Advanced Magnetic Resonance Imaging Applications

Parallel Imaging

Parallel MRI techniques have been introduced by most vendors. Parallel MRI methods allow for faster imaging. In parallel imaging, multiple independent receiver (phase-array) coils placed in a configuration around the subject enable acquisition of fewer data to avoid aliasing to generate an image. In addition to reducing scan time, the advantages of parallel imaging include higher spatial resolution, less motion artifact on single-shot sequences, and reduced specific absorption rate. Parallel imaging techniques can be particularly utilized on higher field strength magnets to reduce the specific absorption rate.

Clinical High Field Strength Imaging with 3.0-Tesla Imaging

In the past few years, there have been numerous installations of the latest 3.0-T clinical scanners with high field strength at various institutions around the world. In addition to research purposes, there has been increasing use of 3.0-T scanners in clinical settings. High field strength imaging with 3.0 T offers significantly higher signal-to-noise ratio in abdominal tissues, particularly when compared with currently widely available 1.5-T scanning. In 3.0-T imaging, there is approximately a twofold increase in signal-to-noise ratio. Many studies have examined the use of 3.0-T scanners in musculoskeletal and neurologic imaging applications.

Various technical issues are unique to 3.0-T imaging. For example, there is an increased specific absorption rate of approximately four times the radiofrequency deposition compared with 1.5 T. Chemical shift and susceptibility artifacts are also increased significantly. Given that there is increased field strength, the T1 relaxation time is also increased for most tissues. The T2* relaxation of tissues is shorter, and that of T2 is nearly identical. Studies are still ongoing in body imaging with high field strength and show significant promise.

Novel Tissue-Specific Contrast Agents