How can we mitigate outrunning of the contrast bolus when using a wide detector MDCT scanner?
Wide-detector MDCT scanners can be slowed by slowing the gantry rotation time, using narrower detector coverage where offered, and by reducing the pitch. Additionally, the threshold attenuation for triggering the scan during bolus tracking can be increased, and the scan delay can also be increased. These measures will ensure that the scan starts later with less chance of outrunning the contrast bolus. Finally, it is prudent to acquire, immediately, a second set of images through the most peripheral part of the peripheral circulation (i.e., through the anatomic region the contrast takes the longest amount of time to reach). For assessment of the arteries of the lower legs, this means a second image acquisition from the knees to the toes.
