LETTER TO THE EDITOR

Comparing the usefulness of four imaging techniques in the same gouty arthritis patient Dear Editor, Gout is a paradoxical disease in that arthritis attacks are only intermittent, whereas the arthritis-causing uric acid is persistently in excess in the form of tophi. For each patient, the ultimate therapeutic ideal should be to completely eliminate all tophi. So far, clinicians have relied on physical examination and plain radiographs to assess the locations and sizes of gouty tophi.1 Pub-lished reports suggest that dual energy computed tomography (DECT), magnetic resonance imaging (MRI) and 2-fluoro-deoxy-D-glucose (FDG) positron emission tomography (PET) each offer a different per-spective of gouty tophi.2 DECT is capable of discrimi-nating urate from non-urate compounds.3,4 MRI is capable of delimiting the sizes of the tophi and their relationship to adjacent tissues.5 PET is capable of assessing the degree of inflammation.6 Because no study had used all four techniques concomitantly, no guidelines are available concerning their applications. In this paper, we used these four techniques to examine the same feet and knees of a patient with chronic topha-ceous in gout. The results indicate two huge tophi that would have eluded detection and assessment by physi-cal examination and plain radiographs alone in this patient. The patient is a 62-year-old man with intermittent gouty arthritis attacks of the joints of the lower extremi-ties for 20 years. Physical examination showed tophi-like swelling at the left big toe, and minor joint swelling of both knees. Serum uric acid was 8.6 mg/L. The diag-nosis of gout was confirmed by crystal examination. Plain radiographs and 3.0T MRI followed conventional methods. DECT and FDG-PET utilized the Siemen