OCT Angiography: Imaging of Choroidal and Retinal Tumors

Abstract

Optical coherence tomography angiography (OCTA) is a new, noninvasive imaging modality used to assess the vasculature in chorioretinal disease. The purpose of this study was to describe OCTA findings in several chorioretinal tumors, specifically melanocytic tumors. We correlate these findings with clinical risk factors (RFs) for growth. This was a cross-sectional, comparative, observational study. We compiled a total of 79 cases consisting of the following: 55 choroidal nevi, 11 choroidal melanomas, 5 choroidal hemangiomas, 3 astrocytic hamartomas, 2 choroidal lymphomas, 1 choroidal metastases, 1 combined hamartoma of the retina and retinal pigment epithelium (RPE), and 1 choroidal osteoma. We performed OCTA of the 79 lesions to create images that were then analyzed by 3 different physicians. In addition to OCTA, we also used multi-imaging studies, including OCT, retinal color and autofluorescence fundus imaging, Doppler echography, and indocyanine/fluorescein angiography. The melanocytic lesions were divided into 6 different groups according on the number of clinical RFs present. We compared each group with the OCTA findings, seeking any correlation between OCTA findings and the number of RFs present. All layers of the OCTA were evaluated and described. In melanocytic lesions, 6 specific variables within the choriocapillaris layer were evaluated. We also studied the quality of the images, the presence of avascular areas within the lesion, heterogeneity of the choroidal plexus over the lesion, the presence of a neovascular membrane associated with the lesion, the definition of the lesion's borders, and the presence of a hyperreflective ring surrounding the lesion. Satisfactory imaging was obtained in 82.7% of the cases. Concordance κ indexes between the observers were satisfactory (0.768-0.958). For melanocytic lesions, the images of choroidal nevi were described mainly as heterogenic (61.4%) and hyperreflective (81.8%). Choroidal melanoma was mainly described as isoreflective or hyporeflective (62.5%) and associated with a hyperreflective ring (62.5%). The presence of a hyporeflective plexus within the tumor (P= 0.002) and the presence of a hyperreflective ring surrounding the lesion (P= 0.001) were associated with lesions with more RFs. General descriptive OCTA findings are made for nonmelanocytic tumors. OCTA is a very promising new technology that can be used in the study of posterior segment ocular tumors. When studying melanocytic tumors, the presence of a hyporeflective plexus or hyperreflective ring (in the choriocapillaris layer) surrounding the tumor is associated with a higher risk of malignancy. Larger studies are needed to corroborate these findings. However, we hope that these data can encourage more regular screening for those detected to be at high risk and, hence, reduce the risk of malignancies detected at a late stage.