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1.
Unfallchirurgie (Heidelb) ; 127(4): 290-296, 2024 Apr.
Article in German | MEDLINE | ID: mdl-37985517

ABSTRACT

BACKGROUND: In order to continue to efficiently provide both personnel-intensive and resource-intensive care to severely injured patients, some hospitals have introduced individually differentiated systems for resuscitation room treatment. The aim of this study was to evaluate the concept of the A and B classifications in terms of practicability, indications, and potential complications at a national trauma center in Bavaria. METHODS: In a retrospective study, data from resuscitation room trauma patients in the year 2020 were collected. The assignment to A and B was made by the prehospital emergency physician. Parameters such as the injury severity score (ISS), Glasgow outcome scale (GOS), upgrade rate, and the indication criteria according to the S3 guidelines were recorded. Statistical data comparisons were made using t­tests, χ2-tests, or Mann-Whitney U­tests. RESULTS: A total of 879 resuscitation room treatments (A 473, B 406) met the inclusion criteria. It was found that 94.5% of resuscitation room A cases had physician accompaniment, compared to 48% in resuscitation room B assignments. In addition to significantly lower ISS scores (4.1 vs. 13.9), 29.8% of B patients did not meet the treatment criteria defined in the S3 guidelines. With a low upgrade rate of 4.9%, 98% of B patients had a GOS score of 4 or 5. CONCLUSION: The presented categorization is an effective and safe way to manage the increasing number of resuscitation room alerts in a resource-optimized manner.


Subject(s)
Resuscitation , Trauma Centers , Humans , Retrospective Studies , Injury Severity Score , Critical Care
2.
Diagnostics (Basel) ; 13(23)2023 Nov 30.
Article in English | MEDLINE | ID: mdl-38066814

ABSTRACT

As the number of coronary computed tomography angiography (CTA) examinations is expected to increase, technologies to optimize the imaging workflow are of great interest. The aim of this study was to investigate the potential of artificial intelligence (AI) to improve clinical workflow and diagnostic accuracy in high-volume cardiac imaging centers. A total of 120 patients (79 men; 62.4 (55.0-72.7) years; 26.7 (24.9-30.3) kg/m2) undergoing coronary CTA were randomly assigned to a standard or an AI-based (human AI) coronary analysis group. Severity of coronary artery disease was graded according to CAD-RADS. Initial reports were reviewed and changes were classified. Both groups were similar with regard to age, sex, body mass index, heart rate, Agatston score, and CAD-RADS. The time for coronary CTA assessment (142.5 (106.5-215.0) s vs. 195.0 (146.0-265.5) s; p < 0.002) and the total reporting time (274.0 (208.0-377.0) s vs. 350 (264.0-445.5) s; p < 0.02) were lower in the human AI than in the standard group. The number of cases with no, minor, or CAD-RADS relevant changes did not differ significantly between groups (52, 7, 1 vs. 50, 8, 2; p = 0.80). AI-based analysis significantly improves clinical workflow, even in a specialized high-volume setting, by reducing CTA analysis and overall reporting time without compromising diagnostic accuracy.

3.
Scand J Gastroenterol ; 58(10): 1194-1199, 2023.
Article in English | MEDLINE | ID: mdl-37191195

ABSTRACT

BACKGROUND: Adenoma detection with polypectomy during total colonoscopy reduces the incidence of colorectal cancer (CRC) and colorectal cancer-associated mortality. The adenoma detection rate (ADR) is an established quality indicator, which is associated with a decreased risk for interval cancer. An increase in ADR could be demonstrated for several artificially intelligent, real-time computer-aided detection (CADe) systems in selected patients. Most studies concentrated on outpatient colonoscopies. This sector often lacks funds for applying costly innovations like CADe. Hospitals are more likely to implement CADe and information about the impact of CADe in the distinct patient cohort of hospitalized patients is scarce. METHODS: In this prospective, randomized-controlled study, we compared colonoscopies performed with or without computer-aided detection (CADe) system (GI Genius, Medtronic) performed at University Medical Center Schleswig-Holstein, Campus Luebeck. The primary endpoint was ADR. RESULTS: Overall, 232 patients were randomized with n = 122 patients in the CADe arm and n = 110 patients in the control arm. Median age was 66 years (interquartile range 51-77). Indication for colonoscopy was most often workup for gastrointestinal symptoms (88.4%) followed by screening, post-polypectomy and post-CRC surveillance (each 3.9%). Withdrawal time was significantly prolonged (11 vs. 10 min, p = 0.039), without clinical relevance. Complication rate was not different between the arms (0.8% vs. 4.5%; p = 0.072). The ADR was significantly increased in the CADe arm compared to the control (33.6% vs. 18.1%, p = 0.008). ADR increase was particularly strong for the detection in elderly patients aged ≥50 years (OR 6.3, 95% CI 1.7 - 23.1, p = 0.006). CONCLUSION: The use of CADe is safe and increases ADR in hospitalized patients.


Subject(s)
Adenoma , Colonic Polyps , Colorectal Neoplasms , Aged , Humans , Prospective Studies , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/epidemiology , Colonoscopy , Computers , Adenoma/diagnosis , Adenoma/epidemiology , Colonic Polyps/diagnosis
4.
Endosc Int Open ; 11(2): E212-E217, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36845275

ABSTRACT

Background and study aims Only a few studies are available regarding endoscopic vacuum-assisted closure (E-VAC) therapy for the post-surgery leakage of the lower gastrointestinal tract. Patients and methods In this multicenter German study, we retrospectively analyzed patients treated with E-VAC therapy due to post-surgery leakage of the lower gastrointestinal tract from 2000-2020 at Hannover Medical School, University Medical Center Schleswig-Holstein, Campus Luebeck, and Robert Koch Hospital Gehrden. Results Overall, 147 patients were included in this study. Most patients had undergone tumor resections of the lower gastrointestinal tract (n = 88; 59.9 %). Median time to diagnosis of leakage was 10 days (interquartile range [IQR] 6-19). Median duration of E-VAC therapy was 14 days (IQR 8-27). Increase of C-reactive protein (CRP) levels significantly correlated with first diagnosis of leakage ( P  < 0.001). E-VAC therapy led to closure or complete epithelialization of leakage in the majority of patients (n = 122; 83.0 %) and stoma reversal was achieved in 60.0 %. Stoma reversal was significantly more often achieved in patients with CRP levels ≤ 100 mg/L at first diagnosis compared to patients with CRP levels > 100 mg/L (78.4 % vs. 52.7 %; P  = 0.012). Odds ratio for failure of stoma reversal was 3.36 in cases with CRP values > 100 mg/L ( P  = 0.017). In total, leakage- and/ or E-VAC therapy-associated complications occurred in 26 patients (17.7 %). Minor complications included recurrent E-VAC dislocations and subsequent stenosis. Overall, 14 leakage- or E-VAC-associated deaths were observed most often due to sepsis. Conclusions E-VAC therapy due to post-surgery leakage of the lower gastrointestinal tract is safe and effective. High levels of CRP are a negative predictor of E-VAC therapy success.

5.
J Heart Lung Transplant ; 42(6): 778-785, 2023 06.
Article in English | MEDLINE | ID: mdl-36710093

ABSTRACT

BACKGROUND: When advanced heart failure occurs in cardiac amyloidosis, prognosis is poor. In this setting heart transplantation (HTX) is a treatment option for selected patients. We here present the results of post-transplantation outcomes in cardiac amyloidosis within the Eurotransplant area, investigating possible predictors of survival. METHODS: Of 115 patients undergoing HTX due to cardiac amyloidosis in the Eurotransplant region between November 1987 and May 2020, detailed assessment prior to transplantation was available in 85 patients. The present study was conducted in a retrospective approach. Primary endpoint was mortality after HTX. Baseline variables were entered in a Cox proportional hazards model with the primary endpoint as a dependent variable. RESULTS: Median overall survival following HTX was 6.3 years in the overall collective and the subgroup. Univariate Cox proportional hazards model revealed a significant relationship between overall survival and the transplantation period (2008 to 2020 vs 1987 to 2007; median survival 9.7 years vs 1.8 years, hazard ratio 0.45, p = 0.01). Further predictors were albumin concentration (hazard ratio 0.92, p < 0.001), and systolic blood pressure (hazard ratio 0.96, p < 0.001). The transplant period as well as albumin concentration remained significant independent predictors in the AL sub cohort in a multivariate Cox proportional hazards model. CONCLUSIONS: HTX is a viable treatment option for patients at an advanced stage of cardiac amyloidosis as overall survival after transplantation has improved in the modern age. Patients at a very advanced stage of the disease, indicated by low serum albumin and blood pressure, show worse outcomes following HTX. Optimal timing and careful patient selection may therefore be particularly important to further improve post-HTX survival in amyloidosis patients.


Subject(s)
Amyloidosis , Heart Failure , Heart Transplantation , Humans , Retrospective Studies , Heart Transplantation/adverse effects , Heart Failure/complications , Heart Failure/surgery , Amyloidosis/complications , Amyloidosis/surgery , Albumins
6.
Polymers (Basel) ; 14(22)2022 Nov 21.
Article in English | MEDLINE | ID: mdl-36433167

ABSTRACT

The paper presents research regarding a thermally supported multi-material clinching process (hotclinching) for metal and thermoplastic composite (TPC) sheets: an experimental approach to investigate the flow pressing phenomena during joining. Therefore, an experimental setup is developed to compress the TPC-specimens in out-of-plane direction with different initial TPC thicknesses and varying temperature levels. The deformed specimens are analyzed with computed tomography to investigate the resultant inner material structure at different compaction levels. The results are compared in terms of force-compaction-curves and occurring phenomena during compaction. The change of the material structure is characterized by sliding phenomena and crack initiation and growth.

7.
Biomedicines ; 10(9)2022 Aug 25.
Article in English | MEDLINE | ID: mdl-36140177

ABSTRACT

The steroid sapogenin diosgenin is a well-known natural product with a plethora of described pharmacological activities including the amelioration of T helper 17 (Th17)-driven pathologies. However, the exact underlying mode of action of diosgenin leading to a dampened Th17 response is still largely unknown and specific molecular targets have yet to be identified. Here, we show that diosgenin acts as a direct ligand and inverse agonist of the nuclear receptor retinoic acid receptor (RAR)-related orphan receptor (ROR)α and RORγ, which are key transcription factors involved in Th17 cell differentiation and metabolism. IC50 values determined by luciferase reporter gene assays, employing constructs for either RORγ-Gal4 fusion proteins or full length receptors, were in the low micromolar range at around 2 µM. To highlight the functional consequences of this RORα/γ inverse agonism, we determined gene expression levels of important ROR target genes, i.e., IL-17A and glucose-6-phosphatase, in relevant cellular in vitro models of Jurkat T and HepG2 cells, respectively, by RT-qPCR (reverse transcription quantitative PCR). Thereby, it was shown that diosgenin leads to a dose-dependent decrease in target gene expressions consistent with its potent cellular ROR inverse agonistic activity. Additionally, in silico dockings of diosgenin to the ROR ligand-binding domain were performed to determine the underlying binding mode. Taken together, our results establish diosgenin as a novel, direct and dual-selective RORα/γ inverse agonist. This finding establishes a direct molecular target for diosgenin for the first time, which can further explain reported amendments in Th17-driven diseases by this compound.

8.
Environ Manage ; 69(6): 1153-1166, 2022 06.
Article in English | MEDLINE | ID: mdl-35378602

ABSTRACT

Increasing farmers' adoption of sustainable nitrogen management practices is crucial for improving water quality. Yet, research to date provides ambiguous results about the most important farmer-level drivers of adoption, leaving high levels of uncertainty as to how to design policy interventions that are effective in motivating adoption. Among others, farmers' engagement in outreach or educational events is considered a promising leverage point for policy measures. This paper applies a Bayesian belief network (BBN) approach to explore the importance of drivers thought to influence adoption, run policy experiments to test the efficacy of different engagement-related interventions on increasing adoption rates, and evaluate heterogeneity of the effect of the interventions across different practices and different types of farms. The underlying data comes from a survey carried out in 2018 among farmers in the Central Valley in California. The analyses identify farm characteristics and income consistently as the most important drivers of adoption across management practices. The effect of policy measures strongly differs according to the nitrogen management practice. Innovative farmers respond better to engagement-related policy measures than more traditional farmers. Farmers with small farms show more potential for increasing engagement through policy measures than farmers with larger farms. Bayesian belief networks, in contrast to linear analysis methods, always account for the complex structure of the farm system with interdependencies among the drivers and allow for explicit predictions in new situations and various kinds of heterogeneity analyses. A methodological development is made by introducing a new validation measure for BBNs used for prediction.


Subject(s)
Farmers , Nitrogen , Agriculture , Bayes Theorem , Farms , Humans , Policy
9.
Micromachines (Basel) ; 12(12)2021 Nov 26.
Article in English | MEDLINE | ID: mdl-34945306

ABSTRACT

Compared to alternative production methods, cold forming offers technological, economic and ecological potential for the mass production of microgears. Within the current boundaries of the technology, the cold forming of modules m < 0.2 mm is not possible due to size effects, high tool stresses and handling problems. The investigations of this contribution present a novel process chain for the multi-step forming of microgears with a module of m = 0.1 mm. For this purpose, a numerical model of the first two steps of the process chain is set up and confirmed based on experimental forming tests. The results have proven the feasibility of the process chain by a complete forming of the gear teeth.

10.
Micromachines (Basel) ; 12(12)2021 Dec 15.
Article in English | MEDLINE | ID: mdl-34945411

ABSTRACT

Product miniaturisation and functional integration are currently global trends to save weight, space, materials and costs. This leads to an increasing demand for metallic micro components. Thus, the development of appropriate production technologies is in the focus of current research activities. Due to its efficiency, accuracy and short cycle times, microforming at room temperature offers the potential to meet the steadily increasing demand. During microforming, size effects occur which negatively affect the part quality, process stability, tool life and handling. Within this contribution, a multi-stage bulk microforming process from sheet metal is investigated for the materials Cu-OFE and AA6014 with regard to the basic feasibility and the occurrence of size effects. The results reveal that the process chain is basically suitable to produce metallic micro parts with a high repeatability. Size effects are identified during the process. Since several studies postulate that size effects can be minimised by scaling down the metallic grain structure, the grain size of the aluminium material AA6014-W is scaled down to less than one micrometre by using an accumulative roll bonding process (ARB). Subsequently, the effects of the ultrafine grain (UFG) structure on the forming process are analysed. It could be shown that a strengthened material state increases the material utilization. Furthermore, too soft materials can cause damage on the part during ejection. The occurring size effects cannot be eliminated by reducing the grain size.

11.
Biomed Opt Express ; 12(1): 125-146, 2021 Jan 01.
Article in English | MEDLINE | ID: mdl-33520381

ABSTRACT

We describe a novel method for non-rigid 3-D motion correction of orthogonally raster-scanned optical coherence tomography angiography volumes. This is the first approach that aligns predominantly axial structural features such as retinal layers as well as transverse angiographic vascular features in a joint optimization. Combined with orthogonal scanning and favorization of kinematically more plausible displacements, subpixel alignment and micrometer-scale distortion correction is achieved in all 3 dimensions. As no specific structures are segmented, the method is by design robust to pathologic changes. Furthermore, the method is designed for highly parallel implementation and short runtime, allowing its integration into clinical workflow even for high density or wide-field scans. We evaluated the algorithm with metrics related to clinically relevant features in an extensive quantitative evaluation based on 204 volumetric scans of 17 subjects, including patients with diverse pathologies and healthy controls. Using this method, we achieve state-of-the-art axial motion correction and show significant advances in both transverse co-alignment and distortion correction, especially in the subgroup with pathology.

12.
Materials (Basel) ; 13(7)2020 Mar 26.
Article in English | MEDLINE | ID: mdl-32225011

ABSTRACT

This paper deals with the investigation of complex corrosion properties of 3D printed AISI 316L steel and the influence of additional heat treatment on the resulting corrosion and mechanical parameters. There was an isotonic solution used for the simulation of the human body and a diluted sulfuric acid solution for the study of intergranular corrosion damage of the tested samples. There were significant microstructural changes found for each type of heat treatment at 650 and 1050 °C, which resulted in different corrosion properties of the tested samples. There were changes of corrosion potential, corrosion rate and polarization resistance found by the potentiodynamic polarization method. With regard to these results, the most appropriate heat treatment can be applied to applications with intended use in medicine.

14.
Article in German | MEDLINE | ID: mdl-30036901

ABSTRACT

BACKGROUND: Due to the increasing threat by terrorism and the resulting range of operations for the emergency medical service, the equipment as well as the rescue strategies are being adapted and expanded. An example is the "Recommended Action for Emergency Medical Services in Special Operations" (REBEL, Handlungsempfehlung für Rettungsdienst bei besonderen Einsatzlagen) of the highest Bavarian rescue service authority. In the following article, three cases are presented using new tools such as hemostyptics, thoracic patches and tourniquet from the REBEL kit in everyday operations. CASES: The first case deals with a seriously injured driver involved in a truck accident suffering from a scalping violation of the facial skeleton with consecutive critical bleeding (use of hemostyptics-coated dressings). The second case describes an accident with a reinforcing steel perforating a builder's chest. After removal of the perforating steel by first aiders, the two open thoracic wounds are supplied with thoracic closure patches. The third case deals with an amputation injury of the lower leg after a traffic accident (use of tourniquet). DISCUSSION: The most common causes of death besides bleeding that can be prevented in patients with severe injuries and multiple trauma are tension pneumothorax and airway obstruction. These diagnoses can be identified and treated properly using the ABCDE algorithm. In these cases, the new tools such as tourniquet, hemostyptics, chest decompression needles and thoracic closure patches can be used, which are increasingly held as an additional equipment in the ambulance vehicle. The application of these adjuvants requires a critical indication, competent knowledge and training of medical and non-medical emergency service personnel in theory and practice.


Subject(s)
Emergency Treatment , Multiple Trauma/therapy , Terrorism , Accidents, Traffic , Adult , Bandages , Glasgow Coma Scale , Hemostatics/therapeutic use , Humans , Male , Middle Aged , Shock, Hemorrhagic/therapy , Thoracic Injuries/therapy , Tourniquets
16.
Am J Ophthalmol ; 162: 140-149.e1, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26548809

ABSTRACT

PURPOSE: To analyze the vitreoretinal interface in diabetic eyes using 3-dimensional wide-field volumes acquired using high-speed, long-wavelength swept-source optical coherence tomography (SSOCT). DESIGN: Prospective cross-sectional study. METHODS: Fifty-six diabetic patients (88 eyes) and 11 healthy nondiabetic controls (22 eyes) were recruited. Up to 8 SSOCT volumes were acquired for each eye. A registration algorithm removed motion artifacts and merged multiple SSOCT volumes to improve signal. Vitreous visualization was enhanced using vitreous windowing method. RESULTS: Of 88 diabetic eyes, 20 eyes had no retinopathy, 21 eyes had nonproliferative diabetic retinopathy (NPDR) without macular edema, 20 eyes had proliferative diabetic retinopathy (PDR) without macular edema, and 27 eyes had diabetic macular edema (DME) with either NPDR or PDR. Thick posterior hyaloid relative to healthy nondiabetic controls was observed in 0 of 20 (0%) diabetic eyes without retinopathy, 4 of 21 (19%) eyes with NPDR, 11 of 20 (55%) eyes with PDR, and 11 of 27 (41%) eyes with DME (P = .0001). Vitreoschisis was observed in 6 of 22 (27%) healthy nondiabetic eyes, 9 of 20 (45%) diabetic eyes without retinopathy, 10 of 21 (48%) eyes with NPDR, 13 of 20 (65%) eyes with PDR, and 17 of 27 (63%) eyes with DME (P = .007). While no healthy nondiabetic controls and diabetic eyes without retinopathy had adhesions/pegs between detached posterior hyaloid and retina, 1 of 21 (4%), 11 of 20 (55%), and 11 of 27 (41%) eyes with NPDR, PDR, and DME, respectively, demonstrated this feature (P = .0001). CONCLUSION: SSOCT with motion-correction and vitreous windowing provides wide-field 3-dimensional information of vitreoretinal interface in diabetic eyes. This may be useful in assessing progression of retinopathy, planning diabetic vitreous surgery, and predicting treatment outcomes.


Subject(s)
Diabetic Retinopathy/diagnosis , Retina/pathology , Tomography, Optical Coherence , Vitreous Body/pathology , Vitreous Detachment/diagnosis , Adult , Aged , Cross-Sectional Studies , Disease Progression , Female , Humans , Image Enhancement/methods , Imaging, Three-Dimensional , Macular Edema/diagnosis , Male , Middle Aged , Prospective Studies , Visual Acuity/physiology
17.
Scand J Trauma Resusc Emerg Med ; 23: 87, 2015 Oct 31.
Article in English | MEDLINE | ID: mdl-26521230

ABSTRACT

BACKGROUND: Patients with cardiac arrest have lower survival rates, when resuscitation performance is low. In In-hospital settings the first responders on scene are usually nursing staff without rhythm analysing skills. In such cases Automated External Defibrillators (AED) might help guiding resuscitation performance. At the Wuerzburg University Hospital (Germany) an AED-program was initiated in 2007. Aim of the presented study was to monitor the impact of Automated External Defibrillators on the management of in-hospital cardiac arrest events. METHODS: The data acquisition was part of a continuous quality improvement process of the Wuerzburg University Hospital. For analysing the CPR performance, the chest compression rate (CCR), compression depth (CCD), the no flow fraction (NFF), time interval from AED-activation to the first compression (TtC), the time interval from AED-activation to the first shock (TtS) and the post schock pause (TtCS) were determined by AED captured data. A questionnaire was completed by the first responders. RESULTS: From 2010 to 2012 there were 359 emergency calls. From these 53 were cardiac arrests with an AED-application. Complete data were available in 46 cases. The TtC was 34 (32-52) seconds (median and IQR).The TtS was 30 (28-32) seconds (median and IQR). The TtCS was 4 (3-6) seconds (median and IQR). The CCD was 5.5 ± 1 cm while the CCR was 107 ± 11/min. The NFF was calculated as 41 %. ROSC was achieved in 21 patients (45 %), 8 patients (17 %) died on scene and 17 patients (37 %) were transferred under ongoing CPR to an Intensive Care Unit (ICU). CONCLUSION: The TtS and TtC indicate that there is an AED-user dependent time loss. These time intervals can be markedly reduced, when the user is trained to interrupt the AED's "chain of advices" by placing the electrode-paddles immediately on the patient's thorax. At this time the AED switches directly to the analysing mode. Intensive training and adaption of the training contents is needed to optimize the handling of the AED in order to maximize its advantages and to minimize its disadvantages.


Subject(s)
Cardiopulmonary Resuscitation/methods , Defibrillators/statistics & numerical data , Heart Arrest/therapy , Hospitalization , Monitoring, Physiologic/methods , Female , Heart Arrest/mortality , Humans , Inservice Training , Male , Patient Care Team/organization & administration , Quality Improvement , Retrospective Studies , Surveys and Questionnaires , Treatment Outcome
18.
PLoS One ; 10(7): e0133080, 2015.
Article in English | MEDLINE | ID: mdl-26172550

ABSTRACT

PURPOSE: To characterize qualitative and quantitative features of the choroid in normal eyes using enface swept-source optical coherence tomography (SS-OCT). METHODS: Fifty-two eyes of 26 consecutive normal subjects were prospectively recruited to obtain multiple three-dimensional 12 x 12 mm volumetric scans using a long-wavelength high-speed SS-OCT prototype. A motion-correction algorithm merged multiple SS-OCT volumes to improve signal. Retinal pigment epithelium (RPE) was segmented as the reference and enface images were extracted at varying depths every 4.13 µm intervals. Systematic analysis of the choroid at different depths was performed to qualitatively assess the morphology of the choroid and quantify the absolute thicknesses as well as the relative thicknesses of the choroidal vascular layers including the choroidal microvasculature (choriocapillaris, terminal arterioles and venules; CC) and choroidal vessels (CV) with respect to the subfoveal total choroidal thickness (TC). Subjects were divided into two age groups: younger (<40 years) and older (≥ 40 years). RESULTS: Mean age of subjects was 41.92 (24-66) years. Enface images at the level of the RPE, CC, CV, and choroidal-scleral interface were used to assess specific qualitative features. In the younger age group, the mean absolute thicknesses were: TC 379.4 µm (SD ± 75.7 µm), CC 81.3 µm (SD ± 21.2 µm) and CV 298.1 µm (SD ± 63.7 µm). In the older group, the mean absolute thicknesses were: TC 305.0 µm (SD ± 50.9 µm), CC 56.4µm (SD ± 12.1 µm) and CV 248.6µm (SD ± 49.7 µm). In the younger group, the relative thicknesses of the individual choroidal layers were: CC 21.5% (SD ± 4.0%) and CV 78.4% (SD ± 4.0%). In the older group, the relative thicknesses were: CC 18.9% (SD ± 4.5%) and CV 81.1% (SD ± 4.5%). The absolute thicknesses were smaller in the older age group for all choroidal layers (TC p=0.006, CC p=0.0003, CV p=0.03) while the relative thickness was smaller only for the CC (p=0.04). CONCLUSIONS: Enface SS-OCT at 1050 nm enables a precise qualitative and quantitative characterization of the individual choroidal layers in normal eyes. Only the CC is relatively thinner in the older eyes. In-vivo evaluation of the choroid at variable depths may be potentially valuable in understanding the natural history of age-related posterior segment disease.


Subject(s)
Aging/physiology , Choroid/anatomy & histology , Choroid/physiology , Retinal Pigment Epithelium/anatomy & histology , Sclera/anatomy & histology , Sclera/physiology , Adult , Aged , Choroid/blood supply , Female , Humans , Male , Microvessels/physiology , Middle Aged , Prospective Studies , Retinal Pigment Epithelium/blood supply , Retinal Pigment Epithelium/physiology , Sclera/blood supply , Tomography, Optical Coherence/methods , Young Adult
19.
Am J Ophthalmol ; 159(4): 634-43, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25528955

ABSTRACT

OBJECTIVE: To define morphologic features of polypoidal choroidal vasculopathy (PCV) using en face images from swept-source optical coherence tomography (SS OCT). DESIGN: Prospective cross-sectional study. METHODS: The study included 10 eyes from 6 patients with PCV and 10 eyes from 5 age-matched normal subjects. All subjects were prospectively scanned with a prototype SS OCT system. A motion correction algorithm was applied to correct and merge scans into a single volumetric dataset. En face images were generated at intervals of 4.13 µm (1 pixel) relative to the Bruch membrane. RESULTS: Age ± standard deviation for the normal group was 62.4 (±12.1) years and for the PCV group was 68.3 (±5.2) years. En face SS OCT imaging of PCV eyes demonstrated the relationship between larger pigment epithelial detachments (PEDs) and small adjoining PEDs that correlated with the polypoidal lesions seen on indocyanine green angiography in all PCV eyes. En face SS OCT demonstrated choroidal vascular abnormalities in 7 out of 7 eyes with PCV, and in 2 out of 3 enrolled fellow eyes in patients with unilateral PCV. Out of 7 PCV eyes, focal choroidal vascular dilation was noted in 3 eyes and diffuse choroidal vascular dilation was noted in 1 eye. In addition, a branching vascular network was noted above the Bruch membrane in 1 eye, below the Bruch membrane within the choriocapillaris in 1 eye, and in the larger choroidal vascular layer in 1 eye. CONCLUSIONS: En face SS OCT provides an in vivo tool to visualize the pathologic features and the choroidal vasculature in PCV.


Subject(s)
Choroid/pathology , Choroidal Neovascularization/diagnosis , Polyps/diagnosis , Retinal Pigment Epithelium/pathology , Aged , Angiogenesis Inhibitors/therapeutic use , Choroidal Neovascularization/drug therapy , Coloring Agents , Cross-Sectional Studies , Female , Fluorescein Angiography , Humans , Indocyanine Green , Middle Aged , Polyps/drug therapy , Prospective Studies , Tomography, Optical Coherence , Vascular Endothelial Growth Factor A/antagonists & inhibitors
20.
Biomed Opt Express ; 5(9): 2931-49, 2014 Sep 01.
Article in English | MEDLINE | ID: mdl-25401008

ABSTRACT

Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of conventional OCT and can assess depth-resolved tissue birefringence in addition to intensity. Most existing PS-OCT systems are relatively complex and their clinical translation remains difficult. We present a simple and robust all-fiber PS-OCT system based on swept source technology and polarization depth-encoding. Polarization multiplexing was achieved using a polarization maintaining fiber. Polarization sensitive signals were detected using fiber based polarization beam splitters and polarization controllers were used to remove the polarization ambiguity. A simplified post-processing algorithm was proposed for speckle noise reduction relaxing the demand for phase stability. We demonstrated systems design for both ophthalmic and catheter-based PS-OCT. For ophthalmic imaging, we used an optical clock frequency doubling method to extend the imaging range of a commercially available short cavity light source to improve polarization depth-encoding. For catheter based imaging, we demonstrated 200 kHz PS-OCT imaging using a MEMS-tunable vertical cavity surface emitting laser (VCSEL) and a high speed micromotor imaging catheter. The system was demonstrated in human retina, finger and lip imaging, as well as ex vivo swine esophagus and cardiovascular imaging. The all-fiber PS-OCT is easier to implement and maintain compared to previous PS-OCT systems and can be more easily translated to clinical applications due to its robust design.

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