Do we need contrast agents for EUS?

Abstract

We recently introduced a series of articles that dealt with controversies in EUS. In Part I, the authors discussed which clinical information is necessary prior to EUS and whether other imaging modalities are required before embarking on EUS examinations. Part II focuses on technical details and controversies about the use of EUS in special situations. In this article, important practical issues regarding the application of contrast-enhanced EUS in various clinical settings are raised and controversially discussed from different points of view.

Diagnostic and Interventional Role of Endoscopic Ultrasonography for the Management of Pancreatic Neuroendocrine Neoplasms

“…However, in the same cohort, the authors observed that the mean strain elastography measured by strain histogram was significantly lower in patients with PDAC compared with those with chronic pancreatitis (45.4 vs. 74.5, p = 0.0007) [74]. Finally, EUS-E can be considered an additional diagnostic tool to select the much suspicious area of the pancreatic mass to be sampled [69][70][71][72][73][74][75][76].…”

“…Color Doppler EUS evaluates the vascularity of pancreatic tumors [31]. Contrastharmonic EUS (CH-EUS) is a technique that allows real-time visualization of microvasculature and pancreatic parenchyma perfusion, without Doppler-related artifacts, showing to be particularly useful in differentiating PDAC from other solid pancreatic lesions [31,[76][77][78]. The development of microbubble-based contrast agents, together with advances in ultrasound technology, has led to improve imaging of fine vascular structures and visualization of microflow patterns within target lesions [76].…”

“…Contrastharmonic EUS (CH-EUS) is a technique that allows real-time visualization of microvasculature and pancreatic parenchyma perfusion, without Doppler-related artifacts, showing to be particularly useful in differentiating PDAC from other solid pancreatic lesions [31,[76][77][78]. The development of microbubble-based contrast agents, together with advances in ultrasound technology, has led to improve imaging of fine vascular structures and visualization of microflow patterns within target lesions [76]. The most commonly used second-generation ultrasound contrast agents are composed of microbubbles of perfluoro gas entrapped into a lipid shell (e.g., Sulfurhexafluoride, Sonovue™, Bracco, Milan, Italy; Perfluorobutane; Sonazoid™, Daiichi-Sankyo, Tokyo, Japan; GE Healthcare, Milwaukee, WI, USA; not available in the USA and Europe).…”

“…After having identified the target lesion, the second-generation contrast agent is injected as a bolus through an antecubital vein, using a 20-gauge catheter, followed by a 10/20 mL saline solution flush. The examination of the lesion lasts a minimum of 45 s after contrast agent injection [76,77]. The definition of 'hypoenhancement' is a pattern of enhancement in which the echo intensity of the lesion is lower than that of the surrounding pancreatic tissue on CH-EUS.…”

“…EUS-TA is not going to be replaced by CH-EUS; however, CH-EUS may contribute to the selective use of EUS-TA [80]. As a result of the reported advantages above, CH-EUS is the imaging modality of choice to discriminate PanNENs from PDAC at the first clinical assessment, particularly in the case of small tumors [76]. Further technical refinements and novel substances are likely to improve its diagnostic potential in the near future.…”