Dual-energy computed tomography vs ultrasound, alone or combined, for the diagnosis of gout: a prospective study of accuracy. (7th January 2021)

• Record Type: Journal Article
• Authors: Singh, Jasvinder A; Budzik, Jean-François; Becce, Fabio; Pascart, Tristan
• Is Part Of: Rheumatology. Volume 60:Number 10(2021)
• Page Start: 4861
• Page End: 4867
• Publication Date: 2021-01-07
• Subjects: dual-energy computed tomography -- ultrasound -- gout -- diagnosis -- accuracy -- sensitivity -- specificity -- predictive value; Rheumatism -- Periodicals; Rheumatology -- Periodicals; 616.723005
• DOI: 10.1093/rheumatology/keaa923
• Languages: English
• ISSNs: 1462-0324

Abstract

Abstract: Objective: To examine the accuracy of dual-energy CT (DECT) vs ultrasound or their combination for the diagnosis of gout. Methods: Using prospectively collected data from an outpatient rheumatology clinic at a tertiary-care hospital, we examined the diagnostic accuracy of either modality alone or their combination, by anatomical site (feet/ankles and/or knees), for the diagnosis of gout. We used two standards: (i) demonstration of monosodium urate crystals in synovial fluid (gold), and (ii) modified (excluding DECT and ultrasound) 2015 ACR–EULAR gout classification criteria (silver). Results: Of the 147 patients who provided data, 48 (33%) had synovial fluid analysis performed (38 were monosodium urate-crystal positive) and mean symptom duration was 9.2 years. One hundred (68%) patients met the silver standard. Compared with the gold standard, diagnostic accuracy statistics for feet/ankles DECT, feet/ankles ultrasound, knees DECT and knees ultrasound were, respectively: sensitivity: 87%, 84%, 91% and 58%; specificity: 100%, 60%, 87% and 80%; positive predictive value: 100%, 89%, 97% and 92%; negative predictive value: 67%, 50%, 70% and 33%; area under the receiver operating characteristic curve: 0.93, 0.72, 0.89 and 0.66. Combining feet/ankles DECT with ultrasound or knees DECT with ultrasound led to a numerically higher sensitivity compared with DECT alone, but overall accuracy was lower. Similarly, combining imaging knees to feet/ankles also yielded a numerically higher sensitivity and negative predictive values compared with feet/ankles DECT alone, without differences in overall accuracy. Findings were replicated compared with the silver standard, but with lower numbers. Conclusions: Feet/ankles or knees DECT alone had the best overall accuracy for gout diagnosis. The DECT–US combination or multiple joint imaging offered no additional increase in overall diagnostic accuracy.