EBUS Elastography for Thoracic Lesions

Abstract

Endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) is a widely used minimally invasive procedure that has been shown to have a high sensitivity and diagnostic yield for detecting metastasis to hilar and mediastinal lymph nodes (LNs). Recently, elastography, a new ultrasonography-associated technology that measures tissue compressibility, was introduced. In principle, pathophysiological processes, such as malignancy, make tissues less deformable or stiff. Elastography, is a new non-invasive EBUS modality that is hypothesized to predict mediastinal and hilar nodal metastasis based on hardness of tissue. Based on our results, we propose a simple EBUS elastography classification that could predict with 96.7% accuracy the presence or absence of mediastinal and hilar nodal metastasis. Type 1 (predominantly non-blue) indicates a benign pathology; Type 2 (part blue, part non-blue) is equivocal; and Type 3 (predominantly blue) indicates malignancy. EBUS elastography is a useful tool with very high sensitivity, specificity and accuracy for differential diagnosis of mediastinal and hilar LNs. Aside from providing complementary information to conventional EBUS imaging, it may potentially increase the diagnostic yield of EBUS-TBNA and reduce the number of unnecessary biopsies.