Bore-Lining Slot Antennas for 7T Body MRI

Magnetic Resonance Imaging (MRI) has become indispensable in numerous areas in medicine and biomedical research. Last year, 7 Tesla (T) MRI became cleared by the Food and Drug Administration (FDA) for head and extremity regions promising improved visualization of small structures and subtle pathologies. In recent years, numerous coil structures have been proposed to improve 7T imaging. These designs rely on narrow conducting elements that are positioned close to the body and rely on the transverse radiofrequency (RF) magnetic fields produced primarily (though not entirely) by the positioning of discrete conductors oriented parallel to the main magnetic field (B0). These designs unfortunately, do not allow efficient excitation in the body with satisfactorily low local Specific Absorption Rate (SAR). Here, we mitigate these challenges using two main themes: 1) by introducing slot antennas which create distribute current patterns on the surface of the conductors and 2) by introducing lifted coil designs placed adjacent to the magnet bore ("bore-lining"). The design minimally affects patient comfort and exhibits improvement in B1+ homogeneity, B1+ efficiency and SAR reduction compared to traditional dipole-like array setups.