**Question:** Contrast media used in ultrasound is

A. SonoVue
B. Levovist
C. Sonazoid
D. Optison

**Correct Answer:** D. Optison

**Core Concept:** Contrast media, also known as ultrasound contrast agents, are substances designed to enhance the visibility of specific structures or organs during ultrasound imaging. They are used to improve the quality of diagnostic imaging and help identify particular anatomical or physiological features.

**Why the Correct Answer is Right:** Optison (technetium-99m macroaggregated albumin) is a type of ultrasound contrast agent that consists of microspheres coated with technetium-99m. These microspheres are large enough to be visible on ultrasound scans, allowing for improved visualization of blood vessels, myocardial perfusion, and lymph nodes. Technetium-99m is a radioisotope that emits gamma radiation, which can be detected by ultrasound machines. This allows for non-invasive visualization of these structures.

**Why Each Wrong Option is Incorrect:**

A. SonoVue (bovine serum albumin microspheres containing sulfur hexafluoride) is a different type of ultrasound contrast agent. While it is also used to visualize blood flow, it is not the correct answer for this question as it is not the specific contrast agent mentioned in the question (Optison).

B. Levovist (sodium sulfide hexafluoride microbubbles) is another type of ultrasound contrast agent, used for visualizing blood flow. However, it is not the correct answer for this question as it is not the specific contrast agent mentioned (Optison).

C. Sonazoid (lipid-coated microbubbles containing sulfur hexafluoride) is a different type of ultrasound contrast agent. Similar to the above options, it is not the correct answer for this question as it is not the specific contrast agent mentioned (Optison).

**Clinical Pearl:** Contrast agents are essential in ultrasound imaging to enhance the visualization of specific structures and improve the diagnostic accuracy of ultrasound exams. Understanding the various types of contrast agents and their specific applications is crucial for accurate interpretation of ultrasound images.