18F-fluorodeoxyglucose positron emission tomography features of idiopathic retroperitoneal fibrosis

J Comput Assist Tomogr. 2007 Jul-Aug;31(4):539-43. doi: 10.1097/01.rct.0000284388.45579.05.


Objective: To evaluate the 18F-fluorodeoxyglucose (FDG) uptake features of idiopathic retroperitoneal fibrosis (IRF).

Methods: 18F-Fluorodeoxyglucose positron emission tomographic (PET) or PET/computed tomographic findings were retrospectively reviewed in 6 patients with IRF. FDG PET or PET/computed tomography was performed 1 and 2 hours after FDG injection. The FDG level was scored using a 4-point scale, and the intensity of FDG uptake was quantified using the maximum standardized uptake value (SUVmax).

Results: In the 1-hours images, intense FDG uptake by IRF was observed in 5 patients before steroid treatment, but no abnormal uptake was noted in 1 patient receiving steroid treatment. The SUVmax in IRF increased from a mean +/- SD of 6.0 +/- 1.2 (range, 4.9-7.6) to 7.6 +/- 1.1 (range, 5.9-8.2) for all 4 patients who underwent 1 and 2 hours dual-time point imaging. Abnormal uptake was also noted in the mediastinum and the pancreas in 1 and 2 patients, and the diagnoses of mediastinal fibrosis and autoimmune pancreatitis were made, respectively. The SUVmax was stable or increased in the 3 lesions of mediastinal fibrosis and autoimmune pancreatitis.

Conclusion: FDG PET may be a reliable means of evaluating disease activity and the extent of IRF, but dual-time point imaging may not be useful to differentiate malignancy from IRF.

MeSH terms

  • Adult
  • Aged
  • Autoimmune Diseases / diagnostic imaging
  • Fluorodeoxyglucose F18*
  • Humans
  • Male
  • Middle Aged
  • Pancreatitis / diagnostic imaging
  • Positron-Emission Tomography*
  • Radiopharmaceuticals*
  • Retroperitoneal Fibrosis / diagnostic imaging*
  • Retrospective Studies
  • Tomography, X-Ray Computed


  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18