Abstract
A new method of endoscopic ultrasound (EUS) guided fine needle aspiration using an ultrasonic endoscope with a curved array transducer mounted in front of the optic lens was developed. As a result of the sector shaped sound field and the direction of the scanning plane it was possible to visualise ultrasonically a needle inserted through the biopsy channel. EUS guided biopsy was performed in 37 patients (with 39 lesions) using three types of needles. Based upon initial testing of several prototype needles a 160 cm long, 0.8 mm diameter needle placed in a Teflon catheter was developed after preliminary results with the first two types were unsatisfactory (positive results for malignancy in 3/11 and 4/8 cases). The third prototype was tested in seven patients with malignant tumours of the upper GI tract. In these patients EUS guided biopsy was positive for malignancy in 7 of 8 solid lesions. Problems related to the technique and criteria for a successful outcome are discussed. The preliminary results show that it is possible to advance a needle into a malignant lesion inside or outside the GI wall during EUS examination and aspirate material for cytologic examination from various lesions. Controlled studies are needed to determine the indications for use and the accuracy of the technique.
