title: Tortuosity of arterioles and venules in quantifying plus disease.
abstract: BACKGROUND
  Plus disease is the major criterion for laser treatment of retinopathy of prematurity. ROPtool is a computer program that traces retinal blood vessels and measures their tortuosity. Our objectives were to determine (1) whether examiners could accurately discriminate between arterioles and venules and (2) whether tortuosity sufficient for plus disease and pre-plus disease was assessed most accurately by considering arterioles, venules, or both.
  
  
  METHODS
  One hundred retinal vessels were identified in 25 images randomly selected from 184 total images. Three pediatric ophthalmologists independently designated vessels as arteriole or venule. Seventy-seven images that had at least 1 traceable arteriole and venule in each quadrant were analyzed by ROPtool, and the results were compared with the consensus of 3 expert examiners. Receiver operating characteristics (ROC) curves were generated and areas under the curves calculated to quantify the diagnostic utility of ROPtool's assessment of tortuosity of arterioles, venules, and both.
  
  
  RESULTS
  Three pediatric ophthalmologists agreed on the designation of arteriole or venule for 83 of 100 blood vessels. With the use of expert consensus as the reference standard, areas under the ROC curves for identification of tortuosity sufficient for plus disease were 0.91, 0.70, and 0.93 for arterioles, venules, and both, respectively. Areas under the ROC curves for identification of tortuosity sufficient for pre-plus disease were 0.91, 0.63, and 0.90 for arterioles, venules, and both, respectively.
  
  
  CONCLUSIONS
  When considering whether tortuosity is sufficient for plus or pre-plus disease, the assessment of either arterioles alone or of arterioles and venules together resulted in high diagnostic accuracy.
authors.affiliation: Duke University Eye Center, Durham, North Carolina 27710, USA.
authors.forename: Suzanne C
authors.initials: SC
authors.lastname: Johnston
authors.forename: David K
authors.initials: DK
authors.lastname: Wallace
authors.forename: Sharon F
authors.initials: SF
authors.lastname: Freedman
authors.forename: Tammy L
authors.initials: TL
authors.lastname: Yanovitch
authors.forename: Zheen
authors.initials: Z
authors.lastname: Zhao
mesh_terms: D001160:Arterioles / Q000473:pathology*; D003936:Diagnosis, Computer-Assisted / Q000379:methods / Q000592:standards*; D003941:Diagnostic Techniques, Ophthalmological / Q000592:standards*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods / Q000592:standards; D007231:Infant, Newborn; D012372:ROC Curve; D012015:Reference Standards; D015203:Reproducibility of Results; D012171:Retinal Vessels / Q000473:pathology*; D012178:Retinopathy of Prematurity / Q000473:pathology*; D012720:Severity of Illness Index; D014699:Venules / Q000473:pathology*