title: Integrated PET/MR mammography for quantitative analysis and correlation to prognostic factors of invasive ductal carcinoma.
abstract: BACKGROUND
  We investigated the relationship between 18F-FDG PET parameters and apparent diffusion coefficient (ADC) values obtained by diffusion weighted MRI (DWI) in patients with invasive ductal carcinoma (IDC). In addition, the prognostic utility of PET/MR mammography parameters was compared with that of known histologic prognostic factors.
  
  
  METHODS
  Forty-six women aged 50.7±10.5 years underwent a preoperative PET/MR mammography assessment using an integrated PET/MR scanner. T1w, T2w, DWI (b value: 50, 400, and 800 s/mm2), dynamic contrast enhancement sequences, and 18F-FDG PET imaging were performed. IDCs were assessed using SUVmax values and intratumoral heterogeneities (IH) from the 18F-FDG PET images and mean (ADCmean) and minimum ADC (ADCmin) values were measured using the DWI images. Relationships between the PET parameters and ADC values were evaluated. Furthermore, SUVmax and ADC values were compared with histologic factors, tumor size, nodal status, lymphovascular invasion, Ki-67 expression and triple negative breast cancer (TNBC).
  
  
  RESULTS
  In total 46 IDCs (2.1-7.5 cm in size) were analyzed. SUVmax (P=0.012) and elevated IH (P=0.041) were negatively correlated with ADCmin, then TNBC (P=0.013) and high Ki-67 expression (P=0.002) were associated with higher SUVmax. IDC with lymphovascular invasion had low ADCmin values (P=0.045).
  
  
  CONCLUSIONS
  18F-FDG PET metabolic parameters and ADCmin were negatively correlated. PET parameters and ADC values might reflect the expression of biological features of tumors and tumor invasiveness, respectively. Integrated PET/MR mammography seemed like to have potential of a one-stop method for evaluating and predicting the prognosis of IDC.
authors.affiliation: Department of Nuclear Medicine, Yeungnam University Medical School and Hospital, Daegu, South Korea.
authors.forename: Eunjung
authors.initials: E
authors.lastname: Kong
authors.affiliation: Department of Nuclear Medicine, Yeungnam University Medical School and Hospital, Daegu, South Korea.
authors.forename: Kyung A
authors.initials: KA
authors.lastname: Chun
authors.affiliation: Department of Pathology, Yeungnam University Medical School and Hospital, Daegu, South Korea.
authors.forename: Young K
authors.initials: YK
authors.lastname: Bae
authors.affiliation: Department of Nuclear Medicine, Yeungnam University Medical School and Hospital, Daegu, South Korea - ihcho@med.yu.ac.kr.
authors.forename: Ihn H
authors.initials: IH
authors.lastname: Cho
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging* / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D064847:Multimodal Imaging; D009361:Neoplasm Invasiveness; D049268:Positron-Emission Tomography; D011379:Prognosis
chemical_list: D019788:Fluorodeoxyglucose F18