Extravasated Contrast Material in Penetrating Abdominopelvic Trauma: Dual-Contrast Dual-Energy CT for Improved Diagnosis—Preliminary Results in an Animal Model

Abstract

Purpose:To compare the diagnostic performance of dual-energy (DE) computed tomography (CT) with two simultaneously administered contrast agents (hereafter, dual contrast) with that of conventional CT in the evaluation of the presence and source of extravasation in penetrating abdominopelvic trauma. Materials and Methods:Institutional animal care and use committee approval was obtained, and the study was performed in accordance with National Institutes of Health guidelines for the care and use of laboratory animals. Five rabbits with bowel trauma, vascular penetrating trauma, or both were imaged with simultaneous iodinated intravenous and bismuth subsalicylate enteric contrast material at DE CT. Four attending radiologists and six radiology residents without prior DE CT experience each evaluated 10 extraluminal collections to identify the vascular and/or enteric origin of extravasation and assess their level of diagnostic confidence, first with virtual monochromatic images simulating conventional CT and then with DE CT material decomposition attenuation maps. Results:Overall accuracy of identification of source of extravasation increased from 78% with conventional CT to 92% with DE CT (157 of 200 diagnoses vs 184 of 200 diagnoses, respectively; P , .001). Nine radiologists were more accurate with DE CT; one had no change. Mean confidence increased from 67% to 81% with DE CT (P , .001). Conclusion:In a rabbit abdominopelvic trauma model, dual-contrast DE CT significantly increased accuracy and confidence in the diagnosis of vascular versus enteric extravasated contrast material.q RSNA, 2013

An Image-Domain Contrast Material Extraction Method for Dual-Energy Computed Tomography

“…Through optimization of the CMEP calibration parameters it is likely that this separation could be improved in the in vivo images, however we wished to demonstrate the robustness of the method using the same parameters derived from the phantom experiments. The addition and color-coding of the extraction images was readily achieved within the Fiji framework, and may help depict anatomy with greater confidence or conspicuity than possible with conventional greyscale images (17, 36). Two unexpected material regions were noted in the rabbit.…”

Complementary contrast media for metal artifact reduction in dual-energy computed tomography

“…38,39 It has been shown preclinically that tungsten and bismuth are separable from soft tissue and also separable from iodinated contrast material, due to their different attenuation ratios. 23,40 This enables the possibility of double-contrast material decomposition where, for example, an iodinated agent is administered simultaneously with a high-Z agent in a different anatomical compartment. Potentially powerful clinical applications of double-contrast material decomposition could be developed, including tasks where simultaneous bowel wall and vascular enhancement are required in the abdomen 23 and for trauma imaging.…”

“…Potentially powerful clinical applications of double-contrast material decomposition could be developed, including tasks where simultaneous bowel wall and vascular enhancement are required in the abdomen 23 and for trauma imaging. 40 Projection-based material decomposition techniques may enhance the decomposition process due to the reduction (ideally, elimination) of beam hardening in the basis material density images which are used to generate the VMS images. The combined use of VMS images and material decomposition techniques may also offer an alternative solution for contrast retention at high keV.…”

Computed Tomographic Imaging of Renal and Ureteral Emergencies

“…52 In the context of penetrating trauma, dual-energy CT may have a role in distinguishing between a vascular or enteric source of extravasated contrast by differentiating between the different contrast media. 53 Ureteral trauma is less common than renal trauma and most commonly occurs at its fixation points at the ureteropelvic or ureterovesical junctions. The most common mechanism of injury is sudden deceleration, which results in laceration of the ureter.…”