Quantitative salivary gland scintigraphy can distinguish patients with primary Sjøgren's syndrome during the evaluation of sicca symptoms.

Abnormal findings on salivary gland scintigraphy (SGS) are part of the classification criteria for Sjøgren's syndrome (SS), but SGS is operator dependent and poorly standardised. We studied the use of quantitative data on the uptake, concentration and excretion of the four major salivary glands in the evaluation of sicca patients. During an initial clinical evaluation for sicca symptoms (mean duration, 51 months), 24 subjects were classified as either SS (n = 8) or isolated sicca (IS; n = 16). SGS was then performed after i.v. injection of 200 MBq pertecnetat. Digitalised quantitative data on time-to-peak uptake (Tmax), peak tracer distribution (C%) and stimulated excretion (E%) were calculated from time-activity curves and compared between groups and controls (n = 8) and correlated to clinical data. Statistical analysis was performed with non-parametric tests. SS patients had longer Tmax in both parotic glands (18.1 min; p < 0.01)) and both submandibular glands (mean 13.7 min, p < 0.05); whereas Tmax in IS patients was similar as in controls in both parotic (10.4 min; p > 0.2) and submandibular glands (9.4 min; p > 0.4). C% was significantly lower in the parotic glands of both the SS and the IS group compared to the controls (p < 0.01). E% was significantly reduced in SS patients (16.3% for parotic and 17.4% for submandibular glands; p < 0.01); whereas in the IS patients, excretion (32, 2% for parotic and 26, 9% for submandibular glands) was similar from all glands as in the control groups (35, 2% for parotic and 27, 8% for submandibular glands). No correlation was found between these SGS results and age, focus score, erythrocyte sedimentation rate, serum creatinin or immunoglobulin levels. No IS patient progressed to full-blown pSS during the 4 years of follow-up. Quantitative SGS data are useful and objective tools to distinguish patients with SS.