title: Fully automatic segmentation of fluorescein leakage in subjects with diabetic macular edema.
abstract: OBJECTIVE
  To create and validate software to automatically segment leakage area in real-world clinical fluorescein angiography (FA) images of subjects with diabetic macular edema (DME).
  
  
  METHODS
  Fluorescein angiography images obtained from 24 eyes of 24 subjects with DME were retrospectively analyzed. Both video and still-frame images were obtained using a Heidelberg Spectralis 6-mode HRA/OCT unit. We aligned early and late FA frames in the video by a two-step nonrigid registration method. To remove background artifacts, we subtracted early and late FA frames. Finally, after postprocessing steps, including detection and inpainting of the vessels, a robust active contour method was utilized to obtain leakage area in a 1500-μm-radius circular region centered at the fovea. Images were captured at different fields of view (FOVs) and were often contaminated with outliers, as is the case in real-world clinical imaging. Our algorithm was applied to these images with no manual input. Separately, all images were manually segmented by two retina specialists. The sensitivity, specificity, and accuracy of manual interobserver, manual intraobserver, and automatic methods were calculated.
  
  
  RESULTS
  The mean accuracy was 0.86 ± 0.08 for automatic versus manual, 0.83 ± 0.16 for manual interobserver, and 0.90 ± 0.08 for manual intraobserver segmentation methods.
  
  
  CONCLUSIONS
  Our fully automated algorithm can reproducibly and accurately quantify the area of leakage of clinical-grade FA video and is congruent with expert manual segmentation. The performance was reliable for different DME subtypes. This approach has the potential to reduce time and labor costs and may yield objective and reproducible quantitative measurements of DME imaging biomarkers.
authors: Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors: Hossein
authors: H
authors: Rabbani
authors: Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States.
authors: Michael J
authors: MJ
authors: Allingham
authors: Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States.
authors: Priyatham S
authors: PS
authors: Mettu
authors: Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States.
authors: Scott W
authors: SW
authors: Cousins
authors: Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, United States Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States.
authors: Sina
authors: S
authors: Farsiu
mesh_terms: D000465:Algorithms; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000503:physiopathology; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000175:diagnosis* / Q000503:physiopathology; D019793:Fluorescein / Q000493:pharmacokinetics*; D005451:Fluorescein Angiography; D006801:Humans; D007089:Image Enhancement; D007090:Image Interpretation, Computer-Assisted; D008269:Macular Edema / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D012984:Software; D014741:Video Recording
chemical_list: D019793:Fluorescein
keywords: diabetic macular edema; fundus fluorescein angiography; leakage segmentation; nonrigid registration
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