Abstract
An intra-corporal scanning ultrasonic probe (MINIATURE ULTRASONIC PROBE) used through a forceps channel of a conventional endoscope was developed cooperatively by Olympus Optical Co. and Aloka Co. We had an opportunity to use two kinds of MINIATURE ULTRASONIC PROBE (Prototype 1 and Prototype 2). The diameter of these instruments is 3.4 mm in both Prototype 1 and Prototype 2 and the ultrasonic frequency is 7-8 MHz in Prototype 1 and 7.5 MHz in Prototype 2. Subjects were a resected stomach with cancer in vitro study and ten patients with the upper G-I tract diseases in vivo study. As concerns the quality of the ultrasound images, Prototype 1 was inferior to the conventional ultrasonic endoscope (GF-UM 3; 7.5 MHz). However, it seemed that the ultrasonic resolution of Prototype 2 was almost the same as that of GF-UM3 (7.5 MHz). The followings were pointed out as important usefulness of MINIATURE ULTRASONIC PROBE. 1) approach to a prepyloric lesion or a severe stenotic lesion due to cancer which can not be easily achieved by conventional endoscopic ultrasonography, 2) visualization of a small lesion under endoscopically visual control, 3) visualization of a biliary tract lesion by scanning at the intra-biliary canal, While, there were some problems which should be improved in the clinical use of a MINIATURE ULTRASONIC PROBE, namely the improvement of the stability of ultra-sonic images and the penetration depth of the ultrasound. Furthermore, it was noted that the attachment of a balloon around the tip of the insturument was required in order to visualize ultrasonic images contacting the probe with the lesion.
