Computer-assisted microaneurysm turnover in the early stages of diabetic retinopathy.
OBJECTIVE
To assess the reliability of microaneurysm turnover, computed from color fundus photographs, in evaluating diabetic retinopathy in patients with type 2 diabetes and nonproliferative retinopathy.


METHODS
A new method (MA-Tracker) was developed to count microaneurysms by mapping their locations through image co-registration. To compute the reliability of microaneurysm turnover, 3 different graders were asked to earmark microaneurysms on the same set of color fundus photographs.


RESULTS
The total numbers of microaneurysms earmarked in each of 5 visits suggest that microaneurysms remain stable over time (p >or= 0.138). However, an analysis of each microaneurysm showed that only 29.4% remained at the same location. By computing the formation and disappearance rates of microaneurysms (2.3 and 1.7 microaneurysms/year, respectively), a significant turnover of microaneurysms was found.


CONCLUSIONS
The formation and disappearance rates of microaneurysms obtained from color fundus photographs using MA-Tracker show very good agreement between different graders, and can be used as indicators of microaneurysm turnover in the initial stages of diabetic retinopathy.
Center of New Technologies for Medicine, University of Coimbra, Portugal. rcb@aibili.pt
Rui
R
Bernardes
Sandrina
S
Nunes
Ivânia
I
Pereira
Teresa
T
Torrent
Andreia
A
Rosa
Dalila
D
Coelho
José
J
Cunha-Vaz
D000328:Adult; D000368:Aged; D000783:Aneurysm / Q000175:diagnosis*; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D003941:Diagnostic Techniques, Ophthalmological; D018450:Disease Progression; D005260:Female; D005451:Fluorescein Angiography; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008269:Macular Edema / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010781:Photography; D015203:Reproducibility of Results; D012171:Retinal Vessels / Q000473:pathology*; D012189:Retrospective Studies