Plain film radiography may be used to evaluate gout; however, radiographic imaging findings generally do not appear until after at least 1 year of uncontrolled disease. Nuclear medicine studies can be used as a tool to measure the extent of gouty arthritis and to confirm clinically suspected disease. Characteristic findings include increased activity in the affected areas in all phases of a triple-phase bone scan. CT scanning can be used to study the effects of gout in areas that are hard to visualize with plain-film radiography. The use of MRI in the radiologic examination of gout has not been extensively studied. However, this modality has excellent potential in the future study of gout. [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18]
Rettenbacher et al compared radiography with ultrasonography in diagnosing gout, and radiography suggested gout with a sensitivity of 31% (32/102) and a specificity of 93% (55/59), whereas US suggested gout with a sensitivity of 96% (98/102) and a specificity of 73% (43/59). Ultrasonography, according to the authors, often provided additional diagnostic information in patients with clinical suspicion of gout when laboratory findings and radiographic results were negative or inconclusive and should therefore be used in such cases. 
In a study by Perez-Ruiz et al, the ultrasound measurement of tophi appeared to be useful as an outcome measure for chronic gout.  However, the authors caution that further randomized trials should be conducted.
Choi et al found that dual-energy CT scanning (DECT) can produce obvious color displays for urate deposits and help identify subclinical tophus deposits and that tophus volume can be measured by DECT scans through automated volume estimation.  Further, after an initial retrospective assessment of 94 patients with suspected gout, Glazebrook et al determined that DECT is a sensitive, noninvasive, and reproducible method for spotting uric acid deposits in joints and periarticular soft tissues. 
Gruber et al studied 21 patients suspected of having gout in 37 joints by comparing the results of DECT with ultrasonography. They concluded that both imaging techniques had comparable sensitivity for detecting gout, but that DECT had some false-negative findings. 
Early radiologic findings in gout are limited to the soft tissues and involve asymmetric swelling in the affected joints. In the intermediate stage of disease, gout causes subtle changes in the bony structures on plain-film radiographs. In the periphery of affected joints, small punched-out lesions arise; obtaining 2 views is important to appreciate these subtle findings. The hallmark sign of late-phase gout is the appearance of large and numerous interosseous tophi on plain-film radiographs. Joint-space narrowing is also prominent in late-phase gout. (See the images below.)
In the early phase of gout, the clinical findings are limited to the soft tissues, of which an asymmetric swelling around the affected joint is typical. Another finding that may be evident is edema of the soft tissues around the joints. In a patient who has had multiple episodes of gouty arthritis in the same joint, a cloudy area of increased opacity may be seen on plain-film radiographs (see the images below).
In the intermediate phase of gout, the earliest bony changes appear, most commonly appearing initially in the first metatarsophalangeal joint area. These changes generally appear outside the joint or are in the juxta-articular area and are often described as punched-out lesions. Such lesions can progress to become sclerotic as they increase in size. In severe cases of intermediate-phase gout, fractures may be present in the affected areas.
In late-phase gout, the hallmark findings are numerous interosseous tophi. Another change that is evident on plain-film radiographs is joint-space narrowing, which can be severe and symptomatic. Marked deformities and subluxation may also be noted in affected areas, as well as calcium deposits in the soft tissues.