Dual energy CT in gout: a prospective validation study.

Area of Science:

• Radiology
• Rheumatology
• Medical Imaging

Background:

• Gout is a common inflammatory arthritis caused by monosodium urate crystal deposition.
• Accurate diagnosis and monitoring of urate deposition are crucial for effective gout management.
• Dual-energy CT (DECT) offers potential for non-invasive detection and quantification of urate crystals.

Purpose of the Study:

• To prospectively evaluate the diagnostic performance of DECT for gout.
• To assess the interobserver and intraobserver reproducibility of DECT-based urate volume measurements.

Main Methods:

• Prospective study involving 40 gout patients and 40 controls with other arthritic conditions.
• All peripheral joints were scanned using DECT with a specific gout protocol.
• Radiologists assessed urate deposition for sensitivity and specificity; automated software quantified urate volumes for reproducibility analysis.

Main Results:

• DECT demonstrated high specificity (0.93) and moderate sensitivity (0.78, improved to 0.84 excluding unreadable scans) for gout diagnosis.
• Urate volumes in tophi ranged from 0.06 to 18.74 cm³, with a mean of 2.45 cm³.
• Interobserver and intraobserver reproducibility for urate volume measurements were excellent (intraclass correlation coefficients of 1.00).

Conclusions:

• DECT is a highly reproducible method for quantifying urate crystal volume in gout.
• DECT exhibits high specificity but moderate sensitivity for gout diagnosis, potentially affected by urate-lowering therapy.
• DECT shows promise as a valuable tool in the diagnosis and management of gout.