High field strength magnetic resonance imaging in children

Thanks to the benefits of 3 tesla (T) magnetic resonance imaging (MRI), its clinical use is increasing in pediatric patients. However, technical considerations and clinical applications of 3T MRI have not been comprehensively reviewed. Potential advantages of 3T imaging over 1.5T imaging include a higher signal-to-noise ratio, higher contrast-to-noise ratio, higher spatial resolution, and shorter scan time. These merits are easily achieved in neuroimaging, musculoskeletal imaging, and pelvic imaging, while body imaging is substantially limited by dielectric shading and an increased specific absorption rate (SAR) owing to B(1) inhomogeneity and increased susceptibility artifacts. T1 and T2 relaxation times as well as chemical shifts are influenced by the higher magnetic field strength. SAR issues and dielectric shading of 3T body MRI are less problematic in pediatric patients having a smaller body size. Improved image quality can be achieved by using parallel imaging, the shortest echo time or echo train length, the highest receiver bandwidth, and improved local shimming. Potential reduction of scan time at 3T should be emphasized for pediatric patients. Three-dimensional MRI with post-processing can improve the image quality in a short acquisition time and, therefore, has become a clinical reality at 3T. A dual-source parallel radiofrequency excitation system can reduce dielectric shading, SAR, and scan time by increasing B(1) homogeneity, which eventually improves the image quality of 3T body MRI. The usefulness of 3T MRI in pediatric patients can be maximized by further technical developments and optimization.