Color-Doppler sonography patterns in endobronchial ultrasoundguided transbronchial needle aspiration of mediastinal lymphnodes

Background: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is commonly used for the pathological diagnosis in patients with mediastinal lymphadenopathy. Even though the accuracy of EBUS-TBNA is considered high, several authors have tried to outline characteristic ultrasound criteria for malignant mediastinal lymph-node identification to maximize this accuracy. Recently, a color-Doppler patterns classification has been proposed by Nakajima to target suspected mediastinal lymph-nodes. The aim of this study was to assess such classification. Methods: Clinical, sonographic and pathological data of patients with suspected malignant mediastinal lymph-nodes on computed tomography (CT) and/or on positron emission tomography (PET) were prospectively recorded. On the basis of color-Doppler patterns, mediastinal lymph-nodes were classified in four grades and the bronchial-artery inflow sign was noted according to the Nakajima classification. The diagnostic sensitivity, specificity, positive predictive value (PPV), negative predicted value (NPV) and accuracy were calculated using standard definitions. Results: Seventy-five patients were enrolled in this prospective study, median age 66 years; 85% of patients had primary lung cancer and 15% had extra-thoracic malignancy. EBUS-TBNA was performed in 87 lymph-nodes (rate 1.16 per patient); 6 lymph-nodes had inadequate samples and were excluded from the analysis; 64 nodes were confirmed as malignant and 17 nodes as benign. Color-Doppler patterns classification was as follow: grade 0-I, 14 lymph-nodes; grade II-III, 67 lymph-nodes; bronchial-artery inflow sign, 8 lymph-nodes. The sensitivity, specificity, PPV, NPV, and diagnostic accuracy of the classification were 0.93, 0.64, 0.84, 0.6 and 0.81 respectively. Conclusions: The color-Doppler sonography is a fast, reproducible and effective tool that could help in targeting suspected malignant lymph-nodes during EBUS-TBNA. The current study validates the efficacy of the color-Doppler patterns classification proposed by Nakajima.