Metal Artefact Reduction in the Oral Cavity Using Deep Learning Reconstruction Algorithm in Ultra-high-resolution Computed Tomography: a Phantom Study
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Objectives: This study aimed to improve the impact of the metal artefact reduction (MAR) algorithm for the oral cavity by assessing the effect of acquisition and reconstruction parameters on an ultra-high-resolution CT (UHRCT) scanner.
Methods: The mandible tooth phantom with and without the lesion was scanned using super-high-resolution, high-resolution (HR), and normal-resolution (NR) modes. Images were reconstructed with deep learning-based reconstruction (DLR) and hybrid iterative reconstruction (HIR) using the MAR algorithm. Two dental radiologists independently graded the degree of metal artefact (1, very severe; 5, minimum) and lesion shape reproducibility (1, slight; 5, almost perfect). The signal-to-artefact ratio (SAR), accuracy of the CT number of the lesion, and image noise were calculated quantitatively. The Tukey-Kramer method with a -value of less than 0.05 was used to determine statistical significance.
Results: The HR visual score was better than the NR score in terms of degree of metal artefact (4.6 ± 0.5 and 2.6 ± 0.5, < 0.0001) and lesion shape reproducibility (4.5 ± 0.5 and 2.9 ± 1.1, = 0.0005). The SAR of HR was significantly better than that of NR (4.9 ± 0.4 and 2.1 ± 0.2, < 0.0001), and the absolute percentage error of the CT number in HR was lower than that in NR (0.8% in HR and 23.8% in NR). The image noise of HR was lower than that of NR (15.7 ± 1.4 and 51.6 ± 15.3, < 0.0001).
Conclusions: Our study demonstrated that the combination of HR mode and DLR in UHRCT scanner improved the impact of the MAR algorithm in the oral cavity.
Sato Y, Endo T, Kayano S, Nemoto H, Shimada K, Ito A Surg Neurol Int. 2021; 12:528.
PMID: 34754578 PMC: 8571191. DOI: 10.25259/SNI_887_2021.