Visualization of intraarticular structures of the acromioclavicular joint in an ex vivo model using a dedicated MRI protocol

OBJECTIVE: The purpose of this study was to develop an MRI protocol that could visualize the intraarticular structures of the acromioclavicular (AC) joint. MATERIALS AND METHODS: Using six fresh specimens from cadaveric shoulders, several MRI sequences were performed on 1.0-T scanners with a superficial coil (the temporomandibular joint coil). After the radiologic examination, the specimens were prepared for histology and 300-microm-thick, toluidine blue-stained sections were prepared that corresponded to the MR images. In each series of sections, immunohistochemistry using a type II collagen antibody was performed to further characterize the intraarticular structures. RESULTS: The coronal 3D T1-weighted fast-field echo water-selective sequence allowed the identification of the intraarticular disk in all cases. Determination on MRI of other intraarticular structures--adipose tissue, synovial fluid, and the borders between neighboring tissues of different types--that corresponded to the histologic sections was possible. The use of a second plane in the 1.0-T sequences did not reveal additional information. CONCLUSION: The described MRI protocol allows the visualization of the intraarticular fibrocartilaginous disk and the border between articular cartilage and the disk. Future clinical studies will indicate the diagnostic value of this protocol. We assume that this MRI protocol could help us to better understand AC joint disorders, in particular those located intraarticularly, and dislocations.