Effect of T1 and T2 Magnetic Resonance Protocols on Bone Volume Measurement and Image Quality During Dental Implant Planning.

Objective: Compare magnetic resonance imaging (MRI) protocols (T1- and T2-weighted) with cone beam computed tomography (CBCT) for measurement of bone volume and image quality in edentulous mandible during dental implant planning.

Methods: A phantom was scanned using CBCT and MRI and two examiners measured bone volume (linear measurements) and assessed image quality (visualization of anatomical structures) with 5-point scale. Linear measurement reliability was assessed with intraclass correlation coefficient, and group differences with Friedman's and Wilcoxon's tests. The image quality ratings were classified as clinically nonvalid (score≤2) or valid (score≥3), reliability was assessed with percentage of agreement, and group differences with chi-squared test.

Results: Reliability of linear measurements was mostly very good for CBCT (0.748- 0.981), good for T1-weighted (0.674-0.924), and fair to T2-weighted images (0.201- 0.851). Significant differences were observed between imaging exams (p⟨.032) and between T1- and T2-weighted images (p⟨.046), except for alveolar ridge height (p=.119). CBCT showed the highest agreement and validity (100%), followed by T2-weighted (80% agreement, 90% validity), and T1-weighted (77% agreement, 82.5% validity), with no significant differences among modalities (p=.054).

Conclusions: Compared to CBCT, T1- and T2-weighted MRI protocols had significantly lower reproducibility and accuracy in measuring bone volume, with reduced image quality, especially for visualizing the mandibular nerve canal.