One hundred and one coronary interventional systems (45 primarily film-based predigital systems, labeled group 1; and 56 filmless digital systems, labeled group 2) were examined over a 5-year period using a standardized imaging phantom. Fluoroscopic image intensifier input dose, high-contrast spatial resolution, low-contrast sensitivity, and static and dynamic low-contrast resolution were assessed under several conditions simulating patient body habitus. The distribution of spatial resolutions in group 2 facilities favored higher line pair resolution over group 1 (P = 0.01). Contrast sensitivity (smallest-diameter hole visualized) was consistently and significantly enhanced with the use of digital imaging under both medium (P = 0.001) and large (P = 0.002) patient habitus simulations. Low-contrast video resolution (number of wires seen) under static (P = 0.007) and dynamic (P = 0.002) conditions was also improved in the digital facilities. However, image intensifer input dose was similar in both groups (group 1 median dose, 23 mR/min; group 2 median dose, 26 mR/min; P = NS). Fluoroscopic spatial resolution in digital filmless laboratories was significantly improved when compared to predigital, film-based laboratories. Low-contrast sensitivity and low- contrast video resolution under both static and dynamic conditions were also significantly improved in the digital laboratories. Notably, the input dose of radiation required to produce these improved fluoroscopic images was similar between groups. Cathet Cardiovasc Intervent 2003;58:383–390. © 2003 Wiley-Liss, Inc.