Theodora Anne Potretzke MD, Presenter: Nothing to Disclose

Christopher L. Brace PhD, Abstract Co-Author: Shareholder, NeuWave Medical Inc Consultant, NeuWave Medical Inc

Meghan G. Lubner MD, Abstract Co-Author: Research support, General Electric Company

Lisa Ann Sampson, Abstract Co-Author: Research Consultant, NeuWave Medical Inc

Bridgett J. Willey, Abstract Co-Author: Consultant, NeuWave Medical Inc

Fred T. Lee MD, Abstract Co-Author: Stockholder, NeuWave Medical, Inc Patent holder, NeuWave Medical, Inc Board of Directors, NeuWave Medical, Inc Patent holder, Covidien AG Inventor, Covidien AG Royalties, Covidien AG

To compare dual-energy CT (DECT) to conventional CT for the detection of early bowel ischemia in a swine model.

Ischemic bowel segments (n=7) were created in swine (n=4) by surgically occluding distal mesenteric vasculature. Ischemia was confirmed grossly and with Doppler ultrasound. DECT and conventional CT were performed in arterial, portal venous, and delayed phases on a single-source fast-switching dual-energy CT scanner. ROIs of bowel wall attenuation were used to compare contrast-to-noise ratios (CNR) between ischemic and perfused segments on iodine material density and monospectral images at 51keV, 65keV (approximates 80kVp), and 80keV (approximates 120kVp). ANOVA and post-hoc t-tests compared pixel intensities and CNR among segments and imaging groups. 

Ischemic bowel exhibited significantly lower attenuation than perfused segments on DECT-iodine material density and 51keV images (P<.001). The differences in attenuation between ischemic and perfused segments on 65keV and 80keV images were not as substantial. As a result, visibility of ischemic segments was significantly greater on DECT-iodine material density and 51keV images than more conventional 65keV or 80keV images (mean CNR of 3.3, 2.7, 1.4 and 0.45, respectively; P<.001). Portal venous and delayed images provided greater CNR than arterial phase images (P<.001). Optimal contrast between ischemic and perfused segments was realized in delayed-phase iodine images (CNR=3.8).

DECT significantly improves the visibility of early bowel ischemia compared to conventional CT images. DECT may offer earlier and more confident diagnosis of bowel ischemia especially in the absence of late secondary signs. It may increase the sensitivity and specificity of CT for bowel ischemia.

Mortality from bowel ischemia is high and increases with delay in diagnosis. Dual-energy CT increases the conspicuity of differential enhancement and may allow earlier diagnosis of bowel ischemia.

Potretzke, T, Brace, C, Lubner, M, Sampson, L, Willey, B, Lee, F, Dual Energy CT Improves Visibility of Early Small Bowel Ischemia Compared to Conventional CT in a Swine Model .  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13018982.html