Costal cartilage mimics urate on DECT

Area of Science:

• Radiology
• Biomedical Engineering
• Materials Science

Background:

• Dual-energy CT (DECT) is a valuable imaging technique for material characterization.
• Distinguishing urate deposits from other calcifications is crucial for diagnosing conditions like gout.
• Isoattenuating material in costal cartilages on DECT has been observed, but its composition remains unclear.

Purpose of the Study:

• To determine if the isoattenuating material observed in costal cartilages on DECT is indeed urate.
• To investigate the nature of this material and its implications for clinical diagnosis.

Main Methods:

• Costal cartilage specimens from 12 cadavers were examined using DECT.
• Specimens were stored in air, ethanol, and saline, with DECT scans performed before and after storage.
• Cadaveric tophi served as positive controls, and storage fluids were analyzed for urate.
• Raman spectroscopy was employed for material identification.

Main Results:

• DECT revealed isoattenuating volumes in costal cartilages, which varied depending on storage conditions.
• Storage in ethanol resulted in zero isoattenuating volumes, while storage in water led to a significant decrease over time.
• Urate levels in costal cartilage storage fluid were zero, contrasting with high levels found in tophus storage fluid.
• Raman spectroscopy confirmed the absence of urate in the costal cartilage specimens.

Conclusions:

• The material in costal cartilages that appears isoattenuating to urate on DECT is not urate.
• This material can simulate the attenuation profile of urate under specific conditions.
• Clinically, isoattenuating material in costal cartilages on DECT should be considered artifactual.