**Core Concept**
Calcification refers to the accumulation of calcium salts in a tissue or organ, which can be a sign of various pathological conditions. In medical imaging, detecting calcification is crucial for diagnosing conditions such as kidney stones, bone tumors, and vascular calcification.

**Why the Correct Answer is Right**
CT scans are highly sensitive and specific for detecting calcification due to their ability to provide high-resolution images of tissues and bones. The CT scan's high attenuation coefficients allow it to accurately differentiate between calcified and non-calcified tissues. This is particularly useful for visualizing calcified structures such as kidney stones, bone spurs, and vascular calcification.

**Why Each Wrong Option is Incorrect**
**Option A:** X-rays are less sensitive for detecting calcification, especially in soft tissues, and are often used for detecting bone fractures and lung abnormalities.

**Option B:** Ultrasound (USG) is not ideal for detecting calcification, as it relies on the reflection of sound waves and may not accurately visualize calcified structures, especially in areas with gas or air.

**Option D:** MRI is not typically used for detecting calcification, as it is not as sensitive to calcium deposits as CT scans. MRI is more useful for visualizing soft tissue structures, such as tumors and inflammation.

**Clinical Pearl / High-Yield Fact**
When evaluating a patient with suspected calcification, it's essential to choose the imaging modality that provides the highest resolution and sensitivity for detecting calcium deposits, as this can significantly impact diagnosis and treatment.

**✓ Correct Answer: C. CT scan**