OCT angiography in assessing choroidal melanoma treatment effectiveness

Relevance In the pathology of the fundus, optical coherence tomography (OCT) and OCT angiography (OCT-A) are used to determine biomarkers of various diseases. They are also used to assess the effectiveness of treatment [1–4]. However, studies on the possibilities of its use in assessing the effectiveness of choroidal melanoma (CM) treatment are rare. Objective To identify OCT angiographic signs of various outcomes of organ-preserving treatment. Material and methods OCT (OCT-2 Spectralis, Heidelberg Engineering, Germany) of 12 eyes on average 66.83 months after organ-preserving treatment. Initial CM prominence was 2.43 ± 1.99 mm, diameter 9.62 ± 3.46 mm; at the time of OCT-A, the prominence was 1.18 ± 0.95. Results The OCT angiogram analysis was performed after manual image segmentation. Large vessels with a straight course that do not give branches were found in the thickness of the chorioretinal scars (at the border with the sclera). The zones of RPE hyperplasia in the scars are avascular. At the border of the scar/preserved retina, "ringed" retinal vessels that do not give anastomoses with the choroidal vessels were found. In the zones of ongoing growth along the edge of the scar, a thin network of vessels of the "arches" and "loops" type was found. In the zone of residual tumor surrounded by the scar, a similar vascular network anastomosing with retinal vessels was found. In the early stages after MX brachytherapy (the period of radiation reaction), in the zone of residual tumor at the level of the projection of the choriocapillaries, there is a dense network of thin vessels with the formation of multiple anastomoses. In the areas of the developing scar, single large atypically running choroidal vessels with developing shunts, however, not connected with retinal vessels, were detected. Conclusion The use of OCT-A in assessing the effectiveness of organ-preserving treatment is possible. In order to avoid diagnostic errors, it is necessary to interpret OCT-angiograms taking into account the ophthalmoscopic picture and the image of the area of ​​interest in en face mode. Key words: choroidal melanoma; optical coherence tomography angiography; organ-preserving treatment