Virtual Pancreatoscopy Using Three-dimensional Endoscopic Ultrasonography

Abstract

Three-dimensional (3D) ultrasonographic images of digestive diseases have made rapid progress recently. Here we evaluated clinical usefulness of virtual pancreatoscopy (VP) obtained with three-dimensional endoscopic ultrasonography (3D-EUS) for pancreatic diseases. Subjects and Methods Sixty-four persons underwent 3D-EUS examinations for pancreatic diseases (pancreatic cancer n=16; chronic pancreatitis n=7; intraductal papillary-mucinous tumor (IPMT) n=24; pancreatic cyst n=8; endocrine tumor n=5; others n=4) between March 2003 and October 2003. We used an electronic radial scanning endoscopic ultrasonography (EG3630UR; Pentax Co., Ltd., Tokyo, Japan) and monitor/processing unit (EUB-8500; Hitachi Co., Ltd., Tokyo, Japan) equipped with software for 3D reconstruction for this study. Color Doppler imaging is available with this instrument system, so that we also made combined VP images mixed with B-mode imaging and color Doppler imaging. Furthermore, we made VP images obtained with contrast-enhanced 3D-EUS in some cases. We automatically produced VP images by volume rendering method and compared them with the resected specimens or pancreatoscopy. Results We could produce VP images in 64 cases. In cases of pancreatic cancer, VP images showed internal structures of dilated main pancreatic ducts. In cases of obstructive jaundice due to pancreatic cancer, VP images showed irregular obstruction of dilated common bile ducts. On the other hand, in cases of chronic pancreatitis, VP images showed relatively smooth obstruction of dilated common bile ducts. In cases of IPMT, VP images clearly displayed the papillary tumors in the pancreatic ducts. In cases of pancreatic cyst, VP images displayed smooth internal appearance of the cysts. On combined VP imaging or contrast-enhanced 3D-EUS modes, we could easily understand distribution of vasculature in pancreatic tumors and relative spatial position between pancreatic tumors and vessels. Conclusions 3D-EUS can visualize internal structures of the dilated main pancreatic ducts, common bile ducts and cysts. Furthermore we can evaluate the vascularity of pancreatic tumors with VP images in combination with color Doppler mode. Although pancreatoscopy is thought to be accurate for diagnosis of pancreas diseases, it is invasive and a burden to the patients. On the contrary, VP images using 3D-EUS is a noninvasive method. It may become more useful to diagnose 3D extent and configurations of pancreatic tumors if software and hardware are improved in future.