MRI MIC Book 1 Questions and Answers
Latest Version Graded A+
Why is the Nyquist theorem important in MRI?
✔✔ It ensures adequate sampling of signals to prevent aliasing
What is the main advantage of fast spin-echo (FSE) sequences?
✔✔ They reduce scan time while maintaining T2 contrast
How does magnetic field strength affect signal-to-noise ratio?
✔✔ Higher field strength improves signal-to-noise ratio, enhancing image quality
Why is cardiac gating used in MRI?
✔✔ To synchronize image acquisition with the cardiac cycle and reduce motion artifacts
What is the main advantage of using STIR sequences in MRI?
✔✔ They suppress fat signal to improve lesion detection
1
,How does motion correction improve MRI scans?
✔✔ It reduces blurring caused by patient movement
What is the purpose of respiratory gating in MRI?
✔✔ To minimize motion artifacts from breathing
Why is gradient duty cycle important in MRI?
✔✔ It determines how frequently gradients can be switched on and off without overheating
How does perfusion imaging help in MRI?
✔✔ It assesses blood flow to tissues, aiding in stroke and tumor evaluation
What does TR stand for in MRI?
✔✔ Repetition time, which controls image contrast and scan time
What is the effect of increasing matrix size in MRI?
✔✔ It improves spatial resolution but may decrease signal-to-noise ratio
2
,How does magnetization transfer imaging enhance contrast?
✔✔ It selectively saturates certain tissues to improve contrast between structures
What is the primary function of the RF coils in MRI?
✔✔ To transmit and receive radiofrequency signals for image formation
Why is a superconducting magnet preferred in MRI?
✔✔ It provides a strong and stable magnetic field with minimal power consumption
What happens when TR is increased in an MRI sequence?
✔✔ Signal-to-noise ratio improves, and T1 contrast decreases
Why is gradient echo imaging more susceptible to susceptibility artifacts?
✔✔ It lacks the 180-degree refocusing pulse found in spin-echo sequences
What is the purpose of a 180-degree pulse in spin-echo sequences?
✔✔ To refocus dephased spins and reduce signal loss
3
, Why is fat suppression used in MRI?
✔✔ To eliminate fat signal and enhance contrast between tissues
What effect does increasing TE have on T2-weighted images?
✔✔ It enhances T2 contrast, making fluid appear brighter
Why is shimming important in MRI?
✔✔ It improves magnetic field homogeneity for clearer images
What happens when slice thickness is reduced in MRI?
✔✔ Spatial resolution improves, but signal-to-noise ratio decreases
Why is gadolinium used as a contrast agent in MRI?
✔✔ It shortens T1 relaxation time, enhancing contrast between tissues
How does diffusion-weighted imaging (DWI) help in stroke detection?
✔✔ It identifies restricted water diffusion, indicating acute ischemia
4
Latest Version Graded A+
Why is the Nyquist theorem important in MRI?
✔✔ It ensures adequate sampling of signals to prevent aliasing
What is the main advantage of fast spin-echo (FSE) sequences?
✔✔ They reduce scan time while maintaining T2 contrast
How does magnetic field strength affect signal-to-noise ratio?
✔✔ Higher field strength improves signal-to-noise ratio, enhancing image quality
Why is cardiac gating used in MRI?
✔✔ To synchronize image acquisition with the cardiac cycle and reduce motion artifacts
What is the main advantage of using STIR sequences in MRI?
✔✔ They suppress fat signal to improve lesion detection
1
,How does motion correction improve MRI scans?
✔✔ It reduces blurring caused by patient movement
What is the purpose of respiratory gating in MRI?
✔✔ To minimize motion artifacts from breathing
Why is gradient duty cycle important in MRI?
✔✔ It determines how frequently gradients can be switched on and off without overheating
How does perfusion imaging help in MRI?
✔✔ It assesses blood flow to tissues, aiding in stroke and tumor evaluation
What does TR stand for in MRI?
✔✔ Repetition time, which controls image contrast and scan time
What is the effect of increasing matrix size in MRI?
✔✔ It improves spatial resolution but may decrease signal-to-noise ratio
2
,How does magnetization transfer imaging enhance contrast?
✔✔ It selectively saturates certain tissues to improve contrast between structures
What is the primary function of the RF coils in MRI?
✔✔ To transmit and receive radiofrequency signals for image formation
Why is a superconducting magnet preferred in MRI?
✔✔ It provides a strong and stable magnetic field with minimal power consumption
What happens when TR is increased in an MRI sequence?
✔✔ Signal-to-noise ratio improves, and T1 contrast decreases
Why is gradient echo imaging more susceptible to susceptibility artifacts?
✔✔ It lacks the 180-degree refocusing pulse found in spin-echo sequences
What is the purpose of a 180-degree pulse in spin-echo sequences?
✔✔ To refocus dephased spins and reduce signal loss
3
, Why is fat suppression used in MRI?
✔✔ To eliminate fat signal and enhance contrast between tissues
What effect does increasing TE have on T2-weighted images?
✔✔ It enhances T2 contrast, making fluid appear brighter
Why is shimming important in MRI?
✔✔ It improves magnetic field homogeneity for clearer images
What happens when slice thickness is reduced in MRI?
✔✔ Spatial resolution improves, but signal-to-noise ratio decreases
Why is gadolinium used as a contrast agent in MRI?
✔✔ It shortens T1 relaxation time, enhancing contrast between tissues
How does diffusion-weighted imaging (DWI) help in stroke detection?
✔✔ It identifies restricted water diffusion, indicating acute ischemia
4
