A pitfall of FDG-PET image interpretation: accumulation of FDG in the dependent area of the urinary bladder after bladder irrigation--the usefulness of the prone position

Clin Nucl Med. 2005 Sep;30(9):638-9. doi: 10.1097/01.rlu.0000174291.53670.a3.


In F-18 FDG PET studies, retrograde irrigation of the urinary bladder is usually used to reduce the interference with physiological urinary accumulation of F-18 FDG in patients with possible pelvic lesions. A 34-year-old female who had recently been diagnosed with cervical cancer had an F-18 FDG-PET scan performed for whole-body evaluation. The bladder was irrigated with physiological saline and filled with 200 mL of irrigation fluid through a 3-way balloon catheter inserted before the scan. Two areas with high FDG accumulation were noted in the posterior pelvis. Tumor invasion or metastasis could not be ruled out. Additional focal imaging of the pelvis was performed with the patient in the prone position. The lesion on the left side of the patient was still noted, whereas the lesion on the right had disappeared, which proved that it was a false-positive lesion. Great caution is required when assessing imaging results to avoid misdiagnosis in patients after bladder irrigation.

MeSH terms

  • Adult
  • Artifacts
  • Diagnostic Errors / prevention & control*
  • Extravasation of Diagnostic and Therapeutic Materials / diagnostic imaging*
  • Extravasation of Diagnostic and Therapeutic Materials / metabolism*
  • Female
  • Fluorodeoxyglucose F18 / pharmacokinetics*
  • Humans
  • Positron-Emission Tomography / methods
  • Prone Position*
  • Radiopharmaceuticals / pharmacokinetics
  • Therapeutic Irrigation / methods
  • Urinary Bladder / diagnostic imaging*
  • Urinary Bladder / metabolism*
  • Urinary Bladder Neoplasms / diagnostic imaging
  • Urinary Bladder Neoplasms / metabolism


  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18