UCSF

Objective

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.

Methods

rsDECT images of 100 consecutive patients (48 male, 52 female, mean age 57 years) were retrospectively evaluated in this institutional review board-approved study. Image reconstructions included virtual monochromatic 70 and 120 keV 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.

Results

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, 120 keV, 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.

Conclusions

Peristalsis-related streak artifacts seen in 70, 120 keV, and water(-iodine) images are substantially reduced in iodine(-water) images at rsDECT.