Clinical Utility of Dual-Energy CT Scans for Diagnosing Gout

Dual-energy computerized tomography (DECT) has high accuracy in detecting in established gout, but low diagnostic sensitivity for recent-onset gout, according to a recent meta-analysis published in Rheumatology

Investigators conducted a systematic search of PubMed, EMBASE, and Cochrane Library for research on the diagnostic utility of DECT for gout. Selected studies used detection of monosodium urate crystals in synovial fluid or another validated set of criteria for gout diagnosis. The Quality Assessment of Diagnostic Accuracy Studies-2 criteria were used to assess the quality of each study. Data from person-based and joint-/localization-based evaluations were pooled separately; diagnostic odds ratios of DECT for imaging monosodium urate deposits were obtained using random-effect models.

Ten studies were selected for analysis, among which 5 presented data from person-based evaluations and 5 presented data from joint-/localization-based evaluation. Three studies conducted subgroup analyses for participants with recent-onset gout (≤6 weeks).

For patient-based evaluations, the pooled sensitivity and specificity were 0.81 (95% CI, 0.77-0.86) and 0.91 (95% CI, 0.85-0.95), respectively; for joint-/localization-based evaluations, these values were 0.83 (95% CI, 0.79-0.86) and 0.88 (95% CI, 0.83-0.92).

The pooled sensitivity among patients with recent-onset gout was 0.55 (95% CI, 0.46-0.64), indicating an appreciable number of false negatives. When calculations were stratified by reference standard, no significant differences in sensitivity and specificity were observed; monosodium urate crystals, Janssens’ score, and American College of Rheumatology 1977 criteria resulted in similar levels of accuracy.

Although DECT displayed high diagnostic accuracy for established gout, sensitivity was low for recent-onset gout.

No major differences in sensitivity and specificity were observed between patient-based evaluations and joint-/localization-based evaluations; further research is necessary to identify how many joints must be scanned to diagnose gout while minimizing cost and radiation exposure.

Reference

Gamala M, Jacobs JWG, van Laar JM. The diagnostic performance of dual energy CT for diagnosing gout: a systematic literature review and meta-analysis [published online May 14, 2019]. Rheumatology. doi:10.1093/rheumatology/kez180