RESUMO

We present a novel method for obtaining a 3D absorption map of a tissue-like turbid slab in the near-infrared spectral range by tomosynthesis. Transmittance data are obtained for a large number of oblique projection directions by scanning a cw laser source across the surface of the slab and by using a CCD camera for spatially resolved light detection. A perturbation model of light transport is used to convert the intensity maps for the different projections into absorption maps. By applying the tomosynthesis approach to these new maps, 3D absorption information on embedded inclusions has been obtained for the first time. The number and the positions of the lateral offset detectors have been optimized by employing a structural similarity index for comparison of the reconstructed with the true absorption data. We present 3D reconstruction of absorption maps using both Monte Carlo simulations and experiments on phantoms with breast-like optical properties. A comparison with conventional 3D reconstruction by a finite element approach shows the superior location performance of tomosynthesis.

Assuntos

RESUMO

ABSTRACT Homocystinuria is one of a group of genetic disorders called inborn errors of metabolism. It is characterized by a deficiency of the enzyme that converts homocysteine to cystathionine. Keratoconus is an ophthalmologic condition characterized by thinning of the corneal stroma, which causes the cornea to assume a conical shape. There is little information in the scientific literature about the association between keratoconus and homocystinuria. We believe that a collagen cross-linking defect may be the key to understand the connection between these two conditions. This case report describes a 38-year-old male patient with a diagnosis of classical homocystinuria since age 13. At the age of 16, he received a diagnosis of asymmetrical keratoconus when referred for lensectomy with vitrectomy of his left eye. To the best of our knowledge, this is the first report of a patient with simultaneous homocystinuria and keratoconus.

RESUMO Homocistinúria é parte de um grupo de doenças genéticas chamado erros inatos do metabolismo. É caracterizada por uma deficiência da enzima que converte a homocisteína em cistationina. O ceratocone é uma patologia oftalmológica caracterizada pelo afinamento do estroma corneano, o que faz com que a córnea assuma um formato cônico. Há pouca informação na literatura científica sobre a associação entre ceratocone e homocistinúria. Acreditamos que um defeito no cross-linking do colágeno possa ser a chave para entender a conexão entre estas duas condições. Este relato de caso descreve um paciente masculino de 38 anos com diagnóstico de homocistinúria clássica desde os 13 anos. Aos 16 anos, recebeu o diagnóstico de ceratocone assimétrico quando foi encaminhado para lensectomia com vitrectomia do olho esquerdo. Até onde sabemos, este é o primeiro relato de um paciente com homocistinúria e ceratocone simultâneos.

Assuntos

RESUMO

Homocystinuria is one of a group of genetic disorders called inborn errors of metabolism. It is characterized by a deficiency of the enzyme that converts homocysteine to cystathionine. Keratoconus is an ophthalmologic condition characterized by thinning of the corneal stroma, which causes the cornea to assume a conical shape. There is little information in the scientific literature about the association between keratoconus and homocystinuria. We believe that a collagen cross-linking defect may be the key to understand the connection between these two conditions. This case report describes a 38-year-old male patient with a diagnosis of classical homocystinuria since age 13. At the age of 16, he received a diagnosis of asymmetrical keratoconus when referred for lensectomy with vitrectomy of his left eye. To the best of our knowledge, this is the first report of a patient with simultaneous homocystinuria and keratoconus.

Assuntos

RESUMO

A challenging issue in photoacoustic biomedical imaging is to take into account the presence of dispersive acoustic media, since these are prone to induce amplitude attenuation and scattering of the photoacoustic frequency components. These perturbations are largely the cause for which the photoacoustic tomographic image reconstruction from projections lacks a plane-wave transport formalism. Attending this problem, we further develop an analytic formalism of the transport and its numerical implementation accounting for dispersive acoustic media. We differentiate three variations of an acoustically perturbing media. Our object of interest is a numerical description of the light absorption map of a coronal human breast image. Then, we analyze conditions for which the propagation of photoacoustic perturbations can obey the generalized Heaviside telegraph equation. In addition, we provide a study of the causality consistency of the wave propagation models. We observe transport implications due to the presence of dispersive acoustic media and derive model adjustments that include attenuation and diffusion approximations within the two-dimensional forward problem. Next, we restore the inverse problem description with the deduced perturbation components. Finally, we solve the nonlinear inverse problem with a numerical strategy for a filtered backprojection reconstruction. At a stage prior to the image reconstruction, we compensate for the effect of acoustic attenuation and diffusion to calculate the inversions of the wave perturbations located within the projections. In this way, we manage to significantly reduce reconstruction artifacts. In consequence, we prevent the use of some additional image processing of noise reduction. We demonstrate a feasible strategy on how to solve the stated nonlinear inverse problem of photoacoustic tomography accounting for dispersive acoustic media. In particular, we emphasize efforts to achieve an analytical description, and thus an algorithm is placed, for imaged sound perturbations to be cleaned from acoustic scattering in a simplified manner.

Assuntos

RESUMO

El objetivo de este trabajo fue determinar el tamaño del disco óptico por tomografía de coherencia óptica (TCO), en una población mayor de 40 años, que asistió a control rutinario oftalmológico desde noviembre el 2015 a febrero del 2016 y que no tenían antecedentes conocidos de glaucoma ni de enfermedades sistémicas. Fueron incluidos en el estudio 52 pacientes que asistieron a la consulta externa de oftalmología de la Fundación Visión, por un examen de rutina. Se le diligenció una historia clínica completa, donde se indagaron los antecedentes patológicos tanto sistémicos como oculares. Se realizó la toma de la agudeza visual utilizando la cartilla de Snellen en cada ojo por separado a 6 metros del paciente, refracción automatizada, prueba refractiva, biomicroscopía en lámpara de hendidura con énfasis en la profundidad de la cámara anterior. Se excluyeron pacientes con cámaras anteriores pandas o estrechas (utilización de gonioscopio mirrow 4 mini) y presión intraocular elevada. Luego de la instilación de Tropicamida 0,5%/Fenilefrina HCL 5% en cada ojo y evaluación del polo posterior en lámpara de hendidura con lente de 90D Superfield, se realizó la Tomografía de coherencia óptica con el equipo The ZEISS Cirrus(tm) HD-TCO Model 4000 (Cirrus HD-TCO).

The objective of this study was to determine the size of the optic nerve by opticalcoherence tomography (TCO) in a population older than 40 years old who attendedroutine ophthalmological control from November 2015 to February 2016 and did not haveknown records of glaucoma or systemic. Fifty two patients were included in the study whoatended the external consulting room of ophthalmology of the Foundation Vision for aroutine control. A full medical history was completed, where the systemic and ocularpathologic records were investigated. Visual acuity test was performed using Snellen chartin each patient separately at 6 meters from the patinet. Automatic refraction, retractiontest, slit lamp biomicroscopy with emphasis in the anterior chamber depth were alsoperformed. Patients with narrow or panda anterior chambers (using the mini 4 mirrorgonioscope and high intraocular pressure were excluded. After instillation of tropicamide0.5%/phenylephrine HCL 5% in each eye and evaluation of the posterior pole in slit lampwith 90D Superfield lens, the optic coherence tomography was made using a ZEISSCirrus™ HD-TCO Model 4000 (Cirrus HD-TCO).

Assuntos

RESUMO

Objetivo: demostrar la utilidad de la microperimetría pre y posoperatoria en operados de agujero macular idiopático entre 2010-2012, en el Instituto Cubano de Oftalmología Ramón Pando Ferrer. Métodos: en una investigación longitudinal-prospectiva de 17 operados de agujero macular, se estudiaron la agudeza visual corregida y la microperimetría preoperatoria y posoperatoria. Se estableció como mejoría de la agudeza visual corregida si mejoraban dos líneas o más y como mejoría de la microperimetría si cumplían al menos dos de los parámetros: desaparición de escotoma absoluto, desaparición de escotoma relativo y mejoría de la sensibilidad retineana. Se efectuó el examen oftalmológico y la tomografía óptica coherente pre y posoperatorios, en los que se precisó la presencia y el cierre del agujero. Resultados: en la microperimetría preoperatoria presentaban escotoma absoluto el 64,71 por ciento, y escotoma relativo el 94,12 por ciento; la sensibilidad retiniana media fue de 8,40 ± 4,39 y la fijación era estable en el 81,82 por ciento de los pacientes. La sensibilidad retineana media preoperatoria presentó significación estadística respecto a la mejoría de la agudeza visual (p= 0,012). De los pacientes con cierre del agujero (64,71 por ciento), el 72,73 por ciento mejoró la agudeza visual (p= 0,006), y el 54,55 por ciento mejoró la microperimetría (p= 0,002). Se encontró significación estadística entre el cierre del agujero macular y la mejoría de la agudeza visual corregida (p= 0,009) y entre el cierre y la mejoría de la microperimetría (p= 0,043). Conclusiones: la sensibilidad retineana preoperatoria puede constituir un factor predictivo para la recuperación funcional del agujero macular. La recuperación de la agudeza visual tras el cierre del agujero conlleva la mejoría de la microperimetría. Esta última constituye un punto de apoyo para continuar la recuperación funcional(AU)

Objetive: to demonstrate utility of microperimetry to the surgery of idiopathic macular hole, among 2010-2012, in the "Ramón Pando Ferrer" Cuban Ophthalmology Institute. Methods: a longitudinal-prospective study of 17 patients who underwent surgery for idiopathic macular hole was carried out. The corrected visual acuity and microperimetry were studied before and after the surgery. If patient improved 2 lines or more of corrected visual acuity and if they having 2 of the items: disappearance of absolute scotoma, disappearance of scotoma relative, improvement of retinal sensitivity; were established improvement of them. Oftalmology exam and optic coherent tomography were studied before and after surgery, specifying the presence and close of the hole. Results: 64,71 percent of patients presented absolute scotoma and 94,12 percent of them had relative scotoma. The mean retinal sensitivity was 8,40 ± 4,39 and fixation was stable in 81,82 percent of them. Better preoperative mean retinal sensitivity showed statistical significance to best corrected visual acuity (p= 0,012). 72,73 percent of patients with close surgical of the hole (64,71 percent) improved corrected visual acuity (p= 0,006), and 54,55 percent of them improved the microperimetry (p= 0,002). The anatomical closing of hole showed statistical significance for the improvement of corrected visual acuity (p=0,009) and for the improvement of microperimetry (p= 0,043). Conclusions: the preoperative retinal sensitivity can predict the functional recovery of the macular hole. After close of the hole, the recovery of visual acuity can precede to improvement of microperimetry. Microperimetry can constitute a support point to continue the functional recovery(AU)

Assuntos

RESUMO

A tomografia de coerência óptica (OCT) é um exame não invasivo e de não contato que permite avaliar a retina e o nervo óptico. As imagens da OCT fornecem informações da constituição da retina e sua integridade estrutural in vivo, gerando imagens de alta resolução, que se assemelham à microscopia óptica. Objetivou-se descrever a técnica de tomografia de coerência óptica (OCT) e sua utilização em cães. Foi possível diferenciar claramente as camadas retinianas de cães hígidos e compará-las com as de cães portadores de atrofia progressiva de retina, que apresentaram perda da estratificação e diminuição significativa das camadas. No descolamento de retina (DR) foi possível observar a separação entre a retina neurossensorial e o epitélio pigmentário da retina (EPR), além da presença de exsudatos intrarretinianos. Assim, a OCT mostrou-se eficaz no diagnóstico de retinopatias.

The OCT is a noninvasive and noncontact exam capable to evaluate the retina and optic nerve. The OCT images provide information of the constitution of the retina and its structural integrity in vivo, providing high-resolution images that resemble optical microscopy. The objective of this paper was to describe and document the use of the optical coherence tomography (OCT) in dogs. It was possible differentiate the retinal layers of healthy dogs and compare them with dogs with progressive retinal atrophy which showed altered stratification and significant reduce of the layers. In cases of retinal detachment was observed separation of neurosensory retina from the retinal pigment epithelium, and the presence of intrarretinal exudates. Thus, the OCT was effective in the diagnosis of retinopathy.

Assuntos

RESUMO

A tomografia de coerência óptica (OCT) é um exame não invasivo e de não contato que permite avaliar a retina e o nervo óptico. As imagens da OCT fornecem informações da constituição da retina e sua integridade estrutural in vivo, gerando imagens de alta resolução, que se assemelham à microscopia óptica. Objetivou-se descrever a técnica de tomografia de coerência óptica (OCT) e sua utilização em cães. Foi possível diferenciar claramente as camadas retinianas de cães hígidos e compará-las com as de cães portadores de atrofia progressiva de retina, que apresentaram perda da estratificação e diminuição significativa das camadas. No descolamento de retina (DR) foi possível observar a separação entre a retina neurossensorial e o epitélio pigmentário da retina (EPR), além da presença de exsudatos intrarretinianos. Assim, a OCT mostrou-se eficaz no diagnóstico de retinopatias.(AU)

The OCT is a noninvasive and noncontact exam capable to evaluate the retina and optic nerve. The OCT images provide information of the constitution of the retina and its structural integrity in vivo, providing high-resolution images that resemble optical microscopy. The objective of this paper was to describe and document the use of the optical coherence tomography (OCT) in dogs. It was possible differentiate the retinal layers of healthy dogs and compare them with dogs with progressive retinal atrophy which showed altered stratification and significant reduce of the layers. In cases of retinal detachment was observed separation of neurosensory retina from the retinal pigment epithelium, and the presence of intrarretinal exudates. Thus, the OCT was effective in the diagnosis of retinopathy.(AU)

Assuntos

RESUMO

A photonic imaging method that gives the possibility to measure egg quality was applied. Since the method is non-contact and non-destructive we believe that this photonic imaging method may be successfully integrated in the automated inspection systems in the poultry industry. The method involves scanning an invisible infrared light beam over the eggshell, allowing to detect possible cracks and reveal information about the structure of the eggshell. The high resolution, high quality measurements obtained through optical coherence tomography (OCT) make it feasible to be utilized as part of an automated inspection system. In this paper we present an OCT scan image of the egg tip and reconstructed volumetric images of the eggshell surface. The method enables the detection of small cracks on eggs and reveals the detailed inner structures of the cracks.

Assuntos

RESUMO

A photonic imaging method that gives the possibility to measure egg quality was applied. Since the method is non-contact and non-destructive we believe that this photonic imaging method may be successfully integrated in the automated inspection systems in the poultry industry. The method involves scanning an invisible infrared light beam over the eggshell, allowing to detect possible cracks and reveal information about the structure of the eggshell. The high resolution, high quality measurements obtained through optical coherence tomography (OCT) make it feasible to be utilized as part of an automated inspection system. In this paper we present an OCT scan image of the egg tip and reconstructed volumetric images of the eggshell surface. The method enables the detection of small cracks on eggs and reveals the detailed inner structures of the cracks.(AU)

Assuntos