Clinical Research Directory

Inclusion Criteria: * Age ≥18 years and ≤ 85 years; * Subepithelial lesion in the gastrointestinal tract identified under white-light endoscopy and scheduled for CEH-EUS examination to determine the nature of the lesion; * EUS image quality meets the following quality control standards: 1. Equipment requirements: EU-ME2 processor (Olympus, Tokyo, Japan) and GF-UCT260 / GF-UE260 echoendoscope (Olympus, Tokyo, Japan); 2. Image acquisition: Five EUS still images clearly displaying the lesion and surrounding structures, including maximum lesion diameter, originating layer, Doppler signals, and internal echo characteristics; a 15-second video clearly demonstrating the lesion without any artificial annotations (e.g., scale, needle, Doppler signal, elastography, etc.); 3. CEH-EUS procedure: Use of extended pure harmonic detection (Ex-PHD) mode with mechanical index (MI) adjusted to 0.3; 2.4 mL of SonoVue contrast agent is injected via the elbow vein within 2-3 seconds, followed by a 5 mL saline flush; real-time dynamic image acquisition continues for 120 seconds, and video recording is collected. * Patients with GIST confirmed by surgical or endoscopic resection pathology, and patients with leiomyoma confirmed by surgical resection, EUS-guided tissue sampling, or other biopsy techniques; * Written informed consent is obtained. Exclusion Criteria: * Age \<18 years or \>85 years; * Hemoglobin level ≤8.0 g/dL; * Known allergy or hypersensitivity to ultrasound contrast agents; * Pregnant women; * Severe cardiopulmonary dysfunction that precludes tolerance of endoscopic ultrasound examination; * Inability to provide written informed consent (e.g., due to psychiatric disorders or substance abuse).