Dual-energy CT imaging of tophi in patients with gout. a This volume-rendered, color-coded, three-dimensional, dual-energy CT image of the right foot and ankle of a 71 year old man with a known diagnosis of gout reveals multiple urate deposits (red), indicative of a severe disease burden and subclinical tophaceous disease. b This 74 year old man underwent dual-energy CT to assess erosions associated with an established inflammatory arthritis. This multiplanar reformat sagittal color-coded two-material decomposition (urate and calcium) image of the right foot and ankle reveals urate crystal tophi (red) along the Achilles tendon, sinus tarsi and at the first metatarsophalangeal joint, consistent with gout. These images and descriptions were generously provided (with permission) by Dr Hyon Choi, Boston University Medical School, Boston, MA, USA.