Although subjective, color Doppler imaging is helpful for distinguishing active inflammatory changes in the thickened bowel wall from other pathologies (Fig. 3) (Wilson 1998; Teefey et al. 1996). Power Doppler imaging may improve the visualization of intramural gastrointestinal vascularity (Clautice-Engle et al. 1996). Thus, recent advances in color Doppler and power Doppler imaging improve the accuracy of sonography by allowing the detection of hyperemia of the inflamed bowel wall and of adjacent inflamed fat.

In the active stage of intestinal tuberculosis, bowel wall thickening is usually accompanied by luminal narrowing, which results from spasm and edema. Later, fibrosis and scarring lead to permanent stricture (Fig. 5). However, it is difficult to detect stricture during sonographic examinations (Kedar et al. 1994).

In active tuberculosis, enlarged mesenteric nodes are frequent. Lymphadenopathy is mainly located at the mesentery around the ileum (Fig. 2) (Lee et al. 1993), but sometimes found at the periportal (Fig. 6), peripancreatic, mesenteric, and upper periaortic regions (Malik and Saxena 2003). However, the retroperitoneal lymph node is rarely involved, which can be explained by the fact that mesenteric lymph nodes drain directly into the thoracic duct via the cisterna chyli (Jain et al. 1995). Enlarged lymph nodes are hypoechoic, round to ovoid, and variable in size. Sometimes the nodes may be calcified (Malik and Saxena 2003; Kedar et al. 1994); calcification in healing tuberculosis is seen as a discrete reflective arc with posterior shadowing.