Imaging modalities and monitoring measures of gout.

PURPOSE OF REVIEW: Imaging modalities for gout have been mostly restrained to radiographs. Ultrasonography, computed tomography and magnetic resonance imaging are emerging techniques that could be used for diagnosis, evaluation, and monitoring acute and chronic gout.

RECENT FINDINGS: Diagnosis of gout is based on urate crystal observation with microscopy. Recently, crystal deposition in the hyaline cartilage has been described to be different in gout from that of calcium pyrophosphate, but validation of the findings is pending. Severity of gout with simple radiographs may not disclose periarticular or intra-articular urate deposition. Ultrasonography, computed tomography and magnetic resonance imaging may improve the evaluation of tophi not apparent in clinical examination or simple radiographs. Monitoring urate deposition may be accomplished with imaging techniques. This would be of outstanding interest for clinical trials, but also for evaluating clinical response to urate-lowering therapy. Although preliminary results evaluating for validity and reliability have been very recently reported for magnetic resonance imaging, computed tomography and ultrasonography, sensitivity to change studies are still pending. Also, monitoring of chronic inflammation with imaging techniques, such as power-Doppler, deserve further studies.

SUMMARY: Evidence exists regarding the usefulness of imaging techniques for diagnosis, evaluation of severity, and monitoring of gout, but further investigation is needed.