Ultrasound Pictures of “Mechanical Bowel Obstruction”

Clinical manifestations Mechanical Bowel Obstruction

Intermittent colicky pain: The pain from a strangulated bowel does not have this
colicky aspect. An obstruction of the small bowel is more painful than an
obstruction of the large bowel.

Vomiting with retention of stool and flatus: The higher the site of the obstruction, the greater the frequency and severity of vomiting.

Distended abdomen

Diagnosis Mechanical Bowel Obstruction: History, auscultation, palpation; ultrasound, plain abdominal radiograph, endoscopy

Sonographic findings Mechanical Bowel Obstruction:

x Circumscribed bidirectional peristalsis
x Dilated bowel loops containing an increased amount of fluid and stool
x Detectable causes:
– Gallstone (rapidly enlarges after entering the duodenum or colon following a
confined gallbladder perforation): Typical echogenic crescent, generally
casting a complete acoustic shadow
– Adhesive band: Echogenic constricting band associated with thickening of
the bowel wall due to venous stasis
– Tumor: Circumscribed swelling of the bowel wall with an abnormal target
pattern
– Intussusception: Target pattern with a hypoechoic inner and outer ring
(bowel wall) separated by an hyperechoic middle ring (bowel lumen between the telescoped wall segments)
– Bezoar: Foreign body obstructing the bowel lumen (hyper- or hypoechoic
structure, often with an irregular surface). Frequently casts an acoustic shadow. May cause intermittent signs of bowel obstruction, and may migrate
initially. Marked symptoms usually appear when the foreign body becomes
lodged at the ileocecal valve.
Accuracy of ultrasound diagnosis: Very high, up to 100 %. More sensitive than radiographs in early cases.

A. ULTRASOUND PICTURES of Mechanical obstruction by a circumferential antral tumor causing high-grade stenosis of the bowel lumen. Ultrasound shows that the wall thickness (W) is increased to 17 mm (cursors).  The patient presented clinically with intractable vomiting

B. ULTRASOUND PICTURES of “Adhesive bowel obstruction”. Midabdominal transverse scan shows an abnormal target pattern with a markedly thickened bowel wall that is tapered inferiorly (adhesive band). The acoustic shadow is from intraluminal air.

a, b ULTRASOUND PICTURES  “Gallstone ileus of the small bowel” a Gas in an intrahepatic bile duct (arrows) following the perforation of a calculus into the duodenum. b Gallstone obstructing the bowel lumen. The stone can be identified by its echogenic crescent and complete acoustic shadow (S). D = dilated bowel loop.

a, b ULTRASOUND PICTURES “Intussusception and bezoar obstruction of the small bowel” a Intussusception (bowel wall in bowel). Arrows: hypoechoic bowel walls. b Bezoar obstruction: fluid-filled bowel (B), nonhomogeneous foreign body with an acoustic shadow (S)