Devices, systems, and methods calculate a first stenosis measurement of a measured location in a lumen based on optical-imaging data of the lumen, on the measured location in the lumen, and on a first reference location in the lumen; and generate a screen that includes a tomographic view of the lumen, a longitudinal view of the lumen, and the first stenosis measurement, wherein the tomographic view of the lumen and the longitudinal view of the lumen are based on the optical-imaging data of the lumen, wherein the tomographic view includes a tomographic-view measured-location indicator that indicates the measured location in the lumen and a first tomographic-view reference indicator that indicates the first reference location in the lumen, and wherein the longitudinal view includes a longitudinal-view measured-location indicator that indicates the measured location in the lumen and a first longitudinal-view reference indicator that indicates the first reference location in the lumen.