Incidental lung nodules on CT examinations of the abdomen: Prevalence and reporting rates in the PACS era

Objectives

To retrospectively evaluate prevalence, reporting rates and clinical implications of incidental pulmonary nodules detected in multidetector computed tomography (MDCT) abdominal studies.

Materials and methods

Abdominal MDCT studies of 243 consecutive patients, 94 of whom had a history of cancer, were evaluated. Lung bases included in the scan were reviewed on a PACS workstation with different window settings and post-processing techniques. Nodules were classified according to their density (calcified, solid noncalcified, non-solid, part-solid) and size (<4 mm; 4-6 mm; 6-8 mm; >8 mm). The study findings were compared with the corresponding radiologic reports. Previous of following CT studies, when available from the PACS, were also reviewed to evaluate changes in number and size of the detected nodules.

Results

An average of 8.2 cm of lung parenchyma was imaged in each patient. 213 noncalcified nodules (NCNs) were identified in 95 patients (39.1%) but only 8 patients (8.4%) had it mentioned in the final report. Comparison CT studies were available for 44 out of the 95 positive patients showing disappearance of the nodules in 2 cases, no interval change in 26 and progression in size and/or number in 16 patients, in whom a final diagnosis of metastasis or primary lung cancers was achieved.

Conclusion

Radiologists tend to overlook lung portions on abdominal CT studies. Underreporting may affect patient care and have medico-legal implications since images are permanently stored in digital format on PACS and CD-ROMs. Management of the discovered nodules should be tailored to the clinical situation of the patient, and particular care should be reserved to patients with oncologic history.