Comparison of dental-dedicated MRI to 2D radiographic images and cone beam CT in the assessment of lower third molars: a prospective study

Objectives The aim of this study is to show that the use of 0.55 T MRI combined with a “dental-dedicated” coil produces images of sufficient diagnostic value to assess lower third molars (LTMs), that are not inferior to currently utilized dental-oriented radiographic images. Methods Dental-dedicated MRI (ddMRI) scans were acquired using a Magnetom Free.Max 0.55 T scanner combined with a dedicated dental coil. Three observers assessed all images according to predefined criteria. 20% of images were assessed twice by all observers. Kappa statistics were performed to assess intra- and inter-observer agreement as well as inter-modality agreement. Results ddMRI was acquired on 67 patients (89 LTMs) in addition to initial radiographic exams (intraoral, panoramic and/or CBCT). Inter-observer agreement for each modality ranged from low to perfect (intraoral/panoramic 0.480-0.942 (average 0.74), CBCT 0.218-1.000 (average 0.69), ddMRI -0.038-0.889 (average 0.53)). Intra-observer agreement ranged from low to perfect (intraoral/panoramic -0.047-1.000 (average 0.76), CBCT 0.389-1.000 (average 0.83), ddMRI -0.025-1.000 (average 0.61)). Inter-modality agreement ranged from low to high (intraoral/panoramic vs. CBCT -0.078-0.743 (average 0.32), intraoral/panoramic vs. ddMRI -0.078-0.752 (average 0.30), CBCT vs. ddMRI 0.074-0.886 (average 0.49)). Conclusion ddMRI could be a feasible diagnostic modality for LTM imaging. The modality shows promise for radiation-free imaging in the future. Advances in knowledge This paper is the first to demonstrate the use of ddMRI in LTM imaging and to compare the modality to existing modalities. The added value of this radiation-free modality can be beneficial to dentists and patients in the future.