Objective To evaluate the image quality of abdominal dual-energy CT virtual monoenergetic imaging (VMI) in patients with early gastric cancer using titanium alloy clips and assess its effectiveness on reducing metal artifacts.

Methods A retrospective study was conducted, including 31 patients with gastric cancer who underwent abdominal dual-energy CT scans with titanium clips inserted in the gastric cavity. Each scan was reconstructed into mixed images (simulated 120 kVp CT) and VMIs with energy levels ranging from 40 keV to 140 keV. Metal artifacts were quantitatively evaluated by measuring the noise values in the lesion and perigastric regions. The contrast-noise ratio (CNR) of the lesion and the corresponding liver tissue was calculated to assess the image quality. Two radiologists independently evaluated the images, considering overall quality, artifact severity, lesion conspicuity, perigastric clarity, and vascular contrast.

Results Quantitative analysis revealed that metal artifacts in both the lesion and perigastric regions decreased as the energy level increased. VMIs at 80-140 keV (lesion site) and 90-140 keV (perigastric space) showed significantly fewer artifacts compared to mixed images (P＜0.05). The CNR of lesions remained stable across VMIs at 50-140 keV, while the CNR of normal liver tissue decreased significantly with increasing energy (P＜0.05). In the subjective assessment, VMIs at 80-140 keV had higher artifact scores than mixed images (P＜0.05). VMIs at 70-90 keV provided better lesion conspicuity and perigastric clarity, although vascular contrast decreased significantly with increasing energy (P＜0.05). VMIs at 70-90 keV showed better overall quality (P＜0.05), though not significantly different from mixed images.

Conclusions VMIs at 80 keV and 90 keV improve the visibility of lesions and perigastric regions affected by metallic clips, which combined with mixed images can enhance radiologists’ diagnostic accuracy.