title: Dual-phase PET-CT to differentiate [18F]Fluoromethylcholine uptake in reactive and malignant lymph nodes in patients with prostate cancer.
abstract: OBJECTIVE
  To investigate whether time-trends of enhanced [(18)F]Fluoromethylcholine ([(18)F]FCH) in lymph nodes (LN) of prostate cancer (PCa) patients can help to discriminate reactive from malignant ones, and whether single time point standardized uptake value (SUV) measurements also suffice.
  
  
  METHODS
  25 PCa patients with inguinal (presumed benign) and enlarged pelvic LN (presumed malignant) showing enhanced [(18)F]FCH uptake at dual-phase PET-CT were analyzed. Associations between LN status (benign versus malignant) and SUV(max) and SUV(meanA50), determined at 2 min (early) and 30 min (late) post injection, were assessed. We considered two time-trends of [(18)F]FCH uptake: type A (SUV early > SUV late) and type B (SUV late ≥ SUV early). Histopathology and/or follow-up were used to confirm the assumption that LN with type A pattern are benign, and LN with type B pattern malignant.
  
  
  RESULTS
  Analysis of 54 nodes showed that LN status, time-trends, and 'late' (30 min p.i.) SUV(max) and SUV(meanA50) parameters were strongly associated (P<0.0001). SUV(max) relative difference was the best LN status predictor. All but one inguinal LN showed a decreasing [(18)F]FCH uptake over time (pattern A), while 95% of the pelvic nodes presented a stable or increasing uptake (pattern B) type.
  
  
  CONCLUSIONS
  Time-trends of enhanced [(18)F]FCH uptake can help to characterize lymph nodes in prostate cancer patients. Single time-point SUV measurements, 30 min p.i., may be a reasonable alternative for predicting benign versus malignant status of lymph nodes, but this remains to be validated in non-enlarged pelvic lymph nodes.
authors.affiliation: Department of Nuclear Medicine and PET Research, VU University Medical Center, Amsterdam, The Netherlands. d.oprea-lager@vumc.nl
authors.forename: Daniela E
authors.initials: DE
authors.lastname: Oprea-Lager
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Vincent
authors.forename: Reindert J A
authors.initials: RJ
authors.lastname: van Moorselaar
authors.forename: Winald R
authors.initials: WR
authors.lastname: Gerritsen
authors.forename: Alfons J M
authors.initials: AJ
authors.lastname: van den Eertwegh
authors.forename: Jonas
authors.initials: J
authors.lastname: Eriksson
authors.forename: Ronald
authors.initials: R
authors.lastname: Boellaard
authors.forename: Otto S
authors.initials: OS
authors.lastname: Hoekstra
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002794:Choline / Q000031:analogs & derivatives*; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging*; D012372:ROC Curve; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; C516370:fluoromethylcholine; D002794:Choline