[Ultrasound ileus diagnosis]

Abstract

Bowel obstruction is an acute alarming situation with limited diagnostic conditions. Therapeutic decisions must be taken in time. Diagnostic differentiation between incomplete or complete bowel obstruction, intestinal obstruction and paralytic ileus is often uncertain and the underlying cause difficult to detect. Besides plain films in acute abdomen the ultrasound examination presents important additional informations: 1st Dilated intestinal loops and gas caps correlate with the characteristic x-ray finding, i.e. erected dilated intestinal loops with fluid levels. The location of the obstruction is defined in small bowel obstruction by differentiation between jejunum (with Kerckring folds) and ileum (without Kerckring folds). In large bowel obstruction the caecum is dilated and a collapse of the distal colon is detectable. 2nd Additional sonographical findings are: oedema of the intestinal walls, hyperpendulum peristalsis or absence of peristalsis, sedimentation of intestinal contents, pearlstring-like lined up gas bubbles under the ventral intestinal walls, and concomitant ascites. Duplex sonographical studies of the intestinal peristalsis may help to differentiate between mechanical obstruction and paralytic ileus. 3rd In bowel obstruction stenoses can be detected as a result of tumour, Crohn's disease diverticulitis, invagination, strangulated hernias or gall stone ileus. Intestinal adhesions cannot be found by ultrasound. Small and large bowel is dilated in paralytic ileus. Numerous causes like acute pancreatitis, ureteral colic, free gastrointestnal perforation and so on can be diagnosed. 4th In ileus of vascular disorder early diagnosis is high important, but inspite of colour flow imaging diagnostic possibilities are limited. 5th Sonographical diagnosis is of special interest when the x-ray plain films is "empty". The lack of massive fluid collection and meteorism allows an optimal ultrasound examination. In this early phase disorders of peristalsis and intestinal walls are reliably found, and it is easier to find the cause of bowel obstruction. In this way the definitive diagnosis can be arrived at earlier, because it still takes up to 6 hours to obtain the classical x-ray finding. There is a rule that the earlier ultrasound is done, the more findings one will get.