MAGNETIC-RESONANCE-IMAGING PROTOCOL OPTIMIZATION FOR EVALUATION OF HYALINE CARTILAGE IN THE DISTAL INTERPHALANGEAL JOINT OF FINGERS

RATIONALE AND OBJECTIVES. To identify a single magnetic resonance imaging (MRI) protocol that will provide optimal signal-to-noise ratio, resolution, and image contrast with minimal susceptibility artifacts and that will allow clear delineation and visualization of cartilage, fluid, bone, tendons, and ligaments within the distal interphalangeal (DIP) joint of the human hand. METHODS. A highly optimized 2.4 T MRI system was constructed from a 31-cm horizontal bore magnet, using a solenoid radiofrequency coil, This was used to study the DIP joints of 16 healthy, asymptomatic volunteers. RESULTS. A range of image contrast protocols were explored, including spin-echo T1 and T2, field echo, chemical shift suppression to give water only images, and magnetization transfer. Susceptibility variations were explored by changing the field strength from 0.6 to 2.4 T. A spin-echo protocol with TR = 1500 msec and TE = 30 msec can routinely produce images with resolution 0.075 X 0.150 for a slice thickness of 1 mm in 13 minutes. That protocol can visualize simultaneously compact and trabecular bone, two layers of cartilage, synovial fluid, and synovium within the joint, tendons and ligaments, and the volar plate. CONCLUSIONS. Although the contrast is not fully optimized for any one tissue, the spin echo protocol (TR = 1500, TE = 30) provides sagittal MR images, which clearly delineate the major structures of interest within the DIP joint, and which will be used in future studies to compare changes in the DIP joint because of aging or osteoarthritis. Experience gained by applying the above methods to a total of 16 healthy, asymptomatic volunteers has enabled a single sequence to he identified, which although not optimized for any one tissue, nevertheless visualized simultaneously and clearly delineated compact and trabecular bone, two layers of cartilage, synovial fluid, and synovium within the joint.