Swept-source optical coherence tomography angiography in serpiginous choroiditis

Quantitative Analysis of the Choroidal Vascularity in Eyes with Uveitis Using Optical Coherence Tomography Angiography: A Systematic Review

PURPOSE

The purpose of this systematic review is to identify techniques used for quantification of choriocapillaris (CC) flow in eyes with uveitis using optical coherence tomography angiography (OCTA), report reliability and level of correlation with techniques such as indocyanine green angiography (ICGA).

METHODS

A systematic search of several databases was done. The studies were analyzed for techniques of measurement, reliability, and correlation with other modalities. Risk of bias assessment was performed.

RESULTS

Thirteen studies were included. CC vessel density (7 studies) and flow deficit area (4 studies) were the most used indices. There was significant heterogeneity in the studies due to differences in the scan protocol, thresholding strategy, and analysis. Comparison with ICGA was performed by only one study, and reliability indices were reported by only two studies.

CONCLUSION

OCTA is a useful tool to measure the CC vascularity in eyes with uveitis. However, standardized acquisition and analysis protocols are needed.

[Acute posterior multifocal placoid pigment epitheliopathy, serpiginous choroiditis and related diseases]

Acute Posterior Multifocal Placoid Pigment Epitheliopathy (APMPPE) and serpiginous choroiditis are two diseases classified as "white spot syndromes." Both are inflammatory/autoimmune diseases with suspected primary involvement of the choriocapillaris. The former usually has an excellent prognosis, while the latter can rapidly induce legal blindness. Whereas these diseases are well defined and well known, other entities (such as persistent placoid maculopathy or ampiginous choroiditis) with features of both APMPPE and serpiginous choroiditis have been described more recently. This review aims to describe demographic characteristics and multimodal imaging features to help differentiate between these four diseases.

Outcome Measures for Disease Monitoring in Intraocular Inflammatory and Infectious Diseases (OCTOMERIA): Understanding the Choroid in Uveitis with Optical Coherence Tomography (OCT)

PURPOSE

To compare imaging modalities for the choroid of the eye, and evaluate various choroidal changes in uveitides entities.

METHODS

A comprehensive systematic literature review was conducted looking at current imaging modalities available to assess choroid architecture and commonly used parameters available to qualify and quantify choroidal changes, before looking at specific uveitides entities with choroidal involvement which have been broadly separated into non-infectious and infectious in etiology.

RESULTS

We describe the various modalities currently available to evaluate the choroid of the eye such as Ultrasound B Scan, ICGA, and OCT. Choroidal changes in various ocular and systemic diseases such as Behcet's Disease, Sarcoidosis, Syphillis, Tuberculosis, and many more have been reported and published.

CONCLUSION

Multiple choroidal tomographic and angiotomographic findings have been demonstrated for evaluation in uveitis. These findings can manifest in multiple ocular and systemic diseases, and can be illustrated using the various imaging modalities at present. Future advancements in choroidal imaging would help to adapt these findings into parameters for clinical practice to properly evaluate these ocular and systemic diseases.

Benefits and Limitations of OCT-A in the Diagnosis and Follow-Up of Posterior Intraocular Inflammation in Current Clinical Practice: A Valuable Tool or a Deceiver?

Purpose: Optical coherence tomography angiography (OCT-A) has been applied to uveitis and intraocular inflammation since its availability after 2014. The imaging of retinal and choroidal vascularization without the use of dyes was a major development and represented a potentially valuable tool in ocular research. In addition to such use, OCT-A is often put forward as being able to potentially replace invasive methods needing dye injection, such as fluorescein angiography (FA) and indocyanine green angiography (ICGA). The aim of this review was to establish whether OCT-A was sufficiently useful in everyday routine clinical practice to monitor disease evolution and to perform treatment adjustments to the extent that it could reliably replace the standard dye methods. Methods: Selective literature review and analysis of own data and experience. Results: OCT-A is a technologically high-grade imaging modality allowing to analyze retinal circulation in inflammatory diseases of the posterior pole with a high sensitivity useful for research purposes. However, there is no evidence that it reaches equal effectiveness in the routine management of posterior uveitis involving the retina. OCT-A is unable to show leakage. In choriocapillaritis involving pre-capillary vessels, it shows capillary drop-out but does not seem to have an advantage over ICGA except that it can be repeated easily, not being invasive, and so allows a closer follow-up. It is, however, less useful in end-choriocapillary non-perfusion, such as in MEWDS. For choroidal stromal inflammation, OCT-A is ill-suited as it only shows inconsistent secondary circulatory changes produced by choroidal foci. OCT-A seems to be useful in the diagnosis and follow-up of inflammatory chorioneovascularisation (iCNV), although dye exams are more precise in showing the activity of the iCNV. Conclusion: In summary, OCT-A is a very sensitive modality for the retinal circulation in uveitis for research purposes; it is sometimes useful for close follow of choriocapillary drop-out but not in end-capillary non-perfusion. Its use for monitoring purposes in stromal choroiditis, however, is questionable. Its claim to possibly replace classical angiographic work-up for the practical management of posterior uveitis is largely overrated.

A Novel Method of Quantifying the Choriocapillaris in Normal and Post-inflammatory Eyes

OBJECTIVE

To assess the reliability and validity of gray level co-occurrence matrices (GLCM) in the quantification of choriocapillaris and describe GLCM features in normal and eyes with resolved acute posterior multifocal placoid pigment epitheliopathy (APMPPE) and serpiginous choroiditis (SC).

METHODS

In this, multicenter, reliability, validity and comparative study; OCTA was performed on eyes with resolved APMPPE and SC and normal individuals. CC texture classification, low flow area measurements and GLCM feature extraction were performed.

RESULTS

A total of 13 normal, 8 APMPPE and 15 SC eyes were analyzed. All GLCM parameters demonstrated an excellent reliability. GLCM parameters were differently distributed across the three groups. Decision-tree based on the random forest predictive model provided an overall accuracy of 86% in classifying the three groups using GLCM features.

CONCLUSION

These data demonstrated an excellent reliability and validity of GLCM features in quantifying the choriocapillaris in healthy and diseased eyes.

Serpiginous Choroiditis Complicated with Choroidal Neovascular Membrane Detected using Optical Coherence Tomography Angiography: A Case Series and Literature Review

Serpiginous choroiditis (SC) is a rare, chronic, recurrent, progressive disease of unknown origin. The inflammatory process of SC can disrupt Bruch’s membrane, allowing occasional choroidal vascular growth, leading to significant visual loss even in the healed stages of the disease. Optical coherence tomography angiography (OCTA) can help in the detection of choroidal neovascular membrane (CNV), leading to a definitive diagnosis and thereby guide the initiation of intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment. We report herein two cases of SC complicated with a CNV detected with OCTA and treated with a series of anti-VEGF injections.

Choriocapillaris: Fundamentals and advancements

The choriocapillaris is the innermost structure of the choroid that directly nourishes the retinal pigment epithelium and photoreceptors. This article provides an overview of its hemovasculogenesis development to achieve its final architecture as a lobular vasculature, and also summarizes the current histological and molecular knowledge about choriocapillaris and its dysfunction. After describing the existing state-of-the-art tools to image the choriocapillaris, we report the findings in the choriocapillaris encountered in the most frequent retinochoroidal diseases including vascular diseases, inflammatory diseases, myopia, pachychoroid disease spectrum disorders, and glaucoma. The final section focuses on the development of imaging technology to optimize visualization of the choriocapillaris as well as current treatments of retinochoroidal disorders that specifically target the choriocapillaris. We conclude the article with pertinent unanswered questions and future directions in research for the choriocapillaris.

Evaluation of change in the vascular density of choriocapillaris on optical coherence tomography angiography in eyes with serpiginous choroiditis

Purpose:

Serpiginous choroiditis (SC) is primarily an inflammation of choriocapillaris leading to nonperfusion. A quantitative assessment of choriocapillaris perfusion can be done by measuring the flow-density by OCT-Angiography (OCTA). This study measures a change in the flow-density of choriocapillaris with the resolution of inflammation.

Methods:

The OCTA images of a choriocapillaris slab of 30 eyes with active SC were subjected to binarization and vessel density was measured at baseline and final visits and compared.

Results:

Upon comparing the vessel density of the affected areas by OCTA of choriocapillaris-slab at baseline and final visits, there was statistically significant (P < 0.0001) improvement after the resolution of inflammation. The vessel density of a demarcated normal area was significantly higher when compared to that of lesions at baseline (P < 0.0001) and final visit (P < 0.0001).

Conclusion:

OCTA is a useful tool to assess reduction in the inflammatory activity on treatment in SC. This study shows that with treatment the perfusion of choriocapillaris improves; however, it remains lower than normal.

LONGITUDINAL FOLLOW-UP OF TUBERCULAR SERPIGINOUS-LIKE CHOROIDITIS USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To analyze and describe serial follow-up of choriocapillaris alterations in tubercular serpiginouslike choroiditis (SLC) using optical coherence tomography angiography (OCTA) and to compare it with multimodal imaging.

METHODS

In this prospective cohort study, patients with active tubercular SLC underwent OCTA using Optovue RTVue XR Avanti and other imaging techniques including enhanced-depth imaging OCT (EDI-OCT) (Heidelberg Spectralis; Heidelberg Engineering, Heidelberg, Germany), fundus autofluorescence, fluorescein angiography, and indocyanine green angiography. Serial imaging was performed for a total follow-up of 3 months. Choriocapillaris alterations at the site of lesions were analyzed on OCTA imaging, and their mean lesion areas were calculated.

RESULTS

Twenty-six eyes (26 patients; 20 males; mean age: 32.68 ± 10.56 years) were included. Fourteen eyes had active multifocal lesions (n = 39), whereas 12 eyes had active placoid lesions (n = 12). At baseline, OCTA showed hyporeflective flow deficit lesions corresponding to the hypofluorescent lesions on indocyanine green angiography in all eyes. In the multifocal type of SLC, the mean lesion area decreased in all eyes compared with baseline, and lesions with a lesion area less than 0.1 mm2 on OCTA showed near-complete resolution with minimal choriocapillaris atrophy. In comparison, all eyes with a placoid type of SLC showed no significant reduction in the lesion area and showed extensive choriocapillaris atrophy.

CONCLUSION

Optical coherence tomography angiography has the unique ability to demonstrate pathological flow impairment at the level of choriocapillaris in active tubercular SLC. Serial OCTA analysis reveals that large tubercular SLC lesions result in choriocapillaris atrophy as the lesions heal, whereas smaller multifocal lesions show resolution of choriocapillaris hypoperfusion with minimal atrophy.

Review of the Current Literature and Our Experience on the Value of OCT-angiography in White Dot Syndromes

PURPOSE

To describe the application of OCT-A in various posterior uveitis disorders in our experience and to compare it with the available literature.

METHODS

Eighteen eyes with the diagnoses of multifocal choroiditis (MFC), multifocal placoid pigment epitheliopathy (APMPPE), multiple evanescent white dot syndrome (MEWDS), tuberculous serpiginous-like choroiditis (SLC), serpiginous choroiditis (SC), and birdshot chorioretinopathy (BSCR) were studied.

RESULTS

We found flow void of the choriocapillaris in patients with APMPPE, SC, MFC, BSCR, and in SLC. In contrast, perfusion of the choriocapillaris seemed normal in patients with MEWDS.

CONCLUSIONS

We confirmed that OCT-A contributes new information on the physiopathology of white dot syndromes and inflammatory chorioretinopathies, notably on whether or not the choriocapillaris is involved. Comparing the OCT-A features allowed us to suggest that both APMPPE and SLC might be part of the same spectrum of inflammatory disease with primary involvement at the level of the choriocapillaris and secondary RPE damage.

Placoid lesions of the retina: progress in multimodal imaging and clinical perspective

Placoid lesions of the retina may be secondary to a wide spectrum of acquired inflammatory conditions that have been reported as single entities with different presentation and clinical course. These conditions include acute posterior multifocal placoid pigment epitheliopathy, persistent placoid maculopathy, serpiginous choroiditis, serpiginous-like choroiditis, relentless placoid chorioretinitis and acute syphilitic posterior placoid chorioretinitis. In this article, we will group these conditions under the name of 'placoids'. The recognition of the specific condition may be challenging in clinical practice, often resulting in diagnostic and therapeutic delay. Given the complex nature of placoids and their similarities, a systematic approach including differentiating between infectious and non-infectious aetiologies increases the chance of reaching the correct diagnosis. Detailed history and comprehensive clinical examination are the first steps to formulate a diagnostic hypothesis that should be corroborated by multimodal imaging and appropriate investigations. The advent of multimodal imaging has made it possible to extensively study placoids and revealed a constellation of specific findings that may help clinicians in the diagnostic process. The treatment of the conditions other than syphilis is complex and sometimes challenging. Our article is aimed at giving an overview of the individual entities associated with placoids and discussing the differential diagnosis. A practical and systematic approach is then proposed.

Vascular abnormalities in uveitis

Inflammation can involve several ocular structures, including the sclera, retina, and uvea, and cause vascular changes in these tissues. Although retinal vasculitis is the most common finding associated with uveitis involving the posterior segment, other vascular abnormalities may be seen in the retina. These include capillary nonperfusion and ischemia, vascular occlusions, preretinal neovascularization, microaneurysms and macroaneurysms, and telangiectasia. Moreover, vasoproliferative tumors and subsequent coat-like response can develop secondary to uveitis. Fluorescein angiography is ideal for the investigation of retinal vascular leakage and neovascularization, while optical coherence tomography angiography can provide depth resolved images from the superficial and deep capillary plexus and can demonstrate vascular remodeling. Choroidal vascular abnormalities primarily develop in the choriocapillaris or in the choroidal stroma and can appear as flow void in optical coherence tomography angiography and filling defect and vascular leakage in indocyanine green angiography. Extensive choriocapillaris nonperfusion in the presence of choroidal inflammation can increase the risk of choroidal neovascular membrane development. Iris vascular changes may manifest as dilation of vessels in stroma due to inflammation or rubeosis that is usually from ischemia in retinal periphery secondary to chronic inflammation. More severe forms of scleral inflammation, such as necrotizing scleritis, are associated with vascular occlusion in the deep episcleral plexus, which can lead to necrosis of sclera layer and uveal exposure.

Imaging in Tubercular Choroiditis: Current Concepts

PURPOSE

Ocular tuberculosis has protean clinical manifestations. Because of its varied clinical presentation, multimodal imaging is very important to characterize the disease activity, presence of inflammation, determining therapeutic response, and detection of complications.

METHODS

Narrative review.

RESULTS

In this review, various imaging modalities employed in the management of ocular tuberculosis including fluorescein angiography (FA), indocyanine green angiography (ICGA), optical coherence tomography (OCT), and optical coherence tomography angiography (OCTA) have been reviewed. Not only do these imaging tools complement each other in providing a comprehensive assessment of the pathology, they also help in gaining valuable insights regarding the evolution of the disease.

CONCLUSIONS

Fundus imaging plays a vital role in the diagnosis and management of patients with posterior uveitis due to tuberculosis. Fundus imaging may have a useful role in defining clinical endpoints for ocular tuberculosis in the future.

Optical coherence tomography angiography (OCTA) findings in Serpiginous Choroiditis

Background

To describe changes in the retina/choroid in patients with Serpiginous Choroiditis (SC) by Optical Coherence Tomography Angiography (OCTA) in a multimodal imaging approach.

Methods

Prospective, monocentric study of 24 eyes of 12 consenting patients diagnosed with SC, who underwent OCTA, which was analyzed and compared to other methods such as enhanced depth imaging-OCT, fluorescein angiography, indocyanine green angiography, and fundus autofluorescence.

Results

The study group consisted of 9 patients with peripapillary SC, 1 macular SC, and 2 atypical cases. All eyes presented an inactive SC confirmed by standard imaging. OCTA demonstrated the lesions tridimensionally in great detail. There was no difference in the angioarchitecture among the 3 forms of SC. A loss of the choriocapillaris/retinal pigment epithelium left a “window-defect”, where the vessels of larger caliber of the choroid became recognizable and their appearance inverted (“white-on-black”). A relationship between the presence of segmentation errors (SE) in the slabs and low visual acuity was established with a one-way ANOVA.

Conclusions

OCTA was able to non-invasively assess vascular lesions of the choroid/retina in patients with SC with a high degree of correlation to other diagnostic modalities. Consequent long-term assessments could lead to a better understanding of disease progression.

Advances in imaging of uveitis

Advances in multimodal imaging have significantly contributed to the management of many uveitis diseases in recent years. The most significant developments include the use of optical coherence tomography to obtain a more accurate and reproducible assessment of ocular inflammation, the application of optical coherence tomography angiography in choroiditis and retinal vasculitis, new possibilities for studying vitritis with ultrawide field imaging, and the most recent applications of fundus autofluorescence in uveitis. In this review, we provide an overview of the most significant advances in multimodal imaging of uveitis achieved in recent years.

Swept-source optical coherence tomography imaging of the retinochoroid and beyond

Introduction: Swept-source optical coherence tomography (SS-OCT) imaging has ushered in an era of rapid and high-resolution imaging of the retinochoroid that provides detailed patho-anatomy of various layers.Areas covered: In this detailed review, the technology of swept-source imaging including its principles and working has been discussed. The applications of SS-OCT in various conditions including age-related macular degeneration, diabetic retinopathy, pachychoroid spectrum of diseases, and inflammatory vitreoretinal conditions have been elaborated. For each disease, a brief review of literature along with the utility of SS-OCT and optical coherence tomography angiography has been provided with supporting figures. The advantages of SS-OCT over spectral-domain have been discussed if there is sufficient evidence in the literature. Finally, the review summarizes the technological advantages in this field of retinal imaging.Expert opinion: The introduction of SS-OCT in our clinics has added newer devices in our armamentarium that can provide high-quality images of the deep retina and choroid. These advances in medical devices can help in improving our knowledge relating to the pathophysiology of diseases and their evolution. In the near future, rapid and high-resolution imaging may provide real-time volumetric information of the whole retina and the choroid that can be readily used for patient care.

Optical coherence tomography angiography in uveitis

Before the introduction of optical coherence tomography angiography (OCTA) in the early 2000s, dye-based angiography was considered the “gold standard” for the diagnosis and monitoring of ocular inflammation. OCTA is a novel technique, which demonstrates capillary networks based on the amount of light returned from moving blood cells, providing further information on pathophysiological changes in uveitis.

The aim of this review is to describe the basic principles of OCTA and its application to ocular inflammatory disorders. It particularly emphasizes on its contribution not only in the diagnosis and management of the disease but also in the identification of possible complications, comparing it with fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA). Although the advent of OCTA has remarkably enhanced the assessment of uveitic entities, we highlight the need for further investigation in order to better understand its application to these conditions.

Textural Properties of Choriocapillaris on OCTA in Healed Inflammatory Choriocapillaropathies

BACKGROUND AND OBJECTIVE

To evaluate the flow characteristics and textural properties of choriocapillaris (CC) on optical coherence tomography angiography in eyes with resolved inflammatory choriocapillaropathies and Vogt-Koyanagi-Harada (VKH) disease.

PATIENTS AND METHODS

A cohort of eyes with healed acute posterior multifocal placoid pigment epitheliopathy (APMPPE), serpiginous choroiditis (SC), and VKH disease were included. A 3 mm × 3 mm OCT angiogram of CC was acquired and graded for flow characteristics and textural properties.

RESULTS

This study included 16 patients. Texture was heterogeneous in all eyes in the SC and VKH groups, and in four eyes (40%) in the APMPPE group. Most of the eyes with VKH disease had severe low flow, whereas most of the SC and APMPPE eyes demonstrated mild low flow. Heal duration had a strong negative correlation with severity of CC low flow and a weak, statistically nonsignificant correlation with texture heterogeneity.

CONCLUSION

Despite the resolution of active inflammation, partial CC hypoperfusion and texture disruptions persist for longer durations and may resolve in a time dependent manner. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:566-572.].

Optical coherence tomography angiography (OCTA) as a new diagnostic tool in uveitis

Background

The broad spectrum of uveitis disorders requires a multimodal imaging approach in the daily practice of an ophthalmologist. As inflammatory conditions, they have in common an alteration in leukocyte migration. In this context, optical coherence tomography angiography (OCTA) might be of great value for diagnosing or following up patients with these disorders. To date, OCTA has rather been used as an additional tool besides the well-established diagnostic imaging tools, but its complementary diagnostic features become increasingly relevant, to follow disease activity and treatment response and for the understanding of pathomechanisms of various uveitis types.

This review summarizes the possible applications of OCTA and its advantages and disadvantages as opposed to dye-based angiographies in uveitic diseases.

Main body

Hitherto gold standards in the diagnostic workup of posterior or intermediate uveitis have been angiography on a dye-based method, which is fluorescein or indocyanine green. It gives information about the status of the blood-retinal barrier and the retinal and choroidal vasculature by visualizing diffuse leakage as a state of inflammation or complications as an ischemia or choroidal neovascularization. As noninvasive methods, fundus autofluorescence depicts the status of metabolic activity of the retinal pigment epithelium and OCT or enhanced depth imaging OCT, respectively, as a depth-resolving imaging method can supply additional information.

OCTA as a non-invasive, depth-resolution imaging tool of retinal and choroidal vessels adds detailed qualitative and quantitative information of the status of retinal and choroidal vessels and bridges the gap between the mentioned conventional diagnostic tools used in uveitis.

It is important, though, to be aware of its limitations, such as its susceptibility to motion artifacts, limited comparability among different devices, and restricted contribution of information regarding the grade of disease activity.

Conclusion

OCTA as a non-invasive, depth-resolution imaging tool can give qualitative and quantitative information about the status of retinal and choroidal vessels, but also has certain limitations. Employing OCTA as a complementary rather than exclusive tool, it can give important additional information about the macro- and microvasculature under inflammatory circumstances. Thereby, it also contributes to the understanding of the pathophysiology of various uveitis entities.