Podcast
Questions and Answers
Which of the following is a cause of phase mismapping artifact?
Which of the following is a cause of phase mismapping artifact?
- Anatomy moving along the phase-encoding gradient (correct)
- Anatomy moving along the frequency encoding gradient
- Anatomy moving along the slice-select gradient
- Anatomy moving during the TR period
What type of motion can cause phase mismapping?
What type of motion can cause phase mismapping?
- Respiration
- Heartbeat
- Swallowing
- All of the above (correct)
What is the effect of distance from the source of motion on ghosting artifact?
What is the effect of distance from the source of motion on ghosting artifact?
- Ghosting becomes more obvious
- Ghosting disappears completely
- Ghosting becomes less obvious (correct)
- Ghosting remains the same
What does the physical separation between each ghost depend on?
What does the physical separation between each ghost depend on?
What is the result of repetitive motion during the scan?
What is the result of repetitive motion during the scan?
What is the term used to describe the incorrect spatial locations of moving anatomy in the image?
What is the term used to describe the incorrect spatial locations of moving anatomy in the image?
Which gradient is applied at a different amplitude every TR?
Which gradient is applied at a different amplitude every TR?
Which direction does ghosting artifact occur along the phase encoding axis of the image?
Which direction does ghosting artifact occur along the phase encoding axis of the image?
What is the purpose of swapping phase and frequency in imaging?
What is the purpose of swapping phase and frequency in imaging?
Which technique can be used to reduce or eliminate motion artifact from respiration in chest and abdominal imaging?
Which technique can be used to reduce or eliminate motion artifact from respiration in chest and abdominal imaging?
What factors affect the separation between ghosts in an image?
What factors affect the separation between ghosts in an image?
What is the purpose of presaturation pulses in imaging?
What is the purpose of presaturation pulses in imaging?
Which type of respiratory sensor tracks the position of the diaphragm using a navigator echo?
Which type of respiratory sensor tracks the position of the diaphragm using a navigator echo?
What is the purpose of reordering the lines of k-space in respiratory compensation techniques?
What is the purpose of reordering the lines of k-space in respiratory compensation techniques?
Which technique utilizes signal collected by the transducer or navigator echoes to select a threshold (gate) that only allows data through when a certain condition is met?
Which technique utilizes signal collected by the transducer or navigator echoes to select a threshold (gate) that only allows data through when a certain condition is met?
What is the main drawback of respiratory triggering?
What is the main drawback of respiratory triggering?
What trade-off is associated with respiratory gating?
What trade-off is associated with respiratory gating?
What is the purpose of increasing the NSA (number of signal averages) in MRI?
What is the purpose of increasing the NSA (number of signal averages) in MRI?
What is the trade-off associated with increasing the NSA in MRI?
What is the trade-off associated with increasing the NSA in MRI?
What is the purpose of cardiac triggering in MRI?
What is the purpose of cardiac triggering in MRI?
Which form of triggering uses electrodes and lead wires attached to the patient's chest to produce an EKG for determining the timing of each RF excitation pulse?
Which form of triggering uses electrodes and lead wires attached to the patient's chest to produce an EKG for determining the timing of each RF excitation pulse?
Which type of triggering is more accurate for imaging the heart itself?
Which type of triggering is more accurate for imaging the heart itself?
Peripheral triggering is effective at reducing phase mismapping when imaging which structures?
Peripheral triggering is effective at reducing phase mismapping when imaging which structures?
What does gradient moment rephasing help reduce?
What does gradient moment rephasing help reduce?
Which type of triggering is used to acquire each slice at the same phase of the cardiac cycle?
Which type of triggering is used to acquire each slice at the same phase of the cardiac cycle?
When is peripheral triggering not very useful for imaging the heart itself?
When is peripheral triggering not very useful for imaging the heart itself?
What is the purpose of pulsation triggering?
What is the purpose of pulsation triggering?
What is the main advantage of EKG triggering over peripheral triggering?
What is the main advantage of EKG triggering over peripheral triggering?
When is peripheral triggering effective at reducing phase mismapping?
When is peripheral triggering effective at reducing phase mismapping?
What is the main purpose of gradient moment rephasing?
What is the main purpose of gradient moment rephasing?
