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1.
Int J Pharm Pract ; 29(2): 164-169, 2021 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-33729525

RESUMEN

OBJECTIVES: This study aimed to evaluate the effect of a closed-loop computerised physician order entry (CPOE) system on prescribing in a general paediatric unit in Hong Kong. We studied the effect of the CPOE system on medication prescribing error and the characteristics of these errors before and after the implementation of the system. METHODS: This was a single-site, prospective, observational study at a public hospital's general paediatric unit in Hong Kong, conducted during the pre- and post-implementation of the system from March to April 2019 and 2020, respectively. Collected data included the number of medication orders processed, the number of prescribing errors identified, and the characteristics of errors, such as the severity, children's age group, drug formulation, and drug class. KEY FINDINGS: The prescribing error rate was significantly reduced from 6.7% to 3.9% after CPOE implementation. The causes of prescribing errors were found to be significantly different, as the implementation eradicated handwriting-related errors and reduced dosage selection-related errors. However, we found that CPOE increased other causes of error, such as missing entry of patient information that might affect the dispensing process, thus delaying patients in receiving their medications on time. CONCLUSION: The CPOE system significantly reduced prescribing errors and altered some of the characteristics of these errors. Poor system design or inadequate user training could result in the creation of new causes of error.


Asunto(s)
Sistemas de Entrada de Órdenes Médicas , Niño , Prescripciones de Medicamentos , Hong Kong , Humanos , Errores de Medicación/prevención & control , Estudios Prospectivos
2.
J Photochem Photobiol B ; 180: 208-217, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29459312

RESUMEN

The drug resistant bacteria and textile contaminations of water cause different sever health problem throughout the world. To overcome this issue, new environmental benign materials and methods are needed. Plant metabolites directed synthesis of nanoparticles is considered eco-friendly and easy in synthesis. Therefore, it was explicit for the synthesis of AgNPs. The prepared AgNPs were evaluated for antibacterial, antioxidant, photo-catalytic and electrochemical degradation properties as well as toxicity of degradation products on aquatic life. X-Ray Photoelectron Spectroscopy (XPS) has been used for analyzing the surface chemistry of prepared AgNPs. The particle size determines the interaction of nanoparticles with pathogens. Both Gram positive and negative bacteria (Escherichia coli and Staphylococcus areous) are used to determine the anti-microbial potency of the green synthesized AgNPs. The synthesized silver nanoparticles showed significant anti-bacterial applications against B. subtilus and S. aureus. The anti-oxidant applications of AgNPs also studied on comparison with vitamin C. The toxicity of the phenolic Azo dyes (PDA) has been studied against Fish, Daphnia and Green Algae. The electrode potential was studied in the electrochemical redox reaction of hydroxy phenol in aqueous media. Simple electrolyte was used to determine the current efficiency. For the stability of electrode multi cyclic voltammetry was also studied during redox reaction, which showed stability under the potential 0.4 to 0.2 V.


Asunto(s)
Antiinfecciosos/química , Antioxidantes/química , Compuestos Azo/química , Nanopartículas del Metal/química , Plata/química , Animales , Antiinfecciosos/farmacología , Antioxidantes/farmacología , Compuestos Azo/toxicidad , Chlorophyta/efectos de los fármacos , Daphnia/efectos de los fármacos , Técnicas Electroquímicas , Electrodos , Peces/metabolismo , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Tecnología Química Verde , Nanopartículas del Metal/toxicidad , Pruebas de Sensibilidad Microbiana , Fenoles/química , Espectroscopía de Fotoelectrones
3.
Artículo en Inglés | MEDLINE | ID: mdl-26599242

RESUMEN

BACKGROUND AND OBJECTIVE: Retinal degeneration in birdshot chorioretinopathy (BSCR) has been assessed qualitatively using spectral-domain optical coherence tomography (SD-OCT). The purpose of this study was to determine whether these changes could be quantified. PATIENTS AND METHODS: The charts of 22 eyes of 11 patients with BSCR and 22 eyes of 22 controls were reviewed. SD-OCT was used to determine the photoreceptor outer segment (PROS) volume and choroidal thickness. RESULTS: PROS volume in patients with BSCR was lower than in controls (P < .003). Furthermore, the PROS volume in BSCR patients with abnormalities on electroretinography (ERG) was lower than the PROS volume in BSCR patients with normal ERGs (P < .02). There was no correlation between PROS volume and choroidal thickness (r = 0.27; P = .22). CONCLUSION: SD-OCT can be used to quantitate retinal degeneration in BSCR. The retinal and choroidal degeneration in BSCR are not correlated, suggesting that the inflammatory pathophysiology affecting these two structures may be different.


Asunto(s)
Coriorretinitis/diagnóstico , Coroides/patología , Degeneración Retiniana/diagnóstico , Segmento Externo de las Células Fotorreceptoras Retinianas/patología , Tomografía de Coherencia Óptica , Adulto , Anciano , Retinocoroidopatía en Perdigonada , Electrorretinografía , Femenino , Humanos , Masculino , Persona de Mediana Edad
4.
Artículo en Inglés | MEDLINE | ID: mdl-26247453

RESUMEN

BACKGROUND AND OBJECTIVE: To determine whether optical density measurements of pigment epithelial detachments (PEDs) in neovascular age-related macular degeneration (AMD) can predict the response to treatment with anti-VEGF therapy. PATIENTS AND METHODS: Retrospective review of SD-OCT scans of 21 eyes of 21 patients with neovascular AMD and PED. Response to treatment was determined using SD-OCT volumetric analysis. The authors used optical density measurements of PED lesions on SD-OCT images to calculate the serous index, which is a measure of the serous component of PEDs. RESULTS: The serous index was found to correlate with the response to anti-VEGF treatment (r = .69, P = .0005), and to be predictive of the response to treatment (P = .007). CONCLUSION: The serous index of PEDs can help predict the response to anti-VEGF treatment. This measure may be useful in decisions regarding switching anti-VEGF agents in the clinical care of patients with neovascular AMD and PED.


Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Bevacizumab/uso terapéutico , Epitelio Pigmentado de la Retina/patología , Líquido Subretiniano , Degeneración Macular Húmeda/tratamiento farmacológico , Anciano , Anciano de 80 o más Años , Barrera Hematorretinal , Colorantes/química , Densitometría , Femenino , Angiografía con Fluoresceína , Humanos , Verde de Indocianina/química , Inyecciones Intravítreas , Masculino , Estudios Retrospectivos , Tomografía de Coherencia Óptica , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Degeneración Macular Húmeda/diagnóstico
5.
Retina ; 35(4): 798-802, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25811950

RESUMEN

PURPOSE: The purpose of the study was to determine if progressive choroidal changes occur in birdshot chorioretinopathy (BSCR). METHODS: Retrospective chart review of all patients with BSCR who were seen over a 3-year period. Controls consisted of healthy age-matched and gender-matched patients. Choroidal thickness at baseline and final follow-up visit was measured with the use of optical coherence tomography. Results were analyzed using univariate and multivariable statistical models. RESULTS: A total of 11 patients (22 eyes) with BSCR were identified. The majority of BSCR eyes (86%) had clinically inactive disease. Follow-up ranged from 2 months to 27 months. Mean age was 55 years. Patients with BSCR had significantly thinner choroid compared with controls (P < 0.001). Furthermore, the rate of choroid thinning for patients diagnosed with BSCR (2.68 µm per month) was significantly higher than that of controls (0.27 µm per month) (P = 0.003). There was no statistically significant difference in the rate of choroidal thinning between the two eyes of patients with BSCR (P = 0.859), indicating that the choroidal thinning was symmetrical. CONCLUSION: Despite having clinically inactive uveitis, eyes with BSCR can develop progressive choroidal thinning. The clinical relevance of this choroidal thinning, or degeneration, remains to be fully elucidated.


Asunto(s)
Coriorretinitis/complicaciones , Enfermedades de la Coroides/etiología , Adulto , Anciano , Retinocoroidopatía en Perdigonada , Enfermedades de la Coroides/diagnóstico , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Estudios Retrospectivos , Tomografía de Coherencia Óptica
6.
Br J Ophthalmol ; 99(10): 1315-9, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25733527

RESUMEN

This report describes a novel, non-invasive and label-free optical imaging technique, speckle variance optical coherence tomography (svOCT), for visualising blood flow within human retinal capillary networks. This imaging system uses a custom-built swept source OCT system operating at a line rate of 100 kHz. Real-time processing and visualisation is implemented on a consumer grade graphics processing unit. To investigate the quality of microvascular detail acquired with this device we compared images of human capillary networks acquired with svOCT and fluorescein angiography. We found that the density of capillary microvasculature acquired with this svOCT device was visibly greater than fluorescein angiography. We also found that this svOCT device had the capacity to generate en face images of distinct capillary networks that are morphologically comparable with previously published histological studies. Finally, we found that this svOCT device has the ability to non-invasively illustrate the common manifestations of diabetic retinopathy and retinal vascular occlusion. The results of this study suggest that graphics processing unit accelerated svOCT has the potential to non-invasively provide useful quantitative information about human retinal capillary networks. Therefore svOCT may have clinical and research applications for the management of retinal microvascular diseases, which are a major cause of visual morbidity worldwide.


Asunto(s)
Retinopatía Diabética/diagnóstico , Angiografía con Fluoresceína/métodos , Flujo Sanguíneo Regional , Oclusión de la Arteria Retiniana/diagnóstico , Oclusión de la Vena Retiniana/diagnóstico , Vasos Retinianos/patología , Tomografía de Coherencia Óptica/métodos , Retinopatía Diabética/fisiopatología , Fondo de Ojo , Humanos , Reproducibilidad de los Resultados , Oclusión de la Arteria Retiniana/fisiopatología , Oclusión de la Vena Retiniana/fisiopatología , Vasos Retinianos/fisiopatología , Factores de Tiempo
7.
J Glaucoma ; 23(6): 360-7, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25075462

RESUMEN

PURPOSE: To compare neural canal opening (NCO) with the clinical optic disc margin (DM) seen and to investigate the planarity of the NCO in normal human optic nerve heads (ONH). METHODS: Sixteen eyes were imaged. Twelve healthy eyes were selected for planarity and 9 for NCO and DM correspondence. All subjects were subjected to a visual field examination, stereo disc photograph (SDP), scanning laser ophthalmoscopy, clinical examination with a fellowship trained glaucoma specialist, and optical coherence tomography imaging. Three reviewers delineated the NCO and inner limiting membrane on optical coherence tomography images. The clinical DM was delineated by a glaucoma specialist while viewing SDPs. Plane error was calculated for NCO and for Bruch membrane (BM) at distances 80 and 120 µm from NCO. RESULTS: The NCO segmentation interrater variability was low with an average coefficient of variation of 2.7%. A regional variation of the SDP and NCO correspondence was observed, wherein the temporal region had the largest coefficient of variation. The plane error of the NCO and BM were similar and was approximately 12 µm, which is small relative to an average DM diameter of 1.7 mm. CONCLUSIONS: The BM opening has a good correspondence with the clinical DM seen in SDPs. NCO delineation seemed to be reliable. The BM and NCO are relatively planar in normal humans and can be further evaluated for longitudinal studies to observe stability.


Asunto(s)
Tubo Neural/anatomía & histología , Disco Óptico/anatomía & histología , Fotograbar , Tomografía de Coherencia Óptica/métodos , Adolescente , Adulto , Lámina Basal de la Coroides/anatomía & histología , Femenino , Humanos , Imagenología Tridimensional , Estudios Longitudinales , Masculino , Oftalmoscopía , Epitelio Pigmentado de la Retina/citología , Campos Visuales/fisiología , Adulto Joven
8.
Am J Ophthalmol ; 158(4): 757-761.e1, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24983793

RESUMEN

PURPOSE: To determine whether baseline drusen load, as measured using spectral-domain optical coherence tomography (SD OCT), is a useful predictor of development of advanced age-related macular degeneration (AMD). DESIGN: Retrospective cohort study. METHODS: setting: Academic clinical practice. study population: All patients with non-neovascular AMD and no retinal pigment epithelial (RPE) atrophy at baseline who were seen between 2007 and 2012 in a single academic retina practice. A minimum of 1 year of follow-up was required. observation: Drusen load (area and volume) was assessed using automated SD OCT software algorithms. main outcome measure: RPE atrophy area, assessed using an automated SD OCT software algorithm, and the development of neovascular AMD. RESULTS: Eighty-three patients met the inclusion criteria with a mean age of 80 years and a mean follow-up time of 2.8 years. Repeated-measures analysis of variance showed an association between drusen area (P = .005) and drusen volume (P = .001) and the development of RPE atrophy. We also found an association between drusen area (P = .001) and drusen volume (P = .001) and the development of neovascular AMD. CONCLUSIONS: Drusen load, as measured using SD OCT, is associated with the development of RPE atrophy and neovascular AMD. SD OCT assessments of drusen load are simple and practical measurements that may be useful in stratifying the risk of developing advanced AMD. These measurements have potential applications in both routine clinical care and clinical trials.


Asunto(s)
Atrofia Geográfica/diagnóstico , Drusas Retinianas/diagnóstico , Epitelio Pigmentado de la Retina/patología , Tomografía de Coherencia Óptica/métodos , Degeneración Macular Húmeda/diagnóstico , Anciano de 80 o más Años , Atrofia , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Masculino , Estudios Retrospectivos
9.
Invest Ophthalmol Vis Sci ; 55(7): 4378-93, 2014 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-24894400

RESUMEN

PURPOSE: To investigate morphological characteristics of optic nerve head and peripapillary region with myopia and glaucoma. METHODS: Ten normal and 17 glaucomatous myopic participants were imaged with a custom 1060-nm swept-source optical coherence tomography system. The three-dimensional images were processed and segmented for inner limiting membrane (ILM), posterior border of retinal nerve fiber layer (RNFL), Bruch's membrane (BM), and posterior border of choroid. Seven shape parameters were measured: nerve fiber layer (NFL) thickness; Bruch's membrane opening (BMO) area, eccentricity, and planarity; BMO and BM depths; and choroidal thickness. The results were analyzed by group and regional sector, and multiple regression was performed on each shape parameter with age, axial length, and glaucoma severity, measured by mean deviation (MD). RESULTS: Bruch's membrane opening area (P < 0.001), eccentricity (P = 0.025), and planarity (P = 0.019) were correlated with axial length but not with MD, such that larger, more elliptical, and less planar BMO was associated with longer axial length. Several BMOs displayed a saddle-like shape configuration whose orientation appeared to be aligned with that of the BMO ellipse. All BM showed posterior deformation toward BMO such that BM closer to BMO was more posterior than that farther from BMO. Bruch's membrane depth was correlated with axial length (P = 0.014) and MD (P = 0.040) in intersubject regression, and BMO depth (P = 0.003) and BM depth (P = 0.006) were correlated with MD in intereye regression. Bruch's membrane depth was also associated with age. Choroidal thickness was negatively correlated with age (P = 0.001) and with axial length to a smaller degree (P = 0.034), but not with glaucoma severity. CONCLUSIONS: Axial length was a significant factor in BMO and BM shape in normal and glaucomatous myopic subjects. Posterior deformation of BM was observed in all eyes and significantly associated with functional glaucomatous damage and age.


Asunto(s)
Glaucoma/patología , Miopía/patología , Disco Óptico/patología , Células Ganglionares de la Retina/patología , Adulto , Glaucoma/complicaciones , Glaucoma/fisiopatología , Humanos , Imagenología Tridimensional , Presión Intraocular , Persona de Mediana Edad , Miopía/complicaciones , Miopía/fisiopatología , Refracción Ocular , Índice de Severidad de la Enfermedad , Tomografía de Coherencia Óptica
10.
Retina ; 34(7): 1308-15, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24451923

RESUMEN

PURPOSE: To study the progression of retinal pigment epithelium (RPE) and choroidal atrophy in patients with neovascular age-related macular degeneration (AMD) and to assess for a possible association with the number and type of anti-vascular endothelial growth factor treatments. METHODS: Patients with neovascular AMD and a minimum of 1-year follow-up were reviewed. Fellow eyes with nonneovascular AMD were used as control eyes. Retinal pigment epithelial atrophy area and choroidal thickness were determined using spectral-domain optical coherence tomography. Multivariable regression models were used for statistical analyses. RESULTS: A total of 415 eyes were included in the study, with a mean follow-up of 2.2 years. Eyes with neovascular AMD had greater progression of RPE atrophy and choroidal atrophy compared with those with nonneovascular AMD (P < 0.001). Progression of RPE atrophy and choroidal atrophy was independently associated with the total number of injections of bevacizumab and ranibizumab (all P values ≤ 0.001). In the subgroup of 84 eyes with neovascular AMD and without RPE atrophy at baseline, only bevacizumab was associated with the progression of RPE atrophy (P = 0.003). This study likely lacked statistical power to detect an association with ranibizumab in this subgroup. CONCLUSION: Retinal pigment epithelial atrophy and choroidal atrophy in neovascular AMD seem to be exacerbated by anti-vascular endothelial growth factor treatment. Possible differences between bevacizumab and ranibizumab require further investigation.


Asunto(s)
Inhibidores de la Angiogénesis/efectos adversos , Coroides/patología , Complicaciones Posoperatorias , Epitelio Pigmentado de la Retina/patología , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Degeneración Macular Húmeda/tratamiento farmacológico , Anciano de 80 o más Años , Inhibidores de la Angiogénesis/uso terapéutico , Anticuerpos Monoclonales Humanizados/efectos adversos , Anticuerpos Monoclonales Humanizados/uso terapéutico , Atrofia , Bevacizumab , Coroides/efectos de los fármacos , Progresión de la Enfermedad , Femenino , Humanos , Inyecciones Intravítreas , Masculino , Ranibizumab , Epitelio Pigmentado de la Retina/efectos de los fármacos , Estudios Retrospectivos , Tomografía de Coherencia Óptica
11.
Artículo en Inglés | MEDLINE | ID: mdl-24111452

RESUMEN

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. Subretinal fluid (SRF) and sub-retinal pigment epithelium (sub-RPE) fluid are signs of AMD and can be detected in optical coherence tomography images. However, manual detection and segmentation of SRFs and sub-RPE fluids are laborious and time consuming. In this paper, a novel pipeline is proposed for automatic detection of SRFs and sub-RPE fluids. First, top and bottom layers of retina are segmented using a graph cut method. Then, a Split Bregman-based segmentation method is used to segment dark regions between layers. These segmented regions are considered as potential fluid candidates, on which a set of features are generated. After that, a random forest classifier is trained to distinguish between the true fluid regions from the falsely detected fluid regions. This method shows reasonable performance in a leave-one-out evaluation using a dataset from 21 patients.


Asunto(s)
Degeneración Macular/diagnóstico , Degeneración Macular/patología , Retina/patología , Epitelio Pigmentado de la Retina/patología , Líquido Subretiniano , Tomografía de Coherencia Óptica/métodos , Algoritmos , Líquidos Corporales , Reacciones Falso Positivas , Humanos , Procesamiento de Imagen Asistido por Computador , Variaciones Dependientes del Observador , Reconocimiento de Normas Patrones Automatizadas , Reproducibilidad de los Resultados , Relación Señal-Ruido
12.
Invest Ophthalmol Vis Sci ; 54(4): 2864-71, 2013 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-23538060

RESUMEN

PURPOSE: We compared the reproducibility and mutual agreement of the subfoveal choroidal thickness measurements by expert raters and an automated algorithm in enhanced depth imaging optical coherence tomography (EDI-OCT) images of eyes with nonneovascular age-related macular degeneration (AMD). METHODS: We recruited 44 patients with nonneovascular AMD and EDI-OCT images were acquired. Subfoveal choroidal thickness was measured manually by two expert raters and automatically by a graph-cut-based algorithm. Drusen area was measured using the automated software (version 6) of Cirrus SD-OCT. The manual and automated choroidal thickness measurements were compared in reproducibility, mutual agreement, and correlation with drusen area. RESULTS: The mean subfoveal choroidal thickness was 246 ± 63 µm for the first rater, 214 ± 68 for the second rater, and 209 ± 53 for the automated algorithm. Intraclass correlation coefficients (ICC) and 95% confidence intervals (CI) were 0.96 (CI 0.94-0.98) between the raters, 0.85 (CI 0.77-0.90) between the first rater and the automated algorithm, and 0.84 (CI 0.75-0.89) between the second rater and the automated algorithm. Repeat scan measurement ICCs were 0.91 (CI 0.86-0.94) for the first rater, 0.96 (CI 0.94-0.97) for the second rater, and 0.87 (CI 0.80-0.92) for the automated algorithm. Manual and automated measurements were correlated with drusen area. CONCLUSIONS: The automated algorithm generally yielded smaller choroidal thickness than the raters with a moderate level of agreement. However, its repeat scan measurement repeatability was comparable to that of the manual measurements. The mean difference between the raters indicated possible biases in different raters and rating sessions. The correlation of the automated measurements with the drusen area was comparable to that of the manual measurements. Automated subfoveal choroidal thickness measurement has potential use in clinical practice and clinical trials, with possibility for reduced time and labor cost.


Asunto(s)
Neovascularización Coroidal/patología , Procesamiento de Imagen Asistido por Computador/métodos , Procesamiento de Imagen Asistido por Computador/normas , Degeneración Macular/patología , Tomografía de Coherencia Óptica/métodos , Tomografía de Coherencia Óptica/normas , Anciano , Anciano de 80 o más Años , Algoritmos , Coroides/patología , Femenino , Fóvea Central/patología , Humanos , Procesamiento de Imagen Asistido por Computador/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Drusas del Disco Óptico/patología , Reproducibilidad de los Resultados , Programas Informáticos , Tomografía de Coherencia Óptica/estadística & datos numéricos
13.
J Curr Glaucoma Pract ; 7(2): 85-7, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-26997786

RESUMEN

BACKGROUND: Imaging of the Schlemm's Canal is complicated by the small physiological size and the location several hundred microns beneath the sclera. Noninvasive imaging of Schlemm's canal and Trabecular Meshwork (TM) in vivo with Fourier Domain Optical Coherence Tomography (FD OCT) can provide clinicians with a powerful tool to visualize ocular angular structures crucial for glaucoma management. PURPOSE: To investigate the appearance of Schlemm's canal and TM on FD OCT images. METHODS: FD OCT images of the Schlemm's canal and TM were obtained with three different wavelengths using prototype FD OCT systems in a normal volunteer. FD OCT images using the 1310 nm wavelength prototype were obtained in three representative cases of glaucoma surgery performed on angle structures. RESULTS: The longer imaging depth and deeper tissue penetration of the 1310 nm system provided the clearest image of the TM and Schlemm's canal in the normal patient. In case 1, images pre- and post-trabectome surgery clearly showed the location and appearance of TM. In case 2, images post-canaloplasty surgery showed the location and appearance of Schlemm's canal. In case 3, images pre- and post-trabeculotomy surgery further confirms the appearance and location of the Schlemm's canal and TM. CONCLUSION: Operating wavelength of the FD OCT system and exact location of the scan across different meridians minimally affects the appearance of the ocular anatomy. The postoperative images of three angle glaucoma surgeries confirmed the location of Schlemm's canal and TM. How to cite this article: Asrani S, Young M, Xu J, Sarunic MV. Imaging of Ocular Angle Structures with Fourier Domain Optical Coherence Tomography. J Current Glau Prac 2013;7(2):85-87.

14.
Biomed Opt Express ; 2(9): 2690-7, 2011 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-21991557

RESUMEN

Volumetric imaging of the Optic Nerve Head (ONH) morphometry with Optical Coherence Tomography (OCT) requires dense sampling and relatively long acquisition times. Compressive Sampling (CS) is an emerging technique to reduce volume acquisition time with minimal image degradation by sparsely sampling the object and reconstructing the missing data in software. In this report, we demonstrated real-time CS-OCT for volumetric imaging of the ONH using a 1060nm Swept-Source OCT prototype. We also showed that registration and averaging of CS-recovered volumes enhanced visualization of deep structures of the sclera and lamina cribrosa. This work validates CS-OCT as a means for reducing volume acquisition time and for preserving high-resolution in volume-averaged images. Compressive sampling can be integrated into new and existing OCT systems without changes to the optics, requiring only software changes and post-processing of acquired data.

15.
IEEE Trans Biomed Eng ; 57(10): 2592-5, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20656652

RESUMEN

We present an automated method for nonrigid registration of the optic nerve head (ONH) surfaces extracted from 3-D optical coherence tomography images to give a one-to-one correspondence between two ONH surfaces. This allows development of population-average ONH surfaces, pooling of morphometric data measured on ONH surfaces from multiple subjects into a single chosen template surface, and statistical analysis (cross sectional, or longitudinal, or both) in a common coordinate system. An application of this coordinate system to construct an average ONH shape across an illustrative dataset is demonstrated, and the impact of template selection is assessed.


Asunto(s)
Procesamiento de Imagen Asistido por Computador/métodos , Disco Óptico/anatomía & histología , Tomografía de Coherencia Óptica/métodos , Interpretación Estadística de Datos , Humanos
16.
Am J Sports Med ; 37(11): 2205-13, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19574474

RESUMEN

BACKGROUND: Most orthopaedic problems experienced by competitive horseback riders are related to pain in the lower back, hip joint, and hamstring muscles. Riders-especially, show jumpers-are frequently hampered in their performance because of lumbar pain. To date, there has been no research into lumbar disk degeneration in elite competitive riders. HYPOTHESIS: Competitive horseback riding accelerates lumbar disk degeneration. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Fifty-eight elite riders (18 men, 40 women; mean age, 32.4 years) and a control group of 30 nonriding volunteers (17 men, 13 women; mean age, 28.7 years) were evaluated for lumbar disk degeneration, cross-sectional area of paraspinal muscles, spondylolysis, and spondylolisthesis, using magnetic resonance imaging (MRI). The prevalence of disk degeneration between the 2 groups was compared, and the relationship was investigated between low back pain (LBP), riding discipline, body mass index (BMI), trunk/leg-length coefficient, and MRI results. RESULTS: Eighty-eight percent of elite riders (n = 51) had a history of LBP, versus 33% of the controls (P < .05). There was no statistical difference for the prevalence of LBP among the different riding disciplines. However, there was a high rate of pathologic T2 signal intensity of the lumbar intervertebral disk among riders-specifically, dressage riders-yet no significant increase when compared with controls. History of LBP symptoms, riding discipline, BMI, and trunk/leg-length ratio had no significant effect on the development of lumbar disk degeneration. Occult fractures of the pars interarticularis and manifest spondylolysis were not seen for any rider. Two controls had spondylolisthesis Meyerding grade 1 not associated with back pain. CONCLUSION: Although riders have a high prevalence of LBP, there is no conclusive MRI evidence to suggest that the cause lies in undue disk degeneration, spondylolysis, spondylolisthesis, or pathologic changes of the paraspinal muscles of the lumbar spine.


Asunto(s)
Traumatismos en Atletas/etiología , Degeneración del Disco Intervertebral/etiología , Dolor de la Región Lumbar/etiología , Vértebras Lumbares/patología , Adolescente , Adulto , Animales , Traumatismos en Atletas/patología , Índice de Masa Corporal , Estudios Transversales , Femenino , Caballos , Humanos , Degeneración del Disco Intervertebral/patología , Dolor de la Región Lumbar/patología , Imagen por Resonancia Magnética , Masculino , Adulto Joven
17.
Cyberpsychol Behav ; 11(1): 55-64, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18275313

RESUMEN

This qualitative study investigated online interpersonal trust formation in knowledge-sharing (KS) practice, with emphasis on the interplay between the physical and virtual social contexts. Data were collected during a 6-month period from phenomenological interviews of 49 elementary and junior high school teachers who used a Web-based knowledge management system (KMS) to share their knowledge. Interpretive analysis revealed three important facets of the interpersonal trust formation process in using Web-based KMS: (a) the social role of the teachers, (b) the rigid and tight professional community, and (c) the keys to breaking through. Results of this study can lead to a better understanding of how an individual's perception is shaped and to what extent social factors affect knowledge-sharing practice in virtual communities. In addition to the practical implications to those who intend to manage knowledge-intensive activities, our study demonstrates the relevance of phenomenology for trust in KS research and provides a new way of viewing knowledge management problems in terms of human consciousness.


Asunto(s)
Actitud , Cognición , Conocimientos, Actitudes y Práctica en Salud , Internet , Relaciones Interpersonales , Facilitación Social , Confianza , Interfaz Usuario-Computador , Adulto , Estado de Conciencia , Femenino , Humanos , Masculino , Medio Social
18.
Cyberpsychol Behav ; 11(1): 87-90, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18275318

RESUMEN

Because the Internet provides an alternative forum for the social interaction of professional groups, understanding how these groups form as virtual communities (VCs) in cyberspace is crucial. In this study, we observe the social interactions of teachers belonging to the largest VC in Taiwan and analyze discourse on an important educational policy, using content analysis to ascertain how virtual group identity is established. Our primary findings show that among the seven identity categories characterizing professional virtual group identity, both alliance and kinship types of identities are the main forces behind the formation of a virtual group. In contrast, the affection, attachment, bonding, closeness, and nostalgia types of identities show minimal effect. Moreover, leadership of the virtual group plays a critical role in the group setting, and participants play a part in restoring a positive sense of self or in shaping the group identity as they encounter threats in this dynamic environment.


Asunto(s)
Internet/estadística & datos numéricos , Conducta Social , Identificación Social , Enseñanza/estadística & datos numéricos , Interfaz Usuario-Computador , Humanos , Relaciones Interpersonales , Ocupaciones , Autoimagen , Taiwán/epidemiología
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