Mo1229 The Value of Air Insufflation CT on Diagnosis of Esophageal Submucosal Tumors

Abstract

Background and Aims: To date, the main examination methods of esophageal submucosal tumors (SMTs) include barium meal, esophagoscopy and endoscopic ultrasonography (EUS). EUS has emerged as a reliable investigative procedure for evaluation of these lesions under both visual control and favourable sound field. However, the limitations of EUS include not only poor observation of the anatomic features of the adjacent structures but also the demand of special instrumenttation and experienced endoscopist. Esophageal lumen is closed under conventional CT and it is difficult to distinguish SMTs clearly from esophageal wall and surrounding tissue. So conventional CT in detecting esophageal SMTs was poor. Because SMTs could be showed more clearly in air insufflated esophageal lumen during endoscopy, this study was conducted to determin the value and effective of air insufflation CT on diagnosis of esophageal SMTs. Methods: From April 2011 to September 2012, 40 patients with esophageal SMTs confirmed by endoscopy and EUS were enrolled in this study. Conventional CT and air insufflation CT were performed to get the informations of lesion szie and its relationship with the adjacent structures. Air insufflation CT procedure: 1) introducing a nasogatric tube into esophageal lumen 30 cm from the incisors; 2) connecting a air bag to nasogatric tube and insufflating air into esophageal lumen continuely by pressuring the air bag; 3) performing chest CT exam after 5 seconds with patient's mouth closed. Following, to compare the imaging of SMTs between conventional CT and air insufflation CT, between EUS and air insufflation CT. The results were analyzed with X2 test. Results: After endoscopic resection or surgery, histological diagnosis was leiomyoma in 27 lesions, gastrointestinal stromal tumor (GIST) in 6, and schwannoma in 4, other 3 patients received follow up. The positive finding rate of conventional CT was 57.5% (23/40) compared with that of air insufflation CT (90.0%, 36/40) , the difference was of statistical significance (X2 = 15.21,P,0.05), and esophageal SMTs were showed by air insufflation CT more clearly than by conventional CT (Figure. 1). Compared lesion size on air insufflation CT with that after resection, 9 cases revealed measurement error more than 30%, but EUS finding match excisional specimen in 4/9 cases; Compared lesion size on EUS with that after resection, 8 cases revealed measurement error more than 30%, but air insufflation CT finding match excisional specimen in 3/8 cases. Conclusion: air insufflation CT on diagnosis of esophageal submucosal tumors is more effective and significant than conventional CT. There is added value of air insufflation CT and EUS in evaluating the origin of esophageal SMTs and the anatomic features of the adjacent structures which benefit to predict the risk of endoscopic treatment or surgery.