What are the differential diagnosis for adult intussusception?
The main differential is that of transient intussusception, which is an incidental finding requiring no treatment or follow-up. Other conditions to be consider include intestinal lipoma (without intussusception), gallstone ileus (cholesterol stones can have a layered appearance with fat density).
What is the typical radiology finding of intussusception on CT?
Best know is the so-called bowel-within-bowel configuration, in which the layers of the bowel are duplicated forming concentric rings. At the proximal end of the intussusception there will be two concentric enhancing / hyperdense rings, formed by the inner bowel and the folded edge of the outer bowel. As one images further along the intussusception the mesentery (fat and vessels) will form a crescent of tissue around the compressed inner most lumen, surrounded by the two layers of the outer enveloping bowel. Even further distally the lead point (if present) will be visualised
Mechanical small bowel obstruction secondary to proximal/ mid ileal intussusception at the left iliac fossa, with the dilated proximal small bowel measuring up to 4 cm in diameter.
No associated mass identified.
Contrast is seen in the distal ileum, suggesting this is not a complete obstruction.
No pneumoperitoneum to suggest perforation. No intraperitoneal free fluid.
Grossly enlarged prostate measuring approximately 72mmx 80mm x 75mm (TR x AP x SI).
Sigmoid diverticular disease without active diverticulitis. Multiple hepatic and bilateral renal cysts. Mildly atrophic bilateral kidneys. Minor fatty infiltration of the liver. Absent gallbladder. Prominent common bile duct. Fat herniation into bilateral inguinal canals.
Nasogastric tube in a satisfactory position.
Image lung bases are clear. Cardiomegaly.
Multilevel lumbar vertebral degenerative changes.
Conclusion:
Mechanical small bowel obstruction was secondary to proximal/ mid ileal intussusception.
This case also demonstrates the relative insensitivity of conventional radiographs for small bowel obstruction.