Reduction of Peristalsis-Related Streak Artifacts on the Liver with Dual-Layer Spectral CT

Abstract

Background: Peristalsis-related streak artifacts on the liver compromise image quality and diagnostic accuracy. Purpose: To assess dual-layer spectral-detector computed tomography (CT) image reconstructions for reducing intestinal peristalsis-related streak artifacts on the liver. Methods: We retrospectively evaluated 220 contrast-enhanced abdominal dual-energy CT scans in 131 consecutive patients (mean age: 68 ± 10 years, 120 men) who underwent routine clinical dual-layer spectral-detector CT imaging (120 kVp, 40 keV, 200 keV, virtual non-contrast (VNC), iodine images). Two independent readers evaluated bowel peristalsis streak artifacts on the liver qualitatively on a five-point Likert scale (1 = none to 5 = severe) and quantitatively by depth of streak artifact extension into the liver and measurements of Hounsfield Unit and iodine concentration differences from normal liver. Artifact severity between image reconstructions were compared by Wilcoxon signed-rank and paired t-tests. Results: 12 scans were excluded due to missing spectral data, artifacts on the liver originating from metallic foreign materials, or oral contrast material. Streak artifacts on the liver were seen in 51/208 (25%) scans and involved the left lobe only in 49/51 (96%), the right lobe only in 0/51 (0%), and both lobes in 2/51 (4%) scans. Artifact frequency was lower in iodine than in 120 kVp images (scans 18/208 vs. 51/208, p < 0.001). Artifact severity was less in iodine than in 120 kVp images (median score 1 vs. 3, p < 0.001). Streak artifact extension into the liver was shorter in iodine than 120 kVp images (mean length 2 ± 4 vs. 12 ± 5 mm, p < 0.001). Hounsfield Unit and iodine concentration differed significantly between bright streak artifacts and normal liver in 120 kVp, 40 keV, 200 keV, and VNC images (p < 0.001, each), but not in iodine images (p = 0.23). Conclusion: Intestinal peristalsis-related streak artifacts commonly affect the left liver lobe at CT and can be substantially reduced by viewing iodine dual-energy CT image reconstructions.

Reducing Visceral-Motion-Related Artifacts on the Liver with Dual-Energy CT: A Comparison of Four Different CT Scanner Techniques

“…In total, 131 of the 458 patients were included in a previous study [ 9 ]. This prior article dealt with visceral-motion-related artifact reduction with a dual-layer spectral detector DECT scanner only, whereas in this manuscript, we report on visceral-motion-related artifact reduction with different DECT scanner models, as DECT methodologies differ significantly between models.…”

“…Visceral-motion-related artifact severity on the liver in 120-kVp(-like), low- and high-keV, VNC, and iodine images was qualitatively evaluated on a five-point Likert scale [ 9 ]: 1 = Absence of visceral-motion-related artifact on the liver; 2 = Visible visceral-motion-related artifact with no effect on diagnosis on the liver; 3 = Moderate visceral-motion-related artifact that may decrease confidence in diagnosing a 0.5 to 0.9 cm liver lesion; 4 = Distinct visceral-motion-related artifact that prevents the diagnosis of a 0.5 to 0.9 cm liver lesion, and that may decrease confidence in diagnosing a ≥ 1.0 cm liver lesion; 5 = Severe visceral-motion-related artifact that prevents the diagnosis of a ≥ 1.0 cm liver lesion [ 9 ].…”

“…The peristalsis-related movement of intraluminal gas in the stomach or bowel during CT scanning can cause bright and dark streak artifacts in CT images [ 2 , 6 , 7 , 8 ]. Due to the anatomical proximity of the liver to the stomach, the liver, particularly the left liver lobe, is frequently affected by visceral-motion-related artifacts [ 7 , 9 ].…”

“…Advances in CT techniques such as rapid scanning and software-based correction algorithms can reduce the severity and frequency of visceral-motion-related artifacts [ 2 , 10 , 11 ]. However, with a prevalence ranging from 25% to 70%, these artifacts remain frequent in CT scans of the abdomen, often affecting the liver [ 2 , 7 , 9 ].…”

“…Furthermore, iodine DECT image reconstructions are helpful in the characterization of liver lesions [ 24 , 25 ]. For dual-layer spectral detector DECT scanners, it was shown that visceral-motion-related artifacts on the liver can be substantially reduced by viewing iodine DECT image reconstructions [ 9 ]. However, as DECT methodologies differ significantly between DECT scanners, it is unclear whether iodine images are useful for visceral-motion-related artifact reduction in other scanner implementations.…”