Soft-tissue fat tumours: differentiating malignant from benign using proton density fat fraction quantification MRI

Highlights: • PDFF can safely differentiate between malignant and benign fat tumors. • ALT and non-classical lipomas cannot be separated using PDFF, FAC or texture analysis. • PDFF helps in selecting which fat tumors should promptly be referred to a sarcoma center. -- Abstract: To evaluate if quantifying proton density fat fraction (PDFF) would be useful in separating lipoma, atypical lipomatous tumour (ALT) and liposarcoma in the extremities and trunk. In addition, differentiating ALT versus non-classical lipomas using magnetic resonance imaging (MRI)-based fatty acid composition (FAC) and three-dimensional (3D) texture analysis was tested.