Endovascular Treatment of Venous Outflow and Portal Venous Complications After Liver Transplantation.

Liver transplantation continues to rapidly evolve, and in 2020, 8906 orthotopic liver transplants were performed in the United States. As a technically complex surgery with multiple vascular anastomoses, stenosis and thrombosis of the venous anastomoses are among the recognized vascular complications. While rare, venous complications may be challenging to manage and can threaten the graft and the patient. In the last 20 years, endovascular approaches have been increasingly utilized to treat post-transplant venous complications. Herein, the evaluation and interventional treatment of post-transplant venous outflow complications, portal vein stenosis, portal vein thrombosis, and recurrent portal hypertension with transjugular intrahepatic portosystemic shunt (TIPS) are reviewed.

Deep learning for automated detection of neovascular leakage on ultra-widefield fluorescein angiography in diabetic retinopathy.

Diabetic retinopathy is a leading cause of blindness in working-age adults worldwide. Neovascular leakage on fluorescein angiography indicates progression to the proliferative stage of diabetic retinopathy, which is an important distinction that requires timely ophthalmic intervention with laser or intravitreal injection treatment to reduce the risk of severe, permanent vision loss. In this study, we developed a deep learning algorithm to detect neovascular leakage on ultra-widefield fluorescein angiography images obtained from patients with diabetic retinopathy. The algorithm, an ensemble of three convolutional neural networks, was able to accurately classify neovascular leakage and distinguish this disease marker from other angiographic disease features. With additional real-world validation and testing, our algorithm could facilitate identification of neovascular leakage in the clinical setting, allowing timely intervention to reduce the burden of blinding diabetic eye disease.

Chain-like gold nanoparticle clusters for multimodal photoacoustic microscopy and optical coherence tomography enhanced molecular imaging.

Colloidal gold nanoparticles (GNPs) serve as promising contrast agents in photoacoustic (PA) imaging, yet their utility is limited due to their absorption peak in the visible window overlapping with that of hemoglobin. To overcome such limitation, this report describes an ultrapure chain-like gold nanoparticle (CGNP) clusters with a redshift peak wavelength at 650 nm. The synthesized CGNP show an excellent biocompatibility and photostability. These nanoparticles are conjugated with arginine-glycine-aspartic acid (RGD) peptides (CGNP clusters-RGD) and validated in 12 living rabbits to perform multimodal photoacoustic microscopy (PAM) and optical coherence tomography (OCT) for visualization of newly developed blood vessels in the sub-retinal pigment epithelium (RPE) space of the retina, named choroidal neovascularization (CNV). The PAM system can achieve a 3D PAM image via a raster scan of 256 × 256 pixels within a time duration of 65 s. Intravenous injection of CGNP clusters-RGD bound to CNV and resulted in up to a 17-fold increase in PAM signal and 176% increase in OCT signal. Histology indicates that CGNP clusters could disassemble, which may facilitate its clearance from the body.

Comparison of automated and expert human grading of diabetic retinopathy using smartphone-based retinal photography.

PURPOSE: The aim of this study is to investigate the efficacy of a mobile platform that combines smartphone-based retinal imaging with automated grading for determining the presence of referral-warranted diabetic retinopathy (RWDR). METHODS: A smartphone-based camera (RetinaScope) was used by non-ophthalmic personnel to image the retina of patients with diabetes. Images were analyzed with the Eyenuk EyeArt® system, which generated referral recommendations based on presence of diabetic retinopathy (DR) and/or markers for clinically significant macular oedema. Images were independently evaluated by two masked readers and categorized as refer/no refer. The accuracies of the graders and automated interpretation were determined by comparing results to gold standard clinical diagnoses. RESULTS: A total of 119 eyes from 69 patients were included. RWDR was present in 88 eyes (73.9%) and in 54 patients (78.3%). At the patient-level, automated interpretation had a sensitivity of 87.0% and specificity of 78.6%; grader 1 had a sensitivity of 96.3% and specificity of 42.9%; grader 2 had a sensitivity of 92.5% and specificity of 50.0%. At the eye-level, automated interpretation had a sensitivity of 77.8% and specificity of 71.5%; grader 1 had a sensitivity of 94.0% and specificity of 52.2%; grader 2 had a sensitivity of 89.5% and specificity of 66.9%. DISCUSSION: Retinal photography with RetinaScope combined with automated interpretation by EyeArt achieved a lower sensitivity but higher specificity than trained expert graders. Feasibility testing was performed using non-ophthalmic personnel in a retina clinic with high disease burden. Additional studies are needed to assess efficacy of screening diabetic patients from general population.

Plasmonic Gold Nanostar-Enhanced Multimodal Photoacoustic Microscopy and Optical Coherence Tomography Molecular Imaging To Evaluate Choroidal Neovascularization.

Although photoacoustic microscopy (PAM) and optical coherence tomography (OCT) allow visualization of the retinal microvasculature, distinguishing early neovascularization from adjacent vessels remains challenging. Herein, gold nanostars (GNSs) functionalized with an RGD peptide were utilized as multimodality contrast agents for both PAM and OCT. GNSs have great absorption and scattering characteristics in the near-infrared region where most vasculature and tissue generates a less intrinsic photoacoustic signal while having a small size, excellent biocompatibility in vivo, and great photostability under nanosecond pulsed laser illumination. This enabled visualization and differentiation of individual microvasculature in vivo using multimodal PAM and OCT imaging. Detailed three-dimensional imaging of GNSs was achieved in an important choroidal neovascularization model in living rabbits. Through the administration of GNSs, PA contrast increased up to 17-fold and OCT intensities increased 167%. This advanced molecular-imaging platform with GNSs provides a unique tool for detailed mapping of the pathogenesis of the microvasculature.

Quantification of Retinal Nonperfusion and Neovascularization With Ultrawidefield Fluorescein Angiography in Patients With Diabetes and Associated Characteristics of Advanced Disease.

Importance: Quantification of nonperfusion (NP) and neovascularization (NV) in diabetic retinopathy (DR) may identify better biomarkers of disease progression. Objective: To identify demographic risk factors and markers of advanced DR that are associated with increased areas of NP and NV in eyes with disease ranging from no DR but diagnosed as having diabetes to proliferative DR (PDR) and to calculate a threshold total area of NP that may be associated with an increased risk of PDR. Design, Setting, and Participants: This retrospective case series was performed on ultrawidefield fluorescein angiography (UWF FA) images from January 2009 to May 2018 at the University of Michigan Kellogg Eye Center. A total of 363 participants (651 eyes) diagnosed as having type 1 or 2 diabetes receiving UWF FA were included. Exclusion criteria included previous panretinal photocoagulation (PRP) and poor-quality images (eg, vitreous hemorrhage and significant cataract). Main Outcomes and Measures: The surface areas in millimeters squared of the foveal avascular zone; total NP; NP at posterior pole, midperiphery, and far periphery; total NV; NV at posterior pole, midperiphery, and far periphery were measured. Results: Of 363 patients, most were male (205 patients [56.5%]) and white (247 [68%]) or black (77 [21.2%]). The mean (SD) age was 59.4 (13.7) years. Seventy-six eyes with no DR, 92 with mild NPDR, 144 with moderate NPDR, 101 with severe NPDR, 220 with PDR, and 18 with DR of unknown severity were included. Male sex had a positive association with total NP (difference, 15.72; 95% CI, 4.83-26.61; P = .005); black race/ethnicity with total NV (difference, 2.32; 95% CI, 0.09-4.55; P = .04); and vitreous hemorrhage with total NP (difference, 30.00; 95% CI, 5.26-54.75; P = .02). A threshold total NP area of 77.48 mm2 (95% CI, 54.24-92.66 mm2) was identified, at greater than which patients may have an increased risk of developing PDR (sensitivity of 59.5% and specificity of 73.6%). Conclusions and Relevance: Our results indicate NP and NV can be quantified on UWF FA. These biomarkers interpreted with demographic risk factors may help predict disease progression. Conclusions are limited by ascertainment and information biases because the results are from retrospective data.

Smartphone-based fundus photography for screening of plus-disease retinopathy of prematurity.

BACKGROUND: Inadequate screening of treatment-warranted retinopathy of prematurity (ROP) can lead to devastating visual outcomes. Especially in resource-poor communities, the use of an affordable, portable, and easy to use smartphone-based non-contact fundus photography device may prove useful for screening for high-risk ROP. This study evaluates the feasibility of screening for high-risk ROP using a novel smartphone-based fundus photography device, RetinaScope. METHODS: Retinal images were obtained using RetinaScope on a cohort of prematurely born infants during routine examinations for ROP. Images were reviewed by two masked graders who determined the image quality, the presence or absence of plus disease, and whether there was retinopathy that met predefined criteria for referral. The agreement between image-based assessments was compared to the gold standard indirect ophthalmoscopic assessment. RESULTS: Fifty-four eyes of 27 infants were included. A wide-field fundus photograph was obtained using RetinaScope. Image quality was acceptable or excellent in 98% and 95% of cases. There was substantial agreement between the gold standard and photographic assessment of presence or absence of plus disease (Cohen's κ = 0.85). Intergrader agreement on the presence of any retinopathy in photographs was also high (κ = 0.92). CONCLUSIONS: RetinaScope can capture digital retinal photographs of prematurely born infants with good image quality for grading of plus disease.

In Vivo 3D Imaging of Retinal Neovascularization Using Multimodal Photoacoustic Microscopy and Optical Coherence Tomography Imaging.

The pathological process of neovascularization of the retina plays a critical role in causing vision loss in several diseases, including diabetes, retinal vein occlusion, and sickle cell disease. Retinal neovascularization can lead to vitreous hemorrhage and retinal detachment, yet the pathological process of neovascularization is a complex phenomenon under active investigation. Understanding and monitoring retinal neovascularization is critically important in clinical ophthalmology. This study describes a novel multimodal ocular imaging system which combines photoacoustic microscopy (PAM) and a spectral domain optical coherence tomography (SD-OCT) to improve the visualization of retinal neovascularization (RNV), their depth, and the surrounding anatomy in living rabbits. RNV was induced in New Zealand rabbits by intravitreal injection of vascular endothelial growth factor (VEGF). The retinal vasculature before and after injection at various times was monitored and evaluated using multimodal imaging including color fundus photography, fluorescein angiography (FA), OCT, and PAM. In vivo experiments demonstrate that PAM imaging distinctly characterized the location as well as the morphology of individual RNV with high contrast at a safe laser energy of 80 nJ. SD-OCT was used to identify a cross-sectional structure of RNV. In addition, dynamic changes in the retinal morphology and retinal neovascularization were observed at day 4, 5, 6, 7, 9, 11, 14, 28, and day 35 after VEGF injection. PAM demonstrated high-resolution optical absorption of hemoglobin and vascular imaging of the retina and choroid with increased depth of penetration. With the current multimodal imaging system, RNV can be easily visualized in both 2D and 3D angiography. This multimodal ocular imaging system provides improved characterization of the microvasculature in a safe manner in larger rabbit eyes.

PEMBROLIZUMAB ADMINISTRATION ASSOCIATED WITH POSTERIOR UVEITIS.

PURPOSE: To describe the development of uveitis and retinal vasculitis in association with pembrolizumab treatment for metastatic uveal melanoma. METHODS: A case report and a brief review of the literature are presented. Information collected and reported include the patient's clinical course, physical examination findings, fluorescein angiogram images, retinal photographs, and her response to treatment. RESULTS: A 54-year-old woman was diagnosed with a large choroidal malignant melanoma and had the affected eye enucleated. Pathology confirmed a mixed cell choroidal melanoma, and gene expression profiling was Class 2. Seventeen months after enucleation, the patient was diagnosed with metastatic uveal melanoma to the liver. Disease progression was observed during ipilimumab treatment. Pembrolizumab treatment was initiated, and after four infusions, she presented to clinic complaining of floaters and blurred vision. Examination revealed a nongranulomatous panuveitis characterized by perivascular retinal pigment epithelium pigmentary changes, retinal venous sheathing, 1+ anterior chamber and vitreous cellular reaction, 2+ vitreous haze, and optic disk edema. A dexamethasone sustained-release implant was administered and the uveitis regressed. A relapse in symptoms occurred but quickly subsided with a repeat injection. CONCLUSION: Pembrolizumab may induce a uveitic reaction. There is mounting evidence that patients using prembrolizumab should be educated and monitored for signs of uveitis.