Purpose:
In order to investigate choroidal vasculature, non-invasively and high-penetration Doppler optical coherence angiography (HP-D-OCA) which is based on 1 um swept-source optical coherence tomography was developed. This study aims at evaluating clinical utility of HP-D-OCA based on a descriptivecase series of exudative macular disease.
Methods:
Seven eyes with exudative macular diseases including 2 eyes of predominantly classic choroidal neovasularization (PC-CNV), 1 eye of PC-CNV treated with ranibizumab and 4 eyes of polypoidal choroidal vasculopathy (PCV) were imaged by HP-D-OCA. Two Doppler scanning modes; fast and slow Doppler modes (FDM and SMD) are employed to image bidirectional blood flow and vascular structure, respectively. The 6 x 6 mm2 areas around macular disease region were scanned with 2048 x 256 A-lines in 6.6 seconds. Doppler signals from CNV were identified by comparing the Doppler image with OCT intensity cross-sectional images.
Results:
In the FDM, bidirectional Doppler signal was observed beneath the pigment epithelium detachment (PED) in 3 of 4 PCV cases and blood flow from PED to choroid was observed in 2 of 4 PCV cases. In the SDM, Doppler signal was found in the sub-retinal region and beneath PED in all PC-CNV and PCV cases, respectively. In the Figure 1 shows representative cases, where left, center and right columns respectively represent indocyanine green angiography (ICGA), SDM en-face projection and cross-sectional OCT/OCA images. SDM en-face images show quite similar vascular structure with that of ICGA. In the cross-sectional images, OCT intensity (gray) and Doppler signal (red) were combined as Figs 1(c), (f) and (i) and their locations are indicated by red arrow-pairs in Figs. 1(b), (e) and (h). Abnormal Doppler signals were clearly appeared in sub-retinal region and beneath PED as indicated by yellow circles.
Conclusions:
The HP-D-OCA noninvasively visualized ocular vasculature pattern which is well correlated with that of ICGA without any vessel contrast agent. In addition, depth location of vessel relative to the tissue structure is obtained. HP-D-OCA would possess a high utility for non-invasive diagnosis of exudative macular diseases.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • choroid: neovascularization • blood supply