MRI Flashcards
What kind of energy is used to make the image?
Non-ionizing electromagnetic energy in the form of radio frequency
What is the unit used to measure magnetic field strength?
Tesla
What is the mechanism for absorption and release of radio frequency energy by body tissues?
Super conductive electromagnets
What atom is used to resonate (absorb and release) radiofrequency energy for MR scans?
Hydrogen
What is gradient?
Change in magnetic field strength along different anatomic axes
How is the resonance frequency of hydrogen controlled in MR imaging?
Manipulation of the magnetic field
What is a “high field” scanner and a “low field” magnet?
One T or above
What are the possible advantages of high field scanners and open magnets?
High field scanners have better images due to better signal to noise ratio
Unlike xrays, different grey-shades are referred to on an MRI image as areas of increased or decreased ____ ____
Signal intensity
The pattern (vector, strength and timing) of radiofrequency energy applied during the MRI scan is known as a ___ sequence
Pulse
Areas on the MR image that appear whiter and lighter grey are referred to as having ___ signal intensity; darker areas (black and darker grey) are ___ signal intensity
Higher
Lower
Water will appear as ___ signal on T2 weighting and ____ on a T1 weighting.
Higher
Lower
Fat will appear as ___ signal on T2 weighting and ___ on T1 weighting
Higher
Higher
