Association between ultrafast breast MRI enhancement timing and 18F-FDG uptake in breast cancer

Purpose: Ultrafast dynamic contrast-enhanced breast magnetic resonance imaging depicts very early contrast kinetics, whereas fluorodeoxyglucose F18 positron emission tomography/computed tomography reflects tumor glucose metabolism. We investigated whether first-enhancement timing is associated with metabolic activity in malignant breast lesions and secondarily assessed correlations in lesion size across modalities.Materials and Methods: This single-center retrospective study included 61 women with 61 histopathologically confirmed malignant breast lesions who underwent both examinations within 4 weeks. The frame of first unequivocal enhancement was recorded. Lesion diameters were measured on the first enhancing ultrafast frame and early arterial phase; positron emission tomography/computed tomography lesion diameter and maximum standardized uptake value were obtained from official reports.Results: Forty-seven lesions (77.0%) first enhanced in frame 1. Later enhancement was associated with lower maximum standardized uptake value (ρ = −0.590), smaller ultrafast magnetic resonance imaging diameter (ρ = −0.343), and smaller early arterial-phase magnetic resonance imaging diameter (ρ = −0.340). Median maximum standardized uptake value was 6.30 in lesions enhancing in frame 1 and 1.94 in lesions enhancing in frame 2 or later. Corresponding median ultrafast magnetic resonance imaging diameters were 21.80 and 12.90 mm, and median early arterial-phase diameters were 22.20 and 13.00 mm, respectively. Lesion diameters measured on positron emission tomography/computed tomography and magnetic resonance imaging were strongly correlated (ρ = 0.800–0.976).Conclusion: Earlier first enhancement on ultrafast breast magnetic resonance imaging was associated with higher fluorodeoxyglucose F18 uptake and larger magnetic resonance imaging-measured lesion size in malignant breast lesions.