Toshimasa Clark, Presenter: Nothing to Disclose

Kelly M Barna DO, Abstract Co-Author: Nothing to Disclose

Nalini Kanth MD, Abstract Co-Author: Nothing to Disclose

Victor J. Scarmato MD, Abstract Co-Author: Nothing to Disclose

Joshua Fogel PhD, Abstract Co-Author: Nothing to Disclose

Trauma CT bolus timing is a compromise between optimizing arterial opacification and solid visceral and collecting system enhancement. Previous research describes 3-phase contrast infusion for CT urography, demonstrating simultaneous arterial, venous-phase, and collecting system opacification. We apply a modified 3-phase technique to trauma CT, which to our knowledge has never been studied.

Standard trauma CT protocol involves 100-150 ml of intravenous contrast injected at 2-3 ml/s with image acquisition at 120 kVp starting 50s after injection. Our experimental protocol involves 140 ml of contrast split into three volumes of 25, 90 and 25 ml (boluses A, B and C). Bolus A is injected at time point 0s at a rate of 2 ml/s; B at 150s at 2 ml/s; C at 195s at 3 ml/sec. Images are acquired at 220s. Using ANOVA, we compared the independent variable of trauma patients with experimental protocol trauma CT (n=50) to those with standard protocol trauma CT (n=100). The primary outcome variable was the total Hounsfield unit (HU) score of the aortic arch, pulmonary artery, superior mesenteric artery, portal vein, left common femoral artery, both liver lobes, both renal upper poles, spleen, and pancreatic head (standard structures). Additional outcomes included the structures of bilateral renal pelves, ureters, and urinary bladder (collecting system) and CT dose index (CTDI). We repeated the above analyses adjusting for demographics (age, sex, race) using ANCOVA.

The split-bolus technique had significantly greater mean HU scores than the standard technique for both the standard structure and standard structure + collecting system totals. Significance was maintained after adjusting for demographics. There were no significant differences in CTDI (See Table 1).

Split-bolus trauma CT provides objectively superior opacification of both standard structures and the renal collecting system. The additional collecting system information obtained with this technique could decrease patient radiation exposure by obviating separate delayed phase CT scans that are at times necessary following standard trauma protocol CT.

Split-contrast bolus trauma CT could lead to improved simultaneous opacification of arterial, venous, and collecting system structures while minimizing radiation exposure.

Clark, T, Barna, K, Kanth, N, Scarmato, V, Fogel, J, Split-contrast-Bolus Trauma CT of the Chest, Abdomen, and Pelvis.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11010524.html