Oscillation of angiogenesis with vascular dropout in diabetic retinopathy by VESsel GENeration analysis (VESGEN).
OBJECTIVE
Vascular dropout and angiogenesis are hallmarks of the progression of diabetic retinopathy (DR). However, current evaluation of DR relies on grading of secondary vascular effects, such as microaneurysms and hemorrhages, by clinical examination instead of by evaluation of actual vascular changes. The purpose of this study was to map and quantify vascular changes during progression of DR by VESsel GENeration Analysis (VESGEN).


METHODS
In this prospective cross-sectional study, 15 eyes with DR were evaluated with fluorescein angiography (FA) and color fundus photography, and were graded using modified Early Treatment Diabetic Retinopathy Study criteria. FA images were separated by semiautomatic image processing into arterial and venous trees. Vessel length density (L(v)), number density (N(v)), and diameter (D(v)) were analyzed in a masked fashion with VESGEN software. Each vascular tree was automatically segmented into branching generations (G(1)...G(8) or G(9)) by vessel diameter and branching. Vascular remodeling status (VRS) for N(v) and L(v) was graded 1 to 4 for increasing severity of vascular change.


RESULTS
By N(v) and L(v), VRS correlated significantly with the independent clinical diagnosis of mild to proliferative DR (13/15 eyes). N(v) and L(v) of smaller vessels (G(> or =6)) increased from VRS1 to VRS2 by 2.4 x and 1.6 x, decreased from VRS2 to VRS3 by 0.4 x and 0.6 x, and increased from VRS3 to VRS4 by 1.7 x and 1.5 x (P < 0.01). Throughout DR progression, the density of larger vessels (G(1-5)) remained essentially unchanged, and D(v1-5) increased slightly.


CONCLUSIONS
Vessel density oscillated with the progression of DR. Alternating phases of angiogenesis/neovascularization and vascular dropout were dominated first by remodeling of arteries and subsequently by veins.
National Aeronautics and Space Administration, John H. Glenn Research Center, Cleveland, Ohio 44135, USA. patricia.a.parsons-wingerter@nasa.gov
Patricia
P
Parsons-Wingerter
Krishnan
K
Radhakrishnan
Mary B
MB
Vickerman
Peter K
PK
Kaiser
D000328:Adult; D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000503:physiopathology*; D018450:Disease Progression; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D007091:Image Processing, Computer-Assisted; D010781:Photography; D011446:Prospective Studies; D012161:Retinal Artery / Q000473:pathology*; D015861:Retinal Neovascularization / Q000175:diagnosis / Q000503:physiopathology*; D012169:Retinal Vein / Q000473:pathology*