WHOLE BODY AND UPPER EXTREMITY ULTRA-HIGH FIELD MAGNETIC RESONANCE IMAGING: COIL DEVELOPMENT AND CLINICAL IMPLEMENTATION

Since Magnetic Resonance Imaging (MRI)’s introduction into the clinical imaging application arena, MRI has become one of the most promising non-invasive methods for evaluating and identifying body organs in normal and diseased conditions. In the last two decades, a few research groups have been working on addressing the challenges to Ultra-High Field (UHF) imaging (≥ 7 Tesla), such as magnetic field inhomogeneities and elevated Radiofrequency (RF) power absorption through technological developments. In recent years, imaging at 7 Tesla has shown an inherent ability to improve scan time and anatomical resolution. To address the current challenges associated with UHF imaging, this thesis presents the development of innovative whole body and extremity RF coil systems for 7 Tesla imaging. For body imaging, the transmit (Tx) coil is based on the innovative Tic-Tac-Toe (TTT) design, which possesses a load insensitive characteristic in terms of magnetic and electric field distributions. 7 Tesla homogenous whole-body in-vivo imaging with and without a receive (Rx) only insert array is demonstrated showing excellent anatomical detail. As a part of upper extremity imaging, we have developed a transverse electromagnetic (TEM) coil as a transmitter in conjunction with an eight channel receive only insert for 7 Tesla hand/forearm imaging. We have acquired a wide variety of different sequences and used post-processing methods to extract specific anatomy from high resolution scans (i.e. nerve and vessels), which in turn has helped in exploring new clinical applications, such as arm transplantation, and has added knowledge to existing ones. The developed RF coil systems and methodologies not only enhance the fundamental scientific knowledge of RF coil design approaches at high frequencies but they also add to the realm of clinical applications of UHF human imaging