Mediastinoscopic ultrasonography (MUS)

Correct pre-therapeutic T4 staging is mandatory for neo-adjuvant studies and for the decision on surgical therapy of high-risk patients. T4-staging of centrally located lung-cancer by means of non-invasive imaging techniques is either of low accuracy (CT and NMR) or important regions are not accessible due to air interference with the tracheo-bronchial tree (trans-esophageal-endosonography, TEE). We here describe for the first time the new technique of mediastinoscopic ultrasonography (MUS). A fingertip ultrasound probe is introduced through the video-mediastinoscope. The probe lies in front of the tracheo-bronchial tree and in direct contact with the vena cava and pulmonary artery. This position allows examining those regions that are not accessible with TEE. In a pilot study with 12 patients, visualization of central vessels and their relation to the tumor was excellent and without artifacts. In 3 patients, MUS did not confirm the T4 stage predicted by CT Scan. Those three patients underwent successful pneumonectomy (R0-resection) while the other nine patients received induction treatment. MUS is a promising addition to CT scanning, NMR, and transesophageal ultrasound in staging of centrally located tumors.