title: Quantitative Assessment of Breast Parenchymal Uptake on 18F-FDG PET/CT: Correlation with Age, Background Parenchymal Enhancement, and Amount of Fibroglandular Tissue on MRI.
abstract: Background parenchymal enhancement (BPE), and the amount of fibroglandular tissue (FGT) assessed with MRI have been implicated as sensitive imaging biomarkers for breast cancer. The purpose of this study was to quantitatively assess breast parenchymal uptake (BPU) on18F-FDG PET/CT as another valuable imaging biomarker and examine its correlation with BPE, FGT, and age.
  
  
  METHODS
  This study included 129 patients with suspected breast cancer and normal imaging findings in one breast (BI-RADS 1), whose cases were retrospectively analyzed. All patients underwent prone18F-FDG PET/CT and 3-T contrast-enhanced MRI of the breast. In all patients, interpreter 1 assessed BPU quantitatively using SUVmaxInterpreters 1 and 2 assessed amount of FGT and BPE in the normal contralateral breast by subjective visual estimation, as recommended by BI-RADS. Interpreter 1 reassessed all cases and repeated the BPU measurements. Statistical tests were used to assess correlations between BPU, BPE, FGT, and age, as well as inter- and intrainterpreter agreement.
  
  
  RESULTS
  BPU on18F-FDG PET/CT varied among patients. The mean BPU SUVmax± SD was 1.57 ± 0.6 for patients with minimal BPE, 1.93 ± 0.6 for mild BPE, 2.42 ± 0.5 for moderate BPE, and 1.45 ± 0.3 for marked BPE. There were significant (P < 0.001) moderate to strong correlations among BPU, BPE, and FGT. BPU directly correlated with both BPE and FGT on MRI. Patient age showed a moderate to strong indirect correlation with all 3 imaging-derived tissue biomarkers. The coefficient of variation for quantitative BPU measurements with SUVmaxwas 5.6%, indicating a high reproducibility. Interinterpreter and intrainterpreter agreement for BPE and FGT was almost perfect, with a κ-value of 0.860 and 0.822, respectively.
  
  
  CONCLUSIONS
  The results of our study demonstrate that BPU varied among patients. BPU directly correlated with both BPE and FGT on MRI, and BPU measurements were highly reproducible. Patient age showed a strong inverse correlation with all 3 imaging-derived tissue biomarkers. These findings indicate that BPU may serve as a sensitive imaging biomarker for breast cancer prediction, prognosis, and risk assessment.
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria Department of Diagnostic and Interventional Radiology, University Hospital Frankfurt, Frankfurt am Main, Germany; and.
authors.forename: Doris
authors.initials: D
authors.lastname: Leithner
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria.
authors.forename: Pascal A
authors.initials: PA
authors.lastname: Baltzer
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria.
authors.forename: Heinrich F
authors.initials: HF
authors.lastname: Magometschnigg
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria.
authors.forename: Georg J
authors.initials: GJ
authors.lastname: Wengert
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Georgios
authors.initials: G
authors.lastname: Karanikas
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria thomas.helbich@meduniwien.ac.at.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Helbich
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Weber
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wadsak
authors.affiliation: Department of Biomedical Imaging and Image-Guided Therapy, Division of Molecular and Gender Imaging, Medical University of Vienna, Vienna, Austria.
authors.forename: Katja
authors.initials: K
authors.lastname: Pinker
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D001692:Biological Transport; D001940:Breast / Q000166:cytology* / Q000000981:diagnostic imaging / Q000473:pathology*; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D000072356:Parenchymal Tissue / Q000166:cytology / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D000072078:Positron Emission Tomography Computed Tomography; D055815:Young Adult
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG PET/CT; breast parenchymal uptake; imaging biomarker; magnetic resonance imaging