Automatic Bolus Tracking Versus Fixed Time-Delay Technique in Biphasic Multidetector Computed Tomography of the Abdomen

Abstract

BackgroundBolus tracking can individualize time delay for the start of scans in spiral computed tomography (CT).ObjectivesWe compared automatic bolus tracking method with fixed time-delay technique in biphasic contrast enhancement during multidetector CT of abdomen.Patients and MethodsAdult patients referred for spiral CT of the abdomen were randomized into two groups; in group 1, the arterial and portal phases of spiral scans were started 25 s and 55 s after the start of contrast material administration; in group 2, using the automatic bolus tracking software, repetitive monitoring scans were performed within the lumen of the descending aorta as the region of interest with the threshold of starting the diagnostic scans as 60 HU. The contrast enhancement of the aorta, liver, and spleen were compared between the groups.ResultsForty-eight patients (23 males, 25 females, mean age=56.4±13.5 years) were included. The contrast enhancement of the aorta, liver, and spleen at the arterial phase was similar between the two groups (P>0.05). Regarding the portal phase, the aorta and spleen were more enhanced in the bolus-tracking group (P<0.001). The bolus tracking provided more homogeneous contrast enhancement among different patients than the fixed time-delay technique in the liver at portal phase, but not at the arterial phase.ConclusionsThe automatic bolus-tracking method, results in higher contrast enhancement of the aorta and spleen at the portal phase, but has no effect on liver enhancement. However, bolus tracking is associated with reduced variability for liver enhancement among different patients.

Optimal scan delay depending on contrast material injection duration in abdominal multi-phase computed tomography of pancreas and liver in normal Beagle dogs

“…To maximize contrast enhancement of the target organ for each phase, contrast-enhanced CT techniques such as fixed scan delay, test bolus, and bolus tracking, which provide information for CT scan timing, have been described for multi-phase CT imaging in humans [1271315]. The test bolus method is the most common protocol used to determine the scan timing in multi-phase CT of the canine liver and pancreas [832].…”

Effect of different contrast administration protocols on contrast enhancement and image quality in CT scan

“…It is found that there was no signi cant difference in parenchymal enhancement between ABT and FTD technique in Mehnert's study [13]. Adibi et al compared liver enhancement between ABT and FTD technique and found that there was no signi cant difference in contrast enhancement of the aorta and spleen at arterial phase, but has no effect on liver enhancement [14]. As for CT scanning in children, White reported that better results was yielded by FTD trials and recommended that after CM administered, the scan to start initiate after a delay of 10-20 second.…”

Multi-Detector Computed Tomography Imaging Techniques in Arterial Injuries

“…This method is adequate for the majority of the population, but is problematic when there is abnormal anatomy, abnormal cardiac function, or severe arterial disease, all of which can significantly alter the transit time of blood. Despite known limitations, there is typically no significant difference in arterial phase enhancement with the fixed time-delay imaging technique in comparison to bolus tracking [ 7 ].…”