Contrast Administration

Question 1

What is contrast media and its main types?

Answer 1

• Contrast medias are used to differentiate anatomic structures depending on their radiographic densities.
• 2 types of CM are positive and negative.
• Positive CM belongs to Radiopaque CM.
• Main RCM in CT exams are Iodine and Barium.

Question 2

Where can Radiopaque CM(water soluble compounds) be administered?

Answer 2

a. Generally into the bloodstream intravenously.
b. Directly into a targeted vein or artery for localized enhancement.
c. Directly into the intrathecal space during CT myelography.
d. Into the joint space during CT arthrography.
e. Orally to opacify the gastrointestinal (GI) tract.

Question 3

What are subclassifications of Contrast medias?

Answer 3

a) Intravascular Radiopaque Contrast media
b) Enteral Radiopaque Contrast media
c) Negative Contrast agents
d) Neutral Contrast agents

Question 4

What happens when Intravascular contrast agent is administered?

Answer 4

a. Initial opacification of blood vessels aids in the diagnosis of many disorders, including aneurysm, thrombus, and stenosis.
b. Over time the contrast agent is distributed from the vasculature into the extravascular space. Visualization of normal and abnormal soft tissues.
c. As the kidneys excrete the contrast agent, opacification improves visualization of the renal pelvis, ureters, and bladder.

This characteristics of iodinated contrast media to move from outside to inside of blood vessel is called OSMOLALITY.

Question 5

What are the two types of iodinated contrast agents?

Answer 5

1. Ionic contrast media are salts consisting of sodium and/or meglumine.
   HOCM
   eg: are iothalamate meglumine (Conray) and diatrizoate sodium (Hypaque).
2. Nonionic contrast media are nonsalt chemical compounds that also contain three atoms of iodine per molecule. DO NOT dissolve in solution.
   LOCM
   eg: iohexol (Omnipaque), iopamidol (Isovue), and ioversol (Optiray).