A new synthetic aperture system for intraluminal imaging has been test
ed using a 32 element, 20 MHz circular array wrapped around the surfac
e of a catheter appropriate for coronary artery applications. This sys
tem is based on an optimal reconstruction method that has been extende
d to reduce grating lobes using a slight modification to classic synth
etic aperture data acquisition. Optimal reconstruction filters have be
en derived for two different operating modes based on this new data ac
quisition strategy. Imaging results on a wire target phantom show that
spatial resolution is a simple linear function of depth, reaching a m
inimum 6 dB beam width of approximately 2.2 wavelengths. Sidelobe leve
ls are inherently high for this system because of the small number of
firings used to synthesize an aperture. Optimal reconstruction filters
, however, can reduce these sidelobes to at least -20 dB in all cases.
Finally, images of an excised segment of porcine femoral artery demon
strate the overall performance of the system as an intraluminal imager
. (C) 1995 Academic Press, Inc.