Visualization of the scleral structure changes at various stages of eyes with myopic maculopathy using polarization-sensitive OCT.

Purpose: To observe the detailed structures of the inner and outer sclera at various stages of myopic maculopathy using polarization-sensitive optical coherence tomography (PS-OCT).

Methods: A PS-OCT system was developed for imaging the posterior eye using a swept laser. Data from highly myopic patients who underwent PS-OCT examination between May and June 2019 were used to generate birefringence images (showing scleral fiber density), optic axis images (visualizing the orientation of scleral fibers), and streamline images (providing 3D reconstructions to visualize scleral fiber stream).

Polarization-Sensitive OCT Imaging of Scleral Abnormalities in Eyes With High Myopia and Dome-Shaped Macula.

Importance: The relevance of visualizing scleral fiber orientation may offer insights into the pathogenesis of pathologic myopia, including dome-shaped maculopathy (DSM).

Objective: To investigate the orientation and density of scleral collagen fibers in highly myopic eyes with and without DSM by polarization-sensitive optical coherence tomography (PS-OCT).

Design, Setting, And Participants: This case series included patients with highly myopic eyes (defined as a refractive error ≥6 diopters or an axial length ≥26.

Retinal pigment epithelium melanin imaging using polarization-sensitive optical coherence tomography for patients with retinitis pigmentosa.

This study aimed to evaluate the distribution of retinal pigment epithelium (RPE) melanin in patients with retinitis pigmentosa (RP) using entropy measurements by custom-made polarization-sensitive optical coherence tomography (PS-OCT) images, and compare entropy with the intensity of short-wavelength (SW) and near-infrared (NIR) autofluorescence (AF). We retrospectively reviewed the retinal images, including PS-OCT, SW-AF, and NIR-AF of patients with RP who had a hyperautofluorescent ring on AF. A total of 12 eyes of 12 patients (8 women and 4 men; mean age: 37.

Visualization of Anterior Chamber Angle Structures With Scattering- and Polarization-Sensitive Anterior Segment Optical Coherence Tomography.

Purpose: The purpose of this study was to compare three optical coherence tomography (OCT) modalities in the observation of anterior chamber angle structures; trabecular meshwork (TM), Schlemm's canal (SC), and band of extracanalicular limbal lamina (BELL).

Methods: Three OCT modalities were used: (1) 2 × 2 Jones-matrix scattering OCT (S-OCT) representing conventional intensity OCT, (2) polarization-diverse S-OCT that was calculated as summation of all elements of the Jones-matrix to eliminate the influence of artifacts caused by sample birefringence, and (3) polarization-sensitive OCT (PS-OCT) to assess depth-resolved phase retardation.

Results: In a total of 97 eyes of 55 subjects, nasal and temporal angles were scanned.

Use of contrast-enhanced ultrasound in pediatrics.

Although contrast-enhanced ultrasound has been shown to provide considerable benefits, particularly in pediatric patients, it is still used relatively rarely in Brazil. It has proven to be a safe technique, and adverse effects are rare. In this review, we address the technique and main applications of contrast-enhanced ultrasound in the pediatric population, including the evaluation of focal liver lesions, abdominal trauma, kidney grafts, liver grafts, bowel loops, and vesicoureteral reflux.

Changes in entropy on polarized-sensitive optical coherence tomography images after therapeutic subthreshold micropulse laser for diabetic macular edema: A pilot study.

Purpose: To investigate the dynamics of the healing process after therapeutic subthreshold micropulse laser (SMPL) for diabetic macular edema (DME) using polarization-sensitive optical coherence tomography (PS-OCT).

Methods: Patients with treatment-native or previously-treated DME were prospectively imaged using PS-OCT at baseline, 1, 2, 3, and 6 months. The following outcomes were evaluated: changes in the entropy value per unit area (pixel2) in the retinal pigment epithelium (RPE) on the B-scan image; changes in the entropy value in each stratified layer (retina, RPE, choroid) based on the ETDRS grid circle overlaid with en face entropy mapping, not only the whole ETDRS grid area but also a sector irradiated by the SMPL; and the relationship between edema reduction and entropy changes.

Assessment of macular function in patients with non-vascularized pigment epithelial detachment.

Non-vascularized pigment epithelial detachments (PED) are usually associated with dry age-related macular degeneration (AMD). In this study, we aimed to investigate the correlation between visual function and morphologic parameters. Seventeen eyes of eleven patients with non-vascularized AMD were enrolled.

Three-Dimensional Distribution Of Fundus Depolarization and Associating Factors Measured Using Polarization-Sensitive Optical Coherence Tomography.

Purpose: To investigate the three-dimensional distribution and associating demographic factors of depolarization, using polarization-sensitive optical coherence tomography (PS-OCT), to evaluate melanin pigmentation in the retinal pigment epithelium (RPE) and choroid in healthy eyes.

Methods: In total, 39 unaffected healthy eyes of 39 subjects were examined using a PS-OCT clinical prototype. The degree of depolarization, expressed as the polarimetric entropy, was assessed in the RPE, the superficial and the total choroid layer, especially in the center, the inner, or the outer areas centered at the fovea.

Vomiting in newborns as a result of a duodenal membrane: two case reports.

Vomiting episodes in newborns are extremely common and often attributed to gastroesophageal reflux. The symptoms of vomiting, however, may be caused by other complications. In this report, we present two cases of a 1-month-old male and a 2-month-old female, both presenting vomiting episodes that led to malnutrition.

Melanin concentration and depolarization metrics measurement by polarization-sensitive optical coherence tomography.

Imaging of melanin in the eye is important as the melanin is structurally associated with some ocular diseases, such as age-related macular degeneration. Although optical coherence tomography (OCT) cannot distinguish tissues containing the melanin from other tissues intrinsically, polarization-sensitive OCT (PS-OCT) can detect the melanin through spatial depolarization of the backscattered light from the melanin granules. Entropy is one of the depolarization metrics that can be used to detect malanin granules in PS-OCT and valuable quantitative information on ocular tissue abnormalities can be retrived by correlating entropy with the melanin concentration.

Imaging of a retinal pigment epithelium aperture using polarization-sensitive optical coherence tomography.

Purpose: To evaluate cases with a retinal pigment epithelium (RPE) aperture using polarization-sensitive optical coherence tomography (PS-OCT).

Study Design: Retrospective consecutive case series.

Methods: A retrospective study that included three eyes (three patients) with RPE aperture and age-related macular degeneration (AMD) evaluated at the Macular Clinic in Tokyo University Hospital.

Usefulness of Polarization-sensitive Optical Coherence Tomography-derived Attenuation-coefficient Images to Visualize the Internal Structure of the Filtering Bleb.

Purpose/aim Of The Study: Polarization-sensitive anterior-segmental optical coherence tomography (PS-OCT) is useful to evaluate the filtering blebs after trabeculectomy. However, the attenuation phenomenon of OCT signal disturbs the visibility of intra-bleb's structure and distribution of birefringence; a specific parameter of PS-OCT. This study aimed to evaluate the effectiveness of the attenuation-coefficient image of the filtering blebs.

Polarization-sensitive optical coherence tomography for estimating relative melanin content of autologous induced stem-cell derived retinal pigment epithelium.

Transplantation of autologous human induced pluripotent stem cell-derived retinal pigment epithelial (hiPSC-RPE) sheets is a promising therapy for age-related macular degeneration (AMD). As melanin content is a representative feature of healthy RPE, we used polarization-sensitive optical coherence tomography (PS-OCT) to estimate the relative melanin content of RPE in diseased and non-diseased area, and in human iPSC-RPE sheets in vitro and in vivo by evaluating the randomness of polarization (entropy). Two aged Japanese women, one with neovascular AMD that underwent transplantation of an autologous hiPSC-RPE cell sheet and another with binocular dry AMD, were selected for this study.

Focal hyperechoic liver lesions in children: far beyond hemangiomas - pictorial essay.

The aim of this report was to present a selection of focal hyperechoic liver lesions of different etiologies, illustrating the wide spectrum of diagnostic possibilities for such lesions in the pediatric population.

Parallel detection of Jones-matrix elements in polarization-sensitive optical coherence tomography.

The polarization properties of a sample can be characterized using a Jones matrix. To measure the Jones matrix without assumptions of the sample, two different incident states of polarization are usually used. This requirement often causes certain drawbacks in polarization-sensitive optical coherence tomography (PS-OCT), e.

Erratum: Estimation of Jones matrix, birefringence and entropy using Cloude-Pottier decomposition in polarization-sensitive optical coherence tomography: erratum.

[This corrects the article on p. 3551 in vol. 7, PMID: 27699120.

The challenging sonographic inguinal canal evaluation in neonates and children: an update of differential diagnoses.

Bulging of the inguinal region is a frequent complaint in the pediatric population and sonographic findings can be challenging for radiologists. In this review we update the sonographic findings of the most common disorders that affect the inguinal canal in neonates and children, with a focus on the processus vaginalis abnormalities such as congenital hydroceles, indirect inguinal hernias and cryptorchidism, illustrated with cases collected at a quaternary hospital during a 7-year period. We emphasize the importance of correctly classifying different types of congenital hydrocele and inguinal hernia to allow for early surgical intervention when necessary.

Estimation of Jones matrix, birefringence and entropy using Cloude-Pottier decomposition in polarization-sensitive optical coherence tomography.

Estimation of polarimetric parameters has been a fundamental issue to assess biological tissues that have form birefringence or polarization scrambling in polarization-sensitive optical coherence tomography (PS-OCT). We present a mathematical framework to provide a maximum likelihood estimation of the target covariance matrix and its incoherent target decomposition to estimate a Jones matrix of a dominant scattering mechanism, called Cloude-Pottier decomposition, thereby deriving the phase retardation and the optic axis of the sample. In addition, we introduce entropy that shows the randomness of the polarization property.

Fiber-based polarization-sensitive OCT for birefringence imaging of the anterior eye segment.

We demonstrate a prototype system of polarization-sensitive optical coherence tomography (PS-OCT) designed for clinical studies of the anterior eye segment imaging. The system can measure Jones matrices of the sample with depth-multiplexing of two orthogonal incident polarizations and polarization-sensitive detection. An optical clock is generated using a quadrature modulator and a logical circuit to double the clock frequency.

Bullet embolism of pulmonary artery: a case report.

The authors report the case of a patient victim of gunshots, with a very rare complication: venous bullet embolism from the left external iliac vein to the lingular segment of the left pulmonary artery. Diagnosis is made with whole-body radiography or computed tomography. Digital angiography is reserved for supplementary diagnosis or to be used as a therapeutic procedure.

Scleral birefringence as measured by polarization-sensitive optical coherence tomography and ocular biometric parameters of human eyes in vivo.

The relationship between scleral birefringence and biometric parameters of human eyes in vivo is investigated. Scleral birefringence near the limbus of 21 healthy human eyes was measured using polarization-sensitive optical coherence tomography. Spherical equivalent refractive error, axial eye length, and intraocular pressure (IOP) were measured in all subjects.

Comparison of three-dimensional optical coherence tomography and combining a rotating Scheimpflug camera with a Placido topography system for forme fruste keratoconus diagnosis.

Objective: To evaluate the ability of parameters measured by three-dimensional (3D) corneal and anterior segment optical coherence tomography (CAS-OCT) and a rotating Scheimpflug camera combined with a Placido topography system (Scheimpflug camera with topography) to discriminate between normal eyes and forme fruste keratoconus.

Methods: Forty-eight eyes of 48 patients with keratoconus, 25 eyes of 25 patients with forme fruste keratoconus and 128 eyes of 128 normal subjects were evaluated. Anterior and posterior keratometric parameters (steep K, flat K, average K), elevation, topographic parameters, regular and irregular astigmatism (spherical, asymmetry, regular and higher-order astigmatism) and five pachymetric parameters (minimum, minimum-median, inferior-superior, inferotemporal-superonasal, vertical thinnest location of the cornea) were measured using 3D CAS-OCT and a Scheimpflug camera with topography.

Anisotropic alteration of scleral birefringence to uniaxial mechanical strain.

Purpose: To investigate the relationship between scleral mechanical properties, its birefringence, and the anisotropy of birefringence alteration in respect of the direction of the strain by using PS-OCT.

Methods: The scleral birefringence of thirty-nine porcine eyes was measured with a prototype PS-OCT. A rectangle strip of sclera with a width of 4 mm was dissected at the temporal region 5 mm apart from the optic nerve head.