PRELIMINARY-RESULTS FROM ATTENUATION-SLOPE MAPPING OF PLAQUE USING INTRAVASCULAR ULTRASOUND

Excised femoral and iliac artery segments have been examined with 20 M Hz intravascular ultrasound followed by histological assessment. Durin g the ultrasound examinations, radio-frequency (RF) data were recorded digitally, and used for calculating local values of attenuation slope throughout the tissue, using a frequency-domain technique. The RF dat a were also reconstructed as conventional ultrasound images, and the a ttenuation-slope information presented as a thresholded colour overlay . Areas identified as degenerative plaque in the histological assessme nts were usually found to correspond to areas of high attenuation slop e, and were clearly identified from the pattern of colours on the comb ined image. Some examples are presented, illustrating the appearance o f various pathologies imaged by this technique.