Which of the following is the best radiological investigation in a case of suspected splenic rupture?

**Core Concept**
In cases of suspected splenic rupture, prompt and accurate imaging is crucial for diagnosis and management. The spleen is a highly vascular organ, and its rupture can lead to severe bleeding. Therefore, the chosen radiological investigation must be able to quickly and accurately detect even small amounts of bleeding or splenic injury.

**Why the Correct Answer is Right**
The best radiological investigation for suspected splenic rupture is non-contrast computed tomography (CT) of the abdomen. Non-contrast CT is highly sensitive for detecting free intraperitoneal fluid, which is often the first sign of splenic rupture. It can also accurately assess the extent of splenic injury and identify any associated injuries to other organs. The non-contrast protocol helps to minimize the risk of artifact from bowel motion and allows for better visualization of the spleen.

**Why Each Wrong Option is Incorrect**
**Option A:** Ultrasound is not the best initial investigation for suspected splenic rupture due to its limited ability to detect free intraperitoneal fluid and its operator dependence.

**Option B:** MRI is not typically used in the acute setting of suspected splenic rupture due to its longer scanning time and lower availability compared to CT.

**Option C:** Plain abdominal X-ray is not sensitive for detecting splenic rupture and is often used as a screening tool to identify more obvious injuries, such as fractures of the pelvis or long bones.

**Clinical Pearl / High-Yield Fact**
In cases of suspected splenic rupture, a non-contrast CT of the abdomen is the investigation of choice due to its high sensitivity and specificity for detecting free intraperitoneal fluid and associated injuries.

**Correct Answer:** C. Non-contrast computed tomography (CT) of the abdomen.