At present there is no consensus about which quantitative indices are more suitable for the diagnosis of Sjogren Syndrome (SS). The aim of this study is to test an alternative approach in functional evaluation of salivary glands respect the standard classification methods.
In one prospective study 88 consecutive patients underwent salivary scintigraphy with standard morphologic evaluation protocol and classified according (Schall GL, JAMA 1971) in 4 levels of functional involvement (0-4) of major salivary glands based on visual quality of glandular uptake and tracer excretion, on curves and functional indices as salivary gland/thyroid uptake %, spontaneous and acid stimolus excretion. Four grades of illness severity have been attributed to each gland (n=351; 1 patient had only one submandibular after sialectomy). Absolute uptake index expressed as % of injected dose (AU) , mean transit time (MTT) have been extracted. Data were compared by ANOVA analysis in SPSS statistical platform. Glands have been also classified in normal (I) or pathologic (II) on the basis of normal or decreased uptake % respect thyroid parenchyma (S/T%) (Dalton A. Nucl Med Commun 2006) and this index was compared with AU and MTT.
According to 4 grades of functional damage the AU and MTT for submandibular (Sm) and parotid (Pd) values mean+/-SD were: AU Sm 0 = 0,16+/- 0.08 %; Sm 1= 0.11+/-0.07%; Sm 2 = 0.11+/-0.1 %; Sm 3 = 0.08+/-0.07 %; Sm 4 = 0.072+/-0.06 %; MTT Sm 0 = 351+/- 59 s; Sm 1= 347+/-81 s; Sm 2 = 355+/-67 s; Sm 3 = 306+/-64 s; Sm 4 = 262+/-51 s; AU Pd 0 = 0,17+/- 0.06 %; Pd 1= 0.12+/-0.1 %; Pd 2 = 0.13+/-0.1 %; Pd 3 = 0.09+/-0.05 %; Pd 4 = 0.075+/-0.06 %; MTT Pd 0 = 470+/- 118 s; Pd 1= 432+/-104 s; Pd 2 = 449+/-87 s; Pd 3 = 368+/-84 s; Pd 4 = 352+/-117 s. ANOVA (Pot-hoc analysis HSD of Turkey) showed a significant difference between groups and particularly group 0 (i.e. normal) was significantly different (p<0.05) in both variables in all groups. Classifying glands data according S/T % in groups I and II, mean AU and MTT were: Au mean Pd I = 0.14+/-0.6 %; Pd II = 0.11+/-0.6 %; MTT mean Pd I = 472+/-96 s; Pd II = 411+/-99 s. Au mean Sm I = 0.12+/-0.7 %; Sm II = 0.084+/-0.05 %; MTT mean Sm I = 358+/-71 s; Sm II = 303+/-65 s.
ANOVA showed a significant difference between two groups (p<0.05 in Pd II e II; p<0.0001 for Sm I e II) for both variables.
According to our results, AU and MTT seem to be markers of salivary injury in patients with suspected SS revealing glands worsening condition. The role in parenchymal damage progression should be proven by prospective follow-up studies and histopathological specimen results.