Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is an established procedure with high diagnostic accuracy for tissue acquisition and pathological diagnosis of pancreatic ductal adenocarcinoma (PDAC) [1]. However, EUS-FNB sometimes demonstrates inconclusive results in PDAC rich in necrotic or fibrotic components [2] [3]. In such cases, identifying hot spot areas with viable cancerous cells is important to obtain adequate samples. Detective flow imaging (DFI) is a novel Doppler imaging technology that visualizes low-velocity blood flow in the absence of motion artifacts [4] [5], which was challenging to visualize on conventional color Doppler imaging. Herein, we present a case in which DFI imaging helped determine the hot spot area during EUS-FNB for a poorly vascularized pancreatic mass.

An 85-year-old male patient was referred to our hospital for pancreatic mass evaluation. Contrast-enhanced computed tomography revealed a large hypodense mass in the pancreatic body and tail with poor contrast enhancement ([Fig. 1]). EUS detected a well-defined heterogeneous mass in the pancreatic body. EUS-FNB was performed using a 22-gauge Franseen needle (Acquire; Boston Scientific, Natick, Massachusetts, United States) with three needle passes. However, the acquired materials contained only fibrotic and necrotic components without epithelial cells. Repeated EUS-FNB was required to confirm the diagnosis. Previous EUS-FNB findings indicated that the tumor contained abundant fibrotic tissues; thus, intratumoral vessel evaluation using the DFI was planned. Conventional color Doppler imaging revealed no intratumoral vessels ([Fig. 2] a), whereas DFI imaging demonstrated fine, irregular intratumoral vessels, indicating a hot spot area ([Fig. 2] b). EUS-FNB with DFI guidance was performed using the same needle type against the area where vessels were displayed on DFI ([Fig. 3] a, [Video 1]). The acquired specimen contained cancerous tissue, resulting in a final diagnosis of PDAC ([Fig. 3] b). This case indicates that DFI helps determine the optimal puncture site for diagnosis of poorly vascularized PDAC.