title: Index lesion characterization by (11)C-Choline PET/CT and Apparent Diffusion Coefficient parameters at 3 Tesla MRI in primary prostate carcinoma.
abstract: BACKGROUND
  Index lesion characterization is important in the evaluation of primary prostate carcinoma (PPC). The aim of this study was to analyze the contribution of (11) C-Choline PET/CT and the Apparent Diffusion Coefficient maps (ADC) in detecting the Index Lesion and clinically significant tumors in PPC.
  
  
  METHODS
  Twenty-one untreated patients with biopsy-proven PPC and candidates for radical prostatectomy (RP) were prospectively evaluated by means of Ultra-High Definition PET/CT and 3T MRI, which included T2-weighted imaging (T2WI) and ADC maps obtained from diffusion weighted imaging (DWI). Independent experts analyzed all the images separately and were unaware of the pathological data. In each case, the Index lesion was defined as the largest tumor measured on histopathology (Index H). In addition, the largest lesion observed on MRI (Index MRI) and the highest avid (11) C-Choline uptake lesion (Index PET) were obtained. The Gleason scores (GS) of the tumors were determined. PET/CT and ADC map quantitative parameters were also calculated. Measures of correlation among imaging parameters as well as the sensitivity (S), specificity (Sp), negative and positive predictive values (NPV and PPV) for tumor detection were analyzed. All data was validated with the pathological study.
  
  
  RESULTS
  In the morphological study, 139 foci of carcinoma were identified, 47 of which corresponded to clinically significant tumors (>0.5 cm(3)). The remaining foci presented a maximum diameter (dmax ) of 0.1 cm ± SD 0.75 and were not classified as clinically significant. Thirty-two tumors presented a GS (3 + 3), nine GS (3 + 4), and six GS (4 + 3). A total of 21 Index H (dmax = 1.37 cm SD ± 0.61) were identified. The S, Sp, NPV, and PPV for tumor detection with PET were 100%, 70%, 83%, 100%, and for MRI were 46%, 100%, 100%, 54%, respectively. Both Index PET and Index MRI were complementary and identified 95% of the Index H when quantitative criteria were used.
  
  
  CONCLUSIONS
  In spite of the fact that PET imaging has higher tumor sensitivity than MRI, (11) C-Choline PET and ADC maps have complementary roles in the evaluation of Index Lesion in PPC. Index PET and Index MRI could be complementary targets in the therapeutic planning of PPC.
authors.affiliation: Department of Nuclear Medicine, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Hernández-Argüello
authors.affiliation: Department of Pathology, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Hernán
authors.initials: H
authors.lastname: Quiceno
authors.affiliation: Department of Urology, Clínica Universidad de Navarra, Pamplona, Spain.|IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Pascual
authors.affiliation: Department of Pathology, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Solorzano
authors.affiliation: IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.|Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Benito
authors.affiliation: Department of Nuclear Medicine, Clínica Universidad de Navarra, Pamplona, Spain.|IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Collantes
authors.affiliation: Department of Nuclear Medicine, Clínica Universidad de Navarra, Pamplona, Spain.|IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
authors.forename: Macarena
authors.initials: M
authors.lastname: Rodríguez-Fraile
authors.affiliation: Department of Pathology, Clínica Universidad de Navarra, Pamplona, Spain.|IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Pardo
authors.affiliation: Department of Nuclear Medicine, Clínica Universidad de Navarra, Pamplona, Spain.|IdiSNA, Navarra Institute for Health Research, Pamplona, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Richter
mesh_terms: D000368:Aged; D001706:Biopsy; D002250:Carbon Radioisotopes / Q000494:pharmacology; D002277:Carcinoma / Q000473:pathology*; D002794:Choline / Q000494:pharmacology; D057186:Comparative Effectiveness Research; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011300:Preoperative Care / Q000379:methods; D011467:Prostate / Q000473:pathology*; D011471:Prostatic Neoplasms / Q000473:pathology*; D019275:Radiopharmaceuticals / Q000494:pharmacology; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D047368:Tumor Burden
chemical_list: D002250:Carbon Radioisotopes; D019275:Radiopharmaceuticals; D002794:Choline
keywords: 11C-Choline; ADC; DWI; index lesion; prostate cancer