Radiology, Vol 133, 681-685, Copyright © 1979 by Radiological Society of North America
Sonographic patterns of distended, fluid-filled bowel
AC Fleischer, AD Dowling, ML Weinstein and AE James Jr
When small or large bowel is distended with fluid, certain characteristic
features can be seen on ultrasound which cannot be visualized when the
bowel is collapsed. The proximal and distal portions of the small bowel can
frequently be differentiated both in vitro and in vivo by the echoes
emanating from the valvulae conniventes ("keyboard sign"). This depends
upon the angle at which the bowel segment is scanned in relation to its
long axis, the relative amount of intraluminal fluid and gas, the diameter
of the bowel in relation to the beam width of the transducer, and the
intrinsic resolution of the scanning system. Similarly, the ascending and
transverse colon can be recognized by haustral sacculations, the distal
rectosigmoid colon and rectum by the rectal valves. The tubular shape,
characteristic arrangement and location, and peristaltic motion of most
fluid-filled bowel segments are helpful in differentiating loops of bowel
from cystic masses in the abdomen or pelvis.
