Clinical and Imaging Factors Associated With the Outcomes of Tubercular Serpiginous-like Choroiditis

[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.

The immune response in tubercular uveitis and its implications for treatment: From anti-tubercular treatment to host-directed therapies

Tubercular uveitis (TB-uveitis) remains a conundrum in the uveitis field, which is mainly related to the diverse clinical phenotypes of TB-uveitis. Moreover, it remains difficult to differentiate whether Mycobacterium tuberculosis (Mtb) is present in the ocular tissues, elicits a heightened immune response without Mtb invasion in ocular tissues, or even induces an anti-retinal autoimmune response. Gaps in the immuno-pathological knowledge of TB-uveitis likely delay timely diagnosis and appropriate management. In the last decade, the immunopathophysiology of TB-uveitis and its clinical management, including experts' consensus to treat or not to treat certain conditions with anti-tubercular treatment (ATT), have been extensively investigated. In the meantime, research on TB treatment, in general, is shifting more toward host-directed therapies (HDT). Given the complexities of the host-Mtb interaction, enhancement of the host immune response is expected to boost the effectiveness of ATT and help overcome the rising burden of drug-resistant Mtb strains in the population. This review will summarize the current knowledge on the immunopathophysiology of TB-uveitis and recent advances in treatment modalities and outcomes of TB-uveitis, capturing results gathered from high- and low-burden TB countries with ATT as the mainstay of treatment. Moreover, we outline the recent progress of HDT development in the pulmonary TB field and discuss the possibility of its applicability to TB-uveitis. The concept of HDT might help direct future development of efficacious therapy for TB-uveitis, although more in-depth research on the immunoregulation of this disease is still necessary.

Stepwise approach for fundus imaging in the diagnosis and management of posterior uveitis

An array of retinochoroid imaging modalities aid in comprehensive evaluation of the immunopathological changes in the retina and choroid, forming the core component for the diagnosis and management of inflammatory disorders such as uveitis. The recent technological breakthroughs have led to the development of imaging platforms that can evaluate the layers of retina and choroid and the structural and functional alteration in these tissues. Ophthalmologists heavily rely on imaging modalities such as dye-based angiographies (fluorescein angiography and indocyanine green angiography), optical coherence tomography, fundus autofluorescence, as well as dye-less angiography such as optical coherence tomography angiograph,y for establishing a precise diagnosis and understanding the pathophysiology of the diseases. Furthermore, these tools are now being deployed with a 'multimodal' approach for swift and accurate diagnosis. In this comprehensive review, we outline the imaging platforms used for evaluation of posterior uveitis and discuss the organized, algorithmic approach for the assessment of the disorders. Additionally, we provide an insight into disease-specific characteristic pathological changes and the established strategies to rule out disorders with overlapping features on imaging.

Imaging-based Assessment of Choriocapillaris: A Comprehensive Review

PURPOSE

Over the past two decades, advancements in imaging modalities have significantly evolved the diagnosis and management of retinal diseases. Through these novel platforms, we have developed a deeper understanding of the anatomy of the choroidal vasculature and the choriocapillaris. The recently developed tools such as optical coherence tomography (OCT) and OCT angiography (OCTA) have helped elucidate the pathological mechanisms of several posterior segment diseases. In this review, we have explained the anatomy of the choriocapillaris and its close relationship to the outer retina and retinal pigment epithelium.

METHODS

A comprehensive search of medical literature was performed through the Medline/PubMed database using search terms: choriocapillaris, choroid, quantification, biomarkers, diabetic retinopathy, age-related macular degeneration, choroidal blood flow, mean blur rate, flow deficit, optical coherence tomography, optical coherence tomography angiography, fluorescein angiography, indocyanine green angiography, OCTA, Doppler imaging, uveitis, choroiditis, white dot syndrome, tubercular serpiginous-like choroiditis, choroidal granuloma, pachychoroid, toxoplasmosis, central serous chorioretinopathy, multifocal choroiditis, choroidal neovascularization, choroidal thickness, choroidal vascularity index, choroidal vascular density, and choroidal blood supply. The search terms were used either independently or combined with choriocapillaris/choroid.

RESULTS

The imaging techniques which are used to qualitatively and quantitatively analyze choriocapillaris are described. The pathological alterations in the choriocapillaris in an array of conditions such as diabetes mellitus, age-related macular degeneration, pachychoroid spectrum of diseases, and inflammatory disorders have been comprehensively reviewed. The future directions in the study of choriocapillaris have also been discussed.

CONCLUSION

The development of imaging tools such as OCT and OCTA has dramatically improved the assessment of choriocapillaris in health and disease. The choriocapillaris can be delineated from the stromal choroid using the OCT and quantified by manual or automated methods. However, these techniques have inherent limitations due to the lack of an anatomical distinction between the choriocapillaris and the stromal choroid, which can be overcome with the use of predefined segmentation slabs on OCT and OCTA. These segmentation slabs help in standardizing the choriocapillaris imaging and obtain repeatable measurements in various conditions such as diabetic retinopathy, age-related macular degeneration, pachychoroid spectrum, and ocular inflammations. Additionally, Doppler imaging has also been effectively used to evaluate the choroidal blood flow and quantifying the choriocapillaris and establishing its role in the pathogenesis of various retinochoroidal diseases. As tremendous technological advancements such as wide-field and ultra-wide field imaging take place, there will be a significant improvement in the ease and accuracy of quantifying the choriocapillaris.

The Role of Optical Coherence Tomography and Optical Coherence Tomography Angiography in the Differential Diagnosis of Posterior Uveitis

PURPOSE

Modalities such as optical coherence tomography (OCT) and OCT angiography (OCTA) have improved the diagnostic utility of fundus imaging in management of uveitis. The purpose of this study is to review role of OCT and OCTA in differential diagnosis of certain posterior uveitic entities.

METHODS

Narrative review.

RESULTS

In this review, we have comprehensively summarized the utility of OCT and OCTA in helping the clinician diagnose common but challenging inflammatory conditions including ocular toxoplasmosis, viral retinitis, and vitreoretinal lymphoma, among others. OCT and OCTA can also be used to assess the choriocapillaris involvement in conditions such as multiple evanescent white dot syndrome, and choroidal granulomas in tubercular and sarcoid uveitis.

CONCLUSIONS

Fundus imaging with OCT and OCTA has assumed a significant role in establishing the diagnosis in uveitis apart from microbiological and other laboratory analysis. Advantages such as rapidity and non-invasiveness make these imaging modalities very useful and convenient.

Automated lesion segmentation and quantification for prediction of paradoxical worsening in patients with tubercular serpiginous-like choroiditis

To develop and evaluate a fully automated pipeline that analyzes color fundus images in patients with tubercular serpiginous-like choroiditis (TB SLC) for prediction of paradoxical worsening (PW). In this retrospective study, patients with TB SLC with a follow-up of 9 months after initiation of anti-tubercular therapy were included. A fully automated custom-designed pipeline was developed which was initially tested using 12 baseline color fundus photographs for assessment of repeatability. After confirming reliability using Bland–Altman plots and intraclass correlation coefficient (ICC), the pipeline was deployed for all patients. The images were preprocessed to exclude the optic nerve from the fundus photo using a single-shot trainable WEKA segmentation algorithm. Two automatic thresholding algorithms were applied, and quantitative metrics were generated. These metrics were compared between PW + and PW- groups using non-parametric tests. A logistic regression model was used to predict probability of PW for assessing binary classification performance and receiver operator curves were generated to choose a sensitivity-optimized threshold. The study included 139 patients (139 eyes; 92 males and 47 females; mean age: 44.8 ± 11.3 years) with TB SLC. Pilot analysis of 12 images showed an excellent ICC for measuring the mean area, intensity, and integrated pixel intensity (all ICC > 0.89). The PW + group had significantly higher mean lesion area (p = 0.0152), mean pixel intensity (p = 0.0181), and integrated pixel intensity (p < 0.0001) compared to the PW- group. Using a sensitivity optimized threshold cut-off for mean pixel intensity, an area under the curve of 0.87 was achieved (sensitivity: 96.80% and specificity: 72.09%). Automated calculation of lesion metrics such as mean pixel intensity and segmented area in TB SLC is a novel approach with good repeatability in predicting PW during the follow-up.

Optical Coherence Tomography Findings in Infectious Posterior Uveitis

PURPOSE

To describe and illustrate the main optical coherence tomography (OCT) findings of infectious uveitis.

METHODS

Narrative review.

RESULTS

Posterior segment OCT in patients with infectious uveitis reveals posterior hyaloid face precipitates, superficial retinal precipitates and infiltrates, foveolitis, retinitis, neuro-retinitis, choroidal granulomas, and choroiditis as main imaging biomarkers. Some of these features are specific to the underlying causing etiology and may support the diagnosis and the initiation of treatment. Some OCT features disappear completely with resolution; some others are associated with irreversible retinal damage.

CONCLUSIONS

OCT identifies different features of infectious uveitis into the vitreous, the retina, and the choroid. OCT characteristics, combined with other multimodal imaging features, are helpful in the differential diagnosis of infectious uveitis, the early detection of complications, and the assessment of the response to therapy.

Semi-automated quantitative analysis of the middle limiting membrane in tubercular serpiginous-like choroiditis using swept-source optical coherence tomography

To analyze the longitudinal changes in the outer plexiform layer (OPL) in patients with tubercular serpiginous-like choroiditis (TB SLC) and compare it to the healthy control population. Clinical and imaging data of subjects with TB SLC (minimum 6-month follow-up) and healthy control subjects were reviewed. Optical coherence tomography (OCT) imaging obtained using swept-source device (DRI Triton, Topcon, Japan) from three visits (baseline, 3 months, and 6 months) were analyzed. Three OCT scans were chosen-one passing through the center of the fovea, one line above, and one line below. After random indexing to anonymize the images, they were pre-processed and fed into an automated pipeline to identify, crop, and measure the area of the OPL in the line scan. Longitudinal comparisons of OPL within the patient group were performed. The study included 32 eyes (16 patients; 11 males; mean age: 32.9 ± 7.8 years) with TB SLC. Twenty-eight eyes (14 subjects; 10 males: mean age: 31.1 ± 6.2 years) of healthy control subjects (age- and gender-matched) were also selected. The area of OPL was significantly different between the baseline and month 6 visit (6288 ± 1803 versus 5487 ± 1461; p = 0.0002) at the central scan passing through the fovea. For the scans above and below the fovea, the reduction in OPL area was significant at each visit (p < 0.0001). In comparison with healthy control subjects, OPL area values in patients with TB SLC were significantly lower at the month-3 (6116 ± 1441 versus 7136 ± 2539; p = 0.04) and the 6-month visit (5487 ± 1461 versus 7136 ± 2539; p < 0.001). The atrophied OPL at month 6 has been referred to as the "middle limiting membrane" (MLM). Subjects with TB SLC may develop progressive atrophy of the OPL resulting in formation of MLM, which is seen as a hyper-reflective line replacing the OPL. The analysis of longitudinal changes in the OPL may be useful in predicting anatomical and functional outcomes in these patients.

Clinical and Multimodal Imaging Clues in Differentiating Between Tuberculomas and Sarcoid Choroidal Granulomas

PURPOSE

To compare the differences among clinical, demographic, and multimodal imaging features of choroidal granulomas associated with tuberculosis and sarcoidosis.

DESIGN

Retrospective comparative case series.

METHODS

Clinical features and fundus imaging, including fluorescein and indocyanine green angiography and optical coherence tomography of patients with tuberculomas and sarcoid choroidal granulomas seen at 3 tertiary care centers, were reviewed. The differences among clinical appearances, including morphology of the lesions (size, shape, extent), vascularity, and multimodal imaging features, were compared. Repeated logistic regression measurements with a multilevel random effects model was used to assess characteristics of individual granulomas that could predict the underlying cause.

RESULTS

The study included 47 eyes of 38 patients (22 with tuberculomas and 16 with sarcoid granulomas; total of 138 granulomas). Patients with tuberculomas were significantly younger (33.8 ± 10.1 vs. 48.6 ± 14.3 years, respectively; P = .002), but no sex differences were observed. In comparison with sarcoid granulomas, tuberculomas were solitary (P <.001), intense yellow, lobulated, full thickness, and located in the perivascular region (all P <.001); they were also larger (16.01 ± 9.7 mm² vs. 2.7 ± 4.5 mm², respectively; P <.001) and were vascularized (P <.001). Sarcoid granulomas were associated with retinal vasculitis (P = .003) and disc hyperfluorescence (P <.001). Logistic regression showed that multiple granulomas were associated with sarcoidosis (odds ratio [OR]: 3.5; 95% confidence interval: 1.8-6.9; P <.001). Granulomas larger than 6.45 mm² had the highest area under the receiver operating curves (0.94) for differentiating tuberculomas from sarcoid granulomas.

CONCLUSIONS

Tuberculomas and sarcoid choroidal granulomas have various clinical and imaging features that help differentiate between the 2 entities with high predictability and can supplement immunological and radiological tests in a diagnosis.

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.

Role of Ocular Imaging in Diagnosis and Determining Response to Therapeutic Interventions in Posterior and Panuveitis

ABSTRACT

This review provides a comprehensive description and careful interpretation of various ocular imaging techniques to visualize the different ocular structures in posterior and panuveitis. This can help in the diagnosis, follow-up, and monitoring the response to treatment in patients with different posterior and panuveitic entities.