A stenting ring made of a tube or rolled-up sheet that has a characteristic wall thickness. The ring defines a lumen and is equipped with at least one marker made of a material different from that of the ring. The ring is expansible from a radially compact disposition with a relatively small circumference to a radially expanded disposition with a relatively large circumference. The ring exhibits in the compact disposition a serpentine arrangement of succeeding struts lying in alternate opposite directions to the longitudinal axis of the lumen. The marker has a thickness in the radial direction of the ring that is less than the characteristic wall thickness, and has a width that extends circumferentially around an arc of the ring. The marker is attached to the ring at a zone located at a point intermediate in the extent of said arc. The marker overlaps with a respective one of said struts, at each end of its circumferential arc, when the ring is in the compact disposition, the respective struts moving away from each other, and from the marker, when the ring expands towards said radially expanded disposition.