Ultra-high resolution photon-counting CT with tin prefiltration for bone-metal interface visualization

Theresa Sophie Patzer; Jan-Peter Grunz; Henner Huflage; Jan-Lucca Hennes; Pauline Pannenbecker; Philipp Gruschwitz; Saif Afat; Judith Herrmann; Thorsten Alexander Bley; Andreas Steven Kunz

doi:10.1016/j.ejrad.2023.111209

Ultra-high resolution photon-counting CT with tin prefiltration for bone-metal interface visualization

Eur J Radiol. 2024 Jan:170:111209. doi: 10.1016/j.ejrad.2023.111209. Epub 2023 Nov 19.

Affiliations

¹ Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany. Electronic address: Patzer_T@ukw.de.
² Department of Diagnostic and Interventional Radiology, University Hospital Würzburg, Oberdürrbacher Straße 6, 97080 Würzburg, Germany.
³ Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Hoppe-Seyler-Str 3, 72076 Tübingen, Germany.

PMID: 37992609
DOI: 10.1016/j.ejrad.2023.111209

Abstract

Purpose: To investigate the metal artifact suppression potential of combining tin prefiltration and virtual monoenergetic imaging (VMI) for osseous microarchitecture depiction in ultra-high-resolution (UHR) photon-counting CT (PCCT) of the lower extremity.

Method: Derived from tin-filtered UHR scans at 140 kVp, polychromatic datasets (T3D) and VMI reconstructions at 70, 110, 150, and 190 keV were compared in 117 patients with lower extremity metal implants (53 female; 62.1 ± 18.0 years). Three implant groups were investigated (total arthroplasty [n = 48], osteosynthetic material [n = 43], and external fixation [n = 26]). Image quality was assessed with regions of interest placed in the most pronounced artifacts and adjacent soft tissue, measuring the respective attenuation. Additionally, artifact extent, bone-metal interface interpretability and overall image quality were independently evaluated by three radiologists.

Results: Artifact reduction was superior with increasing keV level of VMI. While T3D was superior to VMI_70keV (p ≥ 0.117), artifacts were more severe in T3D than in VMI ≥ 110 keV (all p ≤ 0.036). Image noise was highest for VMI_70keV (all p < 0.001) and lowest for VMI_110keV with comparable results for VMI_110keV - VMI_190keV. Subjective image quality regarding artifacts was superior for VMI ≥ 110 keV (all p ≤ 0.042) and comparable for VMI_110keV - VMI_190keV. Bone-metal interface interpretability was superior for VMI_110keV (all p ≤ 0.001), while T3D, VMI_150keV and VMI_190keV were comparable. Overall image quality was deemed best for VMI_110keV and VMI_150keV. Interreader reliability was good in all cases (ICC ≥ 0.833).

Conclusions: Tin-filtered UHR-PCCT scans of the lower extremity combined with VMI reconstructions allow for efficient artifact reduction in the vicinity of bone-metal interfaces.

Keywords: Cancellous bone; Metal artifact reduction; Photon-counting; Tin prefiltration; Tomography, x-ray computed.

MeSH terms

Artifacts
Female
Humans
Image Processing, Computer-Assisted / methods
Metals
Prostheses and Implants
Radiographic Image Interpretation, Computer-Assisted / methods
Reproducibility of Results
Retrospective Studies
Signal-To-Noise Ratio
Tin*
Tomography, X-Ray Computed* / methods

Substances

Tin
Metals