Imaging Flashcards
What is the target HR calculation, based on age?
(220-Age) x 0.85 = target HR
What pre-existing conditions may screw up the cardiac stress test?
if the pt already has baseline ST segment abnormalities
What must you do in conjunction to the EKG stress test to bring the results to 90%?
radionucleotide imaging
This is the version of thallium that u use right after exercise, as it works by being transported into the myocytes by the Na/K ATPase.
Thallium-201 (201Tl)
What will show up on the thallium-201 scan if the myocute is scarred (like in an MI) or ischemic?
The thallium is not taken up
True or False: Thallium-201 redistributes so you can further classify cold spots when you image them 3-4 hours after exercise.
True
What is it called when a previous cold spot “fills in” after 3-4 hours?
Hibernating myocardium
And what if the previous cold spot does not fill in after 3-4 hours? What’s that called?
Fixed defect
This is the radionucleotide that is lipophilic, so it can be taken up into the myocardium in proportion to blood flow.
Tecnetium-99m (99mTc)
True or False: 99mTc does not redistribute and stays solely in the mitochrondria.
true
So injection of 99mTc shows what at the moment of injection?
perfusion
Which radionucleotide (201Tl or 99mTc) has a better detection of myocardial viability?
201Tl
Which radionucleotide (201Tl or 99mTc) has a better image quality?
99mTc
Which radionucleotide (201Tl or 99mTc) has a shorter half life?
99mTc
Which radionucleotide (201Tl or 99mTc) requires separate stress and rest injections to detect regions of myocardial ischemia?
99mTc
Which radionucleotide (201Tl or 99mTc) has a long half life (around 73 hrs)?
201Tl