Contrast Media and Reactions Practice Questions

Q: Which of the following investigations must be performed before giving the agent shown to a patient?

Serum creatinine. ***Serum creatinine*** - The image shows Omniscan (gadodiamide) Injection, which is a **gadolinium-based contrast agent (GBCA)** used in MRI. - GBCAs are primarily excreted by the kidneys, so assessing **renal function** via serum creatinine is crucial to prevent **nephrogenic systemic fibrosis (NSF)** in patients with severe renal impairment. *C3 levels* - **C3 levels** are typically used to evaluate the **complement system**, which is involved in immune responses and conditions like **lupus nephritis** or **glomerulonephritis**. - They are not relevant for assessing **renal clearance** before administering gadolinium-based contrast. *Urine specific gravity* - **Urine specific gravity** measures the urine's concentration, indicating the kidneys' ability to conserve or excrete water. - While it gives some insight into renal function, a **serum creatinine** provides a more direct and accurate measure of **glomerular filtration rate (GFR)**, which is essential for GBCA administration guidelines. *Serum electrolytes* - **Serum electrolytes** (e.g., sodium, potassium) are important for assessing **fluid balance** and various metabolic functions. - While electrolyte imbalances can be associated with **renal dysfunction**, checking these levels alone is not the primary or most direct investigation required to assess the risk of **GBCA-induced nephrotoxicity** or NSF.

Q: Iodine particle ratio for Ionic dimer is

6:2. ***6:2*** - An **ionic dimer** contrast agent contains **six iodine atoms** (three on each monomer unit) and **two osmotically active particles** in solution (one dimer anion and one counter-cation such as sodium or meglumine). - This results in a ratio of **6 iodine atoms** to **2 osmotically active particles**, giving an iodine-to-particle ratio of **6:2** (or 3:1 when simplified). *6:1* - This ratio would imply that for six iodine atoms, there is only **one osmotically active particle**, which is not correct for an ionic dimer. - Ionic dimers dissociate into **two particles** (the dimer anion and its counter-cation), so a 6:1 ratio is chemically incorrect for this type of contrast agent. *3:2* - This ratio accurately describes an **ionic monomer**, not an ionic dimer. - An ionic monomer has **three iodine atoms** and dissociates into **two particles**, giving a 3:2 ratio. - An ionic dimer has **six iodine atoms** (double that of a monomer), making this ratio incorrect for ionic dimers. *2:6* - This ratio is the inverse of the correct answer and implies **fewer iodine atoms** than osmotically active particles, which is physically impossible. - An ionic dimer has **more iodine atoms** (6) than osmotically active particles (2), making this ratio completely incorrect.

Q: Excretory urography is contraindicated in:

Multiple myeloma. ***Multiple myeloma*** - Patients with **multiple myeloma** are at high risk of developing **contrast-induced nephropathy** due to the precipitation of Bence Jones proteins in renal tubules when exposed to iodinated contrast agents. - This can lead to **acute kidney injury** or worsening of pre-existing renal impairment, making excretory urography generally contraindicated. *Single kidney* - While careful consideration is needed, having a **single kidney** does not inherently contraindicate excretory urography if renal function is good. - The primary concern is protecting the remaining kidney from **contrast-induced nephropathy** in patients with pre-existing renal dysfunction, not the number of kidneys. *Trauma* - In cases of **renal trauma**, excretory urography (or more commonly, CT urography) can be used to assess the extent of injury and integrity of the urinary tract. - It is often indicated to evaluate **hematuria** or suspected kidney damage, not contraindicated. *Renal artery hypertension* - Excretory urography was historically used to evaluate for **renal artery stenosis**, a cause of **renal artery hypertension**, by looking for delayed contrast excretion or kidney size differences. - While it has largely been replaced by more modern imaging like CT angiography or MRA, it is not considered a contraindication and can provide some diagnostic information.

Q: All of the following dyes are water soluble except:

Myodil. ***Myodil*** - **Myodil** (Iophendylate) is an **oil-based** contrast medium previously used for myelography. - Due to its **oil-based nature**, it is not water-soluble and had to be removed after the procedure to prevent complications. *Iohexol* - **Iohexol** is a **non-ionic, water-soluble** contrast agent commonly used in various radiological procedures, including myelography. - Its water solubility allows for easy absorption and excretion from the body. *Conray 420* - **Conray 420** (Iothalamate meglumine) is an **ionic, water-soluble** contrast agent often used for angiography and urography. - It readily mixes with bodily fluids due to its water-soluble properties. *Metrizamide* - **Metrizamide** was an early **non-ionic, water-soluble** contrast agent specifically developed for myelography. - Although water-soluble, it had a higher incidence of neurotoxicity compared to newer agents like iohexol.

Q: Dye used in IV cholangiography is:

Billigraffin. ***Billigraffin*** - **Billigraffin** (also known as sodium **iodipamide**) was historically the **primary contrast agent** used in intravenous (IV) cholangiography. - It is an **iodinated contrast medium** specifically designed for excretion into the **biliary system**, allowing visualization of the bile ducts. *Conray* - **Conray** (iothalamate meglumine) is a general-purpose **ionic iodinated contrast medium** primarily used for **angiography, CT scans**, and **excretory urography**. - It is not specifically formulated for optimal **biliary excretion** and would not provide adequate visualization for IV cholangiography. *Myodil* - **Myodil** (iophendylate) is an **oil-based iodinated contrast medium** that was historically used for **myelography** to visualize the spinal canal. - Due to its **oil-based nature** and different excretion pathway, it is entirely unsuitable for **IV cholangiography**. *Dianosil* - **Dianosil** was a trade name for certain **bronchography contrast agents** containing iodized oil, used to visualize the tracheobronchial tree. - This type of contrast medium is designed for **pulmonary application** and would not be used for imaging the biliary system.

Q: Dye used for "Myelography" is:

Iohexol (Omnipaque). ***Iohexol (Omnipaque)*** - Iohexol is a **non-ionic, low-osmolar monomeric contrast agent** and is the **most commonly used agent for myelography** worldwide. - It is **FDA-approved for intrathecal use** and has extensive safety data with **low neurotoxicity**. - Its widespread availability and proven safety profile make it the **standard choice** for myelography in clinical practice. *Iopamidol (Isovue)* - Iopamidol is also a **non-ionic, low-osmolar monomeric agent** that is FDA-approved for myelography. - While it is a suitable alternative to iohexol, **iohexol remains more commonly used** in most centers. - Both agents have similar safety profiles for intrathecal administration. *Iodixanol (Visipaque)* - Iodixanol is an **iso-osmolar dimeric contrast agent** primarily used for **cardiac and vascular imaging**. - While theoretically advantageous due to iso-osmolarity, it has **limited approval and use for myelography** compared to iohexol. - It is **not the standard or most commonly used agent** for this procedure. *Barium sulfate* - This is an **insoluble oral or rectal contrast agent** used exclusively for gastrointestinal imaging. - It is **absolutely contraindicated for intrathecal use** as it causes severe neurotoxicity and potentially fatal reactions. - Only **water-soluble iodinated contrast agents** should be used for myelography.

Q: Gadolinium is a contrast agent used for:

MRI - Imaging. ***MRI - Imaging*** - **Gadolinium** is a paramagnetic substance commonly used as a contrast agent in **Magnetic Resonance Imaging (MRI)**. - It works by altering the **T1 relaxation times** of protons in tissues, enhancing the signal and improving the visibility of certain structures or pathologies like **tumors** or **inflammation**. *CT - angiography* - **CT angiography** typically uses **iodine-based contrast agents**, not gadolinium, to visualize blood vessels. - Iodine contrast agents work by absorbing X-rays, making blood vessels appear bright on CT images. *Bronchography* - **Bronchography** is an older imaging technique that involved introducing an **iodinated contrast medium** directly into the bronchial tree. - It has largely been replaced by **high-resolution CT scans** for evaluating airways. *Contrast Sonography* - **Contrast-enhanced ultrasound (CEUS)**, or contrast sonography, primarily uses **microbubble contrast agents** made of inert gas. - These microbubbles enhance the reflectivity of blood, improving visualization of blood flow and organ perfusion.

Q: Non-Iodine containing contrast is

Gd DTPA. ***Gd DTPA*** - **Gadolinium-DTPA** (diethylenetriamine pentaacetic acid) is a **gadolinium-based contrast agent** used in MRI, which does not contain iodine. - It enhances images by shortening the **T1 relaxation time** of protons in tissues. *Diatrizoate* - **Diatrizoate** is an **iodinated contrast medium** commonly used in radiography and CT scans. - It contains iodine, which opacifies structures by **attenuating X-rays**. *Visipaque* - **Visipaque** (Iodixanol) is an **iodinated, non-ionic, dimeric contrast medium** with iso-osmolar properties. - It explicitly contains iodine as the contrast-enhancing element. *Iohexol* - **Iohexol** is another widely used **iodinated, non-ionic contrast agent** for various radiological procedures. - Its mechanism of action relies on the presence of iodine atoms to block X-rays.

Q: Which of the following contrast agents is used in USG?

SonoVue. ***SonoVue*** - **SonoVue** (also known as Lumason in the US) is the most commonly used **microbubble contrast agent** specifically designed for **ultrasonography (USG)**. - Contains **sulphur hexafluoride gas microbubbles** stabilized by a phospholipid shell. - These microbubbles enhance the echogenicity of blood, improving the visualization of blood flow and tissue perfusion in various organs, particularly in **liver imaging** and **cardiac echocardiography**. - Other USG contrast agents include Definity and Optison. *Urograffin* - **Urograffin** (diatrizoate) is an iodine-based contrast agent primarily used in **X-ray imaging**, particularly for **urography (imaging of the urinary tract)** and **angiography**. - It is not suitable for USG as it does not produce the necessary acoustic impedance difference for ultrasound enhancement. *Omnipaque* - **Omnipaque** (iohexol) is a non-ionic, low-osmolar **iodinated contrast agent** used for various **X-ray and CT procedures**. - Like other iodinated agents, its properties are optimized for X-ray attenuation, not for ultrasound enhancement. *Conray* - **Conray** (iothalamate) is an older generation, high-osmolar, **iodinated contrast agent** used for various **X-ray procedures** like angiography and CT scans. - Similar to Urograffin, it works by X-ray attenuation and is not effective for ultrasound contrast enhancement.

Q: Excretory urography should be cautiously performed in

Multiple myeloma. ***Multiple myeloma*** - Excretory urography (intravenous pyelography or IVP) involves the administration of **iodinated contrast media**, which can precipitate **Bence Jones proteins** in the renal tubules, leading to or worsening **acute kidney injury** in patients with multiple myeloma. - Patients with multiple myeloma often have **pre-existing renal dysfunction** (myeloma kidney) due to light chain deposition, making them highly susceptible to contrast-induced nephropathy. *Bone metastases* - While bone metastases can be painful and may require imaging, they do not directly contraindicate excretory urography; the primary concern with IVP is renal function. - The presence of bone lesions itself does not increase the risk of **contrast-induced nephropathy** in the same way that proteinuria from multiple myeloma does. *Neuroblastoma* - Neuroblastoma is a **childhood cancer** affecting the adrenal glands or sympathetic nervous system, and it is not typically associated with a specific risk for contrast-induced nephropathy from excretory urography. - The primary diagnostic imaging for neuroblastoma often involves ultrasound, CT, or MRI, and while contrast may be used, the specific renal risk seen in multiple myeloma is not present. *Leukemia* - While some forms of leukemia can affect the kidneys, particularly through infiltration, it does not typically pose the same specific risk for **contrast-induced nephropathy** as multiple myeloma. - The renal manifestations in leukemia are generally different from the **light chain proteinuria** seen in multiple myeloma, which directly interacts with iodinated contrast.

Question 1

Which of the following investigations must be performed before giving the agent shown to a patient?

Accepted Answer

Serum creatinine

Answer

C3 levels

Answer

Urine specific gravity

Answer

Serum electrolytes

Question 2

Iodine particle ratio for Ionic dimer is

Accepted Answer

6:2

Answer

6:1

Answer

3:2

Answer

2:6

Question 3

Excretory urography is contraindicated in:

Accepted Answer

Multiple myeloma

Answer

Single kidney

Answer

Trauma

Answer

Renal artery hypertension

Question 4

All of the following dyes are water soluble except:

Accepted Answer

Myodil

Answer

Iohexol

Answer

Conray 420

Answer

Metrizamide

Question 5

Dye used in IV cholangiography is:

Accepted Answer

Billigraffin

Answer

Conray

Answer

Myodil

Answer

Dianosil

Question 6

Dye used for "Myelography" is:

Accepted Answer

Iohexol (Omnipaque)

Answer

Barium sulfate

Answer

Iodixanol (Visipaque)

Answer

Iopamidol (Isovue)

Question 7

Gadolinium is a contrast agent used for:

Accepted Answer

MRI - Imaging

Answer

CT - angiography

Answer

Bronchography

Answer

Contrast Sonography

Question 8

Non-Iodine containing contrast is

Accepted Answer

Gd DTPA

Answer

Diatrizoate

Answer

Visipaque

Answer

Iohexol

Question 9

Which of the following contrast agents is used in USG?

Accepted Answer

SonoVue

Answer

Urograffin

Answer

Omnipaque

Answer

Conray

Question 10

Excretory urography should be cautiously performed in

Accepted Answer

Multiple myeloma

Answer

Bone metastases

Answer

Neuroblastoma

Answer

Leukemia

Contrast Media and Reactions — MCQs

Contrast Media and Reactions — MCQs

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