Frequency and clinical relevance of PET/CT incidentalomas

Abdom Imaging. 2014 Jun;39(3):657-62. doi: 10.1007/s00261-014-0086-0.


Rationale and objectives: To assess the frequency of clinically significant incidental CT findings on PET/CT.

Materials and methods: Reports of 345 cases of baseline standard skull base to thighs PET/CT exams done over the course of a 6 month period at an outpatient facility affiliated with a large tertiary care level 1 trauma medical center were retrospectively reviewed. Incidental CT findings were assigned a level of clinical significance on a scale of 1-5, from doubtful significance to very significant. CT findings already known from prior CT reports were not included. CT findings corresponding to PET findings were also excluded. A score of 3 or greater was considered significant and reportable.

Results: Out of 345 cases, 171 (50%) had a least one CT finding rated at or above a score of 3 on our scale of significance, while 96 (28%) were found to have at least one CT finding with score at or above 4, and 25 cases (7%) showed at least one CT finding rated 5.

Conclusion: A substantial percentage of baseline PET/CT studies contain previously undiagnosed, significant incidental findings on the CT images.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Female
  • Fluorodeoxyglucose F18
  • Humans
  • Incidental Findings*
  • Male
  • Middle Aged
  • Multimodal Imaging / methods*
  • Neoplasms / diagnostic imaging*
  • Neoplasms / epidemiology
  • Positron-Emission Tomography / methods*
  • Radiopharmaceuticals
  • Retrospective Studies
  • Tomography, X-Ray Computed / methods*
  • Young Adult


  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18