CT and MRI Flashcards
Which has the best detail: radiography, CT or MRI?
Radiography
Which has the best contrast resolution: radiography, CT or MRI?
MRI
A function of contrast resolution and detail is known as what?
Conspicuity
The ability of an imaging system to differentiate between two adjacent objects is known as what?
Spatial resolution
Are the differences in spatial resolution between radiography, CT and MRI small or large?
Small
Images in the form of slices are known as what?
Tomography
With CT, what happens to the x-ray beam in relation to the patient?
The x-ray beam rotates around the patient.
What type of CT mode has a continuous table and x-ray tube movement allowing faster scanning?
Helical
With CT, is one or more slices per tube revolution acquired?
More than one.
Building images in other places from transverse data is known as what?
2D Reformatting
A substance used to enhance the contrast of structures or fluids withing the body in medical imaging is known as what?
Contrast medium
What is commonly used to enhance the visibility of blood vessels, vascular leaks and the gastrointestinal tract?
Contrast medium
What is put in IV contrast medium?
Iodine
Contrast medium can help to show what in relation to vasculature?
Increased vascularity/vascular permeability
What are 5 things CT can be used for?
- Nasal disease
- Thoracic masses; resectable
- Fragmented medial coronoid process
- Radiation therapy planning
- Portal vein anomalies
T/F: Contrast resolution is much less in an MRI compared to CT.
False - It is much greater.
Do MRIs use ionizing radiation?
No
Image appearance in an MRI is dependent on what 2 things?
- Water
- Fat
What does an MRI use to create an image?
Magnetism
Are there any radiation hazards with MRIs?
No
What is being imaged in an MRI?
Hydrogen protons (water)
Most lesions have an increased amount of what which can be detected by MRI?
Water
What does the main magnet of an MRI do to the protons?
Causes protons to align with a field.
What knocks the protons out of alignment into the X-Y plane with an MRI?
Radio waves
The signal strength of an MRI is converted to what?
High signal looks what?
Low signal looks what?
- Grey scale in an image.
- White
- Black
What is seen in a T1 MRI?
Fat
What is seen in a T2 MRI?
Free water, tissue water, fat
What is seen in a FLAIR MRI?
Tissue water and Fat
What is seen in a STIR MRI?
Free water and tissue water
What can’t be seen in a STIR MRI?
Fat
What color is bone in an MRI?
Black
What color is bone in a CT?
White
What does FLAIR stand for?
FLuid
Attenuated
Inversion
Recovery
FLAIR nulls the signal from what?
What is an example?
- Free fluid
- CSF
What does STIR stand for?
Short
Tau
Inversion
Recovery
What is a contrast medium used for MRI that speeds up proton relaxation?
Gadolinium
Gadolinium is used only in which MRI sequence?
T1
What is the main use of MRI in veterinary medicine?
Neuroimaging
