In a diagnostic cardiac imaging session of a patient's heart using a computed tomography imaging scanner (10) and a cardiac cycle monitor (42), a diagnostic objective (100) is received. Survey imaging (104) of the heart is performed to determine optimized imaging parameter values for the received diagnostic objective (100). Monitor imaging (108) of a limited portion of the heart is performed during influx of a contrast agent (22) using a low patient x-ray exposure condition to detect a trigger condition. Volume imaging (110) of the heart responsive to detection of the trigger condition is performed using the optimized imaging parameter values to obtain volumetric imaging data. Cardiac cycle data is recorded during at least a portion of the survey imaging (104), the monitor imaging (108), and the volume imaging (110). High resolution reconstructing (130) of at least some volumetric imaging data is performed to produce high resolution image representations (132).