Metal artifacts with dental implants: Evaluation using a dedicated CT/MR oral phantom with registration of the CT and MR images

• Published in: Scientific reports 2019-01, Vol.9 (1), p.754-754, Article 754
• Main Authors: Lee, Min-Young, Song, Kyu-Ho, Lee, Jeong-Woo, Choe, Bo-Young, Suh, Tae Suk
• Format: Article
• Language: English
• Subjects: 59; 59/57; 692/700/1421/1628; 692/700/1421/1770; Computed tomography; Dental implants; Dental prosthetics; Head and neck; Humanities and Social Sciences; multidisciplinary; Registration; Science; Science (multidisciplinary); Teeth; Tomography
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-36227-0

The aims of this study were to develop a computed tomography/magnetic resonance (CT/MR) oral phantom with insertable dental implants and to register CT/MR images to generate artifact-free MR images for patients undergoing teeth restorations. All measurements were done using a human MR scanner with spin echo (SE) and gradient echo (GRE) sequences image scan together with CT image. The metal regions and normal teeth parts are extracted with a suitable threshold from an initial image reconstructed with artifact from the CT images. Corrected metal projection regions of MR images and CT images are fused to produce artifact-free MR image that include dental restorations. After CT/MR registration, artifact size presented differences on the x- (SE, 12.0 mm; GRE, 18.0 mm) and y- (SE, 24.0 mm; GRE, 36.6 mm). When comparing the dental restoration with normal teeth, the structural similarity index metric (SSIM) of GRE 50 was lower than for the GRE 8 sequence and the SSIM of SE 145 shown higher than for the SE 490 sequence. The dedicated phantom provides a useful tool in head and neck research for multi-modality images. Therefore, CT/MR image-based approach for ground truth and registration offers visualization in diagnostic system and radiation treatment planning system.