DECT Diagnosis of Gouty Tophi with Normal Uric Acid: A Case Report

Introduction Gouty tophi are chronic granulomatous structures composed of monosodium urate (MSU) crystals [1]. While arthrocentesis is the diagnostic gold standard, it is invasive and prone to sampling errors [2]. Dual energy computed tomography (DECT) addresses these limitations by utilizing the distinct X-ray attenuation properties of MSU at different energy levels. Case Presentation A 59-year-old male presented with foot swelling. Based on clinical findings, cellulitis and osteomyelitis were initially suspected, and antibiotic therapy was commenced. Initial magnetic resonance imaging also supported the suspicion of osteomyelitis (Fig.1). However, the symptoms showed no significant improvement until dual energy computed tomography (DECT) identified monosodium urate (MSU) crystals (Fig.2), confirming the diagnosis of gouty tophi. The patient’s symptoms resolved following surgical debridement. Discussion DECT enables precise material decomposition through spectral data analysis, allowing for non-invasive differentiation of MSU from calcium or soft tissues. The technology is highly reliable, with a meta-analysis reporting a sensitivity of 84.7% and specificity of 93.7% for gout diagnosis [3]. DECT’s ability to characterize the chemical composition of periarticular masses is invaluable when clinical markers are atypical or unavailable. By confirming the diagnosis non-invasively, DECT helps prevent misdiagnosis and avoid inappropriate management, such as prolonged antibiotic therapy for a potential infection or unnecessary surgical intervention.