TABLE 1.

Available features generated from FRAPPE for each image and the method to group image-based features into artery-based features

Feature category	Image-based features	Feature explanation	Method to group into artery-based feature
Vessel wall thickness	Max wall thickness	Maximum in-plane distance between lumen and outer wall contours along a vector originating from the artery centerline	Maximum among all images
	Mean wall thickness	Mean distance between lumen and outer wall contours	Mean of all images
	Eccentricity ratio	Max wall thickness/Min wall thickness	Mean of all images
Vessel wall area features	Area of vessel wall	Area between the lumen and outer wall contours	Mean of all images
	Area of lumen	Area within the lumen contour	Mean of all images
	Total vessel area	Area inside the outer wall contour	Mean of all images
	Normalized wall index	Area of vessel wall / total vessel area × 100%	Mean and maximum of all images

Abbreviation: FRAPPE, fully automated and robust analysis technique for popliteal artery evaluation.