Ultrasound Diagnosis of Hypoechoic Tracts

Characteristics of Hypoechoic Tracts

Fistulae appear as hypoechoic duct-like structures with or without internal gaseous artifacts, with a cross-sectional diameter <2 cm, and may contain fluid, air, or both, exhibiting peripheral contrast enhancement, as noted by the European Society of Gastrointestinal Endoscopy 1
Sinus tracts are blind-ending defects extending from the serosal surface into the perienteric mesentery without connecting to another structure, and the hypoechoic appearance reflects the inflammatory tract itself, not simply the gastric content within it, according to the European Society of Gastrointestinal Endoscopy 1
Mesenteric inflammatory masses appear as ill-defined hypoechoic masses without a definable wall, usually with detectable internal color Doppler signal, as reported by the European Society of Gastrointestinal Endoscopy 1

When encountering a hypoechoic tract near the stomach, determine the origin, assess for communication, evaluate surrounding structures, and use Doppler to differentiate inflammatory from neoplastic processes, as recommended by the American Gastroenterological Association 1
The American Institute of Ultrasound in Medicine suggests using Doppler to evaluate vascularity, which helps differentiate inflammatory from neoplastic processes 2

Hypoechoic masses in the third or fourth echo layer may represent GISTs, leiomyomas, or other subepithelial tumors requiring tissue sampling, according to the American Gastroenterological Association 3
The American Society for Gastrointestinal Endoscopy recommends that EUS is the modality of choice for characterizing gastric wall lesions 4