Endorectal color and duplex imaging of the normal rectal wall and rectal masses

This study investigates the ability of endorectal ultrasonography aided by color flow and pulse wave Doppler techniques to identify submucosal arterial plexuses of the normal rectal wall and to detect vessels supplying rectal wall masses. Color flow and pulsed wave Doppler analysis of 62 normal submucosal arterial plexuses and vessels feeding rectal wall masses (one rectal endometriosis and seven rectal cancers) was performed. The color signals from normal submucosal arterial plexuses and the one case of rectal endometriosis were judged to be sparse or decreased in comparison to color signals from rectal cancers. The median and mean P1 values for normal submucosal arterial plexuses were significantly greater than those for the central feeding vessels or small peripheral vessels within rectal masses. Our experience with color and duplex endorectal ultrasonography suggests that different vascular structures exist in normal persons compared to those in rectal wall masses. Pathologically, rectal cancers possess vessels with and without a smooth muscle layer, which may produce the high and low resistance signals identified by pulse Doppler.