Abstract
Purpose: Background parenchymal enhancement (BPE), and the amount of fibroglandular tissue (FGT) assessed with magnetic resonance imaging (MRI) have been implicated as sensitive imaging biomarkers for breast cancer. The purpose of the study was to quantitatively assess the parenchymal uptake (BPU) on 18F-Fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) of the breast as another valuable imaging biomarker and examine its correlation with BPE, FGT, and age. Methods: There were 129 patients with normal imaging findings in the one breast (BI-RADS 1) included in this IRB-approved study, whose cases were retrospectively analyzed. All patients underwent prone 18F-FDG PET/CT and 3T CE-MRI of the breast. In all patients, Reader 1 assessed BPU quantitatively using maximum standard uptake values. Two readers assessed FGT and BPE of the normal contralateral breast by subjective visual estimation, as recommended by BI-RADS®. Reader 1 re-assessed all cases and repeated BPU measurements. Appropriate statistical tests were used to assess correlations of BPU, BPE, FGT, and age, as well as inter- and intra-reader agreement. Results: BPU on 18F-FDG PET/CT varied between patients. The mean BPU SUVmax values ± SD for patients with minimal BPE were 1.57 ± SD 0.6, for mild BPE 1.93 ± SD 0.6, for moderate BPE 2.42 ± SD 0.5, and for marked BPE 1.45 ± SD 0.3. There were significant (P<0.001) moderate to strong correlations among BPU, BPE, and FGT. BPU is directly correlated with both BPE and FGT on MRI. Patient age showed a moderate to strong indirect correlation with all three imaging-derived tissue biomarkers. The coefficient of variation for quantitative BPU measurements with SUVmax was 5.6%, indicating a high reproducibility. Inter-reader and intra-reader agreement for BPE and FGT was almost perfect, with a Kappa value of 0.860 and 0.822, respectively. Conclusion: The results of our study demonstrate that BPU varies between patients. BPU is directly correlated with both BPE and FGT on MRI, and BPU measurements are highly reproducible. Patient age showed strong inverse correlation with all three imaging-derived tissue biomarkers. These findings indicate that BPU may serve as a sensitive imaging biomarker for breast cancer prediction, prognosis, and risk assessment.
- Breast
- MRI
- PET/CT
- Breast Parenchymal Enhancement
- Breast Parenchymal Uptake
- [18F]FDG PET/CT
- imaging biomarker
- magnetic resonance imaging
- Copyright © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.