Diagnostic performances of superb microvascular imaging, shear wave elastography and shape index in pediatric lymph nodes categorization: a comparative study.

OBJECTIVE: To determine the diagnostic utility of a vascularity index via superb microvascular imaging in lymph nodes of children with malignant lymphoma and acute lymphadenitis compared to normal lymph nodes. METHODS: We performed a retrospective study for multiparametric lymph node (LN) evaluation. Malignant lymphoma diagnosed via histopathological examination and lymph nodes receiving an acute lymphadenitis diagnosis based on clinical and laboratory findings constituted the study subgroups. We calculated a shape index [SI (percent of shortest to longest diameter)] using grayscale ultrasonography and elasticity and velocity values via shear wave elastography (SWE) as well as a vascularity index (VI) using superb microvascular imaging (SMI) for comparison with normal lymph nodes. RESULTS: 45 lymph nodes diagnosed with malignant lymphoma, 72 lymph nodes diagnosed with acute lymphadenitis and 146 normal lymph nodes were evaluated. For differentiating lymphoma from normal lymph nodes, vascularity index cut-off values higher than 15% represented a diagnostic accuracy of 95%; cut-off elasticity values higher than 17 kPa exhibited a diagnostic accuracy of 99%. Optimal VI, elasticity, velocity and SI cut-off values in differentiating lymphoma from lymphadenitis were 15%, 17 kPa, 2.45 m sn-1 (p < 0.001) and 65% (p < 0.002) with calculated diagnostic accuracies of 83, 87, 88 and 68%, respectively. CONCLUSION: Vascularity index values obtained via superb microvascular imaging and SWE would be reasonably useful in differentiating malignant lymphoma and acute lymphadenitis from normal LNs. SWE would be more efficient in distinguishing malignant lymph nodes from acute lymphadenitis compared with superb microvascular imaging. Advances in knowledge: Vascularity index by superb microvascular imaging would be a novel Doppler parameter in differentiating both lymphoma from lymphadenitis and also lymphadenitis from normal lymph nodes.