ABSTRACT
With high-resolution sonography, or endoluminal sonography, these distinct layers are often readily imaged (4). These include three echogenic layers and two hypoechoic layers (Fig. 2 line drawing). The different layers with their histologic correlations include (i) the echogenic superficial mucosa, including the luminal contents and the
mucosal inner face; (ii) the hypoechoic, deep mucosa, which also includes the muscularis mucosa; (iii) the echogenic submucosa, which includes the interface between the submucosa and the muscularis propria; (iv) the hypoechoic muscularis propria; and (v) the echogenic serosa, which includes the serosal surface and the serosal fat. The normal gut wall has a variable thickness, depending on whether or not it is distended. In general, the normal wall should be no greater than 3 mm when distended but may be minimally thicker in appearance when nondistended (5,6).
