Computed tomography (CT) and magnetic resonance (MR) imaging were performed in 32 cases of clinically suspected chronic tears of the posterior tibial tendon. Surgery was performed in 22 patients (69%). Each case was classified radiographically and surgically as normal or a type 1, type 2, or type 3 rupture. The sensitivity and specificity of CT were 90% and 100%, respectively, while those of MR imaging were 95% and 100%. The accuracy in detecting ruptures was 91% for CT and 96% for MR imaging. The overall accuracy, which reflected the percentage of cases correctly diagnosed as well as those correctly classified, was 59% for CT and 73% for MR imaging. Although the differences between the CT and MR imaging parameters were not statistically significant (possibly due to the small population), the results suggest that MR imaging is the method of choice for detecting ruptures of the posterior tibial tendon. MR imaging provided greater definition of tendon outline, vertical splits, synovial fluid, edema, and degenerated tissue. CT was superior to MR imaging in showing associated bone abnormalities such as periostitis, subtalar osteoarthritis, and subtalar dislocation.

Radiologic assessment of the stage and treatment response of rheumatoid arthritis (RA) is based on the presence of bone erosions, joint-space narrowing, and osteoporosis. Most radiologic methods for staging RA lack interobserver correlation and are time consuming. Magnetic resonance (MR) imaging provides excellent depiction of soft-tissue abnormalities of the joints affected by RA, which allows detection of early changes. Nineteen joints of 17 patients with RA were studied with surface-coil MR imaging. Measurable abnormalities demonstrated by MR imaging but not clearly seen on plain radiographs included bone erosions, joint effusion, synovial sheath effusion, and cartilage irregularity and thinning. Seven patients of this group underwent MR imaging before and after 6 months of gold therapy. Four patients had significant interval changes on MR images that were not seen on plain radiographs. MR imaging may become a sensitive and objective method for quantitative assessment of the joint changes of RA.

High-field surface coil magnetic resonance (MR) images were obtained of 12 ankles: two from healthy volunteers, seven from patients, and three from fresh cadavers. The cadaver ankles were sectioned in the coronal, sagittal, and axial planes for direct comparison with the MR images. Plain film confirmation of pathologic conditions was obtained in all patients, and five underwent arthroscopy or surgery, or both. MR imaging provided excellent delineation of ligaments and cartilaginous structures in all cases.

Thirty asymptomatic ankles were studied with high-resolution surface coil magnetic resonance (MR) imaging to identify normal structures. Several normal variants were demonstrated, including (a) Cortical irregularity of the posterior tibiotalar joint (should not be mistaken for osteonecrosis) in 27 of 30 cases; (b) normal posterior talofibular ligament with irregular and frayed superior edge simulating a tear in 13 of 30 cases; (c) normal navicular insertion of the posterior tibial tendon with heterogeneous signal intensity in 14 of 30 cases; (d) deltoid ligament inhomogeneity in seven of ten cases; and (e) fluid in the shared peroneal tendons sheath (may be confused with a longitudinal tendon tear) in three of 30 cases. Ankle imaging with the use of MR is still a relatively new procedure. Further investigation is needed to better define normal anatomy and normal variants.

Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture.