Bronchoscopic ultrasonography in the diagnosis of lung cancer

An ultrasonic bronchoscope has been newly developed for diagnosis and lymph node staging in the hilum and mediastium. The instrument comprises an Echo-camera, SSD-630 (Aloka), and a transbronchial ultrasonic probe similar to the currently used videobronchoscope. The scope is equipped with an ultrasonic transducer in its tip. The maximum diameter of the probe head is 6.3 mm and that of the transducer, 5.0 mm. The frequency employed is 7.5 Megahertz (MHz) and the direction of scanning is parallel to the bronchoscopic axis. The device can easily be introduced into the lobar bronchus under topical anesthesia in a similar procedure to that used for routine videobronchoscopy. The location of the transducer in the airway is confirmed by monitoring endoscopic images on a TV monitor screen. With the device, 25 patients, who had given their consent for the ultrasonographic study beforehand, were examined during the two-month period, January and February, 1992. Vessels such as the thoracic aorta, pulmonary artery and truncus brachiocephalicus were good landmarks for diagnosis. Lung cancer was detected in five patients by biopsy, three malignant lesions in the hilum were diagnosed by videobronchoscopy while two malignant lesions in the periphery were confirmed by bronchoscopic ultrasonography as anterior mediastinal lymph node swellings.