A radio frequency coil for magnetic resonance imaging includes an active
coil member (70, 70.sub.1, 170, 270) that defines an imaging volume. The
active coil member has a first open end (74) with a first cross-sectional
dimension (dactive). A shield coil member (72, 72.sub.1, 72.sub.2,
72.sub.3, 72.sub.4, 72.sub.5, 172, 172.sub.2, 272) substantially
surrounds the active coil member. The shield coil member has a
constricted open end (88) arranged proximate to the first open end of the
active coil member with a constricted cross-sectional dimension (dconst)
that is less than the cross-sectional dimension (dShieid) of the shield
coil member In some embodiments, the radio frequency coil further
includes an outer shield coil member (100) that is substantially larger
than the shield coil member (72, 72.sub.1, 72.sub.2, 72.sub.3, 72.sub.4,
72.sub.5, 172, 172.sub.2, 272), and surrounds both the active coil member
and the shield coil member.