Computed tomography and magnetic resonance imaging findings in gouty arthritis involving large joints of the upper extremities.

BACKGROUND: We aimed to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of gouty arthritis primarily involving the large joints of the upper limbs, signal or density characteristics of the tophi, growth patterns, involvement of the adjacent joints, and differentiation from other lesions occurring in this area and to discuss the causes of misdiagnosis. METHODS: CT and MRI data were collected from 14 patients with gouty arthritis, primarily involving the shoulder and elbow joints, and their imaging features were analyzed. RESULTS: All the patiens were ranged from 28-85 years old, and the tophi deposition can be observed on either CT or MRI.The tophi deposition apperas as slightly higher density nodules or masses on CT images,or nodules or masses on MRI with isosignal/hypointensity on T1WI and hyperintensity on T2WI. Five patients showed narrowing of the affected joint space, four had different degrees of bone erosion under the articular surface, eight developed joint effusion, and all showed surrounding soft tissue swelling. The tophi grew around the joint, with anterolateral and posterolateral tophi predominantly in the shoulder joint and dorsal tophi predominantly in the elbow joint on the MRI, with compression and edema of the surrounding soft tissues. CONCLUSIONS: Gouty arthritis occurs in the large joints of the upper limbs and is characterized by fluid accumulation in the joint capsule and the formation of tophi. These tophi are usually large, with subcutaneous bone resorption and erosion, with or without cartilage destruction. However, extensive edema appeared in the soft tissue around the tophi, but the edema only produced pressure without any obvious signs of soft tissue infiltration, which may be distinguished from the joint tumor. In addition, the gout incidence rate is increased in young patients. Therefore, when the patient has a large joint mass, it is important to confirm whether there is a history of gout.

[Shoulder MRI evaluation of the association of os acromiale with supraspinatus and infraspinatus injury].

OBJECTIVE: To explore the MRI findings of os acromiale and to analyze the relationship between os acromiale and the supraspinatus and infraspinatus injury. METHODS: From January 2010 to August 2020, 21 patients with os acromiale (os arcomiale group) were compared with 21 subjects with no evidence of os acromiale (no os arcomiale group). There were 14 males and 7 females in the os arcomiate group, aged from 29 to 77 years old, mean aged (55.5±11.5) years old. While in the control group, there were 10 males and 11 females in no os arcomiale group, aged from 31 to 70 years old, mean aged (51.1±10.0) years old. The os acromiales were classified as edematous os acromiale or non-edematous os acromiale based on whether the presence of marrow edema, and as displaced os acromiale or non-displaced os acromiale based on whether the presence of displacement of the os acromiale. The MRI features of os acromiale were analyzed. Statistical analyses were performed to identify the differences between the os arcomiale group and no os arcomiale group regarding rotator cuff tear, supraspinatus and infraspinatus injury. Differences in the supraspinatus and infraspinatus tear between the edematous and non-edematous os acromiale group, the displaced and non-displaced os acromiale group, the displaced os acromiale and no os arcomiale group were also assessed. RESULTS: On MRI, all the 21 os acromiales appeared as a triangular or irregular bone fragment of the distal acromion, and forms a pseudo-acromioclavicular joint with the acromion. Eleven cases were edematous os acromiale, 11 cases were displaced os acromiale. In the os arcomiale group, 17 had supraspinatus tear, 1 had supraspinatus tendinitis, 11 had infraspinatus tear, and 4 had infraspinatus tendinitis. In the no os arcomiale group, 11 had supraspinatus tear, 2 had supraspinatus tendinitis, 5 had infraspinatus tear, and 1 had infraspinatus tendinitis. No statistically significant difference between the os arcomiale group and no os arcomiale group regarding the rotator cuff tear, supraspinatus and infraspinatus injury (P>0.05). In the 11 cases of edematous os arcomiale, 10 had supraspinatus tear and 7 had infraspinatus tear. In the 10 cases of non-edematous os acromiale, 7 had supraspinatus tear and 4 had infraspinatus tear. No statistically significant difference was noted between the edematous os acromiale and non-edematous os acromiale in terms of supraspinatus and infraspinatus tear (P>0.05). In the 11 cases of displaced os acromiale, 11 had supraspinatus tear and 9 had infraspinatus tear. In the 10 cases of non-displaced os acromiale, 6 had supraspinatus tear and 2 had infraspinatus tear. In the no os arcomiale group, 11 had supraspinatus tear and 5 had infraspinatus tear. There was a statistically significant increases in the prevalence of supraspinatus and infraspinatus tear in the displaced os acromiale group compared with non-displaced os acromiale group, the displaced os acromiale group and no os arcomiale group(P<0.05). CONCLUSION: Shoulder MRI can very well depict os acromiale and can reveal associated abnormalities such as adjacent bone marrow edema, displaced deformity, and rotator cuff tear, and it can be used to assess the stability of the os acromiale. The presence of os acromiale may not increase the risk of supraspinatus and infraspinatus tear significantly. However, the presence of displaced os acromiale is at greater risk of supraspinatus and infraspinatus tear.

Imaging features of reactive bursitis secondary to osteochondroma.

PURPOSE: The purpose of this study was to determine imaging features of reactive bursitis secondary to osteochondroma. MATERIALS AND METHODS: Fourteen patients with reactive bursitis secondary to osteochondroma were retrospectively reviewed. RESULTS: The 14 patients were 11 males and 3 females ranging in age from 18 to 67 years (mean, 33.6 years). The locations were as follows: scapula (n = 2), lesser trochanter (n = 6), greater trochanter (n = 1), distal femur (n = 2), distal fibula (n = 1), iliac bone (n = 2). On CT, six bursae were hypodense and 1 was isodense compared to muscle. All bursae had a thickened wall, 6 contained multiple villous projections and septa. Five bursae contained a few calcifications. On enhanced CT, the bursa displayed mild enhancement of the wall, villous projections, and septa. On MRI, one bursa was hypointense, three were hyperintense, and 5 were isointense relative to muscles on T1-weighted images. All bursae were hyperintense relative to muscles on T2-weighted images. All bursae had a thickened wall, eight contained multiple villous projections and septa. In five bursae, a few fatty villous projections can be seen within the bursa. On enhanced MRI, all bursae displayed avid enhancement of the bursal wall, villous projections, and septa. CONCLUSIONS: Reactive bursitis secondary to osteochondroma most often occurred in young male adults. The most common involved site is lesser trochanter. The imaging features is that of an irregular, thick-walled fluid-filled bursa overlying an osteochondroma that containing multiple villous projections and septa. Calcification and/or lipoma arborescens may be developed within the bursa. On contrast-enhanced images, the bursa shows enhancement of the bursal wall, villous projections and septa.

CT image findings of spinal gout.

BACKGROUND: Spinal gout is uncommon. The clinical manifestations of spinal gout are not characteristic. Huge tophi can invade the vertebral joints and protrude into the spinal canal, even causing spinal canal stenosis, which may result in irreparable spinal cord injury. Therefore, early diagnosis and treatment is very important. Summarizing the imaging features of spinal gout may help clinicians with an early diagnosis and promptly intervention. STUDY DESIGN: Retrospective case series. OBJECTIVES: To describe the findings from computed tomography (CT) images of spinal gout, including the tophi location, growth pattern, involvement of adjacent joints, and differentiation from other spinal lesions. METHODS: We analyzed CT images from the atlantoaxial joint and lumbar spine in 17 cases with spinal gout. RESULTS: 17 cases had tophi as high-density masses. 14 (82.4%) cases involved lumbar facet joints, including 7(41.2%)cases involving single vertebral facet joints and 7(41.2%) cases involving multiple vertebral facets. CT imaging showed bone resorption and erosion of the facet joints, as well as narrowing of the joint space. The other three cases (17.6%) involved the atlantoaxial joint, showing a high-density mass around the odontoid process with bone resorption and invasion under the articular surface. One case was secondary to a pathological fracture. Four cases (23.6%) showed a huge mass protruding into the spinal canal where the nerve root was compressed, and even spinal cord injury, leading to serious lower back pain symptomatic of brachial plexus or sciatic nerve compression, and even affected the motor function of lower limbs. CONCLUSIONS: In cases with gouty arthritis involving the axial spine, the lower lumbar spine is mainly involved, high-density tophi grow forward and backward around the facet joints, CT image shows bone resorption, erosion of facet joints, and narrowing of the joint space. With atlantoaxial joint involvement, there was evidence of bone resorption combined with joint.