Comparison of MultiColor fundus imaging and colour fundus photography in the evaluation of epiretinal membrane

Multicolor imaging: Current clinical applications

Multicolor (MC) imaging is an innovative pseudocolor fundus imaging modality based on confocal scanning laser ophthalmoscopy. It effectively scans the retina at different depths to create a composite image. The green reflectance image depicts the middle retinal while blue reflectance image provides images of the retinal surface. The infrared reflectance image depicts retinal structures at the level of outer retina and choroid. We systematically analyze published case reports, case series, and original articles on MC imaging where it has helped in discovering additional clinical features of retinal diseases not readily apparent on conventional color fundus photography and played a role in monitoring the response to treatment.

Clinical application of multicolor scanning laser ophthalmology in diagnosis and grading of central retinal artery occlusion

Purpose

To characterize features of central retinal artery occlusion (CRAO) using multicolor (MC) imaging and to assess the differences in CRAO grading between color fundus photography (CFP) and MC image qualitatively and quantitatively.

Methods

We conducted a prospective, cross-sectional study in the Department of Ophthalmology of Renmin Hospital of Wuhan University. In total, 86 acute CRAO patients were included. Spectral-domain optical coherence tomography (SD-OCT), CFP, and MC examinations were taken at baseline. Based on the findings of these three examinations, CRAO was divided into three grades (incomplete, subtotal, and total). Based on OCT grading criteria, we qualitatively compared the ability of grading CRAO by CFP and MC. CRAO patient's visual acuity (VA) was obtained from the initial visit. The retinal thickness was measured by SD-OCT. Superficial capillary plexus (SCP) and deep capillary plexus (DCP) were obtained from optical coherence tomography angiography (OCTA) examinations. Quantitative data were compared across the three acute CRAO subgroups and against three examination findings.

Results

MC image had significantly higher power of acute CRAO detection than CFP (P = 0.03). In the same group of CRAO patients, there was no significant difference in VA when comparing OCT with the MC grading system or with the CFP grading system (all P > 0.05). Significant differences in VA were found between the three CRAO subgroups only under MC grading (P = 0.016). In incomplete CRAO patients, significant differences were found in central fovea thickness (CFT) when comparing OCT with the CFP grading system (P = 0.019). In the same group of CRAO patients, there was no significant difference in retinal thickness when comparing OCT with the MC grading system (All P > 0.05). Significance differences in CFT (P < 0.001), innermost retinal layer (IMRL; P < 0.01), middle retinal layer (MRL; P < 0.001), and outer retinal layer (ORL; P = 0.021) were found between the three CRAO subgroups by MC grading. Vessel density of SCP showed a statistically increased as the severity of three CRAO subgroups (P = 0.03), whereas DCP did not have significant differences (P = 0.745). Comparisons were made between the OCT grading method and the MC and CFP grading methods; there is no significant difference in vessel density of SCP and DCP (All P > 0.05).

Conclusion

The images obtained by MC are superior to those obtained by CFP in CRAO grading, retinal thickness, and vessel density measurement. MC imaging may be more capable of CRAO grading than OCT. We recommend MC imaging to determine CRAO severity to guide disease treatment and predict visual prognosis.

Comparison of Color Fundus Photography and Multicolor Fundus Imaging for Detection of Lesions in Diabetic Retinopathy and Retinal Vein Occlusion

Purpose

To evaluate the agreement between conventional fundus photography (CFP) and multicolor fundus imaging (MFI) for the detection of lesions of diabetic retinopathy (DR) and retinal vein occlusion (RVO).

Methods

Cross-sectional analysis of eyes with DR or RVO who underwent CFP and MFI. All images were independently analyzed by two observers (O1 and O2), and the evaluated lesions were classified as "present" or "absent". Then, a paired comparison between both exams of the same eye was performed, to assess which made it easier to detect the lesions.

Results

Considering DR, the agreement was substantial for cotton wool spots and photocoagulation scars for both observers (O1: κ=0.75 and κ=0.67; O2: κ=0.71 and κ=0.64, respectively) and for hard exudates for O1 (κ=0.80). These lesions were detected more frequently on MFI. Regarding RVO, the agreement was considered substantial for venous sheathing by O1 (κ=0.64) and moderate for optociliary shunts by O2 (κ=0.60). Optociliary shunts were detected more frequently in CPF by both observers and venous sheathing on MFI by O1. For microaneurysms, retinal hemorrhages, retinal neovascularization, and proliferative membranes, in DR, and retinal hemorrhages, venous engorgement, and retinal neovascularization in RVO, the agreement was almost perfect (κ>0.82). In the paired analysis, both observers considered that, in DR, microaneurysms and retinal hemorrhages were easier to detect on CFP and that retinal neovascularization, cotton wool spots, and photocoagulation scars were easier to identify on MFI. Regarding RVO, optocilliary shunts were easier to identify on CFP and venous engorgement on MFI.

Conclusion

The agreement of MFI and CFP was substantial to almost perfect for most lesions. MFI seems better to detect cotton wool spots and photocoagulations scars in DR and venous sheathing in RVO. Optocilliary shunts seem easier to detect on CFP.

Quantitative approaches in multimodal fundus imaging: State of the art and future perspectives

When it first appeared, multimodal fundus imaging revolutionized the diagnostic workup and provided extremely useful new insights into the pathogenesis of fundus diseases. The recent addition of quantitative approaches has further expanded the amount of information that can be obtained. In spite of the growing interest in advanced quantitative metrics, the scientific community has not reached a stable consensus on repeatable, standardized quantitative techniques to process and analyze the images. Furthermore, imaging artifacts may considerably affect the processing and interpretation of quantitative data, potentially affecting their reliability. The aim of this survey is to provide a comprehensive summary of the main multimodal imaging techniques, covering their limitations as well as their strengths. We also offer a thorough analysis of current quantitative imaging metrics, looking into their technical features, limitations, and interpretation. In addition, we describe the main imaging artifacts and their potential impact on imaging quality and reliability. The prospect of increasing reliance on artificial intelligence-based analyses suggests there is a need to develop more sophisticated quantitative metrics and to improve imaging technologies, incorporating clear, standardized, post-processing procedures. These measures are becoming urgent if these analyses are to cross the threshold from a research context to real-life clinical practice.

Comparison of Multicolor Scanning Laser Imaging and Color Fundus Photography in Evaluating Vessel Whitening in Branch Retinal Vein Occlusion

INTRODUCTION

Few studies have explored MultiColor™ imaging (MCI) in evaluating retinal vascular diseases, particularly branch retinal vein occlusion (BRVO). This study aimed to compare the identification of retinal vessel whitening in BRVO using MCI by scanning confocal laser versus conventional white-flash color fundus photography (CFP).

METHODS

Paired images of consecutive patients diagnosed with BRVO who underwent same-day MCI and CFP were reviewed. Visualization of vessel whitening on MCI and CFP was graded and scored using a scale by two masked graders. A longitudinal analysis of the vessel grading score was performed to evaluate the vessel whitening detection by MCI. A correlation analysis was conducted between vessel whitening on MCI and the measured area of retinal ischemia on fluorescein angiography to evaluate the MCI performance.

RESULTS

Forty-four eyes of 41 patients (mean age 69 ± 14 years; 61% female) were analyzed. MCI demonstrated superior vessel whitening visibility score than CFP (p < 0.001). Longitudinal analysis showed no significant changes in vessel whitening visibility scores over a mean follow-up time of 430 ± 648 days (p = 0.655). There was a significantly positive correlation between the grading score of vessels whitening by MCI and the area of ischemia by fluorescein angiography (r2 = 0.15; p = 0.036).

CONCLUSION

MCI appears to provide a superior detection of whitening BRVO compared to CFP, serving as a rapid and non-invasive correlate of retinal ischemia.

Choroidal Melanocytic Hamartoma

We report on a case series that revealed flat, choroidal lesions on optical coherence tomography (OCT) and on enface MultiColor® (MCI) imaging of the fundus but were not noticeable on clinical examination or conventional color fundus images. This observational study included 12 eyes from 11 patients who had distinct, orange-colored lesions on MCI. Retinal imaging was conducted using conventional color fundus photography and OCT. On the color fundus images and the blue and green reflectance channels of MCI, each of the lesions was difficult to distinguish. On the infrared channel, the lesion was identified as bright white in color and bright orange on the multicolor image. The lesion was identified on OCT as a flat, homogeneous hyperreflective lesion involving the choroid, with an intact overlying retinal pigment epithelium and retinal layers. A comparison of the clinical and imaging features with other known entities led to the conclusion that the lesion was a distinct clinical entity. The presence of melanin in the lesion was confirmed based on the retinal imaging findings and the light absorption properties of melanin. As a result, the lesion was named as 'choroidal melanocytic hamartoma'. A longer follow-up is required to confirm the benign nature of this clinical entity.

Progress of Imaging in Diabetic Retinopathy-From the Past to the Present

Advancement of imaging technology in retinal diseases provides us more precise understanding and new insights into the diseases' pathologies. Diabetic retinopathy (DR) is one of the leading causes of sight-threatening retinal diseases worldwide. Colour fundus photography and fluorescein angiography have long been golden standard methods in detecting retinal vascular pathology in this disease. One of the major advancements is macular observation given by optical coherence tomography (OCT). OCT dramatically improves the diagnostic quality in macular edema in DR. The technology of OCT is also applied to angiography (OCT angiograph: OCTA), which enables retinal vascular imaging without venous dye injection. Similar to OCTA, in terms of their low invasiveness, single blue color SLO image could be an alternative method in detecting non-perfused areas. Conventional optical photography has been gradually replaced to scanning laser ophthalmoscopy (SLO), which also make it possible to produce spectacular ultra-widefield (UWF) images. Since retinal vascular changes of DR are found in the whole retina up to periphery, it would be one of the best targets in UWF imaging. Additionally, evolvement of artificial intelligence (AI) has been applied to automated diagnosis of DR, and AI-based DR management is one of the major topics in this field. This review is trying to look back on the progress of imaging of DR comprehensively from the past to the present.

Retromode Imaging Modality of Epiretinal Membranes

(1) Purpose: To determine the characteristics of macular epiretinal membranes (ERM) using non-invasive retromode imaging (RMI) and to compare retromode images with those acquired via fundus autofluorescence (FAF) and fundus photography. (2) Methods: Prospective observational case-series study including patients with macular ERM with no other ocular disease affecting their morphology and/or imaging quality. We compared RMI, FAF and fundus photography features by cropping and overlapping images to obtain topographic correspondence. (3) Results: In total, 21 eyes (21 patients) affected by ERM were included in this study. The mean area of retinal folds detected by RMI was significantly higher than that detected by FAF (11.85 ± 3.92 mm2 and 5.67 ± 2.15 mm2, respectively, p < 0.05) and similar to that revealed by fundus photography (11.85 ± 3.92 mm2 and 10.58 ± 3.45 mm2, respectively, p = 0.277). (4) Conclusions: RMI appears to be a useful tool in the evaluation of ERMs. It allows for an accurate visualization of the real extension of the retinal folds and provides a precise structural assessment of the macula before surgery. Clinicians should be aware of RMI’s advantages and should be able to use them to warrant a wide range of information and, thus, a more personalized therapeutic approach.

MultiColor imaging in urticarial vasculitis with recurrent branch retinal artery occlusion in a case with positive toxoplasma IgG and interferon-gamma release assay - Case report

Introduction

We report a male who presented with acute visual defect and was diagnosed with urticarial vasculitis with recurrent branch retinal artery occlusion (BRAO) after systemic disease survey, fluorescein angiography (FA), and MultiColor imaging (MCI).

Case report

A 47-year-old male with a history of urticarial vasculitis presented with visual defect OD. Fundus examination showed two foci of ischemic retinal whitening beneath the inferior arcade and above the superior arcade. MCI demonstrated a greenish tinge in the corresponding area. FA revealed segmental arteriolar staining and arterial occlusive changes. BRAO with retinal arteritis was diagnosed. Toxoplasma IgG was positive. Sulfamethoxazole 400mg plus trimethoprim 80mg was given. His vision worsened after 1-week of treatment. The established lesions improved, but new lesions occurred. Interferon-gamma release assay was positive but tuberculosis DNA qualitative amplification test of sputum was negative. Sputum acid-fast stain was positive and culture revealed nontuberculous mycobacteria. Left facial itching and reactive lymphadenopathy developed. Prednisolone and cyclophosphamide were started. The initial retinal artery lesions regained perfusion.

Conclusions

Urticarial vasculitis with recurrent BRAO is an immune complex-mediated disease. Greenish-tinged occlusive lesions were noted from MCI with high resolution and contrast. MCI could be a valuable method for retinal vessel occlusive disease detection before FA and follow up.

Multicolor Scanning Laser Ophthalmoscopy Strengthens Surgeons' Preoperative Decision-Making and Intraoperative Performance on Epiretinal Membrane

Purpose

To determine whether multicolor scanning laser ophthalmoscopy (MC-SLO) was better than color fundus photography (CFP) to enhance residents and specialists’ preoperative decision-making and intraoperative performance on the epiretinal membrane (ERM).

Methods

Consecutive patients with idiopathic ERM were recruited prospectively. All the patients underwent MC-SLO and CFP imagings and were randomized into MC-SLO (n = 20) and CFP (n = 20) groups. Preoperatively, residents and specialists were required to have ERM delineation and select an optimal location for initial ERM peeling independently, based on the MC-SLO (MC-SLO group) or CFP (CFP group) images. Intraoperative optical coherence tomography (iOCT) was introduced to evaluate the accuracy.

Results

Preoperatively, residents and specialists acted more effectively in ERM delineation and selection of initial grasping location in the MC-SLO group (both P < 0.001). In the MC-SLO group, higher resident–specialist agreements were achieved in ERM delineation (P = 0.002) and selection of initial grasping location (P = 0.035). The iOCT revealed greater interobserver (iOCT–resident and iOCT–specialist) agreements of ERM delineation in MC-SLO group (P < 0.001 and = 0.027, respectively). Surgeons acted more effectively on completely peeling the ERM in the MC-SLO group (P < 0.001).

Conclusions

MC-SLO provided a better visual reference for residents and specialists in ERM delineation and the selection of an initial grasping location for the surgery, compared with CFP.

Translational Relevance

MC-SLO is able to help surgeons achieve better intraoperative performance and shorten the learning process for residents.