R A D I O L O G Y

HISTORY:

52 year old woman with two weeks of intermittent crampy abdominal pain, now presents to the emergency room with bloody diarrhea. Plain films of the abdomen were unremarkable. Select images from a CT scan of the abdomen are made available to you.

DIAGNOSTIC IMAGING:
 

FINDINGS:
 
There is no evidence of gastrointestinal tract obstruction. Contrast material is seen within the distal colon, ruling out complete bowel obstruction. A multiple layered lesion of the right colon, which includes fat-density, demonstrates a "target" appearance. This finding is highly suggestive of an ileocolic or colocolic intussusception. A soft tissue density mass at the most distal extent of the intussusception (in the transverse colon) is suspicious for a colonic mass acting as a lead point.

DISCUSSION:

Intussusception can be described as the telescoping of one segment of the bowel into an adjacent one. It is relatively uncommon in adults (6% of all intussusceptions.) However, unlike pediatric cases, there is often a lead point or specific cause in 80% of adult cases. Adult colonic intussusceptions are usually due to a primary colon cancer while those in the small bowel are often due to benign tumors.

Plain films of the abdomen may reveal a soft-tissue mass and/or small bowel obstruction. Approximately 25% of the plain films will be normal. Barium studies can reveal the classic "coil-spring" appearance at the point of intussusception. Cross-sectional imaging such as ultrasound and CT may show the "doughnut/target/bull's eye" sign or a "pseudo-kidney" sign.

REFERENCES:
 
1. RM Gore, MS Levine, I Laufer, "Textbook of Gastrointestinal Radiology", 1994, WB Saunders.

2. W Dahnert, "Radiology Review Manual -Third Ed.", 1996, Williams & Wilkins.