RELIABILITY OF ULTRASONOGRAPHY AND SIALOGRAPHY IN THE DIAGNOSIS OF SJOGRENS-SYNDROME

Objectives. The purpose of this study was to evaluate quantitatively o bserver performance with ultrasonography and sialography in the diagno sis of parotid gland involvement of Sjogren's syndrome. Study design. Sixty-four parotid gland sialograms and 65 ultrasonograms were prepare d For observer performance experiments. They included both modalities in 24 Sjogren's syndrome and 19 nonspecific parotitis cases, 21 normal parotid gland sialograms, and 22 normal ultrasonograms in healthy vol unteers. The images were randomly sequenced and presented to five obse rvers who were asked to describe several findings and finally to deter mine the imaging diagnosis by ranking the abnormal features and the di agnosis on a five-point-rating scale. Observer performance was evaluat ed on the basis of the reliability of findings interpreted and the dia gnostic accuracy of each modality from observers' rating scores. Resul ts. The diagnostic accuracy of sialography was very high, nearly perfe ct. The diagnostic accuracy of ultrasonography was lower than that of sialography, resulting from the lower incidence of characteristic find ings in the disease groups and lower sensitivity on ultrasonography. I n the differentiation of Sjogren's syndrome from the normal, however, the diagnostic accuracy of ultrasonography increased to 80% for all ca ses, and up to nearly 90% in the advanced sialographic stages. Conclus ion. Ultrasonography is useful for the diagnosis of Sjogren's syndrome in the advanced stages. Taking the noninvasiveness of this technique into account, we recommend first applying ultrasonography to the diagn osis of Sjogren's syndrome and performing sialography when no positive findings are detected on ultrasonography.