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Concept: Optical coherence tomography

148

Conventional arthroscopic evaluation of articular cartilage is subjective and poorly reproducible. Therefore, implementation of quantitative diagnostic techniques, such as near infrared spectroscopy (NIRS) and optical coherence tomography (OCT), is essential. Locations (n = 44) with various cartilage conditions were selected from mature equine fetlock joints (n = 5). These locations and their surroundings were measured with NIRS and OCT (n = 530). As a reference, cartilage proteoglycan (PG) and collagen contents, and collagen network organization were determined using quantitative microscopy. Additionally, lesion severity visualized in OCT images was graded with an automatic algorithm according to International Cartilage Research Society (ICRS) scoring system. Artificial neural network with variable selection was then employed to predict cartilage composition in the superficial and deep zones from NIRS data, and the performance of two models, generalized (including all samples) and condition-specific models (based on ICRS-grades), was compared. Spectral data correlated significantly (p < 0.002) with PG and collagen contents, and collagen orientation in the superficial and deep zones. The combination of NIRS and OCT provided the most reliable outcome, with condition-specific models having lower prediction errors (9.2%) compared to generalized models (10.4%). Therefore, the results highlight the potential of combining both modalities for comprehensive evaluation of cartilage during arthroscopy.

Concepts: Scientific method, Spectroscopy, Bone, Cartilage, Optical coherence tomography, Infrared spectroscopy, Infrared, Near infrared spectroscopy

147

The edge vascular response (EVR) has been linked to important prognostic implications in patients treated with permanent metallic stents. We aimed to investigate the relationship of EVR with the geometric changes in the everolimus-eluting bioresorbable scaffold using serial optical coherence tomography (OCT) analysis.Methods and Results:In the first-in-man ABSORB trial, 28 patients (29 lesions) underwent serial OCT at 4 different time points (Cohort B1: post-procedure, 6, 24, and 60 months [n=13]; Cohort B2: post-procedure, 12, 36, and 60 months [n=15]) following implantation of the scaffold. In Cohort B1, there was no significant luminal change at the distal or proximal edge segment throughout the entire follow-up. In contrast, there was a significant reduction of the lumen flow area (LFA) of the scaffold between post-procedure and 6 months (-1.03±0.49 mm(2)[P<0.001]), whereas between 6 and 60 months the LFA remained stable (+0.31±1.00 mm(2)[P=0.293]). In Cohort B2, there was a significant luminal reduction of the proximal edge between post-procedure and 12 months (-0.57±0.74 mm(2)[P=0.017]), whereas the lumen area remained stable (-0.26±1.22 mm(2)[P=0.462]) between 12 and 60 months. The scaffold LFA showed a change similar to that observed in Cohort B1.

Concepts: Optics, Medical imaging, Optical coherence tomography, 6

136

To compare the diagnostic ability of the ganglion cell analysis (GCA) and retinal nerve fiber layer (RNFL) protocol on optical coherence tomography (OCT), to diagnose preperimetric glaucoma.

Concepts: Nervous system, Optics, Diagnosis, Greek loanwords, Retina, Optical coherence tomography, Nerve fiber layer

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OBJECTIVE: To determine the effect of clinical and radiologic disease activity on the rate of thinning of the ganglion cell/inner plexiform (GCIP) layer and the retinal nerve fiber layer in patients with multiple sclerosis (MS) using optical coherence tomography (OCT). METHODS: One hundred sixty-four patients with MS and 59 healthy controls underwent spectral-domain OCT scans every 6 months for a mean follow-up period of 21.1 months. Baseline and annual contrast-enhanced brain MRIs were performed. Patients who developed optic neuritis during follow-up were excluded from analysis. RESULTS: Patients with the following features of disease activity during follow-up had faster rates of annualized GCIP thinning: relapses (42% faster, p = 0.007), new gadolinium-enhancing lesions (54% faster, p < 0.001), and new T2 lesions (36% faster, p = 0.02). Annual GCIP thinning was 37% faster in those with disability progression during follow-up, and 43% faster in those with disease duration <5 years vs >5 years (p = 0.003). Annual rates of GCIP thinning were highest in patients exhibiting combinations of new gadolinium-enhancing lesions, new T2 lesions, and disease duration <5 years (70% faster in patients with vs without all 3 characteristics, p < 0.001). CONCLUSIONS: MS patients with clinical and/or radiologic nonocular disease activity, particularly early in the disease course, exhibit accelerated GCIP thinning. Our findings suggest that retinal changes in MS reflect global CNS processes, and that OCT-derived GCIP thickness measures may have utility as an outcome measure for assessing neuroprotective agents, particularly in early, active MS.

Concepts: Nervous system, Optics, Magnetic resonance imaging, Multiple sclerosis, Retina, Optical coherence tomography, Optic nerve, Nerve fiber layer

28

This work aims to improve the process of speckle noise reduction while preserving edges and other relevant features through filter expansion from 2-D to 3-D. Despeckling is very important for data visual inspection and as a preprocessing step for other algorithms, as they are usually notably influenced by speckle noise. To that intent, a 3-D approach is proposed for the adaptive complex-diffusion filter. This 3-D iterative filter was applied to spectral-domain optical coherence tomography medical imaging volumes of the human retina and a quantitative evaluation of the results was performed to allow a demonstration of the better performance of the 3-D over the 2-D filtering and to choose the best total diffusion time. In addition, we propose a fast graphical processing unit parallel implementation so that the filter can be used in a clinical setting.

Concepts: Medicine, Optics, Medical imaging, Retina, Optical coherence tomography, Tomography, Real number, Image processing

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Abstract Purpose: To evaluate the functional and anatomical outcome after intravitreal ranibizumab injection in 2 patients with cystoid macular edema (CME) related to Irvine-Gass syndrome. Methods: Two patients with pseudophakic CME refractory to current standard topical treatment were enrolled in this study. Intravitreal (0.5 mg/0.05 mL) ranibizumab injection was performed. Baseline visits included best-corrected visual acuity (BCVA), a fundus examination, optical coherence tomography (OCT), and fundus fluorescein angiography (FA). The main outcome measures were changes in visual acuity, retinal thickness on OCT, and complications related to treatment. Results: FA and OCT confirmed the diagnosis of pseudophakic CME in both cases. The initial BCVA was 5/100 in the first case. After 1 injection of intravitreal ranibizumab, retinal edema totally regressed and BCVA improved to 6/10. The central macular thickness (CMT) measured with OCT was 379 μm at baseline and decreased to 227 μm at the 16-month visit. The initial BCVA was 5/10 in the second case. It improved to 8/10 after 2 ranibizumab injections and remained unchanged at the 21-month visit. The CMT measured with OCT was 419 μm at baseline and decreased to 243 μm at the final follow-up. There were no ocular or systemic complications related to the intravitreal injections. Conclusion: Intravitreal ranibizumab appeared to be an effective treatment of macular edema related to Irvine-Gass syndrome. Prospective controlled studies are warranted to compare the long-term safety and efficacy between intravitreal ranibizumab and other treatment options in cases of Irvine-Gass syndrome.

Concepts: Medical imaging, Medical signs, Retina, Ophthalmology, Diabetic retinopathy, Optical coherence tomography, Fluorescein angiography, Macular edema

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Background  Photodynamic therapy (PDT) and laser ablation (LA) are frequently used treatment options for multiple actinic keratoses (AK), yet they have not been compared head to head. Objectives  To compare PDT and carbon dioxide (CO(2) ) LA in the management of multiple AK using objective and subjective outcome measures. Methods  A single-centre, randomized, two-treatment half-side comparative study of PDT vs. CO(2) LA was performed. Patients with at least four bilateral (e.g., scalp, forearms) AK were included. The primary outcome measure was the reduction of AK 3 months (v3) after therapy. Secondary outcome measures included the reduction of AK 4 weeks (v2) after therapy, decrease of epidermal p53 and Ki-67 protein expression, micromorphological changes as assessed by optical coherence tomography (OCT) in vivo, and investigators' and patients' satisfaction scoring. Results  In total, 20 patients (18 men and 2 women) completed the study. Both treatments reduced AK quantity significantly. On v3, relative reduction of AK quantity was significantly higher following PDT (P = 0·0362). Ki-67 and p53 protein expression was reduced significantly from baseline (Ki-67, median 49·5%; p53, median 64·8%) to v2 by both procedures (PDT, median 18·5%, P < 0·0001; LA, median 16·2%, P < 0·0001). AK features as assessed by OCT imaging were also significantly reduced by both procedures. The investigators and patients rated the side-effects and inconveniences of PDT as more severe, but both overall preferred PDT due to the superior clinical outcome. Conclusions  CO(2) LA and PDT are both effective therapy options for multiple AK, yet PDT seems to be superior in terms of AK reduction and participants' and investigators' overall satisfaction.

Concepts: Photosynthesis, Carbon dioxide, Redox, Laser, Nitrogen, Carbon, Optical coherence tomography, Actinic keratosis

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PURPOSE: To report the optical coherence tomography (OCT) and fundus fluorescein angiography (FFA) results of the Macular Epiretinal Brachytherapy in Treated Age-Related Macular Degeneration study. DESIGN: Prospective, multicenter, interventional, noncontrolled clinical trial. PARTICIPANTS: Fifty-three eyes of 53 participants with chronic, active neovascular age-related macular degeneration (AMD) requiring frequent anti-vascular endothelial growth factor retreatment. METHODS: Participants underwent pars plana vitrectomy with a single 24-gray dose of epimacular brachytherapy (EMB), delivered with an intraocular, handheld, cannula containing a strontium 90/yttrium 90 source positioned over the active lesion. Participants were retreated with ranibizumab administered monthly as needed, using predefined retreatment criteria. Patients underwent FFA at baseline, month 1, and month 12. Patients underwent optical coherence tomography (OCT) at baseline and then monthly for 12 months. The FFA and OCT images were evaluated by independent, central reading facilities. MAIN OUTCOME MEASURES: Change in OCT centerpoint thickness and angiographic lesion size 12 months after EMB. RESULTS: Mean centerpoint thickness increased by 50 μm, from 186 to 236 μm (P = 0.292), but 70% of participants had an increase of less than the mean, with a median increase of only 1.8 μm. The FFA total lesion size increased slightly by 0.79 mm(2), from 14.69 to 15.48 mm(2) (P = 0.710). Total choroidal neovascularization (CNV) area increased by 1.17 mm(2), from 12.94 to 14.12 mm(2) (P = 0.556). The classic CNV area decreased substantially by 3.70 mm(2), from 3.90 to 0.20 mm(2) (P<0.01). Predominantly classic lesions showed the greatest response, with mean Early Treatment Diabetic Retinopathy Study visual acuity improving by 1.5 letters (versus -4.0 for all participants combined); mean centerpoint thickness decreased by 43 μm (P = 0.875). The angiographic and OCT response did not correlate with lesion size at baseline. CONCLUSIONS: In chronic, active, neovascular AMD, EMB is associated with nonsignificant changes in centerpoint thickness and FFA total lesion size over 12 months. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Concepts: Retina, Ophthalmology, Vitrectomy, Diabetic retinopathy, Optical coherence tomography, Macular degeneration, Epiretinal membrane, Fluorescein angiography

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BACKGROUND: To assess the role of Spectral Domain Optical Coherence Tomography (SD-OCT) measurements as prognostic factors in myopic macular hole (MMH) surgery. METHODS: In a retrospective cohort study, we evaluated 42 eyes of 42 patients (Spherical equivalent > -6.00 D) who underwent pars plana vitrectomy with internal limiting membrane peeling for MMH without foveoschisis. Statistical analysis was performed to correlate postoperative best corrected visual acuity (BCVA) with preoperative BCVA, age, degree of myopia and seven preoperative OCT measurements: macular hole (MH) base, MH minimum diameter, MH height, Hole Form Factor (HFF), Macular Hole Index (MHI), Diameter Hole Index (DHI) and Tractional Hole Index (THI). RESULTS: Primary and final anatomical success rate were 83.3 % (35/42) and 90.5 % (38/42), respectively. Four patients deferred reoperation and three underwent a second surgical approach to achieve MH closure. A posterior staphyloma was observed in 27 of 42 patients, and in three of them the MH was located in the apex of the staphyloma. Two of these three cases showed an open MH after the first surgery. Postoperative visual acuity improved in 22/42 (52.4 %) patients, worsened in 7/42 (16.7 %) and remained unchanged in 13/42 (30.9 %). Only MH minimum diameter (P = 0.03) and HFF (P = 0.02) correlated significantly with postoperative BCVA. CONCLUSIONS: Minimum diameter and HFF are strongly correlated with postoperative visual outcomes in cases of MMH. Since analyzing MH configuration seems to improve the anatomical success rate after vitreous surgery in highly myopic patients, these parameters should be preoperatively evaluated by SD-OCT.

Concepts: Cohort study, Retina, Ophthalmology, Vitrectomy, Optical coherence tomography, Myopia, Eyeglass prescription, Staphyloma

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: To identify the morphologic changes secondary to macular grid photocoagulation in diabetic macular edema in vivo using spectral domain optical coherence tomography.

Concepts: Optics, Diabetes mellitus, In vivo, Retina, Ophthalmology, Diabetic retinopathy, Optical coherence tomography, Macular edema