Dual-energy multidetector CT: how does it work, what can it tell us, and when can we use it in abdominopelvic imaging?
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.
Coursey
Courtney A
CA
Department of Radiology, Duke University Medical Center, Durham, NC, USA. courtney.coursey@emoryhealthcare.org
Nelson
Rendon C
RC
Boll
Daniel T
DT
Paulson
Erik K
EK
Ho
Lisa M
LM
Neville
Amy M
AM
Marin
Daniele
D
Gupta
Rajan T
RT
Schindera
Sebastian T
ST
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*