Flashcards in Contrast Media and Urinary System Deck (381)
The tissue density and composition of the organs in the abdomen are very ________ as well as the thickness of these organs.
The liver, pancreas, spleen, stomach, kidneys, and bowel will display a low amount of
is the radiographic contrast caused by the difference in the composition of the patient’s body tissues.
The organs of the digestive system, urinary system and cerebrovascular system have similar densities and atomic numbers and will therefore absorb nearly the same amount of radiation and therefore have
Low subject contrast
Are diagnostic agents that are introduced into the body orifices or injected into the vascular system, joints, and ducts to enhance subject contrast in anatomic areas where low subject contrast exists
The ability of the contrast media used in radiographic procedures to enhance subject contrast depends greatly on
The atomic number of the element used in a particular medium and
The concentration of atoms of the element per volume of the medium
Contrast media are generally classified as
negative or positive contrast agents.
Negative contrast agents are (radiolucent or radiopaque?)
Positive contrast agents are (radiolucent or radiopaque?)
The specialty contrast agent for MRI is:
IV contrast agent gadolinium diethylenetriaminepentaacetic acid (gadolinium-DTPA).
Metalic and magnetic agent that affects signal intensity.
The specialty contrast agent for Ultrasound is:
Gas-filled microbubbles that affect the sound wave to enhance ultrasound contrast
Physical properties of negative contrast agents:
Composed of elements with low atomic numbers
Tablets, crystals, soda water
Why is oxygen rarely used alone as a contrast agent?
Cells absorb oxygen quickly.
What is the most common negative contrast agent?
A negative contrast agent may be combined with a positive contrast agent to produce a
double contrast effect.
In a double contrast barium enema, barium is the ______ contrast agent and air is the ______ contrast agent.
An example of a discontinued exam using negative contrast media is:
The uses of negative contrast media are limited because
they may not provide sufficient contrast of a structure when used alone.
Why must negative contrast agents never be injected intravenously?
serious or fatal consequences can result
Three characteristics of positive contrast agents:
Composed of elements with high atomic numbers
Absorbs more x-rays and appears bright on a radiograph
Positive contrast agents absorbs about ___ times more x-rays than bone and ___ times more x-rays as soft tissues.
3 and 5.
Two examples of positive contrast agents:
1. Barium (Z# 56)
2. Iodine (Z#53)
Each of these elements has a much higher atomic number and mass density than does soft tissue (Z# 7.4)
What is the atomic number of Gadolinium?
Two popular types of positive contrast media:
1. Barium Sulfate
2. Iodinated Compounds:
Barium sulfate is a heavy metal element with the atomic number:
Barium sulfate is an inert powder composed of crystals that is used for
examination of the digestive system
What is barium sulfate comprised of?
The element barium is combined with oxygen and sulfate to form the inert compound barium sulfate.
What is the chemical formula of barium sulfate?
Barium sulfate is commonly referred to as: