Gout tophus detection-a comparison of dual-energy CT (DECT) and histology

Objectives: To compare dual-energy CT images (DECT) directly with gold standard histology.

Methods: A 85-year-old woman with chronic recurrent gouty arthritis and macroscopically visible tophi was assessed with DECT-scans of her feet. When she died 7 days later, three tophi in different regions and in different tissues of her left foot were processed for histological examination.

Results: Of the selected tophi, two were almost completely missed by the color-coding DECT sequences. The tophi remained in most of their volume below the detection threshold value of 150HU (default value).

Conclusions: It could be demonstrated that DECT only highlights the dense tophi (corresponding of approximately 15-20vol% urate in the tophus). Less dense tophi, despite considerable size, will be missed in the color-coded images.