CT and MRI

Computed Tomography

• 1972 __________________

• X-ray tube in a tube

• Rows of _________ opposite x-ray tube

• Produces ___________________

1st and 2nd Generation

• 1st generation – _________– Transmits beam then

________– Long scan times

• 2nd generation– _________– Transmits a fan beam

then _________– Faster scanning

3rd and 4th Generation

• 3rd generation– _____________– More detectors

• 4th generation– Detectors

_____________– Continuous rotating x-

ray tube

Helical/Spiral scanning

• ______________technology

• Tube rotation ____________

• Pt movement continuous

• ______________of data

• Faster scanning

Hounsfield UnitsCT Numbers

• Can determine material based on the __________(linear attenuation coefficient)

• __________ = 0

• Cortical bone = +1000

• ________= -1000

Multi slice

• Obtaining multiple slices ____________

• Much faster scanning

• 4, 16, 32, 64 slice

• And More

Contrast

• IV – _____________ same as X-ray

• __________– visualizes GI track

• ______– quicker visualization of Lower GI

MRI• 1983 1st Installed MRI. 1946 discovered.

• Uses primarily– ___________– ________________

• Good anatomical detail

Magnet Types

• Resistive

• ____________

• ________________

MRI (Sort of)

• _______________

• Some ___________ in the magnet– Magnetic moment

• Radiofrequency (RF)– ______________

• Atoms ___________

• Computer recon image

T1 and T2 Weighted

• MRI visual contrast

• T1 – ______________

• T2 – ______________

• Unless it’s blood

MRI IV contrast

• Not like X-ray

• ___________– Metallic based

• ________________than X-ray– Until recently

Safety

• _________________________

• Carefully screen pt

• __________________