Usefulness of Contrast Enhanced Harmonic Endoscopic Ultrasound for Pancreatic Cysts

Usefulness of Contrast-enhanced Harmonic Endoscopic Ultrasound (CH-EUS) for the Differentiation of the Pancreatic Cysts and for Guiding Endoscopic Ultrasound Guided Fine Needle Aspiration (EUS-FNA) From Murale Nodules.

The study evaluates the role of contrast-enhanced harmonic endoscopic ultrasound (CH-EUS) for the differentiation of the pancreatic cysts and their malignant potential.

Due to the increase use of cross-sectional imaging techniques for varied medical conditions more and more pancreatic cysts are incidentally found. Magnetic resonance imaging revealed a prevalence of incidental pancreatic cystic neoplasm (PCN) in adults between 2,4-49,1% and autopsy studies showed that half of the individuals had pancreatic cysts. There is a great variety of pancreatic cysts, they are mainly divided in neoplastic or non-neoplastic (i.e pseudocyst). Pseudocysts appear after acute or chronic pancreatitis and represent only 20% of all pancreatic cysts.. PCN include a diverse group of pancreatic cysts including mucin-producing (Intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN)) and nonmucin-producing lesions (Serous cystadenoma (SCN), Solid pseudopapillary neoplasm(SPN) cystic neuroendocrine tumor(cNET)) with different morphology and progression to malignancy. SPN's,cNET are considered premalignant or malignant conditions and require surveillance or surgical resection. SCN instead are benign and surveillance is not necessary. Resection is considered only if symptoms are present. The discrimination between the different cyst types is crucial for the therapeutic approach. Their morphology can be similar and sometimes it's a challenge to diagnose them.There are many tools but none is good enough to be used alone. Contrast-enhanced harmonic endoscopic ultrasound using low mechanical index (0.12-0.4) is an additional test to assess the vascularization of the cystic wall and the septa and solid component for the differential diagnosis of PCN. Our aim was to identify specific imaging characteristics using CH-EUS in order to increase the diagnostic accuracy for potential malignant pancreatic cysts.

After a careful endoscopic ultrasound examination in B mode of the entire pancreas, contrast enhancement was administrated to the participants. The uptake and the wash-out of the agent were followed and then a morphological diagnose was established. EUS-fine needle aspiration of the cyst wall, septa or solid components was guided by the enhancing pattern.

During the echoendoscopy the image was fixed on the region of interest (pancreatic cyst) and the extended pure harmonic detection mode was selected. 2,4ml contrast enhancement (Sonovue-Bracco Italy) was injected in the right antecubital vein of the participants followed by a flush of 5ml 0.9% saline solution to ensure that the entire quantity of the agent goes in to the blood flow. After the administration the pancreatic cyst was observed for at least 120 seconds.We followed the enhancing behavior of the cyst wall, the septa and the solid components. Arterial enhancement (contrast uptake) was considered the first 25-30 seconds after injection and the venous phase (wah-out) 30-45 seconds after injection. EUS-FNA was performed in all patients without contraindications

To identify specific imaging characteristics using CH-EUS ( the contrast uptake pattern) in order to increase the diagnostic accuracy for the different type of the pancreatic cysts

To asses the improvement of the EUS-FNA results if the lesions are targeted through the enhancement pattern

Inclusion Criteria: presence of an undetermined pancreatic cyst >10mm (Computer tomography, Magnetic resonance imaging); written informed consent. Exclusion Criteria: platelet count under 50.000 platelets per microliter (mcL) patients with cardiorespiratory instability refuse of the patient to participate.

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