Ultrasound contrast agents

Abstract

Endoscopic ultrasound (EUS) plays an important role in imaging of the mediastinum and abdominal organs. Since the introduction of US contrast agents (UCA) for transabdominal US, attempts have been made to apply contrast-enhanced US techniques also to EUS. Since 2003, specific contrast-enhanced imaging was possible using EUS. Important studies have been published regarding contrast-enhanced EUS and the characterization of focal pancreatic lesions, lymph nodes, and subepithelial tumors. In this manuscript, we describe the relevant UCA, their application, and specific image acquisition as well as the principles of image tissue characterization using contrast-enhanced EUS. Safety issues, potential future developments, and EUS-specific issues are reviewed.

Modern ultrasound imaging of pancreatic tumors

“…In addition, 91 of 102 PNETs (89%) were hyperenhancing or isoenhancing, resulting in a correct differential diagnosis of PDAC and non-PDAC in 189 of 219 patients (86%) [32]. The results using CEUS were better compared to CT; CT did not delineate a focal pancreatic lesion in 14 of the 38 patients with complete reports of CE-EUS and CT (37%; PDAC, n=6 and PNET, n=8; median diameter 8 mm [range, 4 to 12 mm]) [32] and the ultrasound contrast agent SonoVue was highly sensitive due to being strictly intravascular [65]. These results are in concordance with the findings published for more than 1,000 histologically proven focal pancreatic lesions and in earlier studies using CEUS techniques [29,49].…”

Contrast‐enhanced ultrasound for quantification of tissue perfusion in humans

“…This prevents quick dissolution of the microbubble and allows these microbubbles to persist in the circulation for several minutes. Overviews of the composition of the different ultrasound contrast agents used in imaging research have been provided previously . In short, the first generation contrast agents consisted of air‐filled microbubbles with a lipid shell while the second generation microbubbles contain gases with a low solubility in water.…”

Detection and characterization of small superficially located focal liver lesions by contrast-enhanced ultrasound with high frequency transducers

“…Although offering a useful adjunct, transabdominal ultrasound examinations with high frequency transducers cannot substitute scanning with a low frequency transducers. We also refer to the use of contrast enhanced endoscopic ultrasound in the detection of superficially located liver tumours [38,[41][42][43].…”