**Question:** String of beads appearance on angiography is seen in

A. Atherosclerosis
B. Vasospasm
C. Dissection
D. Infection

**Core Concept:**
Angiography is a radiological procedure that involves injecting a contrast medium into a blood vessel to visualize its structure and function. In various pathological conditions, the contrast medium may reveal specific patterns on angiography, which can help in diagnosing the underlying cause.

**Why the Correct Answer is Right:**
The string of beads appearance on angiography is most commonly seen in atherosclerosis. Atherosclerosis is a progressive arterial disease characterized by the accumulation of fatty substances, calcium, and cellular components within the arterial walls, leading to the formation of plaques. This plaque buildup narrows the lumen of the artery and can cause local ischemia, which is visualized as a string of beads pattern on angiography.

**Why Each Wrong Option is Incorrect:**
A. Vasospasm (spasm of blood vessels) and dissection (tear in arterial wall) can also show abnormal angiographic findings, but the string of beads pattern is not specific to these conditions.
B. Infection is not directly related to angiographic findings but could potentially lead to embolization, causing distal occlusion that may result in a string of beads appearance. However, this is not the primary cause of the string of beads pattern on angiography.

**Clinical Pearl:**
Atherosclerosis is a significant cause of cardiovascular diseases, and recognizing the string of beads appearance on angiography can help in making an early diagnosis and initiating appropriate interventions to prevent further complications like myocardial infarction, stroke, or peripheral artery disease.

**Correct Answer:** C. Atherosclerosis