Reduction of peristalsis-related gastrointestinal streak artifacts with dual-energy CT: a patient and phantom study.

Abstract

The purpose of the study was to assess the ability of rapid-kV switching (rs) dual-energy computed tomography (DECT) to reduce peristalsis-related streak artifact. rsDECT images of 100 consecutive patients (48 male, 52 female, mean age 57years) were retrospectively evaluated in this institutional review board-approved study. Image reconstructions included virtual monochromatic 70 and 120keV images, as well as iodine(-water) and water(-iodine) material decomposition images. We recorded the presence and severity of artifacts qualitatively (4-point scale) and quantitatively [iodine/water concentrations, Hounsfield units, gray scale values (GY)] and compared to corresponding unaffected reference tissue. Similar measures were obtained in DECT images of a peristalsis phantom. Wilcoxon signed-rank and paired t tests were used to compare results between different image reconstructions. Peristalsis-related streak artifacts were found in 49 (49%) of the DECT examinations. Artifacts were significantly more severe in 70, 120, and water(-iodine) images than in iodine(-water) images (qualitative readout P<0.001, each). Quantitative measurements were significantly different between the artifact and the reference tissue in 70, 120keV, and water(-iodine) images (P<0.001 for both HU and GY for each image reconstruction), but not significantly different in iodine(-water) images (iodine concentrations P=0.088 and GY P=0.111). Similar results were seen in the peristalsis DECT phantom study. Peristalsis-related streak artifacts seen in 70, 120keV, and water(-iodine) images are substantially reduced in iodine(-water) images at rsDECT.