Background Tophi are generally considered as manifestations of chronic gout, but subclinical tophi in intra- and extra-articular structures have been shown to occur in early gout and asymptomatic hyperuricemia. Since occurrence of tophi is linked to joint destruction, it is important to detect tophi early before clinical detection.
Objectives The aim of our study was to evaluate the utility of dual-energy CT (DECT) in detecting subclinical tophi in patients with gouty arthritis.
Methods DECT scans of feet in 65 patients with gout without apparent clinical tophi were evaluated for presence of tophi. Plain X-ray of feet, clinical and laboratory data were obtained simultaneously at the time of the DECT evaluation. Total volumes of tophi in both feet were quantified using an automated software program of DECT.
Results Subclinical tophi were detected in 63 (96.9%) patients and in 341 (18.7%) joints, and median 3 (1 to 22) joints per patient were positive for tophi. The most common sites for tophi were first metatarsophalangeal joints (17.6%), followed by ankle joints (10.9%). Tophi in Achilles tendons were present in 10.8% of patients. Patients with early gout (disease duration <2 years) had tophi in 99 (13.6%) joints. Mean number of tophi was significantly lower in patients with early gout compared to those with chronic gout (3.8 versus 6.2, p=0.038). Mean volume of tophi was not significantly different between early gout and chronic gout.
Conclusions Tophi frequently occur in both intra- and extra-articular structures of gouty arthritis patients despite absence of clinically apparent tophi. DECT is an excellent imaging modality for detecting subclinical tophi.
Disclosure of Interest None declared