The following are radiological features of sigmoid volvulus except –
**Core Concept**
Sigmoid volvulus is a rare cause of intestinal obstruction characterized by the twisting of the sigmoid colon around its mesenteric axis. This twisting leads to ischemia and potentially necrosis of the bowel wall. Radiological features are crucial for diagnosing this condition.
**Why the Correct Answer is Right**
The correct answer is likely to be the option that does not match the typical radiological features of sigmoid volvulus. These features include a "bird's beak" appearance of the sigmoid colon on abdominal X-rays, a "coffee bean" or "U" shape on barium enemas, and a "corkscrew" or "whirlpool" appearance of the colon on CT scans. These signs are due to the twisting and ischemia of the sigmoid colon.
**Why Each Wrong Option is Incorrect**
**Option A:** This option might be a feature of sigmoid volvulus, such as a "bird's beak" appearance or a "coffee bean" shape, making it incorrect.
**Option B:** This option might be a feature of sigmoid volvulus, such as a "corkscrew" or "whirlpool" appearance, making it incorrect.
**Option D:** This option is not a feature of sigmoid volvulus and might be a feature of another condition, such as a "target sign" seen in intussusception.
**Clinical Pearl / High-Yield Fact**
A key radiological feature of sigmoid volvulus is the "bird's beak" appearance, which is due to the distal portion of the sigmoid colon being stretched and narrowed as it twists around its mesenteric axis.
**Correct Answer: D.**