Musculoskeletal ImagingE2572. Gout of This World: Dual-Energy CT and Its Expanded Role in the Assessment and Diagnosis of Gout
Thomas J, Smith S, Rhodes J. Brigham and Women's Hospital, Boston, MA
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Background Information: Gout is the most common inflammatory arthritis affecting men in the developed world and is increasing in prevalence in the United States. It is characterized by the deposition of monosodium urate crystals in the joints, tendons, and periarticular soft tissues. Although historically diagnosed clinically, analysis of crystals within joint fluid aspirate using polarized microscopy is the reference standard. Measurement of serum uric acid levels may also be performed. Given the invasive nature of aspiration, risk of infection, and often difficult to access regions (i.e., spine) there has been an expanded role of dual-energy CT (DECT) as an alternative to joint aspiration in the diagnosis of gout.
Educational Goals/Teaching Points: The purpose of this exhibit is to provide a brief review on the epidemiology and clinical findings of gout, and to review the characteristic imaging findings of gout on radiography, CT) ultrasound, and MRI including its advantages of each. We review the history and technical features of unenhanced dual-energy CT (DECT) and discuss its role in the assessment and diagnosis of gout or exclusion of gout using case examples, and we demonstrate characteristic postprocessing artifacts and pitfalls with descriptions of how to avoid or lessen these issues.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: In this presentation, we review the history of DECT and its application in the diagnosis of gout. We will common imaging findings of gout and correlate them to findings seen on DECT examinations following postprocessing. We also review common artifacts and potential pitfalls seen on DECT examinations and demonstrate methods to optimize scan quality and postprocessing algorithms.
Conclusion: Advanced imaging using DECT can demonstrate both soft tissue and osseous changes of gout, allowing for a noninvasive method in diagnosis. DECT may also be beneficial as it can also be used to differentiate gout from other types of crystal deposition diseases. Although there are artifacts and common pitfalls, recognition of characteristic imaging findings with DECT can assist in the diagnosis of gout, impact treatment decisions, and evaluate response to treatment.