title: Preoperative lymph node staging in patients with primary prostate cancer: comparison and correlation of quantitative imaging parameters in diffusion-weighted imaging and 11C-choline PET/CT.
abstract: OBJECTIVE
  To compare the diagnostic performance of DWI and 11C-choline PET/CT in the assessment of preoperative lymph node status in patients with primary prostate cancer.
  
  
  METHODS
  Thirty-three patients underwent DWI and 11C-choline PET/CT prior to prostatectomy and extended pelvic lymph node dissection. Mean standardised uptake value (SUV(mean)) and mean apparent diffusion coefficient (ADC) of 76 identified lymph nodes (LN) were measured and correlated with histopathology. ADC values and SUVs were compared using linear regression analysis.
  
  
  RESULTS
  A significant difference between benign and malignant LN was observed for ADC values (1.17 vs. 0.96 × 10(-3) mm(2)/s; P < 0.001) and SUV(mean) (1.61 vs. 3.20; P < 0.001). ROC analysis revealed an optimal ADC threshold of 1.01 × 10(-3) mm(2)/s for differentiating benign from malignant LN with corresponding sensitivity/specificity of 69.70%/78.57% and an area under the curve (AUC) of 0.785. The optimal threshold for SUV(mean) was 2.5 with corresponding sensitivity/specificity of 69.72%/90.48% and with an AUC of 0.832. ADC values and SUV(mean) showed a moderate significant inverse correlation (r = -0.63).
  
  
  CONCLUSIONS
  Both modalities reveal similar moderate diagnostic performance for preoperative lymph node staging of prostate cancer, not justifying their application in routine clinical practice at this time. The only moderate inverse correlation between ADC values and SUV(mean) suggests that both imaging parameters might provide complementary information on tumour biology.
  
  
  CONCLUSIONS
  • Conventional imaging shows low performance for lymph node staging in prostate cancer. • DWI and 11C-choline PET/CT both provide additional functional information • Both functional modalities reveal only moderate diagnostic performance.
authors.affiliation: Clinic of Nuclear Medicine, Klinikum Rechts der Isar, Technical University Munich, Ismaninger Strasse 22, 81675, Munich, Germany, tibor.vag@tum.de.
authors.forename: Tibor
authors.initials: T
authors.lastname: Vag
authors.forename: Matthias M
authors.initials: MM
authors.lastname: Heck
authors.forename: Ambros J
authors.initials: AJ
authors.lastname: Beer
authors.forename: Michael
authors.initials: M
authors.lastname: Souvatzoglou
authors.forename: Gregor
authors.initials: G
authors.lastname: Weirich
authors.forename: Konstantin
authors.initials: K
authors.lastname: Holzapfel
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Rummeny
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.forename: Bernd Joachim
authors.initials: BJ
authors.lastname: Krause
authors.forename: Matthias
authors.initials: M
authors.lastname: Eiber
mesh_terms: D000368:Aged; D002250:Carbon Radioisotopes; D002794:Choline; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000556:secondary; D012372:ROC Curve; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D002250:Carbon Radioisotopes; D002794:Choline