Usual Multimodal Imaging Versus Spectralis “En-Face” OCT 2 Angiography: a new semiologic approach in healthy and AMD patients.

Abstract 

 

Purpose

 

To compare the results obtained with standard multimodal imaging versus En-Face OCT 2 ANGIOGRAPHY (OCT2-A) in Patients with exudative AMD and identify similarities or differences in 4 types of choroidal neovascularization.

 

Methods

 

Case series of 10 healthy and 80 eyes of 50 consecutive AMD patients (39 females, mean age 79.4 ± 5.3) diagnosed with different types of CNV (53 type I,12 predominantly classic, 6 Retinal Angiomatous Proliferation, 9 Polypoidal choroidal vasculopathy). Initial diagnosis was based on Fluorescein Angiography (FA), Indocyanine green angiography (ICGA), B-Scan OCT with two different examiners to the ones achieved with En-Face OCT2-A (Spectralis, Heidelberg Engineering) to help for the diagnosis and the decision of treatment. In conventional multimodal imaging, lesions were classified into subepithelial or preepithelial and mixed. The lesion's activity was evaluated according to leakage in FA and fluid accumulation in OCT. The new imaging with OCT2-A associated with En Face allowed to recognize the pattern of active CNV as hyperdense multiramified network due to active blood flow corresponding to hyperreflective network and fluid accumulation on "En Face". The system used by Spectralis is an Amplitude Decorrelation OCT device able to show in a B-scan OCT2-A the relationship between CNV and RPE layer.

 

Results

 

OCT2-A allows recognition of localization of CNV as sub or pre epithelial. The two methods achieved the same diagnosis about presence of subfoveal CNV (52/80).The diagnosis of active CNV based on FA leakage (25/52) was more easy than based on qualitative changes of morphology of CNV on OCT2-A (14/52) . The classification into 4 groups as usual, was applicable for both type I and II with OCT2-A using the unique possibility to have a B-scan section in OCT2-A. The diagnosis of active CNV was achieved with non invasive method (OCT2-A and En Face OCT) in all 52 cases.

 

Conclusions

 

Our study highlights the capability of the method of OCT2-A to determine the presence of subfoveal CNV, the diagnosis of activity, the classification into the well known four groups and particularly to distinguish sub and pre epithelial CNV. Nevertheless, even if FA remains the gold standard for the presence of leakage, the En-Face OCT could easily show fluid accumulation and its variations.