Shunt Study Flashcards
1
Q
what is cardiac shunts?
A
movement of blood across the septum. most are congenital defect.
2
Q
what happen right to left shunts?
A
aorta show before the lungs and right ventricle may larger than the left ventricle.
3
Q
what happen left to right shunts?
A
blood will return prematurely to the pulmonary circulation
4
Q
what is Rp and dose for right to left shunt?
A
Tc99m-MAA 2-5 mCi
5
Q
which areas draw ROI in right to left shunt and how quantification MAA?
A
- Rt ventricle, lt ventricle and lungs.
- for quantification MAA may be used, image ANT/POST whole body, subtract lung ROI from WB ROI
6
Q
How confirm the right to left shunt?
A
the left ventricle spike at the same time as the lungs
7
Q
how to perform left to right shunt?
A
- evaluated by pulmonary time activity curve generated by a first pass
- entire chest image include lung and hear 0.5 sec/frame in 30sec
- ROI drawn one or both lungs, dont include hear or great vessels
- ROI around SVC to ensure a good bolus injection
- Peak SVC have FWHM in 3 secs or less
8
Q
what does normal pulmonary time activity curve should have?
A
- Large and single peak then small peak.
9
Q
What happen to the peak of the pulmonary time activity curve with left to right shunt?
A
a bump on its down slope
