Projection-Resolved Optical Coherence Tomography Angiography Parameters to Determine Severity in Diabetic Retinopathy

Abstract

The purpose of this study was to assess projection-resolved optical coherence tomography angiography (PR-OCTA) vessel density (VD) and foveal avascular zone (FAZ) in determining severity within diabetic retinopathy (DR) and their accuracy in identifying highrisk DR patients. METHODS. This was a retrospective study with 72 eyes of 52 DR patients, assessing the VD and FAZ area of the superficial capillary plexus (SCP) and deep vascular plexus (DVP), for both 3 3 3-mm and 6 3 6-mm scans between the DR groups (mild to moderate, severe and proliferative DR [PDR]). For accuracy, the severe and PDR groups were merged, representing the high-risk DR group for receiver operator characteristic analysis. VD of OCTA images with and without PR were compared. RESULTS. In mild to moderate, severe, and PDR groups, there were 31, 21, and 20 eyes, respectively. PR-OCTA improved VD analysis only in the DVP and particularly in advanced DR stages (P ¼ 0.042). In the 3 3 3-mm PR scans, all superficial and deep parameters were significantly different between severe and PDR groups (P 0.020), but only the mean VD of SCP and DVP was also significant between the mild to moderate and severe groups (P 0.007). In the 6 3 6-mm scans, the superficial VD, deep VD, and superficial FAZ were significantly different between the severe and PDR groups (P 0.029). The superficial VD and deep VD of the 3 3 3-mm scans were good parameters for detecting high-risk patients (area under the curve ¼ 0.829 and 0.895, respectively). CONCLUSIONS. PR-OCTA improved VD analysis of DVP. The 3 3 3-mm SCP and DVP VD were the most accurate in detecting high-risk DR.

Clinically relevant factors associated with quantitative optical coherence tomography angiography metrics in deep capillary plexus in patients with diabetes

“…However, artifacts, particularly projection artifacts, limits the accurate interpretation of DCP vasculature. Despite efforts in resolving the projection artifacts, the projection-resolved OCT-A algorithm still cannot remove the projection artifacts entirely, particularly those from the larger vessels [18][19][20]. For these limitations, our study resorted to enforcing stringent criteria to minimize image artifacts.…”

Retinal microvasculature impairment in patients with congenital heart disease investigated by optical coherence tomography angiography

“…Hence, the DCP would mostly be affected in case of hypoxia. Functionally, DCP located in a watershed zone of oxygen supply 36 . The DCP supplies oxygen to the inner retina and the outer retina, while the SCP only needs to maintain the oxygen stability of the inner retina 37 .…”

Clinical Applications of Optical Coherence Angiography Imaging in Ocular Vascular Diseases

“…Recently, Rodrigues et al showed that the parafoveal vessel density in the DCP was the parameter that was most closely associated with ETDRS grading [32]. Another study showed that the 3 × 3-mm SCP and the DCP vessel density were the most accurate parameters for the detection of high-risk DR [33]. Using a statistical model, another study identified the superficial capillary plexi of the FAZ area, DCP vessel density, and acircularity as parameters that best distinguished between DR severity groups [34].…”

“…Projection artefacts occur when more superficial flow signals are projected onto deeper retina layers [87]. One recent study showed that projection-resolved OCTA parameters significantly improved the vascular density analysis of the DCP [33]. Other artefacts include shadow artefacts from larger retinal vessels and artefacts created by fine movement from pigment epithelial defects and fine tissue [3].…”