What diagnostic test is required after a suspected bladder injury?

In the context of a suspected bladder injury, cystography is the preferred diagnostic test, especially after ensuring that there is no concurrent urethral injury. This procedure involves the use of contrast media and imaging techniques to visualize the bladder and identify any potential ruptures or abnormalities.

Cystography is essential because it provides clear images of the bladder while allowing for a comprehensive assessment of its integrity. It specifically helps in detecting extravasation of the contrast material, which is indicative of a bladder injury.

While CT scans are also valuable for diagnosing abdominal injuries and can visualize bladder injuries, they may not provide the targeted information that cystography offers regarding the bladder's condition post-injury. Ultrasound can be useful but generally lacks the specificity required for assessing bladder injuries comprehensively. An intravenous pyelogram (IVP) is more focused on kidney function and anatomy rather than directly assessing bladder integrity.

Therefore, the correct approach after a suspected bladder injury is to perform cystography once urethral injury has been ruled out, making this the most suitable diagnostic test in this situation.