Muskuloskeletal MR imaging at 3.0 T: current status and future perspectives

Abstract

Magnetic resonance (MR) imaging has become an important diagnostic tool in evaluation of the musculoskeletal system. While most examinations are currently performed at magnetic field strengths of 1.5 T or lower, whole-body MR systems operating at 3.0 T have recently become available for clinical use. The higher field strengths promise various benefits, including increased signal-tonoise ratios, enhanced T2* contrast, increased chemical shift resolution, and most likely a better diagnostic performance in various applications. However, the changed T1, T2, and T2* relaxation times, the increased resonance-frequency differences caused by susceptibility and chemicalshift differences, and the increased absorption of radiofrequency (RF) energy by the tissues pose new challenges and/or offer new opportunities for imaging at 3.0 T compared to 1.5 T. Some of these issues have been successfully addressed only in the very recent past. This review discusses technical aspects of 3.0 T imaging as far as they have an impact on clinical routine. An overview of the current data is presented, with a focus on areas where 3.0 T promises equivalent or improved performance compared 1.5 T or lower field strengths.

Evaluating automated dynamic contrast enhanced wrist 3T MRI in healthy volunteers: One-year longitudinal observational study

“…3 T MRI offers high signal to noise ratio and image resolution [23,24], which are critical to measure disease changes in complex compound joints such as wrist [25], commonly involved in rheumatoid arthritis [26]. Radiographs are still considered to be the gold standard for quantification of RA damage, even though erosive changes, are a relatively late manifestation in RA by comparison with bone marrow oedema which can be detected by MRI.…”

Musculoskeletal MR Imaging at 3 T

“…18 The resulting artifact causes a fat-water displacement in the direction of the frequencyencoding gradient. Because the precessional frequency is related directly to magnetic field, it is doubled at 3 T compared with 1.5 T MR, and the chemical shift artifact is twice as large at 3 T compared with 1.5 T. 20 This artifact often is detected easily (see Fig. 1A) and may not impact on image interpretation.…”

“…It results in an improved resolution of distinct resonances, allows more metabolites and coupling patterns to be identified, and facilitates quantification on magnetic resonance spectroscopy. In addition, the increased chemical shift separation at 3 T allows for shorter fat saturation pulses, thus decreasing the time needed for fat saturation sequences during a multisection acquisition, compared with imaging at 1.5 T. 20 Magnetic susceptibility artifact Magnetic susceptibility artifact also is increased at higher magnetic field strengths. Susceptibility is related to the internal magnetization induced in tissue by the external magnetic field.…”

“…20 This moves the chemical shift away from the area of clinical interest. This approach, however, assumes that the area of interest is known before imaging.…”

Standardized quantitative measurements of wrist cartilage in healthy humans using 3T magnetic resonance imaging

“…It is noteworthy that most of the MRI studies reported so far have been conducted using a conventional magnetic field, i.e., 1.5T but a few studies have clearly indicated that MRI investigations at higher field, e.g., 3T could provide a better signal/noise ratio and a more accurate identification of certain anatomical structures [16][17][18][19] .…”