Quantification of salivary gland Scintigraphy by means of factor analysis

Introduction: In this study the automatic separation of oral and salivary gland activity and spontaneous secretion by means of factor analysis for quantitative salivary gland scintigraphy is introduced. Methods: After intravenous administration of 99mTc sodium pertechnetate, dynamis scintigraphy was performed using a128x128 matrix, acquisition time 30 min, 2 frame/min). 20 minutes after tracer application 2 ml of lemon juice was delivered to stimulate the glands. Applying elliptical regions of interest (ROIs) for oral cavity and four major salivary gland and factor analysis of medical image sequences results in factor image and factor curves, which are used for quantification of the pre- and post-stimulatory oral activity index, and for the four major glands and the sublingual gland, the maximum accumulation (MA), the maximum secretion (MS) and the secretion velocity (SV). Results: With FAMIS it is possible to fully separate automatic separate the three superimposed processes we have in salivary gland scintigraphy: glandular and oral activity and spontaneous secretion. Comparing our quantitative results obtained by FAMIS with ROI analysis we found significant different values that are due to the fact that the spontaneous secretion in the oral cavity superimposes the true oral and glandular activity curves. Conclusion: The application of factor analysis improves the results of salivary gland scintigraphy by separation of superimposed dynamic processes of oral and glandular activity and spontaneous secretion