Introduction

Endobronchial Ultrasound (EBUS) was introduced to clinical practice in the early 1990s[1], and has since become an essential component of lung cancer care. In its earliest applications, EBUS using a large radial probe and a circumferential balloon was used to diagnose and image airway tumors and central lung tumors. Shortly thereafter, Convex Probe (or linear) EBUS was introduced as a novel tool to image and biopsy mediastinal lymph nodes[2] for the purpose of lung cancer staging. Radial Probe (RP-EBUS), using a thin probe without a balloon, also evolved as an effective tool to biopsy peripheral lung tumors. Over the past two decades, the utility of EBUS has been restricted to mediastinal staging and tissue diagnosis of peripheral lung tumors. However, with recent advances in lung cancer diagnosis and treatment, EBUS will play a much more important role in the future of lung cancer care.

It could be argued, that EBUS has supplanted mediastinoscopy as the gold standard for mediastinal staging, due to its higher sensitivity and specificity, but also due to the fact the ultrasonographic imaging of the lymph nodes provides valuable information that is not provided by mediastinoscopy. It could also be argued that RP-EBUS will likely be a central adjunct to our efforts to develop effective lung mapping and nodule targeting techniques. In the following chapter, will describe the technology and applications of EBUS, with special emphasis on mediastinal staging, lung biopsies, and future applications.