Endoscopic ultrasonography for microvascular imaging without contrast enhancement in the differential diagnosis of pancreatic lesions

Abstract

ObjectivesDetective flow imaging endoscopic ultrasonography (DFI‐EUS) is a recent imaging modality developed for detecting fine vessels without the need for ultrasound contrast agents. The aim of the present study was to evaluate the utility of DFI‐EUS for solid pancreatic lesions and to compare the diagnostic ability for pancreatic cancer (PC) between DFI‐EUS, directional power Doppler (eFLOW) EUS, and contrast‐enhanced harmonic (CH)‐EUS.MethodsPatients with a pancreatic lesion who underwent DFI‐EUS, eFLOW‐EUS, and CH‐EUS between March 2019 and November 2023 were retrospectively enrolled. Final diagnoses were confirmed by pathologic examination of EUS‐guided tissue acquisition and/or resected specimens. Lesions were categorized into the three patterns of poor, mild, and rich vascularity on DFI‐EUS and eFLOW‐EUS, and hypo‐, iso‐, and hypervascular on CH‐EUS. PC was defined as a poor pattern on DFI‐EUS and eFLOW‐EUS, and a hypovascular pattern on CH‐EUS.ResultsThe final diagnoses of 90 examined tumors were PC (n = 57), inflammatory mass (n = 6), autoimmune pancreatitis (n = 13), neuroendocrine tumor (n = 9), and others (n = 5). The sensitivity, specificity, and accuracy for diagnosis of PC were 93%, 82%, and 88%, respectively, on DFI‐EUS, 97%, 42%, and 77% on eFLOW‐EUS, and 95%, 89%, and 92% on CH‐EUS. The accuracy of DFI‐EUS was significantly superior to eFLOW‐EUS (P = 0.005), but no significant difference was found between DFI‐EUS and CH‐EUS.ConclusionDFI‐EUS is more sensitive for depicting vasculature than eFLOW‐EUS, and has higher diagnostic sensitivity for PC. Evaluation of vascularity on DFI‐EUS is useful for the differential diagnosis of pancreatic lesions without the need for intravenous contrast agent.