Contrast Media and Reactions Practice Questions

Q: In a patient undergoing a CT scan for suspected pulmonary embolism, which contrast agent is primarily used to enhance imaging?

Iodine. **Iodine** - **Iodine-based contrast agents** are primarily used in **CT scans** to enhance vascular structures and organs due to their high atomic number, which effectively attenuates X-rays. - In suspected **pulmonary embolism**, intravenous iodine contrast allows for visualization of filling defects within the pulmonary arteries, confirming or ruling out the diagnosis. *Gadolinium* - **Gadolinium** is a paramagnetic contrast agent predominantly used in **Magnetic Resonance Imaging (MRI)**, not CT scans. - It works by altering the local magnetic field, which shortens the relaxation times of hydrogen protons in tissues, leading to signal enhancement. *Silver* - **Silver** is not used as a contrast agent in medical imaging due to its toxicity and lack of appropriate X-ray attenuation or magnetic properties. - It has historical applications in histology (e.g., silver stains) but no current role in diagnostic imaging. *Mercury* - **Mercury** is highly toxic and has no role as a contrast agent in modern medical imaging. - Its use would be detrimental to patient health and does not provide diagnostic enhancement.

Q: Which of the following is a nonionic dye used in medical imaging?

Iohexol. ***Iohexol*** - **Iohexol** is a widely used **nonionic, low-osmolality contrast medium** in various medical imaging procedures. - Nonionic contrast agents generally have a **lower incidence of adverse reactions** compared to ionic agents due to their reduced osmolality. *Iothalamate* - **Iothalamate** is an **ionic, high-osmolality contrast medium**. - High-osmolality ionic agents are associated with a **higher risk of adverse events**, such as anaphylactoid reactions and nephrotoxicity. *Ioxaglate* - **Ioxaglate** is an **ionic dimer**, often described as a "monoacidic dimer," which gives it **lower osmolality** than traditional ionic monomers, but it is still fundamentally ionic. - While it has a better safety profile than older ionic monomers, it still differs structurally and functionally from true nonionic agents like iohexol. *None of the options* - This option is incorrect because **Iohexol** is indeed a nonionic dye used in medical imaging, fitting the description.

Q: Substance utilized for a barium meal follow-through study is:

Barium sulphate. ***Barium sulphate*** - **Barium sulphate** is the compound used due to its high radiopacacity, allowing for clear visualization of the gastrointestinal tract on X-ray. - It is chemically inert and poorly absorbed in the gastrointestinal tract, minimizing systemic toxicity. *Barium carbonate* - Barium carbonate is **toxic** if ingested, primarily used in industrial applications and ceramics. - It is not suitable for medical imaging due to its solubility and potential for harmful systemic absorption. *Barium oxide* - Barium oxide is a **highly reactive** and corrosive substance, used in industrial applications. - Ingestion would cause severe irritation and chemical burns to the gastrointestinal tract. *Barium hydroxide* - Barium hydroxide is a strong base and is **corrosive**, making it unsuitable for internal consumption. - It can cause severe gastrointestinal irritation and systemic toxicity if ingested.

Q: Contrast media of choice for a myelogram is

Iohexol. ***Iohexol*** - **Iohexol** is a **non-ionic, low osmolality contrast medium** that is widely considered the contrast agent of choice for myelography due to its safety profile. - It has a lower incidence of neurotoxicity and adverse systemic reactions compared to older ionic contrast agents, making it suitable for direct injection into the **subarachnoid space**. *Urografin 75%* - **Urografin** contains **diatrizoate meglumine and sodium**, which are **ionic contrast agents**. - While suitable for intravenous urography, **ionic contrast agents are generally contraindicated for myelography** due to a higher risk of neurotoxicity, including seizures and arachnoiditis, when injected into the cerebrospinal fluid. *Conray 470* - **Conray 470** contains **iothalamate meglumine**, another **ionic contrast medium**. - Similar to Urografin, its **high osmolality and ionic nature** make it unsuitable for intrathecal administration for myelography, as it can cause significant neurotoxic effects. *Biligrafin* - **Biligrafin** is an **ionic, high osmolality contrast medium** primarily designed for **cholangiography**, typically administered intravenously to visualize the biliary tree. - It is **not used for myelography** due to its neurotoxicity risks and formulation, which is not intended for intrathecal injection.

Question 1

Which of the following dyes is used in the diagnosis of esophageal perforation?

Accepted Answer

Iohexol

Answer

Gadolinium

Answer

Iodine dye

Answer

Barium sulphate

Question 2

In a patient undergoing a CT scan for suspected pulmonary embolism, which contrast agent is primarily used to enhance imaging?

Accepted Answer

Iodine

Answer

Gadolinium

Answer

Silver

Answer

Mercury

Question 3

Which of the following is a nonionic dye used in medical imaging?

Accepted Answer

Iohexol

Answer

Iothalamate

Answer

Ioxaglate

Answer

None of the options

Question 4

Substance utilized for a barium meal follow-through study is:

Accepted Answer

Barium sulphate

Answer

Barium oxide

Answer

Barium hydroxide

Answer

Barium carbonate

Question 5

Contrast media of choice for a myelogram is

Accepted Answer

Iohexol

Answer

Urografin 75%

Answer

Conray 470

Answer

Biligrafin

Contrast Media and Reactions — MCQs

Contrast Media and Reactions — MCQs

On this page

Practice by Chapter

Want unlimited practice?