Chapter 2 Study Questions

  1. What are the three main components of an MRI scanner, as associated with the mnemonic “M-R-I”?
  2. How does an MRI scanner generate the main magnetic field? What two criteria are important for the main magnetic field?
  3. How strong, in units, are the magnetic fields in the MRI scanners typically used for fMRI?
  4. Why are superconducting electromagnets necessary for MRI?
  5. What are the differences between volume coils, surface coils, and phased array coils?
  6. Why are gradients necessary for image generation? What sorts of coils are used to generate these gradients?
  7. What is shimming, and why is it important?
  8. Why might researchers want to monitor physiological changes like cardiac and respiratory rate during an fMRI experiment?
  9. Describe the procedures of a typical fMRI experiment, beginning with recruitment of the subject.
  10. What sorts of conditions/problems would prevent someone from being a subject in an fMRI experiment?
  11. What effects do very strong static magnetic fields have upon human tissue?
  12. In one experimental report, 45% of subjects reported unusual sensations when entering the bore of a 4-T scanner. What was most important yet surprising about this result?
  13. What happens to metal brought within the static magnetic field? Consider both large external objects (e.g., oxygen canisters) and small internal devices (e.g., aneurysm clips).
  14. What effects do the changing gradient fields have upon the human body? How can these effects be minimized?
  15. What is SAR? Why is it important for fMRI?
  16. Why is it important to avoid looping wires or necklaces near the head coil?
  17. What are the most common health risks for MRI studies? How can those risks be minimized?
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