Missed lung cancer at CT: imaging findings in nine patients.

PURPOSE: To assess the imaging findings and course of lung cancers missed on computed tomographic (CT) scans. MATERIALS AND METHODS: A retrospective review of CT scans was performed on nine patients who underwent CT examination for various clinical indications and in whom a lung cancer had been missed. Subspecialty chest radiologists determined whether retrospectively identified lesions were missed due to observer error or technical failure. RESULTS: Five missed tumors were peripheral and four were central in location. All peripheral tumors were less than 3 mm in diameter. The interval from initial examination to detection of peripheral tumors ranged from 8 to 95 months. This interval for central tumors was shorter (3-14 months). Estimated doubling times ranged from 24 to 285 days. CONCLUSION: Small lung cancers that are near the threshold for detectability may be missed at CT. Such failure of detection is attributable primarily to the poor conspicuity of lesions. Retrospective identification at CT raises medicolegal issues.