Linear foreign body in cats: ultrasound signs
1-year-old indoor cat with repeated vomiting and anorexia for 3 days. Its owner is missing a ball of wool. On ultrasound the jejunum appears bunched and pleated.
Which ultrasound finding confirms the suspicion of a linear foreign body, and what should you check on physical examination?
chevron_right Show answer and explanation
A. Loops with a target sign; check the rectum
The target sign is typical of intussusception. Although it may coexist, it is not the hallmark of a linear foreign body, and the anchor is usually in the mouth or pylorus, not the rectum.
B. Thickened intestinal wall with preserved layering; check the peripheral lymph nodes
This pattern is typical of inflammatory enteropathy or small-cell lymphoma, not a linear foreign body.
C. Anechoic free fluid without other findings; check the bladder
Free fluid is non-specific. If accompanied by hyperechoic fat or free gas, it suggests perforation, a complication of linear foreign bodies.
D. A continuous hyperechoic line in the lumen, with or without shadowing, around which the intestine is pleated; check the base of the tongue
Correct. The intestine bunches over the thread, seen as a hyperechoic line in the lumen. In cats the thread is often anchored under the tongue, so always examine it (sedation may be needed).
lightbulb Key takeaway
A linear foreign body is a surgical emergency: peristalsis makes the thread saw through the mesenteric border and perforate the bowel. Never pull on a thread anchored under the tongue or at the anus; cut it and leave removal to surgery. Look for signs of peritonitis (fluid, hyperechoic fat, free gas).
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.