Sixty-four MDCT achieves higher contrast in pancreas with optimization of scan time delay

Abstract

AIM: To compare different multidetector computed tomography (MDCT) protocols to optimize pancreatic contrast enhancement.METHODS: Forty consecutive patients underwent contrast-enhanced biphasic MDCT (arterial and portal-venous phase) using a 64-slice MDCT. In 20 patients, the scan protocol was adapted from a previously used 40-channel MDCT scanner with arterial phase scanning initiated 11.1 s after a threshold of 150 HU was reached in the descending aorta, using automatic bolus tracking (Protocol 1). The 11.1-s delay was changed to 15 s in the other 20 patients to reflect the shorter scanning times on the 64-channel MDCT compared to the previous 40-channel system (Protocol 2). HU values were measured in the head and tail of the pancreas in the arterial and portal-venous phase.RESULTS: Using an 11.1-s delay, 74.2 HU (head) were measured on average in the arterial phase and 111.2 HU (head) were measured using a 15-s delay (P < 0.0001). For the pancreatic tail, the average attenuation level was 76.73 HU (11.1 s) and 99.89 HU (15 s) respectively (P = 0.0002). HU values were also significantly higher in the portal-venous phase [pancreatic head: 70.5 HU (11.1 s) vs 84.0 HU (15 s) (P = 0.0014); pancreatic tail: 67.45 HU (11.1 s) and 77.18 HU (15 s) using Protocol 2 (P = 0.0071)].CONCLUSION: Sixty-four MDCT may yield a higher contrast in pancreatic study with (appropriate) optimization of scan delay time.