Purpose: To investigate the flow characteristics using different thresholding methods on a choriocapillaris optical coherence tomography angiography (OCTA) image complemented with a structural En Face image. Methods: The 42 choriocapillaris OCTA images from healthy subjects were obtained with swept-source OCTA device and the 3 × 3-mm area OCTA images were processed with ImageJ. Using a raw choriocapillaris OCTA image and structural En Face image, we adjusted the different structural signal intensity. Then, the raw images and adjusted images were binarized with a global threshold and an auto local threshold using the Phansalkar method at 1- or 2-intercapillary distance. Then, the mean area, number, and size of the flow void, were compared among the images using different thresholding methods. Results: Mean flow void area, number, and size were different according to the different binarization method both in raw and adjusted images (all p < 0.001). The mean flow void area analyzed with global threshold method were well correlated with those with auto local threshold method both in raw and adjusted images (all intraclass correlations, >0.929). Conclusions Flow void features varied according to the different binarization methods but showed good correlation. The flow void characteristics according to the different binarization methods should be considered for the analysis of the choriocapillaris OCTA images complemented with a structural En Face image.

Purpose: To compare the vessel density (VD) and foveal avascular zone (FAZ) area using four different optical coherence tomography angiography (OCTA) images. Methods: This prospective study analyzed the OCTA images of consecutive healthy subjects using Plex-Elite (Carl Zeiss), DRI OCT-1 Atlantis (Topcon), AngioPlex (Carl Zeiss), and Spectralis OCTA (Heidelberg Engineering). The VD and FAZ areas were calculated using the OCTA images with a 3 x 3 mm2 volume scan pattern centered on the fovea. Results: The VD (%) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) were different using the four devices: Plex-Elite (42.17 ± 2.79, 43.71 ± 2.36), DRI OCT-1 Atlantis (28.70 ± 2.87, 30.27 ± 3.02), AngioPlex (28.32 ± 6.68, 33.33 ± 5.44), and Spectralis OCTA (27.86 ± 4.13, 28.54 ± 3.14), respectively; p < 0.001). The FAZ area (mm2) of the SCP and DCP were different using the four devices: Plex-Elite (0.276 ± 0.097, 0.340 ± 0.100), DRI OCT-1 Atlantis (0.281 ± 0.102, 0.354 ± 0.119), AngioPlex (0.269 ± 0.099, 0.422 ± 0.120), and Spectralis OCTA (0.272 ± 0.079, 0.298 ± 0.106), respectively; p < 0.001). The VD of the SCP and DCP had no significant correlation using the four devices (all, p > 0.05), but the FAZ area had positive correlations using the four devices (all, p < 0.001). Conclusions The four OCTA devices provided different VD and FAZ areas, so these differences should be considered in analyzing OCTA images.

Purpose: To assess the diagnostic value of optical coherence tomography angiography (OCTA), and the factors affecting the diagnosis of polypoidal choroidal vasculopathy (PCV) by OCTA and indocyanine green angiography (ICGA). Methods: The numbers and area of polyps, and the presence and area of a branched vascular network (BVN) as revealed by ICGA and OCTA, were retrospectively analyzed in 43 patients with active PCV. The patients were divided into two groups according to whether the number of polyps matched between the two methods: group 1, equal number of polyps revealed by ICGA and OCTA; group 2, different number of polyps revealed by ICGA and OCTA. Results: In 43 PCV patients, the total number of polyps was 1.47 ± 0.83 in ICGA and 1.07 ± 0.91 in OCTA (p < 0.001), and the polyp area was 0.27 ± 0.42 mm2 in ICGA and 0.17 ± 0.15 mm2 in OCTA (p = 0.023). BVN was found in 33 eyes (76.7%) by ICGA and 29 eyes (67.4%) by OCTA (p < 0.001). The BVN area was 3.61 ± 2.59 mm2 in ICGA and 2.74 ± 2.76 mm2 in OCTA (p = 0.002). Central retinal thickness and central choroidal thickness were significantly greater in group 2 than group 1 (p < 0.001, respectively). Subretinal fluid (SRF) (p = 0.009) and subretinal hemorrhage (SRH) (p = 0.005) were significantly more prevalent in group 2 than group 1. Polyp height (p = 0.022) and diameter (p = 0.042) were significantly greater in group 2 than group 1. Conclusions OCTA is a supplementary diagnostic technique for detecting PCV. The presence of SRF and SHR, and large polyp height and diameter, were associated with the polyp detection rate of OCTA for PCV.

Purpose: To assess the diagnostic value of optical coherence tomography angiography (OCTA), and the factors affecting the diagnosis of polypoidal choroidal vasculopathy (PCV) by OCTA and indocyanine green angiography (ICGA). Methods: The numbers and area of polyps, and the presence and area of a branched vascular network (BVN) as revealed by ICGA and OCTA, were retrospectively analyzed in 43 patients with active PCV. The patients were divided into two groups according to whether the number of polyps matched between the two methods: group 1, equal number of polyps revealed by ICGA and OCTA; group 2, different number of polyps revealed by ICGA and OCTA. Results: In 43 PCV patients, the total number of polyps was 1.47 ± 0.83 in ICGA and 1.07 ± 0.91 in OCTA (p < 0.001), and the polyp area was 0.27 ± 0.42 mm2 in ICGA and 0.17 ± 0.15 mm2 in OCTA (p = 0.023). BVN was found in 33 eyes (76.7%) by ICGA and 29 eyes (67.4%) by OCTA (p < 0.001). The BVN area was 3.61 ± 2.59 mm2 in ICGA and 2.74 ± 2.76 mm2 in OCTA (p = 0.002). Central retinal thickness and central choroidal thickness were significantly greater in group 2 than group 1 (p < 0.001, respectively). Subretinal fluid (SRF) (p = 0.009) and subretinal hemorrhage (SRH) (p = 0.005) were significantly more prevalent in group 2 than group 1. Polyp height (p = 0.022) and diameter (p = 0.042) were significantly greater in group 2 than group 1. Conclusions OCTA is a supplementary diagnostic technique for detecting PCV. The presence of SRF and SHR, and large polyp height and diameter, were associated with the polyp detection rate of OCTA for PCV.

Spherical neural mass (SNM) is a mass of neural precursors that have been used to generate neuronal cells with advantages of long-term passaging capability with high yield, easy storage, and thawing. In this study, we differentiated neural retinal progenitor cells (RPCs) from human induced pluripotent stem cells (hiPSC)-derived SNMs. RPCs were differentiated from SNMs with a noggin/fibroblast growth factor-basic/Dickkopf-1/Insulin-like growth factor-1/fibroblast growth factor-9 protocol for three weeks. Human RPCs expressed eye field markers (Paired box 6) and early neural retinal markers (Ceh-10 homeodomain containing homolog), but did not photoreceptor marker (Opsin 1 short-wave-sensitive). Reverse transcription polymerase chain reaction revealed that early neural retinal markers (Mammalian achaete-scute complex homolog 1, mouse atonal homolog 5, neurogenic differentiation 1) and retinal fate markers (brain-specific homeobox/POU domain transcription factor 3B and recoverin) were upregulated, while the marker of retinal pigment epithelium (microphthalmia-associated transcription factor) only showed slight upregulation. Human RPCs were transplanted into mouse (adult 8 weeks old C57BL/6) retina. Cells transplanted into the mouse retina matured and expressed markers of mature retinal cells (Opsin 1 short-wave-sensitive) and human nuclei on immunohistochemistry three months after transplantation. Development of RPCs using SNMs may offer a fast and useful method for neural retinal cell differentiation.
Animals ; Cell Differentiation ; Humans* ; Immunohistochemistry ; Induced Pluripotent Stem Cells ; Methods ; Mice ; Neurons ; Photoreceptor Cells, Vertebrate ; Polymerase Chain Reaction ; Retina ; Retinal Pigment Epithelium ; Retinaldehyde* ; Reverse Transcription ; Stem Cells* ; Transcription Factors ; Up-Regulation

Since genetic models for retinal degeneration (RD) in animals larger than rodents have not been firmly established to date, we sought in the present study to develop a new rabbit model of drug-induced RD. First, intravitreal injection of N-methyl-N-nitrosourea (MNU) without vitrectomy in rabbits was performed with different doses. One month after injection, morphological changes in the retinas were identified with ultra-wide-field color fundus photography (FP) and fundus autofluorescence (AF) imaging as well as spectral-domain optical coherence tomography (OCT). Notably, the degree of RD was not consistently correlated with MNU dose. Then, to check the effects of vitrectomy on MNU-induced RD, the intravitreal injection of MNU after vitrectomy in rabbits was also performed with different doses. In OCT, while there were no significant changes in the retinas for injections up to 0.1 mg (i.e., sham, 0.05 mg, and 0.1 mg), outer retinal atrophy and retinal atrophy of the whole layer were observed with MNU injections of 0.3 mg and 0.5 mg, respectively. With this outcome, 0.2 mg MNU was chosen to be injected into rabbit eyes (n=10) at two weeks after vitrectomy for further study. Six weeks after injection, morphological identification with FP, AF, OCT, and histology clearly showed localized outer RD - clearly bordered non-degenerated and degenerated outer retinal area - in all rabbits. We suggest our post-vitrectomy MNU-induced RD rabbit model could be used as an interim animal model for visual prosthetics before the transition to larger animal models.
Animals ; Atrophy ; Intravitreal Injections ; Methylnitrosourea ; Models, Animal ; Models, Genetic ; Photography ; Rabbits ; Retina ; Retinal Degeneration ; Retinaldehyde ; Rodentia ; Tomography, Optical Coherence ; Vitrectomy

PURPOSE: With the emergence of next-generation sequencing (NGS) technology, profiling a wide range of genomic alterations has become a possibility resulting in improved implementation of targeted cancer therapy. In Asian populations, the prevalence and spectrum of clinically actionable genetic alterations has not yet been determined because of a lack of studies examining high-throughput cancer genomic data. MATERIALS AND METHODS: To address this issue, 1,071 tumor samples were collected from five major cancer institutes in Korea and analyzed using targeted NGS at a centralized laboratory. Samples were either fresh frozen or formalin-fixed, paraffin embedded (FFPE) and the quality and yield of extracted genomic DNA was assessed. In order to estimate the effect of sample condition on the quality of sequencing results, tissue preparation method, specimen type (resected or biopsied) and tissue storage time were compared. RESULTS: We detected 7,360 non-synonymous point mutations, 1,164 small insertions and deletions, 3,173 copy number alterations, and 462 structural variants. Fifty-four percent of tumors had one or more clinically relevant genetic mutation. The distribution of actionable variants was variable among different genes. Fresh frozen tissues, surgically resected specimens, and recently obtained specimens generated superior sequencing results over FFPE tissues, biopsied specimens, and tissues with long storage duration. CONCLUSION: In order to overcome, challenges involved in bringing NGS testing into routine clinical use, a centralized laboratory model was designed that could improve the NGS workflows, provide appropriate turnaround times and control costs with goal of enabling precision medicine.
Academies and Institutes ; Asian Continental Ancestry Group ; DNA ; Humans ; Korea ; Methods ; Paraffin ; Point Mutation ; Precision Medicine ; Prevalence