title: Assessment of Aggressiveness of Breast Cancer Using Simultaneous 18F-FDG-PET and DCE-MRI: Preliminary Observation.
abstract: OBJECTIVE
  This study aims to investigate the feasibility of using simultaneous breast MRI and PET to assess the synergy of MR pharmacokinetic and fluorine-18 fluorodeoxyglucose (F-FDG) uptake data to characterize tumor aggressiveness in terms of metastatic burden and Ki67 status.
  
  
  METHODS
  Twelve consecutive patients underwent breast and whole-body PET/MRI. During the MR scan, PET events were simultaneously accumulated. MR contrast kinetic model parametric maps were computed using the extended Tofts model, including the volume transfer constant between blood plasma and the interstitial space (K), the transfer constant from the interstitial space to the blood plasma (kep), and the plasmatic volume fraction (Vp).
  
  
  RESULTS
  Patients with systemic metastases had a significantly lower kep compared to those with local disease (0.45 vs. 0.99 min, P = 0.011). Metastatic burden correlated positively with K and standardized uptake value (SUV), and negatively with kep. Ki67 positive tumors had a significantly greater K compared to Ki67 negative tumors (0.29 vs. 0.45 min, P = 0.03). A negative correlation was found between metabolic tumor volume and transfer constant (K or Kep).
  
  
  CONCLUSIONS
  These preliminary results suggest that MR pharmacokinetic parameters and FDG-PET may aid in the assessment of tumor aggressiveness and metastatic potential. Future studies are warranted with a larger cohort to further assess the role of pharmacokinetic modeling in simultaneous PET/MRI imaging.
authors.affiliation: From the *Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology and †Center for Advanced Imaging Innovation and Research (CAI2R), New York University School of Medicine, New York, New York.
authors.forename: Nathaniel E
authors.initials: NE
authors.lastname: Margolis
authors.forename: Linda
authors.initials: L
authors.lastname: Moy
authors.forename: Eric E
authors.initials: EE
authors.lastname: Sigmund
authors.forename: Melanie
authors.initials: M
authors.lastname: Freed
authors.forename: Jason
authors.initials: J
authors.lastname: McKellop
authors.forename: Amy N
authors.initials: AN
authors.lastname: Melsaether
authors.forename: Sungheon Gene
authors.initials: SG
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D064847:Multimodal Imaging; D009362:Neoplasm Metastasis; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18