The clinical utility and diagnostic performance of transabdominal contrast-enhanced ultrasonography using Sonazoid for pancreatic diseases: a narrative review.

This review aims to evaluate the clinical utility of contrast-enhanced ultrasonography (CEUS) in the differential diagnosis and management of solid and cystic pancreatic lesions. We reviewed the characteristic enhancement patterns of various solid and cystic pancreatic diseases, including pancreatic ductal adenocarcinoma (PDAC), mass-forming pancreatitis (MFP), focal autoimmune pancreatitis (AIP), pancreatic neuroendocrine neoplasms (PNENs), solid pseudopapillary neoplasms (SPNs), metastatic tumors, intraductal papillary mucinous neoplasms (IPMNs), serous cystic neoplasms (SCNs), and mucinous cystic neoplasms (MCNs). We also analyzed the role of quantitative perfusion analysis and summarized diagnostic performance based on multicenter studies and meta-analyses. In PDAC, the "irregular rolling sign" and early washout under a hypovascular pattern are critical diagnostic markers reflecting histological desmoplasia. Conversely, MFP typically shows diffuse isovascularity. CEUS facilitates the differentiation of malignant mural nodules from mucus plugs in IPMN with high accuracy. Quantitative perfusion analysis (QPA) using time-intensity curves (TIC) provides objective metrics like peak intensity (PI) and area under the curve (AUC), enhancing diagnostic objectivity. Large-scale studies, such as the Pancreatic Multicenter Ultrasound Study (PAMUS), and several meta-analyses have demonstrated that CEUS achieves a pooled sensitivity of 86-90% and specificity of 75-88% for pancreatic cancer, outperforming or equaling conventional CT and B-mode ultrasound. CEUS is a minimally invasive, rapid, and highly accurate modality that provides essential hemodynamic information. It should be considered a valuable complementary imaging modality for the initial evaluation and stratification of pancreatic neoplastic lesions, particularly when detailed hemodynamic assessment is required alongside conventional screening.