multiphase ct Flashcards
1
Q
what is multiphase ct, why’s it done
A
imaging same anatomical region at different points in time (in same examination)
- done to observe contrast enhancement characteristics
2
Q
what is the contrast passage way and the timings for them
A
- no contrast
- early arterial 15-25s
- late arterial 30-40s
(organs before portal venous) - portal venous 70-90s
- nephrogenic (kidney) 85-125s
- excretory/delayed 3-10mins (wash out of contrast in all abdominal structures except for fibrotic tissue, because fibrotic tissue has a poor late wash out and will become relatively dense compared to normal tissue.)
3
Q
lesions with good arterial blood supply will enhance during arterial phase
abnormalities where arterial blood supply is compromised, won’t enhance e.g infarcts
A
4
Q
what is bolus tracking / fluoroscopic timing aka smart prep
A
the volume of contrast is tracked using a region of interest (abbreviated “R.O.I.”) at a certain level and then followed by the CT scanner once it reaches this level
- 1 low dose slice per sec
- manual or ROI trigger
5
Q
cardiac ct is scanned ovr a whole heart cycle,
evaluates MOTION rather than contrast enhancement characteristics
A
6
Q
check camera roll to see ideal contrast timing for certain structures
A
