[18F]FDG whole-body PET-MR including an integrated breast MR protocol for locoregional and distant staging in breast cancer patients-a feasibility study

PURPOSE: To investigate in a feasibility study the combination of [ F]FDG whole-body (WB) positron emission tomography-magnetic resonance (PET-MR), including an integrated breast MR within a single protocol for locoregional and distant staging in breast cancer patients. METHODS: Consecutive patients with breast cancer diagnoses according to conventional imaging modalities (full-field digital mammography (FFDM) and ultrasound (US)) were prospectively included. All patients underwent [ F]FDG WB PET-MR, including an integrated dedicated breast MR (prone position) and WB PET-MR (supine position) protocol. Results of [ F]FDG WB PET-MR, including integrated breast MR, versus conventional imaging modalities were compared. RESULTS: From April 2021-April 2022, 28 patients were included. On conventional imaging, cT1-2 breast cancer was present in 22 (FFDM) and 23 (US) out of 28 patients. With regard to clinical nodal status, eight patients were considered cN0, eighteen cN1 (1-3 suspicious lymph nodes), and two patients were cN2 (four suspicious axillary lymph nodes/internal mammary lymph node metastasis). [ F]FDG WB PET-MR, including an integrated breast MR protocol, upstaged clinical tumor status in two patients and clinical nodal status in nine patients according to both [ F]FDG WB PET-MR and breast MR findings. In addition, distant metastases were detected in three patients (liver/bone), and another patient was diagnosed with a synchronous primary tumor (lung cancer). CONCLUSION: [ F]FDG WB PET-MR, including an integrated breast MR within a single protocol in breast cancer patients, is feasible and provides a promising new approach in breast cancer patients with regard to locoregional and distant staging. CRITICAL RELEVANCE STATEMENT: [ F]FDG whole-body PET-MR, including an integrated breast MR protocol, is feasible and allows locoregional and distant staging within a single imaging exam in breast cancer patients. KEY POINTS: [ F]FDG PET-MR allows the combination of breast MR and whole-body staging. Therefore, a single protocol of whole-body [ F]FDG PET-MR, including an integrated breast MRI, is investigated. [ F]FDG PET-MR, including an integrated breast MR is feasible and can be considered in daily clinical practice.