In terms of a computer, what do the following acronyms stand for:
CRT
LED
LCD
ROM
RAM Answer - CRT: cathode ray tube
LED: liquid emitting diode
LCD: liquid crystal display
ROM: read only memory (permanent, can't write over)
RAM: random access memory (temporary, lost when computer turns off)
What is used for MRI magnet shielding? What is used for MRI radiofrequency
shielding? Answer - -steel plates
-metal mesh (Faraday cage)
What strength of MRI has been shown to have no biological effects? Answer -
If <10Tesla, then no biological effects
What is the cause for acoustic noise with an MRI machine? Answer - The
switching of gradient fields
,What is the event of a rapid boil-off of the liquid nitrogen or liquid helium
surrounding the MRI magnet, which is a failure of the emergency venting
system and can cause a life-threatening oxygen shortage in the MRI room?
Answer - Quench
What is the resolution of MRI? Spatial accuracy? Answer - -Resolution:
0.3lp/mm
-Spatial accuracy: 1mm-2mm
How can the resolution of an MRI be bettered? Answer - Use stronger
gradients
What are some disadvantages of MRI? Answer - -Image distortion due to lack
of homogeneity of magnetic fields and due to the gradients having slight spatial
non-linearities
-No electron density info
-Long scan times (motion artifacts)
-Spatial resolution not as good as CT
What 9 structures are evaluated on an MRI? Answer - -CSF
-Gray matter
-White matter
-Fat
-Cortical bone
-Air
-Blood
-Oedema
-Protein
, On a T1 MRI image, how does the following anatomy look:
-CSF
-Gray matter
-White matter
-Fat
-Cortical bone
-Air
-Blood
-Oedema
-Protein Answer - -CSF: dark
-Gray matter: gray
-White matter: bright
-Fat: bright
-Cortical bone: dark
-Air: dark
-Blood: dark
-Oedema: grey/dark
-Protein: bright
On a T2 MRI image, how does the following anatomy look:
-CSF
-Gray matter
-White matter
-Fat
-Cortical bone
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