The authors developed and evaluated a quantitative analytic method for interpreting clinical sialograms.
Images were obtained by digital subtraction sialography and transformed into binary form. The duct width of the image was calculated and represented as a normalized histogram. The effects of the volume of contrast medium injected and of the inclination angle of the objects on the histogram were examined.
In model studies, the normalized histogram was affected insignificantly by these factors. Clinical sialograms of 18 patients with normal results, 12 patients with parotitis, and 5 patients with Sjögren syndrome were preliminarily analyzed by the histogram method and four representative parameters of the histogram. Discriminant analysis showed a relatively high correct-predictive rate in the distinction between patients with normal and abnormal results.
This method reduces the effect of observer variation in diagnosing sialograms, and improves diagnostic accuracy for assessing the presence of inflammatory diseases of the parotid gland.