Dual energy computed tomography in tophaceous gout

TLDR

The study aimed to assess the utility of dual‑energy CT for detecting and quantifying urate deposits in peripheral joints of patients with tophaceous gout. Dual‑energy CT was performed using a renal‑stone colour‑coding protocol (urate red, calcium blue) and an automated volumetric algorithm to measure urate volume in all peripheral joint areas. All 20 gout patients showed red‑coded urate deposits while none of the 10 controls did; DECT identified 440 deposit sites versus 111 by physical exam (22 vs 6 per patient, p<0.001) with mean volume 40.20 cm³, demonstrating accurate detection and subclinical identification of tophi.

Abstract

To evaluate the potential utility of a dual energy CT (DECT) scan in assessing urate deposits among patients with tophaceous gout, and obtain computerised quantification of tophus volume in peripheral joints.20 consecutive patients with tophaceous gout and 10 control patients with other arthritic conditions were included. DECT scans were performed using a renal stone colour-coding protocol that specifically assessed the chemical composition of the material (ie, urate coloured in red, calcium coloured in blue). An automated volumetric assessment of DECT was used to measure the volume of urate deposits in all peripheral joint areas.All 20 patients with gout showed red colour-coded urate deposits on their DECT scans, whereas none of 10 controls showed urate deposits. DECT scans revealed a total of 440 areas of urate deposition in 20 patients, whereas physical examination showed 111 areas of urate deposition (mean 22 vs 6 per patient, respectively, p<0.001). Total urate volume in a given patient ranged from 0.63 cm(3) to 249.13 cm(3), with a mean of 40.20 cm(3).DECT scans can produce obvious colour displays for urate deposits and help to identify subclinical tophus deposits. Furthermore, tophus volume can be measured by DECT scans through an automated volume estimation procedure.