Contrast-enhanced endoscopic ultrasound

Abstract

The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) introduced guidelines on the use of contrast-enhanced ultrasound (CEUS) in 2004. This EFSUMB-document focused mainly on liver applications. However, new applications extending beyond the liver were developed thereafter. Increased interest in recent years in CEUS technique and in the application of CEUS in novel fields like endoscopic ultrasound (EUS) has revolutionized indications and applications. As a result, the EFSUMB initiated a new update of the guidelines in 2011 to include this additional knowledge. Some of the contrast-enhanced EUS (CE-EUS) indications are established, whereas others are preliminary; these latter indications are categorized as emergent CEUS applications since the available evidence is insufficient for general recommendation. This article focuses on the use of CE-EUS in various clinical settings. The reader will get an overview of current indications and possible applications of CE-EUS. This involves the introduction of different contrast studies including color Doppler techniques (known as contrast-enhanced high mechanical index endosonography or CEHMI-EUS) as well as more modern high-resolution contrast-enhanced techniques (known as contrast-enhanced low mechanical index endosonography or CELMI EUS).

Keywords: contrast-enhanced; differential diagnosis; endoscopic ultrasound; ultrasound.

Figure 1

Typically hypoenhancing ductal adenocarcinoma of the pancreas.

Figure 2

Typically hyperenhancing neuroendocrine tumor of the pancreas.

Figure 3

Macrocystic cystadenoma with contrast enhancing septae.

Figure 4

Intraductal papillary mucinous neoplasm of the pancreas with perfused intraductular nodules.

Figure 5

3D-reconstruction of CEHMI-EUS and CELMI-EUS of the pancreatic corpus of a patient with autoimmune pancreatitis. A: The Colour Doppler signals of the arterioles and venoules of the pancreas. B: The contrast enhancing effect in the smaller vessels in the same area of the pancreas using low mechanical index technique with 3D reconstruction. CELMI-EUS: contrast-enhanced low-MI endoscopic ultrasound; CEHMI-EUS: contrast-enhanced endoscopic Doppler ultrasound with high-mechanical index.

Figure 6

Gastrointestinal stromal tumor. A: Typical endoscopic features; B: CEHMI-EUS image of the same tumor, and please notice the rich vessel system; C: CELMI-EUS image, and the necrotic area was displayed in the upper area of the tumor; D: The surgical specimen of the tumor. CELMI-EUS: contrast-enhanced low-MI endoscopic ultrasound; CEHMI-EUS: contrast-enhanced endoscopic Doppler ultrasound with high-mechanical index.

Figure 7

CELMI-EUS of a hypoenhancing leiomyoma. CELMI-EUS: contrast-enhanced low-MI endoscopic ultrasound.

Figure 8

CELMI-EUS of a hypoenhancing lipoma. CELMI-EUS: contrast-enhanced low-MI endoscopic ultrasound.