Abstract
It is essential to know the depth of invasion and the presence or absence of metastases in the mediastinal lymphnodes before operation of esophageal cancer. Although several methods of examination have been proposed for this purpose, a reliable method of diagno-sis has not yet been established. We have used linear array ultrasonic fiberendoscopes manufactured by Machida Seisakusho Company and Toshiba Medical Company, to investigata its usefulness in the diagnosis of disases of upper digestive tract since June 1981. The present paper deals with the results of esophageal cancer. Ultrasonography was performed in an excised specimen fixed in air-free water, and then a needle was stuck in each layer of the same and a small amount of India ink was injected. The ultrasonic image obtained was compared with the histologic picture. The esophageal wall was delineated into 5 layers and through this comparison it became clear that the third hyperechoic layer correspond to the submucosa, the fourth hypoechoic layer tothe muscularis propria and the fifth hyperechoic one to the adventitia and adipose tissue. However, the relation of the first hyperechoic and the second hypoechoic layer with the mucous tunic and the muscularis mucosa respectively, needs further studies. A thin hyperechoic layer was present in the fourth layer in some cases. It was confirmed to be due to the connective tissue between the two layers of the muscularis propria. In clinical cases the lymphnodes were seen as hypoechoic lesions and their detection was possible if the diameter was equal or larger than 5 mm. Using the ultrasonic f iberendoscope, it was also possible to detect the depth of the cancerous invasion into the eophageal wall by referring to the normal portion of the same organ as landmark. According to theese results, the linear array ultrasonic fiberendoscope is a new and useful preoperative diagnostic technique of esophageal cancer.
