Guidelines For Clinical Practice
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World J Radiol. Apr 28, 2010; 2(4): 122-134
Published online Apr 28, 2010. doi: 10.4329/wjr.v2.i4.122
Diagnosis of pancreatic tumors by endoscopic ultrasonography
Hiroki Sakamoto, Masayuki Kitano, Ken Kamata, Muhammad El-Masry, Masatoshi Kudo
Hiroki Sakamoto, Masayuki Kitano, Ken Kamata, Masatoshi Kudo, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kinki University School of Medicine, 377-2, Ohno-Higashi, Osaka-Sayama, 589-8511, Japan
Muhammad El-Masry, Hepatogastroenterology and Endoscopy Unit, Department of Internal Medicine, Assiut University Hospitals, Assiut 71515, Egypt
Author contributions: Sakamoto H and Kitano M both contributed equally to writing this manuscript; El-Masry M searched the literature; Kudo M revised the manuscript.
Supported by The Japan Society for Promotion of Science, Research and Development Committee Program of The Japan Society of Ultrasonics in Medicine; Japan Research Foundation for Clinical Pharmacology; Japanese Foundation for Research and Promotion of Endoscopy
Correspondence to: Masayuki Kitano, MD, PhD, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Kinki University School of Medicine, 377-2, Ohno-Higashi, Osaka-Sayama, 589-8511, Japan.
Telephone: +81-72-3660221 Fax: +81-72-3672880
Received: March 8, 2010
Revised: March 29, 2010
Accepted: April 12, 2010
Published online: April 28, 2010

Pancreatic tumors are highly diverse, as they can be solid or cystic, and benign or malignant. Since their imaging features overlap considerably, it is often difficult to characterize these tumors. In addition, small pancreatic tumors, especially those less than 2 cm in diameter, are difficult to detect and diagnose. For characterizing pancreatic tumors and detecting small pancreatic tumors, endoscopic ultrasonography (EUS) is the most sensitive of the imaging procedures currently available. This technique also provides good results in terms of the preoperative staging of pancreatic tumors. EUS-guided fine needle aspiration (EUS-FNA) has also proved to be a safe and useful method for tissue sampling of pancreatic tumors. Despite these advantages, however, it is still difficult to differentiate between benign and malignant, solid or cystic pancreatic tumors, malignant neoplasms, and chronic pancreatitis using EUS, even when EUS-FNA is performed. Recently, contrast-enhanced EUS with Doppler mode (CE-EUS) employing ultrasound contrast agents, which indicate vascularization in pancreatic lesions, has been found to be useful in the differential diagnosis of pancreatic tumors, especially small pancreatic tumors. However, Doppler ultrasonography with contrast-enhancement has several limitations, including blooming artifacts, poor spatial resolution, and low sensitivity to slow flow. Consequently, an echoendoscope was developed recently that has a broad-band transducer and an imaging mode that was designed specifically for contrast-enhanced harmonic EUS (CEH-EUS) with a second-generation ultrasound contrast agent. The CEH-EUS technique is expected to improve the differential diagnosis of pancreatic disease in the future. This review describes the EUS appearances of common solid and cystic pancreatic masses, the diagnostic accuracy of EUS-FNA, and the relative efficacies and advantages of CE-EUS and CEH-EUS along with their relative advantages and their complementary roles in clinical practice.

Keywords: Contrast-enhanced endoscopic ultrasonography, Endoscopic ultrasonography, EUS-guided fine needle aspiration, Pancreas, Sonazoid