title: Dual-energy multidetector CT: how does it work, what can it tell us, and when can we use it in abdominopelvic imaging?
abstract: Dual-energy CT provides information about how substances behave at different energies, the ability to generate virtual unenhanced datasets, and improved detection of iodine-containing substances on low-energy images. Knowing how a substance behaves at two different energies can provide information about tissue composition beyond that obtainable with single-energy techniques. The term K edge refers to the spike in attenuation that occurs at energy levels just greater than that of the K-shell binding because of the increased photoelectric absorption at these energy levels. K-edge values vary for each element, and they increase as the atomic number increases. The energy dependence of the photoelectric effect and the variability of K edges form the basis of dual-energy techniques, which may be used to detect substances such as iodine, calcium, and uric acid crystals. The closer the energy level used in imaging is to the K edge of a substance such as iodine, the more the substance attenuates. In the abdomen and pelvis, dual-energy CT may be used in the liver to increase conspicuity of hypervascular lesions; in the kidneys, to distinguish hyperattenuating cysts from enhancing renal masses and to characterize renal stone composition; in the adrenal glands, to characterize adrenal nodules; and in the pancreas, to differentiate between normal and abnormal parenchyma.
authors.affiliation: Department of Radiology, Duke University Medical Center, Durham, NC, USA. courtney.coursey@emoryhealthcare.org
authors.forename: Courtney A
authors.initials: CA
authors.lastname: Coursey
authors.forename: Rendon C
authors.initials: RC
authors.lastname: Nelson
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Boll
authors.forename: Erik K
authors.initials: EK
authors.lastname: Paulson
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Ho
authors.forename: Amy M
authors.initials: AM
authors.lastname: Neville
authors.forename: Daniele
authors.initials: D
authors.lastname: Marin
authors.forename: Rajan T
authors.initials: RT
authors.lastname: Gupta
authors.forename: Sebastian T
authors.initials: ST
authors.lastname: Schindera
mesh_terms: D006801:Humans; D010388:Pelvis / Q000000981:diagnostic imaging*; D011860:Radiography, Abdominal / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*