A Case of Dialysis-related Amyloidosis of the Hip and Cervical Spine: Imaging Findings

Dialysis-related amyloidosis is a complication of long-term hemodialysis and it is characterized by the accumulation of beta2-microglobulin in the osteoarticular structures. We describe here the imaging findings of a case of dialysis-related amyloidosis involving the hip and cervical spine in a 62-year-old woman who received long-term dialysis. We focus here on the CT and MR imaging findings of the cervical spine and we include a review of the relevant literatures.

MR Imaging Findings of Acute Gouty Arthritis

PURPOSE: The purpose of this study was to describe the clinical and MR imaging features of acute gouty arthritis and to define the characteristic findings that would be helpful for differentiating acute gouty arthritis from septic arthritis. MATERIALS AND METHODS: The authors retrospectively studied seven patients who suffered from acute gouty arthritis. The MR imaging findings were analyzed by two musculoskeletal radiologists who focused on joint effusion, subchondral bone erosion, bone marrow edema, synovial thickening (regular and even, or irregular and nodular), and the soft tissue changes (edema or abscess). The clinical records of the patients were reviewed with regard to age and gender, the clinical presentation and the laboratory findings (serum uric acid, WBC, erythrocyte sedimentation rate, C-reactive protein and synovial fluid culture). RESULTS: The patients consisted of six men and one woman whose mean age was 41 years (age range: 24-65 years). The joints involved were the knee (n=6), and ankle (n=1). Two patients had medical histories of gouty attacks that involved the first metatarsophalangeal joint. In six cases, the serum uric acid level during acute attacks was elevated. In all the patients, the affected joint became swollen, hot, erythematous and extremely tender, and this was accompanied by a high ESR and a high C-reactive protein level at the time of presentation. The results of Gram stain and culture of the synovial fluid were negative. In all patients, the MR images showed large amounts of joint effusion, thick irregular and nodular synovial thickening and soft tissue edema without subchondral bone erosions and soft tissue abscess. In one case, subchondral bone marrow edema of the medial femoral condyle was present. In five cases, there were multiple low signal foci in the joint on the spin-echo T2-weighted MR image. CONCLUSION: Even though the MR imaging findings of acute gouty arthritis are nonspecific, it should be considered as a possible diagnosis when a large amount of joint effusion, irregular and nodular synovial thickening and soft tissue edema without subchondral bone erosion, bone marrow edema or soft tissue abscess are seen in the knee or ankle joint, and especially if this is accompanied by the clinical and laboratory features of infection.

MR Findings of Cervical Lymphadenopathy: Tuberculosis Versus Metastasis

PURPOSE: To determine the MR findings of cervical lymphadenopathy which distinguish tuberculouslymphadenitis(TL) from metastatic lymphadenopathy(ML). MATERIALS AND METHODS: We retrospectively analyzed the MRfindings of 14 patients with TL and 19 with ML. Thirty-nine lesions in 14 patients with TL and 80 lesions in 19with ML were classified into three categories: conglomerate lesion (TL, 7; ML, 8); discrete lesion withoutnecrosis (TL, 3; ML, 15); and discrete lesion with necrosis (TL, 29; ML, 57). Between TL and ML, we compared age,sex, bilaterality, multiplicity, associated pulmonary tuberculosis, infiltration of adjacent fat, muscle, skin andsubcutaneous tissue, margin, and signal intensities on T1- and T2-weighted images. In discrete lesion, we alsocompared the minimal to maximal dimension ratio, and in discrete necrotic lesion, the thickness and evenness ofrim enhancement, and the location and extent of necrosis. RESULTS: There were statistically significantdifferences between TL and ML in age(34.7+/-13.1 years; 56.1+/-14.3 years), male to female ratio(3:11; 13:6),bilaterality(1/14; 10/19), multiplicity(5/14; 14/19), and associated active pulmonary tuberculosis(7/14; 1/19). OnT2-weighted images, TL showed predominantly homogeneous (30/39) or high (20/39) signal intensity, similar to thatof cerebrospinal fluid, but the signal inteusity of ML was predominantly heterogeneous(58/80), or lower than orsimilar to that of fat(41/80). Between TL and ML, however, there were no statistically significant differences ininfiltration of adjacent tissue, margin, signal intensity and its heterogeneity on T1-weighted image, minimal tomaximal dimension ratio, thickness and evenness of rim enhancement, or the location and extent of necrosis. CONCLUSION: In cervical lymphadenopathy, the existence of TL rather than ML is suggested by single or unilaterallesion in a young woman, by associated active pulmonary tuberculosis, or by homogeneous high signal intensity onT2-weighted MR images.