Malignant Incidental Extracardiac Findings on Cardiac CT: Systematic Review and Meta-Analysis

OBJECTIVE. The objective of our study was to systematically review the evidence on incidental extracardiac findings on cardiac CT with a focus on previously unknown malignancies. MATERIALS AND METHODS. A systematic search was performed (PubMed, EMBASE, Cochrane databases) for studies reporting incidental extracardiac findings on cardiac CT. Among 1099 articles initially found, 15 studies met the inclusion criteria. The references of those articles were hand-searched and 14 additional studies were identified. After review of the full text, 10 articles were excluded. Nineteen studies including 15,877 patients (64% male) were analyzed. A three-level analysis was performed to determine the prevalence of patients with incidental extracardiac findings, the prevalence of patients with major incidental extracardiac findings, and the prevalence of patients with a proven cancer. Heterogeneity was explored for multiple variables. Pooled prevalence and 95% CI were calculated. RESULTS. The prevalence of both incidental extracardiac findings and major incidental extracardiac findings showed a high heterogeneity (I-2 > 95%): The pooled prevalence was 44% (95% CI, 35-54%) and 16% (95% CI, 14-20%), respectively. No significant explanatory variables were found for using or not using contrast material, the size of the FOV, and study design (I-2 > 85%). The pooled cancer prevalence for 10 studies including 5082 patients was 0.7% (95% CI, 0.5-1.0%), with an almost perfect homogeneity (I-2 < 0.1%). Of 29 reported malignancies, 21 (72%) were lung cancers; three, thyroid cancers; two, breast cancers; two, liver cancers; and one, mediastinal lymphoma. CONCLUSION. Although the prevalence of reported incidental extracardiac finding at cardiac CT was highly variable, a homogeneous prevalence of previously unknown malignancies was reported across the studies, for a pooled estimate of 0.7%; more than 70% of these previously unknown malignancies were lung cancers. Extracardiac findings on cardiac CT require careful evaluation and reporting.