RELATIONSHIP BETWEEN ANAL-CANAL DIAMETER AND PRESSURE EVALUATED SIMULTANEOUSLY BY ENDOSONOGRAPHY AND MANOMETRY IN NORMAL HUMAN-SUBJECTS

The study investigated the relationship between anal canal size and an al canal pressure measured simultaneously by anal endosonography and a n electronic pressure probe. Twelve normal subjects were studied. Anal endosonography was performed using a 7.5-Mhz rotating transducer of 2 -5 cm focal length covered with a sylastic balloon filled with degasse d water(25 ml). During anal endosonography an electronic manometric pr obe was passed along the side of the probe and positioned in the anal canal, The ultrasonic image was frozen when maximal anal pressure was seen at basal, squeeze, and minimal pressure during straining. An imag e was also obtained at maximal anal relaxation after rectal distension with a balloon filled with 150 ml air. The results showed that anal c anal pressure was significantly and linearly correlated with anal cana l diameter (P<0.001).