Evaluation of 5T Magnetic Resonance Imaging on Oral Cavity: An Observational Cross-Sectional Study Compared With 3T Magnetic Resonance Imaging and Cone Beam Computed Tomography.

INTRODUCTION AND AIMS: The advantages of 5T have been revealed in many clinical applications, there is a lack of research in the oral cavity. This paper is the first to investigate the imaging effect of 5T MRI on tissue structures in the oral cavity, and to compare it with 3T MRI and CBCT. METHODS: Eighteen healthy volunteers (12 females, mean age 28.58 ± 3.12 years; 6 males, mean age 30.67 ± 8.33 years) participated in this study. Four imaging sequences, T1-weighted (T1W), T1-weighted fat-saturated (T1W-FS), T2-weighted fat-saturated (T2W-FS) and proton density-weighted fat-saturated (PDW-FS) sequences were scanned on 5T and 3T MRI for comparison. Two blinded independent observers performed qualitative comparisons between 5T MRI, 3T MRI and CBCT using a 5-point Likert scale. Quantitative comparisons between 5T MRI and 3T MRI were performed using the signal-to-noise ratio (SNR) and contrast ratio (CNR), and the scan times of 5T MRI and 3T MRI were also compared. The 4 sequences on 5T were compared to identify the optimal scanning protocol for different tissue structures. The intraclass coefficients (ICCs), nonparametric tests including Wilcoxon signed-rank test, Friedman test and the pairwise Games-Howell posthoc test were carried out. The Shapiro-Wilk test and the paired t-test were also performed. A P value <.05 indicated a significant difference. RESULTS: The inter-observer and intraobserver agreements of image quality assessment were substantial to excellent (ICCs = 0.654-1.000, P < .05). 5T had significantly higher qualitative ratings, SNR and CNR than 3T in all structures (all P < .05). 5T achieved results close to CBCT, while the T2W-FS sequence exceeded CBCT in contrast (4.53 ± 0.46 vs 4.22 ± 0.38, P < .05), periodontium (4.47 ± 0.46 vs 4.04 ± 0.57, P < .05), gingiva (3.89 ± 0.36 vs 1.00 ± 0.00, P < .001) and maxillary sinus (4.31 ± 0.48 vs 4.04 ± 0.43, P < .05) scores. CONCLUSION: This study found 5T MRI can provide high-quality imaging of oral tissue structures in in-vivo applications, serving as a radiation-free and accurate dental examination tool. CLINICAL RELEVANCE: This study demonstrates the feasibility of 5T MRI for oral tissue imaging. The development of this technology has many potential applications in areas such as the detection and diagnosis of dental diseases, and can serve as a powerful complement to existing testing techniques.