Forward-view Endoscopic Ultrasound: A Systematic Review of Diagnostic and Therapeutic Applications

EUS-guided thrombin injection and coil implantation for gastric varices: feasibility, safety, and outcomes

BACKGROUND AND AIMS

Gastric varices (GVs) are reported in up to 20% of patients with portal hypertension, and bleeding is often more severe and challenging than esophageal variceal bleeding. Data are limited on prophylaxis of GV bleeding or management in the acute setting, and different techniques are used. This study evaluated outcomes after EUS-guided placement of coils in combination with thrombin to manage GVs.

METHODS

We retrospectively reviewed all patients treated with combination EUS-guided therapy with coils and thrombin between October 2015 and February 2020.

RESULTS

Twenty patients underwent 33 procedures for GV therapy; 16 of 20 (80%) had type 1 isolated GVs and 4 patients had type 2 gastroesophageal varices. The median follow-up was 842 days (interquartile range [IQR], 483-961). Seventeen patients (85%) had underlying cirrhosis, the most common etiologies being alcohol-related liver disease and nonalcoholic steatohepatitis. The median Child-Pugh score was 6 (IQR, 5-7). In 11 patients (55%), the indication was secondary prophylaxis to prevent recurrent bleeding; in 2 of 20 patients (10%), the bleeding was acute. Technical success was achieved in 19 patients (95%). During follow-up, the obliteration of flow within the varices was achieved in 17 patients (85%). The 6-week survival rate was 100%, and 2 adverse events, recurrent bleeding at day 5 and at day 37, were reported; both recurrent bleeding events were successfully managed endoscopically.

CONCLUSIONS

EUS-guided GV obliteration combining coil placement with thrombin, in our experience, was technically safe with good medium-term efficacy. A multicenter randomized controlled trial comparing different treatment strategies is desirable to understand options better.

Clinical utility of the forward-viewing echoendoscope in patients after pancreatoduodenectomy: A prospective study

Background and Objectives

Endoscopic treatment of obstructive jaundice and pancreatitis due to hepaticojejunostomy (H-J), pancreatojejunostomy (P-J) strictures, and tumor recurrence after pancreatoduodenectomy (PD) is technically challenging. Treatment of P-J strictures results in poor outcomes. Although conventional EUS that has an oblique view is not suitable for such patients, forward-viewing EUS (FV-EUS) may become a useful option. This study aimed to evaluate the feasibility and efficacy of FV-EUS in patients who have undergone PD.

Methods

Patients with PD who were scheduled to undergo diagnosis and treatment using FV-EUS for H-J or P-J lesions were enrolled in this single-center prospective study. After observation of the P-J and H-J using FV-EUS according to a predetermined protocol, treatment using FV-EUS was performed as needed.

Results

A total of 30 patients were enrolled, and FV-EUS was used to observe P-J and H-J in 24 and 28 patients, respectively. The detection rates of P-J and H-J by endoscopy were 50% (12/24) and 96.4% (27/28), respectively, and by EUS were 70.8% (17/24) and 100% (28/28), respectively. Of these, P-J and H-J were found by endoscopy only after EUS observation in 3 and 1 patient, respectively. The success rates of endoscopic treatment using FV-EUS were 66.7% (2/3), 95.2% (20/21), and 25% (1/4) for benign P-J strictures, benign H-J strictures, and tumor recurrence, respectively.

Conclusions

Endoscopic treatment using FV-EUS is feasible and effective for patients after PD. Moreover, FV-EUS increases the P-J lesion detection rate by adding EUS observation.

Needle Tip Detection Using Ultrasound Probe for Vertical Punctures: A Simulation and Experimental Study

Current ultrasound-guided punctures are difficult to perform as they are performed at an angle to the ultrasound image of the affected area, resulting in longer puncture times, lower success rates, and higher unexpected injury rates. Vertical puncture techniques have also been investigated, but the principle of needle tip detection remains unclear. To optimize ultrasound probes for puncture, the principle of needle tip detection should be understood. This study aimed to verify the principle of needle tip detection and optimal measurement conditions for vertical puncture. Needle tip detection was performed in animal experiments using a probe with a central puncture slit. Moreover, the needle tip was detected at short distances using a puncture spacer. We also investigated the signal from the needle tip using a ring probe and confirmed the principle of needle tip detection, effect of needle tip angle, and insertion depth on needle tip detection through simulation and experiments. Needle tip detection using ultrasound-guided waves was described, and the relationship among needle tip angle, detection intensity, and phase change was verified. The needle tip can be detected by the leakage of the ultrasound-guided wave generated inside the needle tip.

A state-of-the-art comprehensive review summarizing the emerging data on endoscopic ultrasound-guided liver diseases management

Liver diseases are among the most common diseases worldwide accounting for substantial morbidity and mortality. Most liver diseases necessitate radiological evaluation or accurate diagnosis and recently for management as well. In the last decade, the application of therapeutic endoscopic ultrasound (EUS) procedure has been increasingly utilized for the management of various liver diseases. In this comprehensive narrative review article, we provide systematic overview on EUS-guided therapeutic interventions in various liver diseases summarizing most updated data regarding technical success, outcomes and safety profiles. Overall, 35 articles have reported on the use of EUS in the treatment of liver diseases with excellent technical success, favorable radiological response and high safety profiles for EUS-guided treatment of solid and cystic liver lesion and for EUS-guided angiotherapy for gastric varices, except for EUS-guided cyanoacrylate glue injection which was associated with life-threatening fatal systemic embolization adverse events. This suggests that EUS-guided intervention is a new promising therapeutic intervention for the treatment of various liver diseases with durable effect and a limited potential for adverse events.

Forward-Looking Multimodal Endoscopic System Based on Optical Multispectral and High-Frequency Ultrasound Imaging Techniques for Tumor Detection

We developed a forward-looking (FL) multimodal endoscopic system that offers color, spectral classified, high-frequency ultrasound (HFUS) B-mode, and integrated backscattering coefficient (IBC) images for tumor detection in situ. Examination of tumor distributions from the surface of the colon to deeper inside is essential for determining a treatment plan of cancer. For example, the submucosal invasion depth of tumors in addition to the tumor distributions on the colon surface is used as an indicator of whether the endoscopic dissection would be operated. Thus, we devised the FL multimodal endoscopic system to offer information on the tumor distribution from the surface to deep tissue with high accuracy. This system was evaluated with bilayer gelatin phantoms which have different properties at each layer of the phantom in a lateral direction. After evaluating the system with phantoms, it was employed to characterize forty human colon tissues excised from cancer patients. The proposed system could allow us to obtain highly resolved chemical, anatomical, and macro-molecular information on excised colon tissues including tumors, thus enhancing the detection of tumor distributions from the surface to deep tissue. These results suggest that the FL multimodal endoscopic system could be an innovative screening instrument for quantitative tumor characterization.

Outcomes of biliopancreatic EUS in patients with surgically altered upper gastrointestinal anatomy: a multicenter study

Background and study aims  Little is known about outcomes of biliopancreatic endosonography (EUS) in patients with surgically altered upper gastrointestinal (gastrointestinal) anatomy. We aimed to assess the rate of procedural success and EUS-related adverse events (AEs), according to post-surgical anatomies. Patients and methods  Retrospective study including patients with post-surgical altered upper gastrointestinal anatomy who underwent EUS for evaluation of the biliopancreatic region between January 2008 and June 2018 at eight European centers. Results  Of 242 patients (162 males, mean age 66.4 ± 12.5), 86 had (35.5 %) Billroth II, 77 (31.8 %) pancreaticoduodenectomy, 23 (9.5 %) Billroth I, 19 (7.9 %) distal esophagectomy, 15 (6.2 %) total gastrectomy, 14 (5.8 %) sleeve gastrectomy, and eight (3.3 %) Roux-en-Y. Sleeve gastrectomy, Billroth I, and pancreaticoduodenectomy were associated with high rates of success (100 %, 95.7 %, and 92.2 %, respectively). Visualization of the head of the pancreas was significantly impacted by total gastrectomy, Billroth II, and Roux-en-Y (success rates 6.7 %, 53.7 %, and 57.1 %, respectively). Examination of the pancreatic body and tail was impaired in esophagectomy and total gastrectomy (82.4 % and 71.4 %, respectively). Technical success and diagnostic accuracy of EUS-guided tissue acquisition (EUS-TA) was 78.2 % and 71.3 % (95 % CI, 60.6-80.5), respectively. Four (1.6 %) AEs were observed: one mucosal tearing in a Billroth II patient, one cardiac arrest in a distal esophagectomy patient, one bleed after EUS-TA in a Billroth I patient, and one acute pancreatitis after EUS-TA in a sleeve gastrectomy patient. Conclusions  The yield of bilio-pancreatic EUS is dependent on lesion location and surgery type. Before considering EUS in these patients, one must carefully consider whether the lesion may be approachable by EUS.

EUS-guided biliary drainage for postsurgical anatomy

ERCP is the mainstay of therapy for pancreatobiliary diseases in patients with native upper gastrointestinal (UGI) anatomy. However, when UGI anatomy is surgically altered, standard ERCP becomes technically challenging or not possible. In such instances, EUS-guided biliary drainage (EUS-BD) has been increasingly employed by advanced endoscopists as a safe and effective method of access to the biliary tree. In this study, we review the technical aspects and outcomes of EUS-BD in patients with surgical UGI anatomy.

Evaluation of a new slim radial echoendoscope: A better option for an aging population

Background and Objectives:

The radial echoendoscope is still widely used for the investigation of abnormalities in the gastrointestinal wall and for stone detection in the extrahepatic biliary tree. Due to aging patient population, EUS is frequently performed in fragile and elderly individuals. We aimed to compare the maneuverability and image quality of a new thin radial echoendoscope to the current one.

Patients and Methods:

This evaluation was conducted at a referral academic EUS center. The new radial echoendoscope has a thinner shaft and distal tube and a shorter bending section compared to the previous one. Patients referred for diagnostic EUS with a radial echoendoscope were enrolled. Indications included pancreaticobiliary disease, esophagogastric abnormalities, and neoplasms and rectal cancer staging.

Results:

We enrolled 177 patients (122 pancreaticobiliary, 48 esophagogastric, and 7 rectal cases). Overall, the new echoendoscope performed better than the previous model in terms of maneuverability during esophageal intubation and transition from the duodenal bulb to the second portion. On the other hand, pylorus traversing was comparable to the current radial echoendoscope. No loss in image quality was appreciated at predefined stations (esophagus, stomach, and duodenum) compared to the current model. On the other hand, image penetration depth in tissue harmonic mode was significantly improved with the new echoendoscope.

Conclusions:

A new thinner radial echoendoscope showed improved maneuverability compared to the existing version. Image quality was also improved thanks to increased penetration depth in the tissue harmonic mode. We speculate that this new echoendoscope may allow for safer and faster EUS examination, which may prove useful in an aging patient population.

What should be known prior to performing EUS exams? (Part II)

In “What should be known prior to performing EUS exams, Part I,” the authors discussed the need for clinical information and whether other imaging modalities are required before embarking EUS examinations. Herewith, we present part II which addresses some (technical) controversies how EUS is performed and discuss from different points of view providing the relevant evidence as available. (1) Does equipment design influence the complication rate? (2) Should we have a standardized screen orientation? (3) Radial EUS versus longitudinal (linear) EUS. (4) Should we search for incidental findings using EUS?

A prospective, controlled assessment of the technical characteristics of a novel forward-viewing echoendoscope

INTRODUCTION

endoscopic ultrasound (EUS) is a highly useful technique for the diagnosis and management of different gastrointestinal (GI) tract conditions.

OBJECTIVE

to prospectively assess the clinical usefulness of a novel forward-viewing echoendoscope (FV-CLA).

METHODS

this was a cross-sectional observational study. All patients that underwent EUS over a two-month period were considered for the study. All mediastinal, perigastric and periduodenal stations were consistently assessed with a rating from 0 to 10 points with regard to the ease to obtain ultrasonographic sections and the quality of ultrasound images. The identified lesions were punctured when clinically indicated.

RESULTS

a total of 45 patients were included. EUS was completed in 100% of patients, with two minor complications recorded. Echoendoscope maneuverability was graded as "A" (9-10 points), overall plane visibility was graded as "B" (7-8 points) and only stations 4L and 5 visualization were graded as "D" (< 7 points). Visualization of the pancreas and the rest of the EUS stations were rated as excellent or very good. The feasibility to perform EUS-FNA, even from the second portion of the duodenum, was graded excellent or very good.

CONCLUSION

the FV-CLA allows a complete, high-quality examination of the upper GI tract, including EUS-FNA punctures. Some mediastinal stations are hardly accessible with this new device. A formal validation of the FV-CLA for EUS-guided therapy would be of interest.

Training in endoscopic ultrasonography: An Asian perspective

Training of endoscopic ultrasonography (EUS) in Asia faces two major challenges: (i) the ever-increasing demand for skills to handle a growing range of interventional EUS procedures; and (ii) a continual shortage of EUS training programs. As the therapeutic application of EUS continues to expand, the need to train more new endosonographers and upgrade skills of existing ones has become more critical than ever before. A formal fellowship to acquire EUS knowledge and skills in an advanced endoscopy center has always been perceived as the best way of training novices, but such opportunities remain limited in most Asian countries. To keep up with the pace of development in EUS, more short-term EUS programs have been conducted across Asia in recent years. Such programs are generally intensive and may combine didactic lectures, live-case demonstrations, and hands-on training on phantoms, or live animal models for teaching. Although not as rigorous as conventional full-time EUS fellowships, such short-term programs are not necessarily inferior in quality. With courses offered from basic to advanced levels, and at regular intervals, busy practising endoscopists have the flexibility to attend the course that best matches their individual levels of experience, learn at their own pace and acquire EUS knowledge and skills over as many courses as desired. This open-ended progressive learning model is more agile than established fixed-term learning models and is expected to adapt better to future needs.

A Sub-Nyquist, Variable Sampling, High-Frequency Phased Array Beamformer

A digital receive beamformer implementing a "one sample per pixel" variable sampling technique is described. The sampling method reduces the required sampling rates by a factor of 3, and reduces the data capture rate by a factor of 2, in comparison with the previous systems based on variable sampling. The sampling method is capable of estimating broadband pulse envelopes accurate for bandwidths up to 83.0%. This beamforming method has been implemented on a field-programmable gate array with maximum transmit and receive delay errors measured to be less than ±1.0 ns. The beamformer was tested and verified on a previously described 45-MHz 64-element phased array. The system generates images with 128 lines, 512 pixels per RF line, and 2 transmit focal zones. The system generates images with approximately 55 dB of dynamic range and was tested by imaging wire targets submersed in a water bath, wire targets embedded in a tissue phantom, and real-time in vivo imaging of a human wrist.

Endoscopic Management of Pancreatic Fluid Collections

Pancreatic fluid collections (PFCs) may develop due to inflammation secondary to acute and/or chronic pancreatitis, trauma, surgery, or obstruction from solid or cystic neoplasms. PFCs can be drained percutaneously, surgically, or endoscopically with endoscopic ultrasound-guided cyst gastrostomy and/or transpapillary drainage through endoscopic retrograde cholangiopancreatography. There has been a paradigm shift in the endoscopic management of PFCs in the past few years with newer techniques including utilization of self-expanding metal stents and multiport devices. This review is a comprehensive update on the classification of PFC, indications for drainage, optimal approach, and techniques.

Pancreatic pseudocyst drainage performed with a new prototype forward-viewing linear echoendoscope

Interventional endoscopy is a field that continues to grow rapidly. A novel prototype forward-viewing echoendoscope (FV-EUS) has been recently developed in an attempt to overcome some of the limitations of conventional curved linear-array echoendoscopes (OV-EUS). We present a case of a successful endoscopic ultrasound-guided drainage of a pancreatic pseudocyst using a forward-viewing echoendoscope. Although the utilization use of this newly developed echoendoscope has not yet become widespread, its unique characteristics can help to easily perform routine therapeutic procedures and contribute to the expansion of interventional endoscopic utrasoundultrasound.

Endoscopic ultrasound-guided biliary intervention in patients with surgically altered anatomy

AIM

To evaluate the efficacy of endoscopic ultrasound guided biliary drainage (EUS-BD) in patients with surgically altered anatomies.

METHODS

We performed a search of the MEDLINE database for studies published between 2001 to July 2014 reporting on EUS-BD in patients with surgically altered anatomy using the terms "EUS drainage" and "altered anatomy". All relevant articles were accessed in full text. A manual search of the reference lists of relevant retrieved articles was also performed. Only full-text English papers were included. Data regarding age, gender, diagnosis, method of EUS-BD and intervention, type of altered anatomy, technical success, clinical success, and complications were extracted and collected. Anatomic alterations were categorized as: group 1, Billroth I; group 2, Billroth II; group 4, Roux-en-Y with gastric bypass; and group 3, all other types.

RESULTS

Twenty three articles identified in the literature search, three reports were from the same group with different numbers of cases. In total, 101 cases of EUS-BD in patients with altered anatomy were identified. Twenty-seven cases had no information and were excluded. Seventy four cases were included for analysis. Data of EUS-BD in patients categorized as group 1, 2 and 4 were limited with 2, 3 and 6 cases with EUS-BD done respectively. Thirty four cases with EUS-BD were reported in group 3. The pooled technical success, clinical success, and complication rates of all reports with available data were 89.18%, 91.07% and 17.5%, respectively. The results are similar to the reported outcomes of EUS-BD in general, however, with limited data of EUS-BD in patients with altered anatomy rendered it difficult to draw a firm conclusion.

CONCLUSION

EUS-BD may be an option for patients with altered anatomy after a failed endoscopic-retrograde-cholangiography in centers with expertise in EUS-BD procedures in a research setting.

Clinical observations on the treatment of prolapsing hemorrhoids with tissue selecting therapy

AIM: To compare the effects and postoperative complications between tissue selecting therapy stapler (TST) and Milligan-Morgan hemorrhoidectomy (M-M).

METHODS: Four hundred and eighty patients with severe prolapsing hemorrhoids, who were admitted to the Shenyang Coloproctology Hospital between 2009 and 2012, were randomly divided into observation (n = 240) and control (n = 240) groups. Hemorrhoidectomies were performed with TST in the observation group and with the M-M technique in the control group. The therapeutic effects, operation security, and postoperative complications in the two groups were compared. The immediate and long-term complications were assessed according to corresponding criteria. Pain was assessed on a visual analogue scale. The efficacy was assessed by specialized criteria. The follow-up was conducted one year after the operation.

RESULTS: The total effective rates of the observation and control groups were 99.5% (217/218) and 98.6% (218/221) respectively; the difference was not statistically significant (P = 0.322). Their were significant differences between observation and control groups in intraoperative blood loss (5.07 ± 1.14 vs 2.45 ± 0.57, P = 0.000), pain (12 h after the surgery: 5.08 ± 1.62 vs 7.19 ± 2.01, P = 0.000; at first dressing change: 2.64 ± 0.87 vs 4.34 ± 1.15, P = 0.000; first defecation: 3.91 ± 1.47 vs 5.63 ± 1.98, P = 0.001), urine retention (n = 22 vs n = 47, P = 0.001), anal pendant expansion after the surgery (2.35 ± 0.56 vs 5.16 ± 1.42, P = 0.000), operation time (18.3 ± 5.6 min vs 29.5 ± 8.2 min, P = 0.000), and the length of hospital stay (5.3 ± 0.6 d vs 11.4 ± 1.8 d, P = 0.000). Moreover TST showed significant reductions compared to M-M in the rates of long-term complications such as fecal incontinence (n = 3 vs n = 16, P = 0.003), difficult bowel movement (n = 1 vs n = 9, P = 0.011), intractable pain (n = 2 vs n = 12, P = 0.007), and anal discharge (n = 3 vs n = 23, P = 0.000).

CONCLUSION: TST for severe prolapsing hemorrhoids is a satisfactory technique for more rapid recovery, lower complication rates, and higher operation security.

Forward-viewing linear echoendoscope: a new option in the endoscopic ultrasound armamentarium (with video)

The forward-viewing linear echoendoscope (FV-EUS) has been developed with the aim of overcoming limitations of standard curved linear-array echoendoscopes (CLA-EUS) and to further expand interventional applications of EUS. The main characteristic of the FV-EUS is a shifting in the orientation of both endoscopic and ultrasound views from oblique to forward, with the exit of the working channel at the tip of the instrument. This allows exit of the devices parallel to the longitudinal axis of the endoscope, thus resulting in a more direct and stable access to the lesion while increasing the precision and force applied to the target. Accumulating evidence has shown that the FV-EUS can be used instead of the standard CLA-EUS scope for routine fine needle aspiration, with extremely good performance for subepithelial lesions and for difficult to reach locations. Several areas of use of this echoendoscope are yet to be better defined, such as its potential for therapeutic and interventional procedures, as well as for natural orifice transluminal endoscopic surgery. The current report provides an updated overview of the available evidence for both diagnostic and interventional uses of the FV-EUS.

EUS assisted transmural cholecystogastrostomy fistula creation as a bridge for endoscopic internal gallbladder therapy using a novel fully covered metal stent

Background

Laparoscopic cholecystectomy (LC) has become the “gold standard” for treating symptomatic gallstones. Innovative methods, such as a scarless therapeutic procedure through a natural orifice are being introduced, and include transgastric or transcolonic endoscopic cholecystectomy. However, before clinical implementation, instruments still need modification, and a more convenient treatment is still needed. The aim of this study was to evaluate the feasibility of endoscopic internal gallbladder therapy such as cholecystolithotomy in an animal survival model.

Methods

Four pigs underwent endoscopic-ultrasound (EUS)-guided cholecystogastrostomy and the placement of a novel covered mental stent. Four weeks later the stents were removed and an endoscope was advanced into the gallbladder via the fistula, and cholecystolithotomy was performed. Two weeks later the pigs were sacrificed, and the healing of the fistulas was assessed.

Results

EUS-guided cholecystogastrostomy with mental stent deployment was successfully performed in all the animals. Four weeks after the procedure, the fistulas had formed and all the stents were removed. Endoscopic cholecystolithotomy was performed through each fistula. All the animals survived until they were sacrificed 2 weeks later. The fistulas were found to be completely healed.

Conclusions

This study reports the first endoscopic transmural cholecystolithotomy after placement of a novel mental stent in an animal survival model.

Performance of the forward-viewing linear echoendoscope for fine-needle aspiration of solid and cystic lesions throughout the gastrointestinal tract: a large single-center experience

BACKGROUND

A newly developed forward-viewing linear echoendoscope (FV-EUS) has recently become available. To date, however, only scanty data on the performance of the FV-EUS scope for fine-needle aspiration (FNA) of lesions throughout the gastrointestinal (GI) tract are available. This study aimed to evaluate the technical performance of the FV-EUS scope for FNA of solid and cystic lesions located throughout the GI tract in a large cohort of patients referred to a tertiary care center.

METHODS

All patients who underwent endoscopic ultrasound (EUS)-guided FNA using the FV-EUS scope between January 2007 and December 2008 were included in this retrospective study. The performance of the FV-EUS scope for FNA was evaluated.

RESULTS

During the study period, 285 patients with solid or cystic lesions throughout the GI tract underwent the procedure with the FV-EUS scope. A total of 300 FNAs were attempted, 6 (2%) of which could not be performed. Of the 294 successful EUS-FNA procedures, 130 (44.2%) were performed using a 22-gauge needle, 89 (30.3%) using a 25-gauge needle, and 75 (25.5%) using a 19-gauge needle. In all 67 cases of pancreatic cyst or dilated pancreatic duct, a specimen for cystic fluid analysis or cytologic examination could be obtained. Among the remaining 217 patients with solid lesion, a definitive diagnosis could be established for 211 patients (97.2%). The FV-EUS scope had a sensitivity of 74.7% (95% confidence interval [CI] 68.1-80.6%), a specificity of 100% (95% CI 89.9-100%), a positive likelihood ratio of infinity, and a negative likelihood ratio of 0.251 (95% CI 0.196-0.323).

CONCLUSIONS

The FV-EUS scope is highly effective for FNA of solid and cystic lesions throughout the GI tract. Prospective studies comparing the FV-EUS scope and a curved linear scope are needed.