Salivary gland ultrasonography: can it be an alternative to sialography as an imaging modality for Sjogren's syndrome?

OBJECTIVES Salivary ultrasonography (US) was evaluated as an alternative imaging modality to sialography for Sjögren's syndrome (SS). METHODS Parotid sialography and parotid and submandibular US were performed in 360 patients (188 with SS and 172 non-SS) who were suspected of SS and had fulfilled the American-European criteria (AEC) for SS or had received > or =3 of the objective examinations that were considered minimal requirements for classifying non-SS and had undergone both the imaging examinations. The glands were considered positive for SS if they exhibited peripheral sialoectatic changes on sialography and/or hypoechoic areas, echogenic streaks and/or irregular gland margins on US. The images obtained were independently rated as SS-positive or SS-negative by three radiologists in a blind fashion and the final decision was made by consensus. Interobserver and intermodality agreement was evaluated using kappa values for sialography and parotid and/or submandibular US. RESULTS Average kappa values for the interobserver agreement were 0.81, 0.80 and 0.82 in sialography, parotid and submandibular US, respectively, indicating very good or good agreement. The kappa value for intermodality agreement between sialography and parotid US was 0.81 and between sialography and submandibular US was 0.76, indicating very good and good agreement, respectively. The diagnostic ability of parotid US was significantly lower than that of sialography (p<0.001, McNemar test). However, the diagnostic ability of submandibular US was comparable to that of sialography (p=0.153). CONCLUSIONS Submandibular US is a promising technique that can be used as a practical alternative to sialography in the classification of SS.