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