The complexity of the medical expertise required for endoscopic manipulation and image interpretation complicates the implementation of echo-endoscopy (or EUS for "Endoscopic Ultrasound").

The "EZ-EUS" system is designed to help the operator understand the orientation and the position of the probe tip in the patient. This system offers navigation similar to that of the Global Positioning System (GPS), but for EUS procedures. To achieve this, it uses a 3D model based on scanner imaging data recorded before the procedure.

In this study, the intended purpose of the "EZ-EUS" system is to help echo-endoscopy operators to easily identify and assess the pancreatic gland, and to facilitate the detection of any lesions.

The hypothesis is that, thanks to this tool, procedure times will be shortened, and the pancreas and its lesions will be fully imaged to facilitate their localization and characterization.

Since its inception in the 1980s, the field of endoscopic ultrasound (EUS) has experienced significant expansion and evolution and is now a pivotal component of pancreatobiliary assessment. Proficiency in EUS necessitates a synthesis of cognitive and technical competencies encompassing endoscopic manipulation, image interpretation, and an extensive comprehension of intraabdominal anatomical structures. Acquisition of these competencies is a progressive and highly operator-dependent process, and thereby necessitates an extended learning curve for practitioners.

The American Society for Gastrointestinal Endoscopy (ASGE) has recommended the performance of a minimum of 190 supervised EUS for practicing autonomous EUS. However, the compliance of these parameters does not guarantee competence achievement, and there is a wide variability between endoscopists leading to disparities in the techniques' quality and irregular outcomes.

The "EZ-EUS" system is designed to help the operator understand the orientation and the position of the probe tip in the patient. This system offers navigation similar to that of the Global Positioning System (GPS), but for EUS procedures. To achieve this, it uses a 3D model based on scanner imaging data recorded before the procedure.

In this study, the intended purpose of the "EZ-EUS" system is to assist echo-endoscopy operators in accurately locating the pancreatic gland, conducting a comprehensive evaluation of the region of interest, and facilitating the detection and identification of lesions within it. We hypothesize that this tool will streamline procedure times and enable comprehensive imaging of the pancreas and its lesions, thereby reducing the need for expert guidance for trainees and shortening the EUS learning curve. This study is exploratory, prospective, monocentric and will compare two randomized groups (with and without the EZ-EUS navigation system).

Inclusion Criteria:

• Man or woman over the age of 18 years old.
• Patient having a EUS procedure for pancreas study planned within the frame of his or her clinical care.
• Patient whom pre-operative imaging indicates one lesion, a suspicion of lesion, chronic pancreatitis or fatty pancreas.
• Patient with a good definition on the CT scan done within the year to the EUS.
• Patient able to receive and understand information related to the study and give his or her written consent.
• Patient affiliated to the French social security system.

Exclusion Criteria:

• Patient with altered anatomy of the upper digestive tract due to previous surgery.
• Patient with known abnormal anatomy of the upper digestive tract.
• Patient wearing a pacemaker.
• Patients with comorbidities that may increase the risk of perforation.
• Patient presenting, according to the investigator's judgment, a disease which may prevent participation in the procedures provided for by the study.
• Patient with an ASA >3. Patient with ASA=3 must be validated by the Principal
• Investigator (PI).
• Patient unable to tolerate general anesthesia.
• Patient with a body mass index (BMI) < 18,5 and > 40.
• Patient with weight variations >10% between the date on which the CT scan was performed and the date of the procedure.
• Pregnant or lactating patient.
• Patient in exclusion period (determined by a previous or a current study).
• Patient under guardianship or trusteeship.
• Patient under the protection of justice of deprives of liberty.
• Patient in situation of emergency

Perprocedure exclusion criteria

• Patient in need of the balloon during the navigation will be excluded of the study (Experimental group)