Quadrature radio frequency coil for magnetic resonance imaging

摘要

In a magnetic resonance imaging apparatus, a radio frequency coil (40) is disposed closely adjacent the patient's head. The radio frequency coil includes a first annular ring (80, 114) around the patient's head from which a first plurality of legs (82, 116) extend. Opposite legs are interconnected equidistant from the first annular ring to form a virtual ground connection (84, 118). In the embodiment of FIGURE 6, a second annular ring (120) is disposed parallel to the first annular ring with a second plurality of legs (122) extending between the first and second annular rings. By adjusting a ratio rho of the current flow in the loops defined by the first legs, the first annular ring and virtual ground relative to the current loops defined by the second legs and the first and second annular rings, the linearity of the B1 field within the head coil is selectively adjustable (FIGURE 8). <IMAGE>