Aims: Dual-energy computed tomography (DECT) and magnetic resonance imaging (MRI) are advanced imaging methods used to visualise joint pathology in people with gouty arthritis. DECT can identify monosodium urate crystals and also has conventional CT properties, allowing assessment of tophus and bone pathology. MRI is used to assess inflammation, bone erosion and cartilage damage in gout. This study aimed to compare DECT and MRI with anatomical pathology in the assessment of gout.

Methods: Cadaveric joint specimens from two donors; one with crystal-proven tophaceous gout and one control donor (12 joints from each) were scanned by DECT and MRI, and then processed for histology. Each joint was scored for urate deposition (DECT), presence of tophus (CT and MRI), bone erosion (CT and MRI), and cartilage damage (MRI). The same features were also assessed by histopathological macroscopic and microscopic analysis. All imaging and pathology readers were blinded to the diagnosis and each other’s scores. Comparisons between imaging and anatomical pathology assessments were analysed using kappa values. 

Results: For DECT there was complete agreement with histopathology for urate and tophus (kappa 1.0 for all). MRI also had high concordance with histopathology for tophus (kappa 0.92). For bone erosion, there was higher concordance between CT and the macroscopic and microscopic analyses (kappa 0.96 and 0.79, respectively), than between MRI and the macroscopic and microscopic analyses (kappa 0.79 and 0.56, respectively). There was poor concordance between MRI and the macroscopic and microscopic analyses for visualization of cartilage damage (kappa 0.24 and 0.41, respectively).

Conclusions: DECT has excellent concordance with anatomical pathology for urate deposition, tophus and bone erosion in gout. MRI also allows excellent visualisation of tophus, but less reliable assessment of bone erosion or cartilage damage. These data provide further validation for the use of DECT in the assessment of gout.