To assess the ability of US contrast-enhanced time-intensity curves to depict the changes connected with sicca syndrome, a fairly common condition that is often associated with autoimmune disorders such as Sjogren's syndrome or other diseases. Diagnostic criteria are complex and controversial and although no single test can be considered the gold standard, salivary gland scintigraphy and biopsy are reliable diagnostic methods.
Sixty consecutive patients with sicca syndrome, 40 of whom had primary (n = 23) or secondary (n = 17) Sjogren's syndrome and 20 had non-Sjogren's sicca syndrome, selected according to European Community Study Group diagnostic criteria for Sjogren's syndrome and subjected to contrast-enhanced US imaging of the parotids using a second-generation contrast agent with analysis of time-intensity curves at rest and during salivary stimulation, Tc99m salivary gland scintigraphy and labial gland biopsy.
In the 40 Sjogren's patients, US enhancement values were significantly lower (P < 0.0001 and P < 0.00003, respectively) than in the 20 non-Sjogren's patients both at rest and during stimulation. In the 23 subjects with the primary syndrome, values during stimulation were significantly lower than in the 17 subjects with the secondary syndrome (P < 0.0006), whereas at rest differences were not significant. Contrast-enhanced US imaging allowed to discriminate Sjogren's from non-Sjogren's sicca patients with 87.5% sensitivity, 85% specificity and 86.7% accuracy and the primary from the secondary syndrome with 78.2% sensitivity, 70.5% specificity and 75% accuracy. Interestingly, in eight patients with the primary syndrome, i.e. those with the more severe gland involvement, enhancement values were lower during stimulation than at rest.
Preliminary results indicate that contrast-enhanced US imaging can provide useful information on sicca characterisation and severity.