title: Quantifying Microvascular Density and Morphology in Diabetic Retinopathy Using Spectral-Domain Optical Coherence Tomography Angiography.
abstract: To quantify changes in retinal microvasculature in diabetic retinopathy (DR) by using spectral-domain optical coherence tomography angiography (SD-OCTA).
  
  
  
  Retrospective, cross-sectional, observational study of healthy and diabetic adult subjects with and without DR. Retinal microvascular changes were assessed by using SD-OCTA images and an intensity-based optical microangiography algorithm. A semiautomated program was used to calculate indices of microvascular density and morphology in nonsegmented and segmented SD-OCTA images. Microvascular density was quantified by using skeleton density (SD) and vessel density (VD), while vessel morphology was quantified as fractal dimension (FD) and vessel diameter index (VDI). Statistical analyses were performed by using the Student's t-test or analysis of variance with post hoc Tukey honest significant difference tests for multiple comparisons.
  
  
  
  Eighty-four eyes with DR and 14 healthy eyes were studied. Spearman's rank test demonstrated a negative correlation between DR severity and SD, VD, and FD, and a positive correlation with VDI (ρ = -0.767, -0.7166, -0.768, and +0.5051, respectively; P < 0.0001). All parameters showed high reproducibility between graders (ICC = 0.971, 0.962, 0.937, and 0.994 for SD, VD, FD, and VDI, respectively). Repeatability (κ) was greater than 0.99 for SD, VD, FD, and VDI.
  
  
  
  Vascular changes in DR can be objectively and reliably characterized with SD, VD, FD, and VDI. In general, decreasing capillary density (SD and VD), branching complexity (FD), and increasing average vascular caliber (VDI) were associated with worsening DR. Changes in capillary density and morphology were significantly correlated with diabetic macular edema.
authors.affiliation: Department of Ophthalmology USC Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States.
authors.forename: Alice Y
authors.initials: AY
authors.lastname: Kim
authors.affiliation: Departments of Bioengineering and Ophthalmology, University of Washington, Seattle, Washington, United States.
authors.forename: Zhongdi
authors.initials: Z
authors.lastname: Chu
authors.affiliation: Department of Ophthalmology USC Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States.
authors.forename: Anoush
authors.initials: A
authors.lastname: Shahidzadeh
authors.affiliation: Departments of Bioengineering and Ophthalmology, University of Washington, Seattle, Washington, United States.
authors.forename: Ruikang K
authors.initials: RK
authors.lastname: Wang
authors.affiliation: Department of Ophthalmology USC Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States.
authors.forename: Carmen A
authors.initials: CA
authors.lastname: Puliafito
authors.affiliation: Department of Ophthalmology USC Eye Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California, United States.
authors.forename: Amir H
authors.initials: AH
authors.lastname: Kashani
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D002196:Capillaries / Q000473:pathology; D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005500:Follow-Up Studies; D005654:Fundus Oculi; D006801:Humans; D008269:Macular Edema / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012171:Retinal Vessels / Q000473:pathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence / Q000379:methods*