**Core Concept**
Calcification detection relies on the differential attenuation of X-rays and the ability of imaging modalities to differentiate between soft tissues and dense mineral deposits. Among imaging techniques, the presence of calcium causes high attenuation, which is best visualized when the modality has high spatial resolution and excellent contrast resolution.

**Why the Correct Answer is Right**
CT (computed tomography) provides superior soft tissue and bone contrast due to its high X-ray attenuation sensitivity. Calcium deposits absorb X-rays significantly, appearing as bright white structures on CT scans. Unlike MRI, which is less sensitive to calcifications (as calcium does not alter T1/T2 signals significantly), and USG, which often fails to detect calcifications due to poor acoustic shadowing, CT offers both high resolution and excellent contrast for mineralized lesions. X-ray is less sensitive and has lower spatial resolution compared to CT, making it inferior in detecting small or subtle calcifications.

**Why Each Wrong Option is Incorrect**
Option B: MRI is poor at detecting calcification because calcium does not produce strong signal changes on T1 or T2 weighted images, and its sensitivity to mineralization is low.
Option C: X-ray can detect calcification but lacks the resolution and contrast of CT, especially in small or deep lesions, and is prone to artifacts.
Option D: Ultrasound (USG) is limited in detecting calcifications due to acoustic shadowing and poor penetration through dense mineral deposits.

**Clinical Pearl / High-Yield Fact**
In cases of suspected bony or soft tissue calcification (e.g., in metabolic diseases, tumors, or infections), CT is the gold standard due to its ability to detect even small calcifications with high accuracy.

✓ Correct Answer: A. CT