We highlight the common main incidental imaging findings on PET CT imaging.

Computed tomography (CT) combined with positron emmission tomography (PET) now forms the basis of radiologic diagnosis and staging of many forms of malignancy. FDG-PET CT combines functional nuclear medicine imaging with the anatomical detail of multidetector CT, giving the benefits of both. It is an extremely sensitive imaging tool which regularly identifies incidental abnormalities.

The radiological reports of 629 consecutive PET CT examinations were reviewed and all clinically relevant incidental findings were recorded. In particular we review 2nd primary lesions, thyroid and adrenal lesions, aortic aneurysms and other incidental findings.2nd primary malignancyDiscovery of a 2nd primary malignancy is probably the most importantincidental finding on a PET CT scan. The records of all patients withscans showing a possible 2nd primary malignancy were audited.ColonAll patients scans with focal colonic FDG uptake were audited. 8 cases of bowel adenocarcinoma and 6 cases...

Incidental imaging findings in FDG PET CT are regularly identified, many of which require further investigation. A suspected second primary malignancy is one of the most common and serious discoveries, however further investigation of any incidental finding must be balanced with a patient's known malignancy and prognosis.

Mark Knox,Department of Radiology,St James's Hospital,Dublin 8,Ireland.

1. Incidental thyroid lesions detected by FDG-PET/CT: prevalence and risk of thyroid cancer. Ja Seong Baeet al. WJ Surg Onc 2009, 7:63.