Bolus tracking

What is the purpose of bolus tracking in contrast administration, and how this method works?
Individual timing of contrast material
injection (bolus tracking or test bolus injection)
is mandatory to take advantage of phaseresolved
image acquisition.
To individualize the timing of contrast material
injection, automatic bolus tracking techniques
(Smart Prep, CARE Bolus, and Sure Start) can
be employed (2). These techniques are fast and
easy to use and require only a single contrast material
injection. The disadvantage is that a large
target vessel for monitoring the contrast material

arrival is required, and an additional delay for
table movement and patient instruction is necessary.
Test bolus injection is the alternative to assess
the individual circulation time. Its major advantage
is that it provides information about the timing
of both arterial and venous enhancement in
the vessels of interest. The individual start
delay can be optimized by placing the scan between
the arterial peak and venous contrast material
upslope. Table movement and patient instructions
can be performed prior to the optimal
image acquisition window. The disadvantage is
the necessity for an additional injection of about
10 mL of contrast agent (10%–20% increase of
total amount).