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Dual-energy CT in emergency neurologic imaging is a powerful tool that may be helpful for interpreting CT angiographic findings, identifying contrast material extravasation, increasing the conspicuity of hemorrhage, and characterizing the material composition of indeterminate lesions.

Dual-energy computed tomography (CT) is a powerful diagnostic tool that is becoming more widely clinically available. Dual-energy CT has the potential to aid in the detection or add diagnostic confidence in the evaluation of a variety of emergent neurologic conditions with use of postprocessing techniques that allow one to take advantage of the different x-ray energy–dependent absorption behaviors of different materials. Differentiating iodine from hemorrhage may help in delineating CT angiographic spot signs, which are small foci of intracranial hemorrhage seen on CT angiograms in cases of acute hemorrhage. Bone subtraction can be used to effectively exclude osseous structures surrounding enhancing vessels at imaging for improved vessel visualization and to create images that are similar in appearance to three-dimensional magnetic resonance imaging vessel reconstructions. Bone subtraction may also be helpful for improving the conspicuity of small extra-axial fluid collections and extra-axial masses. Material characterization can be helpful for clarifying whether small foci of intermediate attenuation represent hemorrhage, calcification, or a foreign material, and it may also be useful for quantifying the amount of hemorrhage or iodine in preexisting or incidentally detected lesions. Virtual monochromatic imaging also can be used to problem solve in challenging cases.

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Article History

Received: Mar 23 2016
Revision requested: May 20 2016
Revision received: May 30 2016
Accepted: June 15 2016
Published online: Nov 10 2016
Published in print: Nov 2016