Rationale and Objectives
The purpose of this study was to evaluate the diagnostic utility of iterative metal
artifact reduction (iMAR) in computed tomography (CT)-imaging of oral and oropharyngeal
cancers when obscured by dental hardware artifacts and to determine the most appropriate
iMAR settings for this purpose.
Materials and Methods
The study retrospectively enrolled 27 patients (8 female, 19 male; mean age 64 ± 12.7 years) with histologically confirmed oral or oropharyngeal cancer obscured by dental
artifacts in contrast-enhanced CT. Raw CT data were reconstructed with ascending iMAR
strengths (levels 1/2/3/4/5) and one reconstruction without iMAR (level 0). For subjective
analysis, two blinded radiologists rated tumor visualization and artifact severity
on a five-point Likert scale. For objective analysis, signal-to-noise ratio (SNR),
contrast-to-noise ratio (CNR), and artifact index (AI) were determined.
Results
iMAR reconstructions improved the subjective image quality of tumor edge and contrast,
and the objective parameters of tumor SNR and CNR, reaching their optimum at iMAR
levels 4 and 5 (P < .001). AI decreased with iMAR reconstructions reaching its minimum at iMAR level 5
(P < .001). Tumor detection rates increased 2.4-fold with iMAR 5, 2.1-fold with iMAR 4,
and 1.9-fold with iMAR 3 compared to reconstructions without iMAR. Disadvantages such
as algorithm-induced artifacts increased significantly with higher iMAR strengths
(P < .05), reaching a maximum with iMAR 5.
Conclusion
iMAR significantly improves CT imaging of oral and oropharyngeal cancers, as confirmed
by both subjective and objective measures, with best results at highest iMAR strengths.
Abbreviations:
AI (artifact index), ANOVA (analysis of variance), CI (confidence interval), CNR (contrast-to-noise ratio), CT (computed tomography), FSMAR (frequency-split metal artifact reduction), ICC (intraclass correlation coefficient), iMAR (iterative metal artifact reduction), NMAR (normalized metal artifact reduction), pT (pathologic tumor stage), ROI (region of interest), SD (standard deviation), SNR (signal-to-noise ratio), TNM (tumor, nodes, metastasis), UICC (Union for International Cancer Control)Key Words
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Article info
Publication history
Published online: May 11, 2023
Accepted:
April 7,
2023
Received in revised form:
April 2,
2023
Received:
February 8,
2023
Publication stage
In Press Corrected ProofIdentification
Copyright
© 2023 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved All rights reserved.
