title: [The potential of dual-energy virtual monochromatic imaging in reducing renal cyst pseudoenhancement: a phantom study].
abstract: Renal cyst pseudoenhancement, an artifactual increase of computed tomography (CT) attenuation for cysts with increased iodine concentrations in the renal parenchyma, complicates the classification of cysts and may thus lead to the mischaracterization of a benign non-enhancing lesion as an enhancing mass. The purpose of this study was to use a phantom model to assess the ability of dual-energy virtual monochromatic imaging to reduce renal pseudoenhancement. A water-filled cylindrical cyst model suspended in varying concentrations of iodine solution, to simulate varying levels of parenchymal enhancement, was scanned with a dual-energy CT scanner using the following three scanning protocols with different combinations of tube voltage: 80 and 140 kV; 80 and 140 kV with tin filter; and 100 and 140 kV with tin filter. Virtual monochromatic images were then synthesized for each dual-energy scan. Single-energy scan with a tube voltage of 120 kV was also performed to obtain polychromatic images as controls. Mean attenuation values (in Hounsfield units) of cyst proxies were measured on both polychromatic and virtual monochromatic images. Pseudoenhancement was considered to be present when the cyst attenuation level increased by more than 10 HU as the background iodine concentration increased from 0.0% to 0.4%, 1.5%, or 2.5%. Our results revealed that pseudoenhancement was not observed on any of the monochromatic images, but appeared on polychromatic images at a background iodine concentration of 2.5%. We thus conclude that dual-energy virtual monochromatic images have a potential to reduce renal pseudoenhancement.
authors.affiliation: Department of Radiology, Osaka University Hospital.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Yamada
authors.forename: Takashi
authors.initials: T
authors.lastname: Ueguchi
authors.forename: Isao
authors.initials: I
authors.lastname: Ukai
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Nagai
authors.forename: Masanobu
authors.initials: M
authors.lastname: Yamakawa
authors.forename: Eku
authors.initials: E
authors.lastname: Shimosegawa
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimazu
authors.forename: Jun
authors.initials: J
authors.lastname: Hatazawa
mesh_terms: D003287:Contrast Media; D007089:Image Enhancement; D052177:Kidney Diseases, Cystic / Q000175:diagnosis*; D019047:Phantoms, Imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media