Multiparametric ¹⁸F-FDG PET/MRI of the Breast: Are There Differences in Imaging Biomarkers of Contralateral Healthy Tissue Between Patients With and Without Breast Cancer?

Abstract

The rationale was to assess whether there are differences in multiparametric 18 F-FDG PET/MRI biomarkers of contralateral healthy breast tissue in patients with benign and malignant breast tumors. Methods: In this institutional review board-approved prospective single-institution study, 141 women with imaging abnormalities on mammography or sonography (BI-RADS 4/5) underwent combined 18 F-FDG PET/MRI of the breast at 3T with dynamic contrastenhanced MRI, diffusion-weighted imaging, and the radiotracer 18 F-FDG. In all patients, the following imaging biomarkers were recorded for the contralateral (tumor-free) breast: breast parenchymal uptake (BPU) (from 18 F-FDG PET), mean apparent diffusion coefficient (from diffusion-weighted imaging), background parenchymal enhancement (BPE), and amount of fibroglandular tissue (FGT) (from MRI). Appropriate statistical tests were used to assess differences in 18 F-FDG PET/MRI biomarkers between patients with benign and malignant lesions. Results: There were 100 malignant and 41 benign lesions. BPE was minimal in 61 patients, mild in 56, moderate in 19, and marked in 5. BPE differed significantly (P , 0.001) between patients with benign and malignant lesions, with patients with cancer demonstrating decreased BPE in the contralateral tumorfree breast. FGT approached but did not reach significance (P 5 0.055). BPU was 1.5 for patients with minimal BPE, 1.9 for mild BPE, 2.2 for moderate BPE, and 1.9 for marked BPE. BPU differed significantly between patients with benign lesions (mean, 1.9) and patients with malignant lesions (mean, 1.8) (P , 0.001). Mean apparent diffusion coefficient did not differ between groups (P 5 0.19). Conclusion: Differences in multiparametric 18 F-FDG PET/MRI biomarkers, obtained from contralateral tumor-free breast tissue, exist between patients with benign and patients with malignant breast tumors. Contralateral BPE, BPU, and FGT are decreased in breast cancer patients and may potentially serve as imaging biomarkers for the presence of malignancy.

Simultaneous FAPI PET/MRI Targeting the Fibroblast-Activation Protein for Breast Cancer

“…Although the number of patients in our study was not sufficiently powered to exclude differences, the findings were well in line with immunohistochemical data on consistent FAP expression in breast cancer samples independent of tumor type (13). Background uptake in healthy breast tissue correlated with young age and dense breasts but only slightly higher than published data at 18 F-FDG-PET/MRI (eg, mean SUV max = 1.8 [range, 0.9-4.6]) (23).…”

Evaluation of primary breast cancers using dedicated breast PET and whole-body PET

“…We observed inter-patient heterogeneity in the contralateral breast background signal in both modalities, which resulted in minimal difference in tumor-background ratio following normalization by the contralateral breast in wbPET. Similar variation in background parenchymal FDG uptake have been observed in other studies 24 , 25 . While limiting the PET scans at the early follicular phase of the menstrual cycle may minimize the background parenchymal signal 26 , the patient’s treatment planning should be taken into consideration for scheduling without imposing additional burden.…”

Evaluation of the Predictive Potential of 18F-FDG PET and DWI Data Sets for Relevant Prognostic Parameters of Primary Soft-Tissue Sarcomas

“…A few studies have already demonstrated the potential of integrated PET/MR imaging for local and whole-body staging as well as treatment monitoring of sarcoma patients [ 14 , 22 , 23 ]. Furthermore, this new hybrid imaging modality enables simultaneous acquisition of certain quantitative imaging parameters, reflecting different aspects of the underlying tumor biology [ 24 , 25 ]. It has previously been reported that histopathological response can be predicted based on changes in the metabolic activity of the tumors under neoadjuvant treatment.…”