Value of contrast-enhanced ultrasound and PET/CT in assessment of extramedullary lymphoma

Objective: The aim of the study was to evaluate clinical value of contrast-enhanced ultrasonography (CEUS) and PET/CT for assessment of extramedullary lymphoma, using histopathology as reference standard. Method: A total of 63 patients with histopathologically-confirmed extramedullary lymphoma who had underwent CEUS and PET/CT examinations of suspicious lymph nodes included in the study. CEUS patterns and parameters (arrival time, peak time and intensity, base intensity, area under the time-intensity curve, ascending and descending slopes) and PET/CT parameters including maximum standardized uptake value, mean standardized uptake value, and metabolic tumor volume (MTV) were evaluated. Patients were classified into Hodgkin lymphomas (HL), non-Hodgkin lymphomas (NHL), early (stage I and II) and advanced (stage III and IV) lymphoma, B cells and T cells lymphoma, and aggressive and indolent lymphoma. The differences between the two independent samples were compared using non-parametric rank and inspection, P < 0.05 was considered statistically significant. The optimal cut-off value for parameters was used to predict the staging and pathology using Receiver Operating Characteristic (ROC) curve analysis. Result: In the early and advanced group, the differences between triangle T and ascending slope (AS) were statistically significant (p = 0.010, 0.024 < 0.05). Hodgkin lymphomas (HL) or non-Hodgkin lymphomas (NHL) results were determined by optimal cut-off value of AT and TP (p = 0.001, 0.001 < 0.05). Aggressive or indolent lymphoma were determined by optimal cut-off values of Color Doppler flow resistance index (P = 0.001 < 0.05) and SUVmax (p = 0.001 < 0.05). There was no statistically significant difference between B and T cell lymphoma. And there was no statistically significant difference among the qualitative indexes. The optimal cutoff value for statistically significant indicators was calculated by ROC. Conclusion: The quantitative parameters of CEUS and SUVmax of PET/CT are proven useful in assessment of different clinical and pathologic patterns of extramedullary lymphoma.