IADR Abstract Archives
Lateral Cephalometric Analysis in Orthodontics Based on Magnetic Resonance Imaging
Objectives: The objective of this study was to evaluate whether magnetic resonance imaging (MRI) can serve as a non-ionizing alternative to lateral cephalometric radiographs (LCR) in cephalometric analysis.
Methods: This prospective study was approved by the local research ethics committee, informed patient consent was obtained. The applied MRI technique was optimized for detection of cephalometric landmarks and geometric accuracy. Prior to orthodontic treatment, 20 patients (mean age ± SD, 13.95 years ± 5.34; 8 females) received MRI and LCR. MRI datasets were postprocessed into lateral cephalograms (AMIRA-3D v5.4.1). Based on 10 midsagittal and 9 bilateral landmarks 24 widely used cephalometric measurements (14 angles, 10 distances) were taken twice by two observers for both modalities (Planmeca Romexis v4.4.0). Statistical analysis was performed by using intraclass correlation coefficient (ICC), Bland-Altman analysis and two one-sided tests (TOST) with an equivalence margin of ± 2 °/mm.
Results: Geometric accuracy of the MRI technique was confirmed. Mean intraobserver ICC were 0.977/0.975 for MRI and 0.975/0.961 for LCR. Average interobserver ICC were 0.980 for MRI and 0.929 for LCR. Bland-Altman analysis showed high of levels agreement between the two modalities, bias range (mean ± SD) was -0.66 to 0.61 mm (0.06 ± 0.44) for distances and -1.33 to 1.14 ° (0.06 ± 0.71) for angles. Except for the interincisal angle (P = .17) all measurements were statistically equivalent (P < .05).
Conclusions: MRI datasets can be transformed into lateral cephalograms allowing reliable measurements as applied in orthodontic routine with high levels of agreement to the corresponding measurements performed on LCR. Thus, MRI-based orthodontic treatment planning appears feasible.
Methods: This prospective study was approved by the local research ethics committee, informed patient consent was obtained. The applied MRI technique was optimized for detection of cephalometric landmarks and geometric accuracy. Prior to orthodontic treatment, 20 patients (mean age ± SD, 13.95 years ± 5.34; 8 females) received MRI and LCR. MRI datasets were postprocessed into lateral cephalograms (AMIRA-3D v5.4.1). Based on 10 midsagittal and 9 bilateral landmarks 24 widely used cephalometric measurements (14 angles, 10 distances) were taken twice by two observers for both modalities (Planmeca Romexis v4.4.0). Statistical analysis was performed by using intraclass correlation coefficient (ICC), Bland-Altman analysis and two one-sided tests (TOST) with an equivalence margin of ± 2 °/mm.
Results: Geometric accuracy of the MRI technique was confirmed. Mean intraobserver ICC were 0.977/0.975 for MRI and 0.975/0.961 for LCR. Average interobserver ICC were 0.980 for MRI and 0.929 for LCR. Bland-Altman analysis showed high of levels agreement between the two modalities, bias range (mean ± SD) was -0.66 to 0.61 mm (0.06 ± 0.44) for distances and -1.33 to 1.14 ° (0.06 ± 0.71) for angles. Except for the interincisal angle (P = .17) all measurements were statistically equivalent (P < .05).
Conclusions: MRI datasets can be transformed into lateral cephalograms allowing reliable measurements as applied in orthodontic routine with high levels of agreement to the corresponding measurements performed on LCR. Thus, MRI-based orthodontic treatment planning appears feasible.
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