**Question:** X-ray Artifact is -

A. Enhancement
B. Superposition
C. Composition
D. Attenuation

**Core Concept:** X-ray artifacts are visual distortions or errors that occur during radiographic imaging, potentially leading to misinterpretation of the acquired image. The four options describe different types of artifacts caused by various factors related to X-ray properties and patient characteristics.

**Why the Correct Answer is Right:**

X-ray artifacts are caused by the interaction between X-rays and the body, and the correct answer, **Superposition (B)**, represents an artifact that occurs when adjacent structures overlap and obscure the visualization of the underlying structures. This can lead to misinterpretation of the image and inaccurate diagnosis.

**Why Each Wrong Option is Incorrect:**

A. **Enhancement (A)** refers to the process by which X-rays are absorbed, scattered or absorbed by a medium, not an artifact.
C. **Composition (C)** describes the interaction between X-rays and the composition of tissues, typically used to differentiate between different types of tissues. This is distinct from the concept of artifacts.
D. **Attenuation (D)** is the measurement of how much X-rays are absorbed or scattered by a medium, not an artifact.

**Why Correct Answer is Right:**

Superposition (B) is the correct answer because it describes a specific phenomenon that occurs when adjacent structures overlap and obscure the visualization of the underlying structures in X-ray images. This can lead to misinterpretation of the image and potentially incorrect diagnosis.

**Why Each Wrong Option is Incorrect:**

A. Enhancement (A) refers to the process of X-rays interacting with matter, not an artifact.
C. Composition (C) describes the interaction between X-rays and tissue composition, which is distinct from the concept of artifacts.
D. Attenuation (D) refers to the measurement of how much X-rays are absorbed or scattered by a medium, not an artifact.

**Clinical Pearls:**

1. Understanding X-ray artifacts is crucial for accurate radiological interpretation. Adequate knowledge of these artifacts can help radiologists and physicians to differentiate between normal anatomy and pathology, and thus make accurate diagnoses.
2. To minimize artifacts, proper positioning, patient preparation, and image acquisition techniques should be employed during radiological procedures.
3. In some cases, artifacts may be used intentionally to highlight specific anatomical features or pathologies, for example, bone windows in bone imaging or soft tissue windows in chest imaging.