Lung cancer detected at cardiac CT: Prevalence, clinicoradiologic features, and importance of full-field-of-view images

Purpose: To retrospectively evaluate the prevalence and clinicoradiologic features of lung cancer detected at cardiac computed tomography (CT) and compare the detection rates at different field-of-view (FOV) settings. Materials and Methods: The institutional review board approved this retrospective study and waived the requirement for patient consent. Patients with lung cancer initially detected at cardiac CT were identified by means of a retrospective search of a lung cancer registry patient database between January 2004 and December 2007. Patients known to have lung cancer at the time of cardiac CT were excluded. The prevalence and clinical and radiologic features of lung cancer were evaluated. The rates of lung cancer detection at three FOVs - limited and full FOV at cardiac scanning and full FOV at thoracic scanning - were compared by using McNemar testing. Results: The prevalence of lung cancer detected at CT was 0.31% (36 of 11 654 patients, 16 [44%] never smokers) and was higher in patients suspected or known to have coronary artery disease (0.43% [24 of 5615 patients]) than in asymptomatic screening-examined patients (0.20% [12 of 5924 patients]) (P = .0457). Adenocarcinoma was the most common (in 31 [86%] of 36 patients) histologic subtype. Of 34 non-small cell lung cancers, 23 (68%) - including 16 stage IA cancers - were resectable. Four (11%) and 19 (53%) of the 36 CT-depicted cancers were visible in limited and full FOV at cardiac scanning, respectively, and 17 (47%) were visible in full FOV at thoracic scanning only. Conclusion: The prevalence of lung cancer at cardiac CT was 0.31%; and 68% of these malignancies were at a resectable stage. Use of a limited FOV at cardiac scanning led to a large majority (89% [32 of 36 cancers]) of the lung cancers detected at full thoracic scanning being missed; thus, inclusion of the entire chest at cardiac CT is advisable.