Intro to Medical Imaging Flashcards
MOST IMPORTANT LOS
Differentiate imaging modalities that use X-rays for image production
Describe the differences between an AP and PA plain film radiograph
Explained how computed tomography builds upon plain film
Hounsfield scale
MRI
Ultrasonography; huge now…that’s it
X-rays (photons) from the ___________ pass through the body to expose the recording plate
Tungsten Target
The greater the attenuatinon or absorption of the photons by tissues = ____________?
Whiter the density
Organs with air will appear _______
Dark
Barium is used as a contast agent in the :
GUT
Iodine is used as a contast agent in the :
Brain
Describe the view of the left image and the right image
Left: PA
Right: AP
What is Fluoroscopy?
Continuous stream of X-ray to view structures in real time
Used for barium contast studies
What is digital subtraction (DS) angiography?
Form of fluoroscopy
“Subtract tissues” from what you want to see
What is computed tomography (CT)?
- Take images and adjust the gray scale to pull out certain tissues
- CT are generated w/ X-rays passing through the body in helical fashion
How are you looking at a CT?
Feet up
What is the Hounsfield Scale?
Zero=water
Air= -1000
Compact bone= +3095
Soft tissues = (-100) to (+100)
What is the window level?
Number on hounsfield scale set to middle gray
ADD REMAINDER OF HOUNSFIELD SCALE
What are CTs useful for imaging?
Bone
Chest and abdomen organs/pathology
Blood vessels
Intercranial bleeding
What is Magnetic Resonance Imaging?
Utilizes nuclear spin
As they return to equilibrium, the radiofrequency energy emitted by protons during “RELAXATION TIME” can be measured
Fluid is _______ in T1
DARK
Fluid is _______ in T2
LIGHT
What is the difference b/w T1 and T2?
Note the examples of T1/T2
What are MRIs useful for?
- No ionizing radiation
- Better soft tissue contrast than CT
- Extremly versatile
Disadvantages of MRI?
- Long time
- Expensive
- Pt. cannot have metal in body
- Not good for claustophobic pts.
GENERALLY what is nuclear medicine imaging?
Measures physiological activity rather than anatomy
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