Background We compared photon-counting detector computed tomography (PCD-CT) polyenergetic images, PCD-CT virtual monoenergetic images (VMI), and energy-integrating detector computed tomography (EID-CT) polyenergetic images regarding bone visualization and metal artifacts in patients with titanium wrist prostheses. Methods After ethical approval, 15 patients were examined with PCD-CT and EID-CT. Polyenergetic images were reconstructed, as well as 130-keV VMI for PCD-CT. Five radiologists evaluated bone visualization, interpretability at metal-bone interface and metal artifacts using a 7-point ordinal scale. Streak artifacts and artifacts at the bone-metal interface were quantitatively assessed. Differences between image setups were analyzed using Friedman test and one-way ANOVA with post hoc tests. Results Bone visualization was superior in PCD-CT polyenergetic images (median rating 6, range 3–7) compared with VMI (5, 3–7; p < 0.001) and EID-CT (5, 3–7; p = 0.018). Streak artifacts were more pronounced with PCD-CT polyenergetic images (4, 3–6) compared with EID-CT (5, 4–6; p = 0.003) and PCD-CT VMI (5, 3–7; p = 0.002), with quantitative results showing least streak artifacts in PCD-CT VMI, followed by EID-CT and PCD-CT polyenergetic images (50 ± 7%, 70 ± 6%, and 79 ± 5%, respectively; p < 0.001). Interpretability at bone-metal interface was better with PCD-CT polyenergetic images (5, 2–7; p = 0.045) and EID-CT (5, 3–6; p = 0.018) compared with PCD-CT VMI (4, 2–6), without quantitative differences. Conclusion Streak artifacts from titanium wrist prostheses were reduced using 130-keV PCD-CT VMI, while bone visualization was highest using PCD-CT polyenergetic images. Relevance statement In patients with wrist implants, photon-counting detector CT allows for effective metal artifact reduction using virtual monoenergetic images and improved bone visualization using polyenergetic images. As polyenergetic images and VMI have different advantages, access to both image setups may benefit diagnostic evaluation. Key Points <UnorderedList Mark="Bullet"> <ItemContent> Virtual monoenergetic images (VMI) presented a substantial reduction of metal streak artifacts. </ItemContent> <ItemContent> Polyenergetic images exhibited better image quality for bone imaging compared with VMI. </ItemContent> <ItemContent> A combination of image reconstructions should be preferred depending on the diagnostic task. </ItemContent> </UnorderedList> Graphical Abstract

Assessment of metal artifacts from titanium wrist prostheses: photon-counting versus energy-integrating detector CT

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发表日期：

2025年5月1日

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Nina Kämmerling,
Simon Farnebo,
Mårten Sandstedt,
Ronald Booij,
Anders Persson,
Erik Tesselaar

摘要

Background

We compared photon-counting detector computed tomography (PCD-CT) polyenergetic images, PCD-CT virtual monoenergetic images (VMI), and energy-integrating detector computed tomography (EID-CT) polyenergetic images regarding bone visualization and metal artifacts in patients with titanium wrist prostheses.

Methods

After ethical approval, 15 patients were examined with PCD-CT and EID-CT. Polyenergetic images were reconstructed, as well as 130-keV VMI for PCD-CT. Five radiologists evaluated bone visualization, interpretability at metal-bone interface and metal artifacts using a 7-point ordinal scale. Streak artifacts and artifacts at the bone-metal interface were quantitatively assessed. Differences between image setups were analyzed using Friedman test and one-way ANOVA with post hoc tests.

Results

Bone visualization was superior in PCD-CT polyenergetic images (median rating 6, range 3–7) compared with VMI (5, 3–7; p < 0.001) and EID-CT (5, 3–7; p = 0.018). Streak artifacts were more pronounced with PCD-CT polyenergetic images (4, 3–6) compared with EID-CT (5, 4–6; p = 0.003) and PCD-CT VMI (5, 3–7; p = 0.002), with quantitative results showing least streak artifacts in PCD-CT VMI, followed by EID-CT and PCD-CT polyenergetic images (50 ± 7%, 70 ± 6%, and 79 ± 5%, respectively; p < 0.001). Interpretability at bone-metal interface was better with PCD-CT polyenergetic images (5, 2–7; p = 0.045) and EID-CT (5, 3–6; p = 0.018) compared with PCD-CT VMI (4, 2–6), without quantitative differences.

Conclusion

Streak artifacts from titanium wrist prostheses were reduced using 130-keV PCD-CT VMI, while bone visualization was highest using PCD-CT polyenergetic images.

Relevance statement

In patients with wrist implants, photon-counting detector CT allows for effective metal artifact reduction using virtual monoenergetic images and improved bone visualization using polyenergetic images. As polyenergetic images and VMI have different advantages, access to both image setups may benefit diagnostic evaluation.

Key Points

Virtual monoenergetic images (VMI) presented a substantial reduction of metal streak artifacts.

Polyenergetic images exhibited better image quality for bone imaging compared with VMI.

A combination of image reconstructions should be preferred depending on the diagnostic task.

Graphical Abstract