Investigation on monosodium urate deposition in the first metatarsophalangeal joint and ankle of primary gout patients using dual-energy computed tomography

Background: Gout is caused by deposition of monosodium urate (MSU) crystals. One of the tools of choice to identify MSU crystals is the Dual-Energy Computed Tomography (DECT). This study aims to determine MSU crystal deposition using DECT by comparing its detection in the first metatarsophalangeal joints (MTPJ) with that in the ankles, as well as to analyse the association between the crystal deposition and anthropometrics, clinical characteristics, and serum biochemical levels of a primary gout patient. Materials and methods: This cross-sectional study included patients (n = 94) from the Clinic Hoa Hao Medic Medical Centre in Vietnam, who were diagnosed with primary gout with pain/swelling of at least one ankle or first MTPJ. DECT of both joints was used to identify MSU. Statistical analyses were performed using the Student's t-test, Wilcoxon ranksum, Pearson's chi-square, and Spearman's tests. Results: Approximately 80% had MSU crystal deposition in the ankle and/or first MTPJ with no significant difference in deposition between the two joints. MSU deposition was significantly associated with disease duration (p = 0.003), flare-ups (p = 0.006), and cut-off of 6 weeks' duration (p = 0.006), bone erosion (p = 0.006), and palpable tophi (p = 0.003). There was no association between MSU deposition with age, body mass index (BMI), hypertension, serum levels of uric acid (UA), creatinine, high-sensitive C-reactive protein (hsCRP), total cholesterol (C-total), and triglyceride (TG). Conclusions: MSU deposition occurred in both ankle and first MTP at the same rate. The deposition was associated with disease duration and flare-ups. Prevention of flare-ups seems helpful to limit MSU crystal deposition. � 2022, Malaysian Medical Association. All rights reserved.