Role of Endoscopic Ultrasound Elastography in Diagnosis of Gastrointestinal Subepithelial and Mediastinal Lesions

Inclusion Criteria: * Age: Adults ≥ 12 years. * Clinical indication: Patients referred for diagnostic EUS of a 1\_mediastinal mass or mediastinal lymphadenopathy detected on prior imaging (CT/MRI) . 2- subepithelial lesions lesion detected by endoscopy . * Lesion accessibility: Lesion judged by the endosonographer to be accessible to EUS imaging and elastography and amenable to EUS-guided sampling Exclusion Criteria: * • patient Refusal or inability to provide informed consent * Uncorrectable coagulation disorder * Presence of contraindicating endoscopy/sedation * Lesion inaccessible to EUS or elastography (e.g., too far from the esophagus/airway to obtain reliable elastography or visualization) as judged by the performing endosonographer.