Abstract
Purpose: :
Plus disease is defined as arteriolar tortuosity and venous dilation greater than that of a standard published photograph. This study examines the tortuosity of arterioles in this image using computer-based image analysis, and compares these values to expert interpretations of an independent set of retinal images.
Methods: :
Twenty-two ROP experts independently interpreted a set of 34 wide-angle retinal images for presence of plus disease. A reference standard diagnosis based on expert consensus was defined for each image. The semi-automated Retinal Image multiScale Analysis system was used to calculate tortuosity index (TI) for all arterioles in each image, defined as arc length of the vessel divided by length of a line segment connecting the endpoints. Sensitivity and specificity of arteriolar TI for plus disease diagnosis were plotted as a function of threshold used to separate "plus" from "not plus." The standard published photograph was analyzed using the computer-based system to measure mean arteriolar TI in that image.
Results: :
In the 34 wide-angle images, mean arteriolar TI was 1.23 in eyes with plus disease according to expert consensus and 1.07 in eyes without plus disease (p=0.05). In the published standard photograph, mean arteriolar TI was 1.15. Based on diagnostic opinions from 22 study experts reviewing wide-angle images, using the standard published photograph as the cutoff for arteriolar TI in plus disease diagnosis would have sensitivity 0.84 and specificity 0.39.
Conclusions: :
Arteriolar TI of the standard published photograph is lower than what it used by many experts in plus disease diagnosis.
Keywords: retinopathy of prematurity • imaging/image analysis: clinical • clinical (human) or epidemiologic studies: systems/equipment/techniques