Visualization of 3 Distinct Retinal Plexuses by Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy.
OBJECTIVE
Projection artifacts in optical coherence tomography angiography (OCTA) blur the retinal vascular plexuses together and limit visualization of the individual plexuses.


OBJECTIVE
To describe projection-resolved (PR) OCTA in eyes with diabetic retinopathy (DR) and healthy eyes.


METHODS
In this case-control study, patients with DR and healthy controls were enrolled in this observational study from January 26, 2015, to December 4, 2015, at a tertiary academic center. Spectral-domain, 70-kHz OCT obtained 3 × 3-mm macular scans. The PR algorithm suppressed projection artifacts. A semiautomated segmentation algorithm divided PR-OCTA into superficial, intermediate, and deep retinal plexuses. Two masked graders examined 3-layer PR-OCTA and combined angiograms for nonperfusion and abnormal capillaries.


METHODS
Retinal nonperfusion and capillary abnormalities and the diagnostic accuracy of detecting DR.


RESULTS
Twenty-nine eyes of 15 healthy individuals (mean [SD] age, 36.2 [13.4] years; 11 women) and 47 eyes of 29 patients with DR (mean [SD] age, 55.5 [11.9]; 10 women) underwent imaging. PR-OCTA revealed 3 distinct retinal plexuses in their known anatomical locations in all eyes. The intermediate and deep plexuses of healthy eyes revealed capillary networks of uniform density and caliber, whereas the superficial plexus revealed vessels in the familiar centripetal branching pattern. In eyes with DR, 3-layer PR-OCTA disclosed incongruent areas of nonperfusion and varied vessel caliber and density in the deeper plexuses. Masked grading of capillary nonperfusion on 3-layer PR-OCTA detected DR with 100% sensitivity (95% CI, 90.8%-100%) and 100% specificity (95% CI, 85.4%-100%). With unsegmented retinal angiograms, the sensitivity and specificity were 78.7% (95% CI, 63.9%-88.8%) and 100% (95% CI, 85.4%-100%), respectively (P = .002 for sensitivity). On 3-layer PR-OCTA, sensitivity was 72.2% (95% CI, 54.6%-85.2%) for severe nonproliferative DR and proliferative DR eyes with generalized nonperfusion in 2 or more individual plexuses, but on combined angiogram, sensitivity was 25.0% (95% CI, 12.7%-42.5%) for generalized nonperfusion (P < .001). PR-OCTA disclosed dilated vessels in the intermediate and deep plexuses in 23 eyes (100%) with proliferative DR, 13 eyes (100%) with severe nonproliferative DR, 8 eyes (73%) with mild to moderate nonproliferative DR, and 0 control eyes.


CONCLUSIONS
By presenting 3 retinal vascular plexuses distinctly, PR-OCTA reveals capillary abnormalities in deeper layers with clarity and may distinguish DR from healthy eyes and severe DR from mild DR with greater accuracy compared with conventional OCTA.
Casey Eye Institute, Oregon Health & Science University, Portland.
Thomas S
TS
Hwang
Casey Eye Institute, Oregon Health & Science University, Portland.
Miao
M
Zhang
Casey Eye Institute, Oregon Health & Science University, Portland.
Kavita
K
Bhavsar
Casey Eye Institute, Oregon Health & Science University, Portland.
Xinbo
X
Zhang
Casey Eye Institute, Oregon Health & Science University, Portland.
J Peter
JP
Campbell
Casey Eye Institute, Oregon Health & Science University, Portland.
Phoebe
P
Lin
Casey Eye Institute, Oregon Health & Science University, Portland.
Steven T
ST
Bailey
Christina J
CJ
Flaxel
Casey Eye Institute, Oregon Health & Science University, Portland.
Andreas K
AK
Lauer
Casey Eye Institute, Oregon Health & Science University, Portland.
David J
DJ
Wilson
Casey Eye Institute, Oregon Health & Science University, Portland.
David
D
Huang
Casey Eye Institute, Oregon Health & Science University, Portland.
Yali
Y
Jia
D000328:Adult; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012160:Retina / Q000000981:diagnostic imaging*; D012171:Retinal Vessels / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence / Q000379:methods*