Image Modalities Flashcards
Scintigraphy
IV injection of radioactive material
which method of imaging involves no ionizing radiation?
MRI
Which method of imaging uses x-rays and computer to produce images with cross sections of anatomy?
CT
Which injectable contrast is used during MRI studies?
Gandolinium
What is the Hounsfield radiodensity unit of air?
-1,000 HU
Which diagnostic tests use bursts of gamma protons to identify areas of injury?
Scintigraphy
insufflation during endoscopy is generally performed using
CO2
Why is insufflating when using an endoscope important?
opens up the lumen, allowing for better inspection and navigation
When is a rigid endoscope generally used?
for structures that aren’t tubular
the MRI affects ____ in the body to produce a picture
Protons
Anechoic
do not generate an echo from US waves
hypoechoic
little returning echo - appears dark gray
hyperechoic
high-intensity returning echo, very bright on US image.
what causes comet tail artifact?
sound waves interact with metal objects
which ultrasound technique is commonly used in echos?
M-mode
Attenuation
loss of amplitude of US waves
what range of frequencies is most often used for small animal ultrasound?
2-15 MHz
which US control modulates the amount of contrast to the image?
Dynamic range control
Which control allows the US image to be modified so inherent brightness of superficial structures is minimized?
time-gain compensation
What are the types of transducers?
- sector array
- linear array
- curvilinear array
- phased array
- annular array
What is the most commonly used display mode?
B-mode
what is myelography used to evaluate?
spinal cord
What positive contrast is not diluted by secretion or absorbed through intestines?
Barium sulfate
which contrast study views the kidney structure and collection systems?
excretory urogram
what contrast is used for suspected perforation of the small bowel?
Triiodinated compound
What is the best contrast procedure for the urinary bladder mucosa?
double-contrast cystography
what media should be used for radiolucent bladder stones?
Ionic organic iodides
What are 4 types of contrast agents, and which one is negative?
- soluble ionic radiopaque media
- soluble nonionic radiopaque media
- insoluble inert radiopaque media
- radiolucent gases - this one is negative
what types of radiolucent gases are used in vet med?
air, o2, co2, and nitrous oxide.
When is myelography used?
when MRI and CT are unavailable
dose creep
increases in exposure factors to reduce the amount of image noise
what causes ghosting
incomplete erasure of the imaging plate
how much of the image on an imaging plate will be lost in 8 hours?
approx 25%
What type of cassette screen is used in computed radiography?
a screen composed of photostimulable phosphors
