLUSIONS: An exact quantification of fluid in different anatomic compartments based on SD-OCT imaging, using appropriate segmentation software systems, may be useful to determine optimal treatment and retreatment parameters and explains the lack of correlation of best-corrected visual acuity and conventional OCT values.


Subject(s)
Angiogenesis Inhibitors/therapeutic use , Antibodies, Monoclonal/therapeutic use , Choroidal Neovascularization/drug therapy , Retina/pathology , Retinal Pigment Epithelium/pathology , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Wet Macular Degeneration/drug therapy , Antibodies, Monoclonal, Humanized , Choroidal Neovascularization/diagnosis , Choroidal Neovascularization/metabolism , Exudates and Transudates , Follow-Up Studies , Humans , Imaging, Three-Dimensional , Intravitreal Injections , Middle Aged , Ranibizumab , Retina/drug effects , Retinal Pigment Epithelium/drug effects , Subretinal Fluid/metabolism , Tomography, Optical Coherence , Visual Acuity/physiology , Wet Macular Degeneration/diagnosis , Wet Macular Degeneration/metabolism
10.
Acta Ophthalmol ; 89(3): 235-40, 2011 May.
Article in English | MEDLINE | ID: mdl-20636487

ABSTRACT

PURPOSE: Investigating segmentation procedures and morphological findings in time domain (TD) and current spectral domain (SD) optical coherence tomography (OCT) devices in patients with geographic atrophy (GA). METHODS: Fifty eyes of 46 patients with GA secondary to AMD and 15 control eyes were examined in this prospective noninterventional comparative case series. All patients underwent Stratus (model 3000), Cirrus (Carl Zeiss Meditec), Spectralis (Spectralis HRA+OCT; Heidelberg Engineering) and 3D-OCT-1000 (Topcon). Automated segmentation analyses were compared. An overlay of scanning laser ophthalmoscope (SLO) and three-dimensional retinal thickness (RT) maps were used to investigate whether areas of retinal thinning correspond to areas of retinal pigment epithelium (RPE) atrophy. RESULTS: Geographic atrophy areas identified in SLO scans were significantly larger than areas of retinal thinning in RT maps. No convincing topographic correlation could be found between areas of retinal thinning and actual GA size as identified in SLO and fundus photography. Spectralis OCT showed significantly more mild and severe segmentation errors than 3D and Cirrus OCT. CONCLUSION: This study showed substantial limitations in identifying zones of GA reliably when using automatic segmentation procedures in current SD-OCT devices. This limitation should be addressed to visualize and document RPE loss realistically in a frequent disease like GA.


Subject(s)
Geographic Atrophy/diagnosis , Macular Degeneration/diagnosis , Retina/pathology , Retinal Pigment Epithelium/pathology , Tomography, Optical Coherence/instrumentation , Aged , Female , Humans , Male , Ophthalmoscopy , Prospective Studies , Reproducibility of Results , Tomography, Optical Coherence/standards
11.
Invest Ophthalmol Vis Sci ; 51(12): 6715-21, 2010 Dec.
Article in English | MEDLINE | ID: mdl-21123769

ABSTRACT

PURPOSE: To evaluate the performance of automated analyses integrated in three spectral-domain optical coherence tomography (SD-OCT) devices to identify drusen in eyes with early (i.e., nonatrophic and nonneovascular) age-related macular degeneration (AMD). METHODS: Twelve eyes of 12 AMD patients, classified as AREDS 2 and 3 and having a mean count of 113 drusen were examined with three clinical SD-OCT devices (Cirrus [Carl Zeiss Meditec, Dublin CA], 3DOCT-1000 [Topcon, Tokyo, Japan], and Spectralis [Heidelberg Engineering, GmbH, Heidelberg, Germany]) and five different scan patterns. After standard automated segmentation of the RPE was performed, every druse in each B-scan was identified and graded by two independent expert graders. Errors in the segmentation performance were classified as negligible, moderate, or severe. Correlations were based on the diameter and height of the druse and its automated segmentation. The overall drusen pattern identified by experts' detailed delineation was plotted with a custom-made computer program to compare automated to manual identification outcomes. RESULTS: A total of 1356 drusen were analyzed. The automated segmentation of the retinal pigment epithelium (RPE) by Cirrus made significantly fewer errors in detecting drusen than did the 3DOCT-1000 (P < 0.001). The Cirrus 200 × 200 scan pattern detected 30% of the drusen with negligible errors. Spectralis did not offer a true RPE segmentation. The drusen counts by expert graders were significantly higher in the scans than in the standard fundus photographs (P < 0.05). CONCLUSIONS: SD-OCT imaging proved an excellent performance in visualizing drusen-related RPE disease. However, the available automated segmentation algorithms showed distinct limitations to reliable identification of the amount of drusen, particularly smaller drusen, and the actual size.


Subject(s)
Diagnostic Techniques, Ophthalmological , Macular Degeneration/diagnosis , Retinal Drusen/diagnosis , Tomography, Optical Coherence/methods , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Retinal Pigment Epithelium/pathology
12.
J Biomed Opt ; 15(6): 061704, 2010.
Article in English | MEDLINE | ID: mdl-21198152

ABSTRACT

We present polarization-sensitive optical coherence tomography (PS-OCT) for quantitative assessment of retinal pathologies in age-related macular degeneration (AMD). On the basis of the polarization scrambling characteristics of the retinal pigment epithelium, novel segmentation algorithms were developed that allow one to segment pathologic features such as drusen and atrophic zones in dry AMD as well as to determine their dimensions. Results from measurements in the eyes of AMD patients prove the ability of PS-OCT for quantitative imaging based on the retinal features polarizing properties. Repeatability measurements were performed in retinas diagnosed with drusen and geographic atrophy in order to evaluate the performance of the described methods. PS-OCT appears as a promising imaging modality for three-dimensional retinal imaging and ranging with additional contrast based on the structures' tissue-inherent polarization properties.


Subject(s)
Macular Degeneration/pathology , Microscopy, Polarization/instrumentation , Pattern Recognition, Automated/methods , Retina/pathology , Retinal Drusen/pathology , Retinoscopes , Tomography, Optical Coherence/instrumentation , Aged , Equipment Design , Equipment Failure Analysis , Female , Humans
13.
Invest Ophthalmol Vis Sci ; 51(4): 2149-57, 2010 Apr.
Article in English | MEDLINE | ID: mdl-19797228

ABSTRACT

Purpose. Spectral-domain optical coherence tomography (SD-OCT) provides new insights into the understanding of age-related macular degeneration (AMD) but limited information on the nature of hyperreflective tissue at the level of the retinal pigment epithelium. Therefore, polarization-sensitive (PS) SD-OCT was used to identify and characterize typical RPE findings in AMD. Methods. Forty-four eyes of 44 patients with AMD were included in this prospective case series representing the entire AMD spectrum from drusen (n = 11), geographic atrophy (GA; n = 11), neovascular AMD (nAMD; n = 11) to fibrotic scars (n = 11). Imaging systems were used for comparative imaging. A PS-SD-OCT instrument was developed that was capable of recording intensity and polarization parameters simultaneously during a single scan. Results. In drusen, PS-SD-OCT identified a continuous RPE layer with focal elevations. Discrete RPE atrophy (RA) could be observed in two patients. In GA, the extension of the RA was significantly larger. Residual RPE islands could be detected within the atrophic zone. PS-SD-OCT identified multiple foci of RPE loss in patients with nAMD and allowed recognition of advanced RPE disease associated with choroidal neovascularization. Wide areas of RA containing residual spots of intact retinal pigment epithelium could be identified in fibrotic scars. Conclusions. PS-SD-OCT provided precise identification of retinal pigment epithelium in AMD. Recognition of these disease-specific RA patterns in dry and wet forms of AMD is of particular relevance to identify the status and progression of RPE disease and may help to better estimate the functional prognosis of AMD.


Subject(s)
Macular Degeneration/diagnosis , Retinal Pigment Epithelium/pathology , Tomography, Optical Coherence/methods , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized , Choroidal Neovascularization/diagnosis , Choroidal Neovascularization/drug therapy , Fluorescein Angiography , Geographic Atrophy/diagnosis , Geographic Atrophy/drug therapy , Humans , Macular Degeneration/drug therapy , Prospective Studies , Ranibizumab , Retinal Drusen/diagnosis , Retinal Drusen/drug therapy
14.
Acta Ophthalmol ; 88(2): 181-7, 2010 Mar.
Article in English | MEDLINE | ID: mdl-18937811

ABSTRACT

PURPOSE: Optical coherence tomography (OCT) is used to image branch retinal vein occlusion (BRVO) but lacks information about leakage dynamics and perfusion status. Topographical angiography (TAG) is capable of providing this information and has been described previously in age-related macular degeneration. This study evaluates TAG in BRVO. METHODS: We included 56 eyes of 40 consecutive patients with BRVO and a reduction in central vision. Two groups were established based on whether argon laser coagulation was performed or not. A standardized follow-up was performed. The chorioretinal fluorescence pattern was reconstructed following TAG. Quantitative measurements were also performed. RESULTS: TAG performed from indocyanine green angiography (ICGA) showed smaller lesion size (LS) compared to fluorescein angiography (FA) (mean difference: early phase = -1.6 mm(2), late phase = -1.8 mm(2)). The extent of mean LS from early to late phase increased by 0.8 mm(2) in FA and by 0.6 mm(2) in ICGA. TAG could visualize different degrees of leakage topographically. CONCLUSION: TAG gives new insights into the pathophysiology of BRVO: it enables the visualization of dynamics of leakage and the demonstration of the effects of intravasal stasis. Furthermore, TAG is less impaired by masking phenomena than FA. Functional retinal imaging shows distinct advantages over OCT: quantification of leakage activity is possible using TAG.


Subject(s)
Fluorescein Angiography , Imaging, Three-Dimensional , Retinal Vein Occlusion/diagnosis , Retinal Vein/pathology , Capillary Permeability , Coloring Agents , Humans , Indocyanine Green , Laser Coagulation , Retinal Vein Occlusion/surgery , Sensitivity and Specificity , Visual Acuity
15.
Acta Ophthalmol ; 87(5): 511-6, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19508461

ABSTRACT

PURPOSE: Optical coherence tomography (OCT) is restricted by its low scanning speed and limited resolution. High-definition raster-scanning OCT (HD-OCT) was used to evaluate changes in retinal microstructure in patients with acute central serous chorioretinopathy (CSCR) and to find new morphological features. METHODS: Eighteen patients with subretinal fluid accumulation caused by acute CSCR were imaged in a cross-sectional study design. High-speed frequency-domain HD-OCT was used to image an area of 6 x 6 mm in the macular retina. Three-dimensional analyses were performed using en-face imaging and section analysis of single HD-OCT scans. RESULTS: Detailed information about fluid accumulation can be obtained in all compartments. Discrete changes in reflectivity are visualized within the outer nuclear or plexiform layers in > 90% of patients. Subretinal fluid appears as a dome-shaped pool of fluid and is not associated with a loss of photoreceptor layer integrity. Deposits are demarcated beneath the outer cone segments. Multiple small pigment epithelial detachments are present in > 60% of patients. CONCLUSIONS: High-definition OCT provides extensive information regarding precise topographic and layer-specific localization of discrete morphological changes. Along with well-known changes in the retinal microstructure, hyper-reflectivity can be imaged in the outer nuclear or plexiform layers and may represent intraretinal changes indicating the presence of subretinal pathologies or retinal maladjustment caused by the underlying pathology.


Subject(s)
Choroid Diseases/diagnosis , Retinal Detachment/diagnosis , Tomography, Optical Coherence/methods , Acute Disease , Adult , Body Fluids/metabolism , Choroid Diseases/metabolism , Cross-Sectional Studies , Female , Humans , Imaging, Three-Dimensional , Male , Photoreceptor Cells, Vertebrate/pathology , Retina/metabolism , Retina/pathology , Retinal Detachment/metabolism , Retinal Pigment Epithelium/pathology
16.
Opt Express ; 17(5): 4151-65, 2009 Mar 02.
Article in English | MEDLINE | ID: mdl-19259252

ABSTRACT

Polarization sensitive OCT has recently been shown to provide tissue specific contrast, enabling direct identification of retinal layers based on the intrinsic properties of their interaction with light. However, the capabilities of displaying and analyzing 3D datasets in scientific publications were rather limited. Within the framework of the Interactive Science Publishing project, we present new ways of displaying and analyzing 3D sets of various polarization parameters recorded in healthy and diseased human retinas. These datasets can be interactively explored by the reader. Furthermore, we provide data of the 3D distribution of backscattered Stokes vectors to allow the reader to develop and test their own data processing algorithms.


Subject(s)
Retina/anatomy & histology , Tomography, Optical Coherence/methods , Adult , Aged , Algorithms , Atrophy , Choroid Neoplasms/pathology , Choroidal Neovascularization/pathology , Databases, Factual , Female , Fluorescein Angiography , Humans , Imaging, Three-Dimensional , Macular Degeneration/pathology , Male , Middle Aged , Models, Theoretical , Nevus/pathology , Optical Phenomena , Retina/pathology , Retinal Pigment Epithelium/pathology , Tomography, Optical Coherence/statistics & numerical data
17.
Eur J Ophthalmol ; 19(2): 321-3, 2009.
Article in English | MEDLINE | ID: mdl-19253259

ABSTRACT

PURPOSE: To clarify the origin of the coexisting fluid in an optic disc pit case by using optical coherence tomography (OCT). METHODS: High resolution OCT (Cirrus prototype, Carl Zeiss Meditec) was used for image acquisition;three dimensional segmentation was performed using Food and Drug Administration-approved imaging software (3D-Doctor V4.0, Able software Corp., Lexington, MA) to demonstrate the structural changes of the optic nerve head and the retina. RESULTS: Using high resolution OCT, the authors demonstrated that this case of optic pit had a possible connection between the subretinal and the intraretinal space. CONCLUSIONS: The authors assume that the intraretinal space is progressively filled with subarachnoidal fluid, leading to a tearing force within the outer neurosensory layers. A connection between the outer nuclear layer and the subretinal space may lead to a serous retinal detachment as a secondary event. Vision loss could consecutively be induced by a serous retinal detachment. High resolution OCT technology is able to visualize discrete changes of the microarchitecture of the optic nerve as well as the retina when combined with appropriate imaging software.


Subject(s)
Eye Abnormalities/diagnosis , Optic Disk/abnormalities , Tomography, Optical Coherence , Aged , Female , Fluorescein Angiography , Humans , Imaging, Three-Dimensional
18.
Invest Ophthalmol Vis Sci ; 50(7): 3417-24, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19168899

ABSTRACT

PURPOSE: To investigate the potential role of optical density ratios (ODRs) obtained from subretinal fluid analysis in exudative macular disease and to identify the predictive role of ODRs under therapy in comparison to conventional morphometric measurements (CMMs). METHODS: Fifteen patients with neovascular age-related macular degeneration (nAMD) and 15 with acute central serous chorioretinopathy (CSC) were included in this prospective comparative and interventional case series. High-definition optical coherence tomography (SD-OCT) was performed according to a standardized protocol. nAMD patients received a standard treatment consisting of three monthly doses of intravitreous ranibizumab. Best corrected visual acuity (BCVA) was assessed at baseline (BSL) and weeks 2, 4, and 12. SD-OCT parameters were compared between CSC and nAMD at baseline. Predictive factors for functional recovery under ranibizumab treatment were identified in patients with nAMD. RESULTS: ODR showed highly significant differences between CSC and nAMD, whereas it was not possible to differentiate between these diseases on the basis of CMM. During follow-up, CMM correlated with BCVA at BSL only, whereas ODR showed a significant correlation with BCVA at week 4 and 12 during antiangiogenic therapy. CONCLUSIONS: Results suggest that CMM may correlate with BCVA at BSL, but has limited predictive value regarding recovery of visual function. Most interesting, ODR correlated with BCVA under therapy and was the only parameter that was pathognomic for nAMD in contrast to CSC in this study. ODR may reflect the status of the blood-retina barrier and may be used for pathophysiologic differentiation and prognostic purposes in exudative macular disease.


Subject(s)
Biomarkers/metabolism , Body Fluids/metabolism , Choroidal Neovascularization/metabolism , Macular Degeneration/metabolism , Visual Acuity/physiology , Adult , Aged , Angiogenesis Inhibitors/therapeutic use , Antibodies, Monoclonal/therapeutic use , Antibodies, Monoclonal, Humanized , Blood-Retinal Barrier , Choroidal Neovascularization/diagnosis , Choroidal Neovascularization/drug therapy , Densitometry , Exudates and Transudates , Female , Fluorescein Angiography , Humans , Imaging, Three-Dimensional , Macular Degeneration/diagnosis , Macular Degeneration/drug therapy , Male , Prognosis , Prospective Studies , Ranibizumab , Retinal Diseases/diagnosis , Retinal Diseases/metabolism , Tomography, Optical Coherence , Vascular Endothelial Growth Factor A/antagonists & inhibitors
19.
Opt Express ; 16(21): 16410-22, 2008 Oct 13.
Article in English | MEDLINE | ID: mdl-18852747

ABSTRACT

We present a new method for identifying and segmenting the retinal pigment epithelium (RPE) in polarization sensitive optical coherence tomography (PS-OCT) images of the human retina. Contrary to previous, intensity based segmentation algorithms, our method uses an intrinsic tissue property of the RPE: its depolarizing, or polarization scrambling effect on backscattered light. Two different segmentation algorithms are presented and discussed: a simpler algorithm based on retardation data, and a more sophisticated algorithm based on local variations of the polarization state calculated from averaged Stokes vector elements. By using a state of the art spectral domain PS-OCT instrument, we demonstrate the method in healthy and diseased eyes.


Subject(s)
Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Refractometry/methods , Retinal Pigment Epithelium/anatomy & histology , Tomography, Optical Coherence/methods , Humans , Reproducibility of Results , Sensitivity and Specificity
20.
Ophthalmology ; 115(8): e39-46, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18675694

ABSTRACT

PURPOSE: To analyze the effect of ranibizumab therapy on retinal and subretinal compartments in age-related macular degeneration and to compare the time course of compartment specific effects to visual function. DESIGN: Prospective noncomparative case series. PARTICIPANTS: Fourteen patients with changes in 3 major compartments owing to neovascular age-related macular degeneration. METHODS: Standard treatment with 3 monthly doses of intravitreal ranibizumab was performed. Eyes were examined at baseline and weeks 1, 4, and 12 using a standardized protocol. Manual segmentation was applied to all 128 B-scans contained in a macular raster scan (MRS). MAIN OUTCOME MEASURES: Morphology and time course of different retinal and subretinal compartments. RESULTS: High-definition optical coherence tomography and manual segmentation allowed for precise identification of volumes within individual compartments. All morphologic parameters responded positively to therapy, but demonstrated a specific time course. Subretinal fluid was identified as the most relevant factor for visual function, whereas changes in retinal and subpigment epithelial volumes did not correlate with the time course of functional rehabilitation. CONCLUSION: Analysis of MRS identified a characteristic impact of therapy on retinal and subretinal morphology.


Subject(s)
Angiogenesis Inhibitors/therapeutic use , Antibodies, Monoclonal/therapeutic use , Choroidal Neovascularization/pathology , Macular Degeneration/pathology , Retina/pathology , Tomography, Optical Coherence , Aged , Aged, 80 and over , Antibodies, Monoclonal, Humanized , Choroidal Neovascularization/drug therapy , Choroidal Neovascularization/etiology , Female , Fluorescein Angiography , Follow-Up Studies , Humans , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Injections , Macular Degeneration/complications , Macular Degeneration/drug therapy , Male , Middle Aged , Pigment Epithelium of Eye/pathology , Ranibizumab , Retina/drug effects , Time Factors , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Visual Acuity , Vitreous Body
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