PURPOSE: The vascular resistive index (RI) is measured by Doppler ultrasound and can be correlated with certain disease states. The range of RI in enlarged mediastinal lymph nodes is not known.
METHODS: Consecutive patients with enlarged mediastinal LN were examined. Recruitment continued until 100 patients who had RI measurements was achieved. RI measurements were performed using EBUS-TBNA Duplex Doppler ultrasound (Aloka Alpha 5, Aloka, Japan). All patients underwent surgical lymph node sampling to establish the relationship between histology (malignant or non- malignant) and RI.
RESULTS: 152 pts were examined to include 100 in whom we were able to measure RI (54 male, 46 female, mean age 49 years). In 52 patients, we were not able to visualise vessels within the lymph nodes and no RI measurement was possible. The histology revealed malignancy in 70 cases and the RI was significantly higher in those than in patients without malignancy. Using the Youden Index we calculated a RI of 0.69 as the cut-off point for best discrimination (sensitivity 91.4 %, specificity 90 %, p< 0.001). The AUC was 0.965 with an excellent discriminatory power (95 % confidence interval 0.931 to 0.998).
CONCLUSION: An increased RI appears to be highly correlated with malignant histology in mediastinal lymph nodes.
CLINICAL IMPLICATIONS: It may be possible to safely avoid further histological sampling when EBUS-TBNA produces a non- malignant biopsy result in lymph nodes with a low RI.
DISCLOSURE: Felix Herth, No Financial Disclosure Information; No Product/Research Disclosure Information