Role of II generation contrast-enhanced ultrasonography (CEUS) in diagnosis of pacreatic lesions

The development of CEUS has contributed to major breakthroughs in the diagnosis of pancreatic lesions. However, only few controlled studies are available. We aimed to prospectively evaluate the role of CEUS in characterization of pancreatic lesions.

28 patients (18 male, median age 73yrs, range 45–83) with 33 histologically proven pancreatic lesions detectable at the US were investigated. At the final diagnosis 8 were adenocarcinoma, 3 insulinomas, 5 mass forming pancreatitis (MFP), and 17 cystic lesions (2 intraductal papillary mucinous tumors [IPMT], 7 pseudocystis, 2 serous [SCA] and 2 mucinous [MCA]cystadenoma). After standard US, 2.4 mL of Sonovue i.v. was administered. Perfusion images of CEUS were evaluated to detect the lesions and parenchymal vascularity. The CEUS findings were compared with those obtained by computed tomography (CT) or magnetic resonance (MRI). The histological diagnosis in all cases was obtained either from biopsy or surgical specimens.

Based on CEUS findings, solid lesions showing hypovascular pattern were diagnosed as carcinomas, those with hypervascular pattern as neuroendocrin tumors, and the hysovascular ones as MFP. All lesions fit these US criteria according to final diagnosis (sensitivity, specificity and accuracy:100%). CT or MRI findings in all cases were also confirmed at the final diagnosis (sensitivity, specificity and accuracy: 100%). Concerning the cystic lesions, all except one were non vascular, even when a corpuscular content was found at basal US (sensitivity 90%). More interestingly, in all cases of SCA and MCA with intralesional septis, CEUS demonstrated a vascular enhancement (sensitivity 100%). In contrast, in the absence of intralesional features within cystic lesions differential diagnosis could not be achieved (sensitivity 65%).

Our data, although preliminary, demonstrate that the study of the pancreas is a promising application of CEUS. In case of solid lesions, a 100% accuracy and concordance with CT/MRI imaging and histologic diagnosis was obtained. In contrast, in presence of cystic lesions the accuracy of CEUS compared to CT/MRI and histologic diagnosis was 75% and 70%. However, when intralesional septis were found, the accuracy of CEUS increased to 90%. Based on these findings CEUS should be further assessed as a complementary imaging modality in the characterization of pancreatic lesions.