Ultrasound characteristics of gouty tophi in the olecranon bursa and evaluation of their reproducibility

Abstract Objectives To describe the ultrasound characteristics of gouty tophi in the olecranon bursa and to evaluate their reproducibility. Methods A prospective study of the ultrasound features of 35 sites of tophi nodulations in the elbows of 31 men (mean 54.6 years). The findings were evaluated dynamically following pre-established standards. The static images were evaluated by another radiologist and were reviewed by the first examiner. Results The most frequent characteristics of tophi are: hyperechogenicity (91.7%), poorly defined contours (88.6%), multiple grouped nodules (85.6%) and heterogeneity (68.6%). Intra-observer agreement is almost perfect for echogenicity ( K  = 1.0), moderate for the involvement of the olecranon bursa ( K  = 0.47) and fair for other characteristics. Inter-observer agreement is substantial for the echogenicity ( K  = 0.65), fair for the echotexture ( K  = 0.27) and the presence of a perilesional hypoechoic halo ( K  = 0.34) and slight for other characteristics. Conclusions The most frequent characteristic of tophi is hyperechogenicity. The intra-observer and inter-observer concordance for echogenicity are almost perfect and substantial, respectively. Knowledge of characteristics of the tophi in the elbow and their intra and inter-observer reproducibility may assist in establishing parameters for monitoring treatment and setting up criteria for differential diagnosis of processes involving the olecraneon bursa.