title: Intra-individual comparison of (68)Ga-PSMA-11-PET/CT and multi-parametric MR for imaging of primary prostate cancer.
abstract: OBJECTIVE
  Multi-parametric magnetic resonance imaging (MP-MRI) is currently the most comprehensive work up for non-invasive primary tumor staging of prostate cancer (PCa). Prostate-specific membrane antigen (PSMA)-Positron emission tomography-computed tomography (PET/CT) is presented to be a highly promising new technique for N- and M-staging in recurrent PCa-patients. The actual investigation analyses the potential of (68)Ga-PSMA11-PET/CT to assess the extent of primary prostate cancer by intra-individual comparison to MP-MRI.
  
  
  METHODS
  In a retrospective study, ten patients with primary PCa underwent MP-MRI and PSMA-PET/CT for initial staging. All tumors were proven histopathological by biopsy. Image analysis was done in a quantitative (SUVmax) and qualitative (blinded read) fashion based on PI-RADS. The PI-RADS schema was then translated into a 3D-matrix and the euclidian distance of this coordinate system was used to quantify the extend of agreement.
  
  
  RESULTS
  Both MP-MRI and PSMA-PET/CT presented a good allocation of the PCa, which was also in concordance to the tumor location validated in eight-segment resolution by biopsy. An Isocontour of 50 % SUVmax in PSMA-PET resulted in visually concordant tumor extension in comparison to MP-MRI (T2w and DWI). For 89.4 % of sections containing a tumor according to MP-MRI, the tumor was also identified in total or near-total agreement (euclidian distance ≤1) by PSMA-PET. Vice versa for 96.8 % of the sections identified as tumor bearing by PSMA-PET the tumor was also found in total or near-total agreement by MP-MRI.
  
  
  CONCLUSIONS
  PSMA-PET/CT and MP-MRI correlated well with regard to tumor allocation in patients with a high pre-test probability for large tumors. Further research will be needed to evaluate its value in challenging situation such as prostatitis or after repeated negative biopsies.
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany. frederik@egiesel.com.|Unit of Radiopharmaceutic Chemistry, German Cancer Research Center, Heidelberg, Germany. frederik@egiesel.com.
authors.forename: F L
authors.initials: FL
authors.lastname: Giesel
authors.affiliation: Department of RadioOncology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Sterzing
authors.affiliation: Department of Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: H P
authors.initials: HP
authors.lastname: Schlemmer
authors.affiliation: Department of Biostatistics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Holland-Letz
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Mier
authors.affiliation: Institute of Transuranium Elements, European Commission (EC), Karlsruhe, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Rius
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.|Unit of Radiopharmaceutic Chemistry, German Cancer Research Center, Heidelberg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Afshar-Oromieh
authors.affiliation: Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Kopka
authors.affiliation: Department of RadioOncology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Debus
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.|Unit of Radiopharmaceutic Chemistry, German Cancer Research Center, Heidelberg, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Haberkorn
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.|Unit of Radiopharmaceutic Chemistry, German Cancer Research Center, Heidelberg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Kratochwil
mesh_terms: D000368:Aged; D004492:Edetic Acid / Q000031:analogs & derivatives*; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D009842:Oligopeptides; D000072078:Positron Emission Tomography Computed Tomography; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
chemical_list: D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D009842:Oligopeptides; C000718244:gallium 68 PSMA-11; D004492:Edetic Acid
keywords: Multi-parametric MRI; PSMA; Prostate cancer; T-staging