title: Quantitative graphical analysis of simultaneous dynamic PET/MRI for assessment of prostate cancer.
abstract: OBJECTIVE
  Dynamic FDG imaging for prostate cancer characterization is limited by generally small size and low uptake in prostate tumors. Our aim in this pilot study was to explore feasibility of simultaneous PET/MRI to guide localization of prostate lesions for dynamic FDG analysis using a graphical approach.
  
  
  METHODS
  Three patients with biopsy-proven prostate cancer underwent simultaneous FDG PET/MRI, incorporating dynamic prostate imaging. Histology and multiparametric MRI findings were used to localize tumors, which in turn guided identification of tumors on FDG images. Regions of interest were manually placed on tumor and benign prostate tissue. Blood activity was extracted from a region of interest placed on the femoral artery on PET images. FDG data were analyzed by graphical analysis using the influx constant Ki (Patlak analysis) when FDG binding seemed irreversible and distribution volume VT (reversible graphical analysis) when FDG binding seemed reversible given the presence of washout.
  
  
  RESULTS
  Given inherent coregistration, simultaneous acquisition facilitated use of MRI data to localize small lesions on PET and subsequent graphical analysis in all cases. In 2 cases with irreversible binding, tumor had higher Ki than benign using Patlak analysis (0.023 vs 0.006 and 0.019 vs 0.008 mL/cm3 per minute). In 1 case appearing reversible, tumor had higher VT than benign using reversible graphical analysis (0.68 vs 0.52 mL/cm3).
  
  
  CONCLUSIONS
  Simultaneous PET/MRI allows localization of small prostate tumors for dynamic PET analysis. By taking advantage of inclusion of the femoral arteries in the FOV, we applied advanced PET data analysis methods beyond conventional static measures and without blood sampling.
authors.affiliation: From the *Department of Radiology, and †Division of Urologic Oncology, Department of Urology, NYU Langone Medical Center, New York, NY.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Rosenkrantz
authors.forename: Thomas
authors.initials: T
authors.lastname: Koesters
authors.forename: Anne-Kristin
authors.initials: AK
authors.lastname: Vahle
authors.forename: Kent
authors.initials: K
authors.lastname: Friedman
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Bartlett
authors.forename: Samir S
authors.initials: SS
authors.lastname: Taneja
authors.forename: Yu-Shin
authors.initials: YS
authors.lastname: Ding
authors.forename: Jean
authors.initials: J
authors.lastname: Logan
mesh_terms: D000368:Aged; D003627:Data Interpretation, Statistical; D019788:Fluorodeoxyglucose F18; 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; D019788:Fluorodeoxyglucose F18