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 imag ing (MRI) protocol that will provide optimal signal-to-noise ratio, re solution, and image contrast with minimal susceptibility artifacts and that will allow clear delineation and visualization of cartilage, flu id, bone, tendons, and ligaments within the distal interphalangeal (DI P) joint of the human hand. METHODS. A highly optimized 2.4 T MRI syst em was constructed from a 31-cm horizontal bore magnet, using a soleno id radiofrequency coil, This was used to study the DIP joints of 16 he althy, asymptomatic volunteers. RESULTS. A range of image contrast pro tocols were explored, including spin-echo T1 and T2, field echo, chemi cal shift suppression to give water only images, and magnetization tra nsfer. Susceptibility variations were explored by changing the field s trength from 0.6 to 2.4 T. A spin-echo protocol with TR = 1500 msec an d 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 vis ualize simultaneously compact and trabecular bone, two layers of carti lage, synovial fluid, and synovium within the joint, tendons and ligam ents, and the volar plate.CONCLUSIONS. Although the contrast is not fu lly optimized for any one tissue, the spin echo protocol (TR = 1500, T E = 30) provides sagittal MR images, which clearly delineate the major structures of interest within the DIP joint, and which will be used i n 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 se quence to he identified, which although not optimized for any one tiss ue, nevertheless visualized simultaneously and clearly delineated comp act and trabecular bone, two layers of cartilage, synovial fluid, and synovium within the joint.