Diagnostic value of endoscopic ultrasound-guided directional eFLOW in solid pancreatic lesions

Ultrasound using microbubble-based contrast agents is useful for vascular imaging. Directional eFLOW (D-eFLOW) is a novel technology for vascular assessment that provides high spatial and temporal resolution. The purpose of this study was to investigate the utility of endoscopic ultrasound (EUS)-guided D-eFlow before and after administration of an ultrasound contrast agent (USCA) for assessing the vascularity of solid pancreatic lesions.

D-eFlow was compared to power Doppler EUS (PD-EUS) or color Doppler EUS (CD-EUS) before and after USCA injection. We also evaluated the Visual Vascular Assessment (ViVA) scale for the estimation of vascularity and investigated its reliability using the interclass correlation coefficient (ICC). From January 2007 to March 2007, 35 patients (mean age, 64.5 years old; age range, 28-81 years) underwent EUS followed by D-eFLOW EUS, PD-EUS, and CD-EUS before and after administration of USCA. The pancreatic parenchymal ViVA score, pancreatic vascular pattern, and ICC were evaluated for all lesions.

Concerning the sensitivity for detection of the hypovascular pattern in pancreatic adenocarcinoma, D-eFLOW (before and after USCA) had similar sensitivity to PD-EUS (before and after USCA) and CD-EUS (before and after USCA). D-eFLOW after contrast showed the highest accuracy (82.3 %) and negative predictive value (53.8 %) among all the modalities investigated. There was a good correlation among the ViVA scores for D-eFLOW before contrast, those for D-eFLOW EUS, and those for PD-EUS and CD-EUS. The reliability of the ViVA scale was excellent with an ICC of 0.81. In conclusion, D-eFLOW EUS is a sensitive, reliable, and highly accurate method of assessment of pancreatic vascularity. D-eFLOW EUS with contrast was more sensitive than PD-EUS and CD-EUS for assessment of pancreatic vascularity.