title: Usefulness of MRI-assisted metabolic volumetric parameters provided by simultaneous (18)F-fluorocholine PET/MRI for primary prostate cancer characterization.
abstract: OBJECTIVE
  The aim of this study was to determine the usefulness of MRI-assisted positron emission tomography (PET) parameters provided by simultaneous (18)F-fluorocholine (FCH) PET/MRI for characterization of primary prostate cancer.
  
  
  METHODS
  Thirty patients with localized prostate cancer (mean age 69.4 ± 6.7 years) confirmed by biopsy were prospectively enrolled for simultaneous PET/MRI imaging. The patients underwent (18)F-FCH PET/MRI 1 week before undergoing total prostatectomy. Multiple parameters of diffusion-weighted MRI [minimum and mean apparent diffusion coefficient (ADCmin and ADCmean)], metabolic PET [maximum and mean standardized uptake value (SUVmax and SUVmean)], and metabolic volumetric PET [metabolic tumor volume (MTV) and uptake volume product (UVP)] were compared with laboratory, pathologic, and immunohistochemical (IHC) features of the prostate cancer specimen. PET parameters were divided into two categories as follows: volume of interest (VOI) of prostate by SUV cutoff 2.5 (SUVmax, SUVmean, MTVSUV, and UVPSUV) and MRI-assisted VOI of prostate cancer (SUVmaxMRI, SUVmeanMRI, MTVMRI, and UVPMRI).
  
  
  RESULTS
  The rates of prostate cancer-positive cases identified by MRI alone, (18)F-FCH PET alone, and (18)F-FCH PET/MRI were 83.3, 80.0, and 93.3%, respectively. Among the multiple PET/MRI parameters, MTVMRI showed fair correlation with serum prostate-specific antigen (PSA; r = 0.442, p = 0.014) and highest correlation with tumor volume (r = 0.953, p < 0.001). UVPMRI showed highest correlation with serum PSA (r = 0.531, p = 0.003), good correlation with tumor volume (r = 0.908, p < 0.001), and it was significantly associated with Gleason score (p = 0.041). High MTVMRI and UVPMRI values were significant for perineural invasion, lymphatic invasion, extracapsular extension, seminal vesicle invasion, and positive B-cell lymphoma 2 (Bcl-2) expression (all p < 0.05).
  
  
  CONCLUSIONS
  Simultaneous (18)F-FCH PET/MRI demonstrated a better diagnostic value for localized prostate cancer detection than each individual modality. MRI-assisted metabolic volumetric PET parameters (MTVMRI and UVPMRI) provided more accurate characterization of prostate cancer than conventional PET and MRI parameters.
authors.affiliation: Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Yong-Il
authors.initials: YI
authors.lastname: Kim
authors.forename: Gi Jeong
authors.initials: GJ
authors.lastname: Cheon
authors.forename: Jin Chul
authors.initials: JC
authors.lastname: Paeng
authors.forename: Jeong Yeon
authors.initials: JY
authors.lastname: Cho
authors.forename: Cheol
authors.initials: C
authors.lastname: Kwak
authors.forename: Keon Wook
authors.initials: KW
authors.lastname: Kang
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
authors.forename: Euishin Edmund
authors.initials: EE
authors.lastname: Kim
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002794:Choline / Q000031:analogs & derivatives*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; C514960:fluorocholine; D002794:Choline