XP Midterm Extras Flashcards
5 Image Quality Characteristics
*Affect visibility
Spatial Artifacts Detail (Blurring) Noise Contrast Sensitivity
T or F: In X-ray there is a strong relationship between image quality and radiation dose to the patient.
True
“The Medical Image” is
The extension of human vision
oooo ahhhh
T or F: Imaging equipment extends our vision to normally invisible regions of the body.
True
When testing your “contrast sensitivity” of our visual system, what are we testing?
The characteristic of an imaging system that determines the *lowest contrast object that can be seen.
Example of visualizing objects and structures in the body that have very low contrast.
Looking at the differences between soft tissue masses surrounding normal tissues.
What is a disadvantage of having an image with high contrast?
Can see high contrast objects (bone, bullets),
but CANNOT see low contrast objects (soft tissue masses).
The “Three B’s” that have very high physical contrast compared to its surrounding soft tissue.
Bone
Barium
Bullets
Images with low contrast sensitivity can only show
High contrast objects
Do you need high or low contrast sensitivity to see many low contrast structures/objects/signs of pathology in the body.
High Contrast Sensitivity
For xrays and CT, what are the 2 sources of physical contrast?
Differences in
- Density
- Atomic number
What type of contrast sensitivity is used for chest imaging, why?
Low contrast sensitivity
*d/t the high physical contrast (variation in density)
What type of contrast sensitivity is used for mammography?
High contrast sensitivity
d/t low physical contrast of the boobies
If something has high physical contrast… use ___ contrast sensitivity.
Low contrast sensitivity
Example of high physical contrast
Air + Tissue
Example of low physical contrast
Tissue + Tissue
Ultrasound “B Mode” (Brightness)
Acoustic impedance of the tissues
*Bright spot = strong echo
Ultrasound “Doppler Mode”
RBC motion
Examples of radionuclide imaging
SPECT
PET
The variation of the radioactivity throughout a body section
Radionuclide Imaging
What are the 3 forms of fluid movement in MRI?
Vascular - angiography
Perfusion
Diffusion
When it comes to contrast sensitivity…
CT + Digital Radiography > Film based Radiography
In CT, visual contrast is adjusted by what
Windowing!
*Changing the level/width/scale of contrast
