How I Do It: Using the Dixon Method and Fat-Water Imaging in Musculoskeletal MRI.

Abstract

The Dixon method is a fat suppression method based on the separation of fat and water signals. Originally limited to gradient-echo sequences, it can now be integrated with fast/turbo spin-echo MRI sequences, unlocking its potential for musculoskeletal imaging. Key advantages include robust fat suppression and the ability to generate four image contrasts from a single acquisition-including fat-only images, which are specific to the signal of fat-thereby providing opportunities for protocol optimization. Additionally, quantitative data readily available from Dixon sequences provide information on intralesional fat, which may serve as a diagnostic aid complementing the morphologic assessment. The Dixon method has been increasingly used in musculoskeletal MRI, primarily in bone marrow imaging to help detect and characterize focal marrow lesions, vertebral compression fractures, and degenerative spine conditions. Other applications include whole-body imaging, imaging of rheumatologic and neuromuscular disorders, tumor characterization, and imaging near metallic implants. Limitations include fat-water swapping artifacts and unreliable fat quantification (eg, when mineralization is increased). This article covers the strengths, applications, and limitations of the Dixon method in musculoskeletal MRI, with practical tips for incorporating this method into routine protocols, highlighting its most effective applications and noting areas where it is less reliable.