**Core Concept**
Intracranial calcification is a type of calcification that occurs within the brain, which can be a sign of various pathologies, including tumors, infections, and vascular diseases. Calcification is the accumulation of calcium salts in a tissue, which can be detected using various imaging modalities.

**Why the Correct Answer is Right**
Computed Tomography (CT) scans are the best imaging modality for detecting intracranial calcification due to their high sensitivity and specificity for calcium. CT scans use X-rays to produce detailed images of the brain, and the high density of calcium allows it to be easily visualized. This is because calcium has a high atomic number, which results in a high attenuation coefficient on CT scans, making it stand out from surrounding tissues.

**Why Each Wrong Option is Incorrect**
**Option A:** Magnetic Resonance Imaging (MRI) is not the best modality for detecting calcification, as calcium is not as visible on MRI scans. MRI uses magnetic fields and radio waves to produce images, but it is less sensitive to calcium than CT scans.

**Option B:** Ultrasound is not typically used for detecting intracranial calcification, as it is not as effective for imaging the brain as CT or MRI scans. Ultrasound uses high-frequency sound waves to produce images, but it is not as sensitive to calcium as other modalities.

**Option C:** Plain X-rays can detect calcification, but they are not as sensitive or specific as CT scans. Plain X-rays use low-energy X-rays to produce images, but they are not as effective for visualizing calcium within the brain.

**Clinical Pearl / High-Yield Fact**
When interpreting CT scans, it's essential to note that calcification can be seen in various pathologies, including primary brain tumors, metastatic tumors, and vascular malformations. Familiarity with the typical locations and patterns of calcification can help in identifying these conditions.

**Correct Answer: C. Plain X-rays**