Artifact reduction and diagnostic value of monoenergetic reconstructions from split-filter and dual-layer spectral detector dual-energy CT in early gastric cancer with titanium clip localization

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OBJECTIVE: Metal clip artifacts impair CT evaluation of early-stage gastric cancer (EGC). While various metal artifact reduction techniques exist, their application in this specific clinical context remains insufficiently explored. We assessed virtual monoenergetic images (VMIs) from two dual-energy CT (DECT) systems for reducing titanium clip artifacts in abdominal CT scans. DATA AND METHODS: Fifty-one EGC patients with gastric titanium clips underwent abdominal DECT using Siemens split-filter DECT (sfDECT) or Philips dual-layer spectral detector CT (DLSCT). Composite images (120 kVp-equivalent image) and VMIs (ranging from 40 to 140 keV) were generated for each patient. Quantitative assessment of image quality was performed by evaluating artifact reduction through noise measurements in the clip-affected region and contrast-to-noise ratios (CNRs) for both lesions and adjacent liver tissue. Two radiologists rated subjective image quality—including overall evaluation, artifacts, lesion visibility, and vascular contrast—using a five-point Likert scale. T staging accuracy on composite images and optimal keV VMIs was compared with pathologic T staging as the reference standard. RESULTS: Artifacts decreased progressively with higher keV. VMIs at 80–140 keV showed significantly fewer artifacts than composite images (p < 0.05). CNRs declined with increasing keV. Subjective artifact scores improved significantly at 80–140 keV for sfDECT and 90–140 keV for DLSCT compared to composite images. (p < 0.05). Lesion visibility peaked at 70/80 keV for sfDECT and 90/100 keV for DLSCT, while vascular contrast declined at higher keV. T staging accuracy improved from 25.8% with composite images to 80.6% at 70 keV VMIs (sfDECT), and from 30.0% to 85.0% at 90 keV VMIs (DLSCT). CLINICAL RELEVANCE STATEMENT: Combining optimal keV VMIs with composite images improved radiologists’ diagnostic confidence and enhanced T-staging accuracy in EGC patients with titanium clips, compared to composite imaging alone. CONCLUSIONS: VMIs at ≥ 80 keV significantly reduced titanium clip artifacts in our cohort but concurrently decreased image contrast. Medium-energy VMIs improve lesion visibility and T staging accuracy in EGC cases. CLINICAL TRIAL NUMBER: Not applicable.

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