Contrast-enhanced ultrasonography compared to gray-scale and power doppler in the diagnosis of peripheral lymphadenopathy.

The aim of the study was to evaluate the ability of contrast-enhanced ultrasonography compared to gray-scale B-mode and power Doppler in distinction between benign and malignant lymphadenopathy. In a prospective study ultrasonography was performed in 133 patients with superficial lymphadenopathy (73 men, 60 women; mean age of 51 years, range: 18-86 years), who were examined for palpable mass in the neck, axilla or groin (104/133) and for clinical suspicion of lymphoma on the basis of positive PET/CT (29/133). 133 nodes were examined, subsequently preoperatively localized under ultrasound guidance and surgically removed; longitudinal to transverse ratio, location of nodal vessels by power Doppler and pattern of enhancement by contrast-enhanced ultrasonography with 1.5ml intravenous bolus of sulphur hexafluoride contrast agent were documented. The ultrasound findings were compared with the histology. Of all the nodes extirpated, 33 were benign, 100 were malignant (40 metastases, 60 lymphomas). Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of conventional techniques were 72%, 63.6%, 85.7%, 42.9%, 67.8% for longitudinal to transverse ratio; 73%, 60.6%, 84.9%, 42.6%, 68.3% for power Doppler versus 98.0%, 54.5%, 86.7%, 90.0%, 76.3% for contrast-enhanced ultrasonography according to Receiver Operating Characteristic analysis. Receiver Operating Characteristic analysis confirmed higher degree of diagnostic accuracy of contrast-enhanced ultrasonography in comparison with conventional techniques. Evaluation of nodal perfusion after intravenous administration of microbubble contrast agent can be helpful in differentiation of benign from malignant nodes.