Identifying early recurrence of choroidal neovascularization during treatment with ranibizumab using C-scan

To demonstrate a new parameter to identify early recurrence of choroidal neovascularization (CNV) during treatment with ranibizumab using summated en face (C-scan).

Seventeen patients with CNV secondary to age-related macular degeneration were enrolled in this retrospective study. Each patient received ranibizumab administered monthly for 3 months and their progress was monitored at 1 week and then at monthly intervals. RTVue spectral domain optical coherence tomography (OCT) was performed in all patients monthly using summated en face (C-scan) subanalysis and was compared with the standard programs for qualitative analysis (Line Scan) and quantitative analysis (macular thickness-MM5 Scan).

We observed during the control examination an increase of hyporeflective area (dark spot) mean early fluid accumulation in the layer corresponding to the outer segment of photoreceptors. We did not observe any morphologic characteristics of recurrence of CNV in the standard SD OCT examination. At this time, no treatment was done. We scheduled a new examination in 30 days. After 30 days, the patients presented initial signs of CNV recurrence, and ranibizumab reinjection was necessary. In all cases, we observed change in the C-scan 30 to 60 days before the recurrence signs in the standard OCT program.

The data suggest that summated en face (C-scan) is useful to identify early recurrence of CNV during treatment with ranibizumab. Further studies are required to allow for appropriate clinical use of this new technique.