Endoscopic ultrasound (EUS) is useful in assessing gastric lesions found on endoscopy. EUS can assess the 5 layers of the gastric wall and is the most useful modality for staging tumors of the stomach, including adenocarcinoma and lymphoma. For subepithelial gastric lesions, EUS can assess the echogenicity of a lesion, which layer of the gastric wall is involved, and assess for the presence of blood flow with Doppler ultrasound. These characteristics help to determine the likely etiology of the lesion. Fine needle aspiration may also provide additional information, especially when mucosal biopsies are nondiagnostic.