Diagnostic Endoscopic Ultrasound: Technique, Current Status and Future Directions

Abstract

Endoscopic ultrasound (EUS) is now well established as an important tool in clinical practice. From purely diagnostic imaging, it has progressed to include tissue acquisition, which provided the basis for therapeutic procedures. Even as interventional EUS developed, there has been ongoing progress in EUS diagnostic capabilities due to improved imaging systems, better needles for tissue acquisition and development of enhanced imaging functions such as contrast harmonic EUS (CHEUS) and EUS elastography. EUS is well established for differentiation of subepithelial lesions, for T-staging of luminal gastrointestinal and pancreaticobiliary malignancies, for differentiation of benign pancreaticobiliary disorders and for diagnostic tissue acquisition, which can be achieved by EUS-guided fine needle aspiration or by EUS-guided fine needle biopsy using dedicated biopsy needles. This review briefly describes the technique of performing EUS and then discusses its clinical utility in terms of gastrointestinal cancer staging, the evaluation of pancreaticobiliary disorders and tissue acquisition. Enhanced imaging techniques such as CHEUS and EUS elastography are briefly reviewed.

Ultrasonographic measurement of the thickness of cervical oesophagus layers in the reflux oesophagitis: Association with clinical findings

“…Endoscopic ultrasonography can be used for the evaluation of the upper digestive tract, as well as for the easy assessment of the layers of the wall of the gastrointestinal tract. The main use of this procedure in the oesophagus is the detection of subepithelial lesions and T‐staging of tumours 12 . It can provide detailed images and delicate measurement of the oesophageal layers, but it has the same disadvantages of conventional endoscopy discussed above.…”

Concise review on the comparative efficacy of endoscopic ultrasound-guided fine-needle aspiration vs core biopsy in pancreatic masses, upper and lower gastrointestinal submucosal tumors

“…Recently, several guidelines have been published. Ang et al[ 8 ] addressed the enhanced diagnostic importance in tissue acquisition and improved diagnostic accuracy when using FNB needles. Moreover, recent ESGE released guidelines recommended the use of either FNA or FNB needles (22 or 25-gauge) for routine EUS-guided sampling of solid masses and lymph nodes.…”

“…Since then, three different FNB needles have been produced, which are easier to use than FNA needles. Examples include the Procore ® needle, which is characterized by a cutting bevel (reverse for 19, 22 and 25-gauge and 20-gauge antegrade beveled side slot) at the needle tip (Cook Medical Inc.), the Acquire™ end-cutting needle, which is characterized by a three-point needle tip (22 and 25-gauge; Boston Scientific Corp., Marlborough, MA, United States), and the SharkCore™ needle, which is characterized by six distal cutting edges at the needle tip (19, 22 and 25-gauge; Medtronic, Minneapolis, MN, United States)[ 8 ]. Regarding needle sizes, several studies have examined the impact of needle sizes on diagnostic accuracy and yield.…”

“…However, the limiting factor in usage of 19-gauge needles is its higher rate of complication and technical failure. On the other hand, the smaller needle sizes (22 and 25-gauge) are more technically feasible[ 8 ]. Moreover, when cytology is supposed to be enough for making a diagnosis, such as the case in pancreatic lesions, previous meta-analysis demonstrated similar diagnostic yield of 22 and 25-gauge needles and non-superiority of the larger 19-gauge needle in diagnostic yield[ 9 ].…”

Present and Future of Endoscopic Ultrasound-Guided Tissue Acquisition in Solid Pancreatic Tumors

“…2B), and (3) SharkCore TM needle (Medtronic, Minneapolis, MN, USA) with six distal cutting edges at the needle tip (19, 22, and 25 G) (Fig. 2C) [16]. However, higher rates of adverse events and technical failure are noted with the use of large needles.…”