## **Core Concept**
The question pertains to the radiological signs suggestive of urinary tract obstruction on a Computed Tomography (CT) scan. Urinary tract obstruction can result from various causes, including stones, tumors, or strictures, leading to the accumulation of urine and subsequent dilation of the renal pelvis and calyces.

## **Why the Correct Answer is Right**
The correct answer, , includes signs such as hydronephrosis (dilation of the renal pelvis and calyces due to urine accumulation), which is a direct consequence of urinary tract obstruction. This condition can lead to renal impairment if not promptly addressed. The presence of hydronephrosis on a CT scan is a key indicator of urinary tract obstruction.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option might include signs not specific to urinary tract obstruction or might not encompass the most relevant signs such as hydronephrosis.
- **Option B:** Similarly, this could include less specific or irrelevant signs, not directly pointing towards urinary tract obstruction.
- **Option D:** This option might represent signs that are either not directly related to urinary tract obstruction or are less commonly associated with this condition.

## **Clinical Pearl / High-Yield Fact**
A crucial point to remember is that while CT scans can identify signs of urinary obstruction like hydronephrosis, the clinical context (e.g., acute kidney injury, flank pain) is essential for diagnosing urinary tract obstruction. Additionally, contrast-enhanced CT scans can help in identifying the level and sometimes the cause of obstruction.

## **Correct Answer:** .