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

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.