**Question:** Which of the following is the most sensitive imaging modality for the diagnosis of ureteric stones in a patient with acute colic?

**Core Concept:** The correct imaging modality for diagnosing ureteric stones depends on the stage of the disease and the availability of imaging facilities. In acute colic, the goal is to identify the stone, locate it, and determine the best management strategy.

**Why the Correct Answer is Right:** Computed tomography (CT) scan with IV contrast is the most sensitive imaging modality for the diagnosis of ureteric stones in acute colic. CT scan provides high-resolution images of the urinary tract, allowing for identification of the stone, its size, location, and the presence of surrounding inflammation or complications like hydronephrosis or renal calculi.

**Why Each Wrong Option is Incorrect:**

A. Ultrasonography (USG): While USG is a non-invasive and readily available imaging modality, it is less sensitive as compared to CT scan in detecting ureteric stones, especially for stones smaller than 5mm.

B. X-ray KUB (Kidney, Ureter, and Bladder): X-ray KUB is a basic radiological procedure, which is less sensitive than CT scan in detecting stone size, location, and complications.

C. Plain abdominal X-ray: Plain abdominal X-ray is the least sensitive imaging modality for ureteric stones, as it is unable to visualize the ureteric stone and has limited ability to detect complications.

D. Magnetic resonance urography (MRU): MRU is a newer technique, but it is less readily available than CT scan and is more time-consuming, making CT scan a more practical choice for acute colic patients.

**Core Concept:** In emergency situations, CT scan is the preferred imaging modality for diagnosing ureteric stones due to its high sensitivity in detecting stone size, location, and complications.

**Core Concept:** Acute colic patients require a rapid diagnosis to guide appropriate management and prevent complications like hydronephrosis, sepsis, and renal failure. A timely diagnosis using a sensitive imaging modality like CT scan enables prompt intervention, such as ureteroscopy or analgesic management, and reduces the risk of complications.

**Why Each Wrong Option is Incorrect:**

A. Ultrasonography (USG): USG is less sensitive than CT scan in detecting ureteric stones and is not as valuable for detecting complications.

B. X-ray KUB: X-ray KUB is less sensitive than CT scan in detecting stone size, location, and complications and lacks the ability to differentiate ureteric stones from other causes of colic pain.

C. Plain abdominal X-ray: Plain abdominal X-ray is less sensitive than CT scan in detecting stone size, location, and complications and has limited ability to differentiate ureteric stones from other causes of colic pain.

D. Magnetic resonance urography (MRU): MRU is less sensitive than CT scan in detecting stone size, location, and complications and is less readily available than CT scan in many settings.

**Cl