Samira Rathnayake, Presenter: Nothing to Disclose

John Mongan MD, PhD, Abstract Co-Author: Spouse, Employee, Quanticel Pharmaceuticals Inc

Yanjun Fu PhD, Abstract Co-Author: Nothing to Disclose

Andrew S Torres PhD, Abstract Co-Author: Employee, General Electric Company

Robert E Colborn PhD, Abstract Co-Author: Employee, General Electric Company

Dongwei Gao MD, Abstract Co-Author: Nothing to Disclose

Margaret Jane Wong MENG, BS, Abstract Co-Author: Nothing to Disclose

Wilbur Wang BA, Abstract Co-Author: Nothing to Disclose

Benjamin M. Yeh MD, Abstract Co-Author: Research Grant, General Electric Company Consultant, General Electric Company

To investigate the effectiveness of double contrast DECT obtained with iodinated intravenous and non-iodinated enteric contrast for small bowel wall and vasculature visualization, compared with conventional CT.

Thirteen rabbits were imaged on a rapid kVp switching CT scanner with intravenous iohexol and an experimental positive enteric contrast agent: bismuth subsalicylate (n=5), tungsten oxide (n=4), or tantalum oxide (n=4). These enteric agents can be separated from iodine at DECT due to their relative high and low x-ray attenuation coefficients. DECT “iodine-only” density maps and conventional CT images were obtained from the thirteen studies to generate 94 pairs of small bowel and 34 pairs of vasculature image comparisons. Four sub-specialty trained abdominal imaging attending radiologists without prior DECT experience independently viewed each comparison to record relative clarity of small bowel wall and abdominopelvic vasculature and completeness of enteric contrast subtraction using a visual analog scale (0%=contrast materials not distinguished to 100%=perfect separation). Significance of differences was determined by t-tests.

Small bowel wall was observed to be 44% (95% CI: 34%-47%, p<0.001) clearer at DECT than conventional CT. Enteric contrast subtraction was 42% (95% CI: 33%-52%, p<0.001) better with tungsten oxide and 45% (95% CI: 36%-54%, p<0.001) better with tantalum oxide than bismuth subsalicylate enteric contrast, respectively. The abdominopelvic vasculature on the DECT iodine density maps was 49% (95% CI: 37%-61%, p<0.001) clearer with tungsten oxide and 71% (95% CI: 64%, 79%, p<0.001) clearer with tantalum oxide than bismuth subsalicylate enteric contrast, respectively. 

Double contrast DECT provides better simultaneous visualization of bowel wall and vasculature than conventional CT in vivo. DECT “iodine-only” maps obtained with a tungsten- or tantalum-based enteric contrast agent were clearer than with a bismuth-based enteric agent.

Development of tantalum or tungsten enteric agents should enable clearer bowel wall and abdominopelvic vasculature visualization for double contrast DECT than conventional CT. 

Rathnayake, S, Mongan, J, Fu, Y, Torres, A, Colborn, R, Gao, D, Wong, M, Wang, W, Yeh, B, Comparison of Bismuth, Tungsten, and Tantalum Enteric Contrast Agents to Complement Iodine for Double Contrast Dual-energy CT Enterography.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13011698.html