Morphologic characterization of meniscal root ligaments in the human knee with magnetic resonance microscopy at 11.7 and 3 T.

Objective: To determine the feasibility of using MR microscopy to characterize the root ligaments of the human knee at both ultra-high-field (11.7 T) and high-field (3 T) strengths.

Materials And Methods: Seven fresh cadaveric knees were used for this study. Six specimens were imaged at 11.7 T and one specimen at 3 T using isotropic or near-isotropic voxels. Histologic correlation was performed on the posteromedial root ligament of one specimen. Meniscal root ligament shape, signal intensity, and ultrastructure were characterized.

Results: High-resolution, high-contrast volumetric images were generated from both MR systems. Meniscal root ligaments were predominantly oval in shape. Increased signal intensity was most evident at the posteromedial and posterolateral root ligaments. On the specimen that underwent histologic preparation, increased signal intensity corresponded to regions of enthesis fibrocartilage. Collagen fascicles were continuous between the menisci and root ligaments. Predominantly horizontal meniscal radial tie fibers continued into the root ligaments as vertical endoligaments.

Conclusion: MR microscopy can be used to characterize and delineate the distinct ultrastructure of the root ligaments on both ultra-high-field- and high-field-strength MR systems.