Advances of 3T MR Imaging in Visualizing Trabecular Bone Structure of the Calcaneus Are Partially SNR-Independent: Analysis Using Simulated Noise in Relation to Micro-CT, 1.5T MRI, and Biomechanical Strength

Purpose: To investigate differences in magnetic resonance imaging (MRI) of trabecular bone at 1.5T and 3.0T and to specifically study noise effects on the visualization and quantification of trabecular architecture using conventional histomorphometric and nonlinear measures of bone structure. Materials and Methods: Sagittal MR images of 43 calcaneus specimens (donor age: 81 10 years) were acquired at 1.5T and 3.0T using gradient echo sequences. Noise was added to obtain six sets of images with decreasing signal-to-noise ratios (SNRs). Micro-CT images were obtained from biopsies taken from 37 calcaneus samples and bone strength was determined. Morphometric and nonlinear Structure parameters were calculated in all datasets. Results: Originally, SNR was 1.5 times higher at 3.0T. In the simulated image sets, SNR was similar at both fields. Trabecular dimensions measured by LCT were adequately estimated by MR]. with residual errors (e.), ranging from 16% to 2.7% at 3.0T. Comparing e. at similar SNR. 3.0T consistently displayed lower errors than 1.5T (eg. bone fraction at SNR approximate to 4: e(r)[3.0T] = 15%; e(r)[1.5T] = 21%, P < 0.05). Conclusion: The advances of 3.0T compared to 1.5T in visualizing trabecular bone structure are partially SNR-independent. The better performance at 3.0T may be explained by pronounced susceptibility. enhancing the visualization of thin trabecular structures.