60
Bolus Tracking
Additional Important Information1. The preset start delay time for monitoring scans
depends on whether the subsequent spiral scan will
be acquired during the arterial phase or venous
phase. The default value is 10 s. You can modify it
accordingly.
2. It should be pointed out that when using “Test
Bolus”, there may be residual contrast in the liver
and kidneys prior to scanning. This may result in
an inaccurate arterial and equilibrium phase.
3. The trigger threshold is not an absolute value but
a relative value compared to the non-contrast scan.
E.g. if the CT value is 50 HU in the non-contrast
image, and your trigger level is 100 MU, then the
absolute CT value in the contrast image will be
150 HU.
4. If you change slice collimation, rotation time or kV
in the spiral scanning protocol after CARE Bolus
is inserted, a longer spiral start delay time will be
the result, e.g. 14 s. This is due to the necessary
mechanical adjustments, e.g. moving the slice
collimators. Therefore, it is recommended that you
modify the parameters of the spiral scanning
beforeinserting the CARE Bolus.