This study aimed to evaluate the role of screening computed tomography (CT) of the thorax in cardiac surgery by analysing the presence of CT aortic calcifications in association with changes in operative strategy and postoperative stroke, and the CT features of emphysema with development of pneumonia. All patients who underwent cardiac surgery from January 2013 to October 2017 by a single surgeon were retrospectively studied. Patients who underwent screening CT thorax before cardiac surgery (CT group) were compared to those who did not (no CT group). Multivariate subgroup analyses were performed to determine significant association with postoperative outcomes. A total of 392 patients were included, of which 156 patients underwent preoperative screening CT thorax. Patients in the CT group were older (63.9 vs. 59.0 years, P = 0.001), had fewer recent myocardial infarctions preoperatively (41% vs. 56.4%, P = 0.003) and had better ejection fraction (>30%; P = 0.02). Operative strategy was changed in 4.3% of patients, and 4.9% of patients suffered stroke postoperatively. The presence of CT aortic calcifications was significantly associated with change in operative strategy (P = 0.016) but not with postoperative stroke (P = 0.33). Age was an independent risk factor for change in operative strategy among patients with CT thorax (P = 0.02). Multivariate age-adjusted analysis showed only palpable plaque to be significantly associated with change in operative strategy (P < 0.001). None of the patients with CT emphysema features developed pneumonia. The results of this study do not support routine use of preoperative screening CT thorax. Contrasted CT may be advisable in older patients and for other operative planning purposes.