19 Questions
What is CNR?
The difference in the SN between two adjacent areas
What is the most critical factor affecting image quality?
Contrast
How can CNR be increased?
By increasing intrinsic parameters
What is a hyperintense area on an MR image?
An area of high signal
What is the proton density of a tissue?
The number of mobile hydrogen protons per unit volume of that tissue
What factors affect TI and T2 relaxation?
Molecular tumbling rate and molecular spacing
Which artifact produces replications of moving anatomy across the image in the phase encoding direction?
Phase mismapping
What can cause motion artifacts in MRI images?
All of the above
Which technique can be used as a remedy for motion artifacts in MRI?
Respiratory compensation
Which artifact is caused by anatomy outside the FOV being folded onto the top of anatomy inside the FOV?
Appearance Aliasing
What causes anatomy outside the FOV to produce a signal within the receiving volume of the receiver coil?
Effects of the gradients
What happens to the frequencies of the signal from anatomy outside the FOV?
They can be higher or lower than those within the FOV
What is the artifact called when frequencies outside the FOV are aliased along the frequency encoding axis?
Frequency wrap
Which direction of the FOV is smaller than the anterior-to-posterior dimensions of the head in Figure 8.10?
Phase direction
Which artifact is caused by anatomy outside the FOV being folded onto the top of anatomy inside the FOV?
Aliasing
What is the artifact called when frequencies outside the FOV are aliased along the frequency encoding axis?
Frequency wrap
What is the artifact called when anatomy outside the FOV is folded onto the top of anatomy inside the FOV?
Wrap
What causes anatomy outside the FOV to produce a signal within the receiving volume of the receiver coil?
Gradients
What happens to the frequencies of the signal from anatomy outside the FOV?
They become lower frequencies
Study Notes
Test your understanding of image quality with this quiz focused on Contrast-to-Noise Ratio (CNR). Learn about the factors that impact CNR and how it affects image contrast. Sharpen your knowledge with this informative quiz.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
