Diagnostic value of different imaging features for patients with suspected gout: A network meta-analysis

Microscopic identification of monosodium urate (MSU) crystals is the gold standard for gout diagnosis. However, joint aspiration is not always practical, and imaging is increasingly used in clinical practice. This study aimed to assess the diagnostic accuracy of imaging features for gout compared with microscopy, using network meta-analysis methodology.

MEDLINE, EMBASE, PubMed and Cochrane databases were searched for studies reporting on the use of imaging modalities to diagnose gout in patients with an unclear diagnosis or suspected gout, which was later confirmed by microscopy. A combination of direct and indirect comparisons were performed by network meta-analysis to evaluate the combined odds ratios for sensitivity, specificity, and accuracy. To assist interpretation, the surface under the cumulative ranking curve (SUCRA) scores were calculated to provide a ranking of the imaging features.

Fifteen eligible studies were included. Compared to the gold standard microscopic identification of MSU crystals, dual energy computed tomography (DECT) MSU crystal deposition and ultrasound double contour had greater sensitivity than ultrasound tophus. DECT, ultrasound double contour sign and ultrasound tophus all had greater specificity than ultrasound aggregates. The SUCRA scores ranked DECT as highest for overall accuracy, followed by ultrasound double contour, aggregates, and tophus, while ultrasound snowstorm was ranked the lowest. However, there were no significant differences in the odds ratios for overall accuracy between these imaging features.

DECT and ultrasound are both useful modalities for the detection of imaging features of MSU crystal deposition, and have a similar overall diagnostic accuracy for gout diagnoses.