Nonhypovascular pancreatic ductal adenocarcinomas: CEUS imaging findings and differentiation from other types of solid pancreatic lesions

OBJECTIVES: To observe and assess the diagnostic value of contrast-enhanced ultrasound (CEUS) in patients with iso-/hypervascular solid pancreatic lesions. METHODS: 70 pancreatic lesions (all confirmed by surgery or biopsy pathology) that manifested iso-/hyperenhancement on CEUS were retrospectively studied from January 2018 to January 2022, including 24 pancreatic ductal adenocarcinomas (PDAC), 15 mass-forming pancreatitis (MFP), 24 pancreatic neuroendocrine tumors (PNET) (14 hyper-PNETs, 10 iso-PNETs), and 7 solid pseudopapillary tumors (SPTP). 65 pancreatic ductal adenocarcinomas (PDAC) that manifested hypoenhancement on CEUS were retrospectively studied from January 2020 to January 2022. CEUS patterns and the clinical and pathologic features were analyzed, and the diagnostic ability of CEUS for iso/hyperenhanced solid pancreatic lesions was assessed. RESULTS: Centripetal enhancement, heterogeneous enhancement, early washout, and hypoenhancement in the late phase mostly appeared in iso-/hyper-PDACs (p < 0.05). Heterogeneous enhancement in small lesions (< 3 cm) as the diagnostic criterion for iso-/hyper-PDACs had an accuracy of 74.3% and a specificity of 91.3%. Iso-PNETs more commonly had larger tumor sizes and more often showed heterogeneous enhancement than hyper-PNETs (p = 0.007, p = 0.035, respectively). The characteristics of the combination of isoenhancement, homogeneous enhancement, and synchronous wash-in/out for MFP had a high accuracy of 90%. Capsular enhancement with heterogeneous enhancement inside for solid pseudopapillary tumors had an accuracy of 97.1%. CONCLUSION: CEUS enhancement patterns have potentially great value in the differentiation of iso-/hyperenhanced pancreatic lesions.