Fat suppression at three-dimensional T1-weighted MR imaging of the hands: Dixon method versus CHESS technique

Abstract

The Dixon method yields more effective fat suppression and higher SNR than the CHESS technique at 3D T1-weighted MR imaging of the hands.

Applications of the Dixon technique in the evaluation of the musculoskeletal system

“…The multi-point Dixon techniques (with three or more echoes) do not exhibit significant interference by magnetic field heterogeneity and therefore result in efficient fat suppression and are considered by some studies to be better than STIR because they have better SNRs, shorter acquisition times, and equivalent or better spatial resolution (2,5) . Therefore, as previously demonstrated (2,5,27) , the Dixon technique allows satisfactory images to be obtained in regions with heterogeneity in the local magnetic field (near metallic materials or tissues with excess iron caused by hemosiderosis), as well as in highly susceptible anatomical areas where chemical fat saturation becomes difficult Figure 2. Contrast-enhanced coronal images of the thighs of a 59-year-old female patient with various pulse sequences: T1-weighted FSE sequence with fat suppression (A) and T1-weighted IDEAL sequence (B).…”

“…The Dixon technique has several characteristics that broaden its clinical applications, including homogeneous fat suppression, reduction of magnetic susceptibility artifacts in the presence of metallic materials, and the use after intravenous contrast administration, as well as fat quantification. Of those applications, fat suppression is notable, because it improves the contrast between tissues and highlights certain pathological changes (5,26,27) .…”

“…In STIR sequences, the inversion time is chosen to nullify the contribution of fat after inverting the longitudinal magnetization, being little affected by heterogeneity of the B0 magnetic field. The disadvantages of the STIR sequence include the smaller SNR and the fact that it is not suitable for intravenous contrast-enhanced imaging, because it suppresses the fat signal based on its short T1, and other tissues with a short T1 (such as intravenous contrast-enhanced areas) are therefore also suppressed (4,5,27) . In addition, the STIR sequence is affected by the lack of uniformity of the B1 magnetic field, which leads to imperfect inversion in certain regions and ineffective fat suppression.…”

“…The choice of the best fat suppression sequence should take into consideration the anatomy of the region analyzed. Therefore, although fat saturation is the sequence most commonly applied in daily practice-because of its fat selectivity, high SNR, and relatively fast examination time at sites where the anatomy presents irregular contours with abrupt changes between soft tissues, bone and metalic implants, as well as in areas requiring a large field of view (spine, thighs, and legs)-the technique promotes artifacts that do not satisfactorily suppress fat (26)(27)(28) , as shown in Figure 2.…”

Comparison between 3-point Dixon- and CHESS-based OMERACT-recommended MRI protocols in hands of patients with suspicion of early rheumatoid arthritis

“…Previous studies compared fat suppression effectiveness and image quality between Dixon and CHESS sequences in hands of healthy volunteers [11][12][13]. To our knowledge, no previous study compared complete Dixon-and CHESS-based OMERACT recommended MRI protocols for the quantification of synovitis, tenosynovitis, osteitis and erosions according to RAMRIS in hands of patients with suspected RA [11].…”