Optical Coherence Tomography Angiography of Inflammatory Choroidal Neovascularization Early Response after Anti-VEGF Treatment

Optical Coherence Tomography Angiography (OCT-A) in Uveitis: A Literature Review and a Reassessment of Its Real Role

BACKGROUND

The global and precise follow-up of uveitis has become possible with the availability of dual fluorescein (FA) and indocyanine green angiography (ICGA) since the mid-1990s. Progressively, additional non-invasive imaging methods have emerged, bringing value-added precision to the imaging appraisal of uveitis, including, among others, optical coherence tomography (OCT), enhanced-depth imaging OCT (EDI-OCT) and blue light fundus autofluorescence (BAF). More recently, another complementary imaging method, OCT-angiography (OCT-A), further allowed retinal and choroidal circulation to be imaged without the need for dye injection.

PURPOSE

The purpose of this review was aimed at examining the evidence in published reports indicating whether OCT-A could possibly replace dye angiographic methods, as well as the real practical impact of OCT-A.

METHODS

A literature search in the PubMed database was performed using the terms OCT-angiography and uveitis, OCTA and uveitis and OCT-A and uveitis. Case reports were excluded. Articles were classified into technical reports, research reports and reviews. Articles in the two latter categories were analyzed in a more detailed, individual fashion. Special attention was paid to whether there were arguments in favor of an exclusive rather than complementary use of OCT-A. Furthermore, a synthesis of the main practical applications of OCT-A in the management of uveitis was attempted.

RESULTS

Between 2016 (the year of the first articles) and 2022, 144 articles containing the search terms were identified. After excluding case report articles, 114 articles were retained: 4 in 2016, 17 in 2017, 14 in 2018, 21 in 2019, 14 in 2020, 18 in 2021 and 26 in 2022. Seven articles contained technical information or consensus-based terminology. Ninety-two articles could be considered as clinical research articles. Of those, only two hinted in their conclusions that OCT-A could hypothetically replace dye methods. The terms mostly used to qualify the contribution of the articles in this group were "complementary to dye methods", "adjunct", "supplementing" and other similar terms. Fifteen articles were reviews, none of which hinted that OCT-A could replace dye methods. The situations where OCT-A represented a significant practical contribution to the practical appraisal of uveitis were identified.

CONCLUSION

To date, no evidence was found in the literature that OCT-A can replace the classic dye methods; however, it can complement them. Promoting the possibility that non-invasive OCT-A can substitute the invasive dye methods is deleterious, giving the elusive impression that dye methods are no longer inevitable for evaluating uveitis patients. Nevertheless, OCT-A is a precious tool in uveitis research.

Subretinal Hyperreflective Material (SHRM) as biomarker of activity in Exudative and Non- exudative inflammatory choroidal neovascularization

AIM

To analyze the structural features and therapeutic response in clinical and subclinical inflammatory choroidal neovascularization (i-CNV) detected inside subretinal hyperreflective material (SHRM) using swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography (SS-OCTA).

METHODS

In this prospective interventional study, subjects with quiescent posterior uveitis presenting with SHRM on SS-OCT and CNV network on SS-OCTA were included. Subjects with intraretinal fluid/subretinal fluid (IRF/SRF) received intravitreal antivascular endothelial growth factor (anti-VEGF) injections, while those with no IRF/SRF either received treatment or observation for 6 months until they developed IRF/SRF or decrease in best-corrected visual acuity (BCVA)/metamorphopsia. Serial comparisons included SHRM width and height and intrinsic flow signal on OCTA.

RESULTS

28 eyes of 22 subjects (12 males; mean age: 29.52 ± 12.56 years) were evaluated. Subjects with IRF/SRF at baseline (n = 6 eyes; termed as exudative iCNVs) receiving treatment showed significant improvement in BCVA (p = .017), SHRM width/height and flow signal (p < .05). Among eyes with no IRF/SRF (n = 22; termed as non-exudative iCNVs), 7 received treatment and showed significant improvement in SHRM parameters and BCVA (p < .05). 4/15(26.67%) eyes that received no treatment developed IRF/SRF upon 6-month follow-up.

CONCLUSION

SHRM may act as a useful biomarker to monitor activity and response to therapy in eyes with iCNV.

ROLE OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN DETECTING AND MONITORING INFLAMMATORY CHOROIDAL NEOVASCULARIZATION

PURPOSE

To investigate the utility of optical coherence tomography angiography (OCTA) for the detection of inflammatory choroidal neovascularization (iCNV) and monitoring their response to treatment.

METHODS

A retrospective review of patients with a diagnosis of uveitis and associated iCNV with active exudation was performed. Active iCNV was determined by spectral domain OCT and/or fluorescein angiogram. Spectral domain OCTA outer retina to choriocapillaris slabs was evaluated for the presence of iCNV. Follow-up OCTA images were qualitatively assessed to determine whether regression of iCNV occurred after treatment.

RESULTS

Thirteen eyes of 12 patients were included. The etiologies of uveitis include punctate inner choroidopathy (n = 4), multifocal choroiditis (n = 2), presumed sarcoid uveitis (n = 2), tuberculous choroiditis (n = 1), birdshot chorioretinopathy (n = 1), syphilitic uveitis (n = 1), serpiginous choroiditis (n = 1), and idiopathic panuveitis (n = 1). Inflammatory choroidal neovascularization was detected on en face OCTA in 10 of 13 eyes (76.9%). After iCNV treatment, en face OCTA demonstrated complete regression of iCNV in 5 of 10 eyes (50%), partial regression in 2 of 10 eyes (20%), and no regression in 3 of 10 eyes (30%).

CONCLUSIONS

Optical coherence tomography angiography is an effective modality for detecting iCNV and could provide detailed visualization regarding location, morphologic structure, and flow of the iCNV and its response to therapy.

Review for Diagnostics of the Year: Inflammatory Choroidal Neovascularization – Imaging Update

Inflammatory choroidal neovascularization (iCNV) is a rare complication of uveitis but is a major cause of vision compromise in affected patients. Fluorescein angiography (FA) has been the gold standard for diagnosis. However, it is an invasive modality and when used alone, it might be difficult to distinguish iCNV from inflammatory lesions. Optical coherence tomography (OCT) is a noninvasive and rapid imaging modality that can provide additional features to diagnose iCNV. OCT angiography (OCTA) uses intrinsic motion contrast to visualize flow and is useful to distinguish iCNV from inflammatory lesions. However, its role in evaluating iCNV activity and treatment response is still unclear and more studies are required to reach consensus. In conclusion, the use of data from multimodal imaging is necessary to identify and promptly treat iCNV, thus preserving patient vision.

Long-Term Analysis of Clinical Features and Treatment Outcomes of Inflammatory Choroidal Neovascularization

PURPOSE

To investigate the long-term clinical features and treatment outcomes of patients with inflammatory choroidal neovascularization (CNV) treated with intravitreal anti-vascular endothelial growth factor (anti-VEGF).

DESIGN

Retrospective, interventional, consecutive case series.

METHODS

Sixty-five eyes of 65 patients with inflammatory CNV treated with anti-VEGF injections and followed up at least 12 months were included. Retrospective chart review was conducted at a single tertiary referral center.

RESULTS

Study participants were followed up for 60.6 ± 42.8 (range, 16-160) months. Mean age was 33.4 ± 10.8 years, and mean refractive error was -3.94 ± 1.35 D in spherical equivalent. Final best-corrected visual acuity (BCVA) was 0.21 ± 0.20 logMAR after treatment. Patients were treated with bevacizumab (76.9%), ranibizumab (4.6%), aflibercept (3.1%), and drug combinations (15.4%). Systemic corticosteroid or immunosuppressant use was not correlated with visual outcome, required number of anti-VEGF injections, and recurrence. Commonly occurring optical coherence tomography (OCT) features included ellipsoid zone disruption, choroidal hypertransmission, retinal pigment epithelium atrophy or absence (RPEA), intraretinal hyperreflective foci (HRF), choroidal vessel engorgement, focal choroidal excavation, and irregular vascular loops (on OCT angiography). RPEA after treatment (β = 0.238, P = .036) and BCVA (β = 0.267, P = .029) showed significant correlation with final BCVA. A total of 28 patients (43.1%) experienced recurrence; intraretinal HRF after treatment was the single risk factor for recurrence (odds ratio = 2.712, P = .031).

CONCLUSIONS

Inflammatory CNV recurrence showed higher rates over time after anti-VEGF treatment than previously reported, even though the overall visual outcome was good. Baseline BCVA and RPEA after treatment are significant predictors for visual outcome. Intraretinal HRF after anti-VEGF treatment suggests the potential risk of recurrence.

Wide-Field Swept-Source Optical Coherence Tomography Angiography Analysis of the Periarterial Capillary-Free Zone in Branch Retinal Vein Occlusion

Purpose

To investigate the characteristics of the retinal periarterial capillary-free zone (paCFZ) with wide-field swept-source optical coherence tomography angiography (SS-OCTA) in eyes with branch retinal vein occlusion (BRVO).

Methods

Seventy treatment-naïve eyes with BRVO and 35 healthy eyes were included. The paCFZ areas, artery calibers, and areas of the major arteries in the unaffected quadrants of BRVO eyes were measured in 12 × 12-mm SS-OCTA images and compared with those of the contralateral eyes and healthy eyes. Other multimodal imaging data were collected.

Results

There were no significant differences in the unaffected artery caliber or area among the three groups (all P > 0.05). The unaffected paCFZ areas and the ratios of the unaffected paCFZ area to the counterpart artery area (paCFZ/artery area) of the major arteries were significantly larger than those in the contralateral or healthy eyes (all P < 0.05). Subgroup analysis revealed that the paCFZ/artery area value differed significantly between ischemic and nonischemic BRVO eyes (P < 0.01). The paCFZ/artery area value was positively correlated with logMAR best-corrected visual acuity, symptom duration, central macular thickness, and retinal nonperfusion area in BRVO.

Conclusions

Quantitative SS-OCTA measurements confirmed enlarged paCFZs along the unaffected major retinal arteries in BRVO eyes. The paCFZ parameters were correlated with symptom duration, retinal ischemia, and visual function.

Translational Relevance

Retinal periarterial capillary-free zones in BRVO can be non-invasively measured by SS-OCTA, assisting in clinically identifying retinal ischemia and evaluating visual function.