Abstract
BACKGROUND: OCT-A is a recent imaging technique allowing a non-invasive assessment of the retinal and choroidal microvasculature, providing valuable data for the diagnosis and monitoring of wet AMD. We aim to determine the diagnosis accuracy, describe the morphological features, and assess the clinical activity of MNV in wet AMD using OCT-A. MATERIALS AND METHODS: We conducted a descriptive cross-sectional study over a 15-month period. We enrolled patients with treatment-naive and treated MNV secondary to wet AMD. Macular OCT-A images were obtained using a swept-source OCT-A device (Triton SS-OCT, Topcon, Tokyo, Japan). Morphologic characteristics and semi-automated measurements were analyzed on the en face projection OCT-Angiograms. For the qualitative analysis, determined the sensitivity of detection of the MNV using OCTA. When detected, we described its shape, branching pattern, anastomoses and loops, and vessel termination. We looked for the halo sign and the feeder vessel. We then defined the lesion's "pattern" reflecting its exudative activity. For the quantitative analysis, we measured the lesion's area in square millimeters, when its borders were clearly defined. RESULTS: 70 eyes from 55 patients were enrolled in this study. Type 1 MNV was identified in 57,1% eyes, type 2 in 21,4%, mixed type 1 and2 in 1,4%, type 3 in 1,4% and unclassified fibrotic MNV in 18,6%. 55,7% were active and 44,3% were inactive. Sensitivity of detection was 85% for type 1 lesions, 100% for type 2, mixed and type 3 lesions, and 92% for unclassified fibrotic lesions. It was 84,6% for active lesions and 96,8% for inactive lesions. For each detected lesion, shape was well-defined (medusa, glomerulus, seafan), long liner vessels or ill-defined. Branching pattern was dense or loose. Anastomoses and vascular loops were numerous or few. Termination was in an anastomotic arcade or in a dead-tree aspect. Halo sign was present or absent and feeder vessel was detected or not. All types combined, 41,3% of the lesions were "pattern I" and 58,7% were pattern II. We reported a correlation rate of 84,8% between the lesion's activity on MI and « pattern I » on OCT-A, and of 96,6% between absence of activity signs on MI and « pattern II » on OCT-A The mean area of inactive lesions was slightly larger than that of active lesions with respective values of 3.86 mm(2) and 2.92 mm(2). CONCLUSION: OCT-A is a non-invasive, safe, and reproducible retinal imaging technique with a high sensitivity of detection of MNV in AMD. It provides useful qualitative and quantitative data. The involvement of OCT-A in the treatment decision for MNV in AMD is linked to identifying the "pattern" of the lesion reflecting its active or inactive status.