To test whether contrast-enhanced low mechanical index (low MI) sonography is superior to non enhanced B-Mode sonography in differentiating synovitis and joint effusion.
In a retrospective study, 22 patients with proven rheumatoid arthritis underwent B-Mode sonography and low-MI sonography of 25 symptomatic joints of the upper and lower limbs. For low-MI sonography, 5 ml Sonovue (Bracco Altana Pharma GmbH, Konstanz) were injected as an intravenous bolus followed by 10 ml of 0.9 % saline solution. Magnetic resonance imaging (MRI) was obtained additionally in 3 joints. With non-enhanced sonography, we diagnosed a synovitis in case of an echogenic and a joint effusion in case of an anechoic mass. With contrast-enhanced sonography, we diagnosed a synovitis in case of enhancement and a joint effusion in the absence of enhancement of the intraarticular mass.
In 13 joints, synovitis and joint effusion were differentiated by both non-enhanced and enhanced sonography. In 12 joints, this differentiation was only possible with contrast-enhanced sonography. In 3 patients diagnosed by sonography as having a synovitis, this diagnosis was proven by MRI.
Contrast-enhanced low-MI sonography is superior to non-enhanced B-Mode sonography in differentiating synovitis and joint effusion.