The design of a radiofrequency coil of U-shaped geometry, specifically
intended to image individual knuckle joints of the hand, has been inv
estigated, The coil geometry is that of a ''split and opened'' birdcag
e coil, The optimum leg positions for such a U-shaped coil have been t
heoretically predicted using a novel technique that considers both the
signal-to-noise ratio and the homogeneity of the field-of-view. Two p
articular coils of this type have been constructed, each optimum for a
different size of image space and assuming a different source of imag
e noise (sample-dominated or coil-dominated). The experimentally deter
mined radiofrequency fields produced by the coils correspond well to t
heory, Either coil can be used to obtain good-quality, high-resolution
(130 mu m x 130 mu m in-plane) images in vivo of the first, second, o
r fifth metacarpophalangeal joints of the hand, sites of particular in
terest in the study of arthritis.