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Fundamentals
MRI fundamentals
Question | Answer |
---|---|
A positive change in frequency followed by an equal negative change in frequency, both for the same duration, will________ the net phase of stationary protons? | have no effect on |
which of the following is a linearly varying magnetic field?a. raw datab. a gradientc. | a gradient |
which physical gradient must be used for slice selection in order to produce a sagittal image? | x gradient |
The slice select gradient must be turned on turned on during which of the following events? | application of RF energy |
Which of the following is NOT determined by the slice select process? | field of view |
which of the following has an effect on the resulting slice thickness? | the range of frequencies at which the RF energy is applied |
To make an oblique image which is oriented at an angle between transverse and coronal, which of the following physical gradients must be applied for slice select gradient? | y and z together |
Given a sagittal image, which of the following statements is ALWAYS TRUE? | slice selection was accomplished with the x-gradient |
The frequency encoding gradient must be turned on during which of the following events? | readout of the echo |
In a vertical field magnet, which axis corresponds to the longitudinal direction, if the patient is in a head-first, supine position? | y axis |
To completely phase encode a single slice, how many TR periods are required? | as many TR periods as phase line in the resulting image matrix. (phase encodings) |
During a six minute scan, when is the data used to form the lower third of the image collected? | throughout the entire scan |