Prospective comparison of radial and linear endoscopic ultrasound for diagnosis of chronic pancreatitis

Endoscopic Ultrasound in Pancreatology: Focus on Inflammatory Diseases and Interventions

Background

Endoscopic ultrasound (EUS) is a main tool in pancreatology for both diagnosis and therapy. It allows minimally invasive differentiation of various diseases, with a minimal degree of inflammation or anatomic variations. EUS also enables interventional direct access to the pancreatic parenchyma and the retroperitoneal space, the pancreatic duct, the pancreatic masses, cysts, vascular structures for diagnostic and therapeutic purposes.

Summary

This review aimed to summarize the new developments of EUS in the field of pancreatology, with special interest on inflammation and interventions. EUS enables way to perform pseudocyst drainage, necrosectomy, transenteral drainage and transenteric access of the main pancreatic duct, or the direct visualization or therapy of vascular structures adjacent to the pancreas.

Key Messages

EUS has a deep impact on pancreatology, and the development of new diagnostic and interventional approaches to the retroperitoneal space and the pancreas has increased in the last years exponentially, allowing minimal invasive diagnostics and therapy and avoiding surgery and percutaneous therapy.

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.

Diagnostic Endoscopic Ultrasound: Technique, Current Status and Future Directions

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.

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?

Comparison of Combined Endoscopic Ultrasonography and Endoscopic Secretin Testing With the Traditional Secretin Pancreatic Function Test in Patients With Suspected Chronic Pancreatitis: A Prospective Crossover Study

OBJECTIVE

We aimed to determine the feasibility and accuracy of a combined endoscopic ultrasonography (EUS) with a shortened pancreatic function testing (sEUS) for structural and functional assessment using a single instrument in patients with suspected chronic pancreatitis (CP).

METHODS

We completed a prospective crossover study, enrolling patients with suspected CP. Patients who underwent both traditional 1-hour secretin pancreatic function test (sPFT) and sEUS were included in the analysis. We compared study results for test concordance and for correlation of peak bicarbonate concentrations.

RESULTS

Eleven (64.7%) of 17 patients had concordant sPFT and sEUS findings when the cutoff for peak bicarbonate was 80 mEq/L. Six patients had discordant findings with a negative sPFT and positive sEUS. This poor concordance suggests that sEUS is an unreliable functional test. Lowering the sEUS cutoff to 70 mEq/L resulted in improved concordance (64.7% vs 70.6%). Finally, there was no significant correlation between peak bicarbonate concentrations (r = 0.47; 95% confidence interval, -0.02 to 0.79) in these 2 functional tests.

CONCLUSIONS

We demonstrate poor concordance between sPFT and sEUS suggesting that a combined shortened functional and structural test using a single instrument may not be a feasible test for diagnosis of suspected CP when a cutoff of 80 mEq/L is used.

Diagnostic performance of imaging modalities in chronic pancreatitis: a systematic review and meta-analysis

OBJECTIVES

Obtain summary estimates of sensitivity and specificity for imaging modalities for chronic pancreatitis (CP) assessment.

METHODS

A systematic search was performed in Cochrane Library, MEDLINE, Embase and CINAHL databases for studies evaluating imaging modalities for the diagnosis of CP up to September 2016. A bivariate random-effects modeling was used to obtain summary estimates of sensitivity and specificity.

RESULTS

We included 43 studies evaluating 3460 patients. Sensitivity of endoscopic retrograde cholangiopancreatography (ERCP) (82%; 95%CI: 76%-87%) was significant higher than that of abdominal ultrasonography (US) (67%; 95%CI: 53%-78%; P=0.018). The sensitivity estimates of endoscopic ultrasonography (EUS), magnetic resonance imaging (MRI), and computed tomography (CT) were 81% (95%CI: 70%-89%), 78% (95%CI: 69%-85%), and 75% (95%CI: 66%-83%), respectively, and did not differ significantly from each other. Estimates of specificity were comparable for EUS (90%; 95%CI: 82%-95%), ERCP (94%; 95%CI: 87%-98%), CT (91%; 95% CI: 81%-96%), MRI (96%; 95%CI: 90%-98%), and US (98%; 95%CI: 89%-100%).

CONCLUSIONS

EUS, ERCP, MRI and CT all have comparable high diagnostic accuracy in the initial diagnosis of CP. EUS and ERCP are outperformers and US has the lowest accuracy. The choice of imaging modality can therefore be made based on invasiveness, local availability, experience and costs.

KEY POINTS

• EUS, ERCP, MRI and CT have high diagnostic sensitivity for chronic pancreatitis • Diagnostic specificity is comparable for all imaging modalities • EUS and ERCP are outperformers and US has the lowest accuracy • The choice of imaging can be made based on clinical considerations.

Linear-array EUS improves detection of pancreatic lesions in high-risk individuals: a randomized tandem study

BACKGROUND

Studies comparing linear and radial EUS for the detection of pancreatic lesions in an asymptomatic population with increased risk for pancreatic cancer are lacking.

OBJECTIVES

To compare pancreatic lesion detection rates between radial and linear EUS and to determine the incremental diagnostic yield of a second EUS examination.

DESIGN

Randomized controlled tandem study.

SETTING

Five academic centers in the United States.

PATIENTS

Asymptomatic high-risk individuals (HRIs) for pancreatic cancer undergoing screening EUS.

INTERVENTIONS

Linear and radial EUS performed in randomized order.

MAIN OUTCOME MEASUREMENTS

Pancreatic lesion detection rate by type of EUS, miss rate of 1 EUS examination, and incremental diagnostic yield of a second EUS examination (second-pass effect).

RESULTS

Two hundred seventy-eight HRIs were enrolled, mean age 56 years (43.2%), and 90% were familial pancreatic cancer relatives. Two hundred twenty-four HRIs underwent tandem radial and linear EUS. When we used per-patient analysis, the overall prevalence of any pancreatic lesion was 45%. Overall, 16 of 224 HRIs (7.1%) had lesions missed during the initial EUS that were detected by the second EUS examination. The per-patient lesion miss rate was significantly greater for radial followed by linear EUS (9.8%) than for linear followed by radial EUS (4.5%) (P = .03). When we used per-lesion analysis, 73 of 109 lesions (67%) were detected by radial EUS and 99 of 120 lesions (82%) were detected by linear EUS (P < .001) during the first examination. The overall miss rate for a pancreatic lesion after 1 EUS examination was 47 of 229 (25%). The miss rate was significantly lower for linear EUS compared with radial EUS (17.5% vs 33.0%, P = .007).

LIMITATIONS

Most detected pancreatic lesions were not confirmed by pathology.

CONCLUSION

Linear EUS detects more pancreatic lesions than radial EUS. There was a "second-pass effect" with additional lesions detected with a second EUS examination. This effect was significantly greater when linear EUS was used after an initial radial EUS examination.

Endoscopic ultrasound features of chronic pancreatitis: A pictorial review

As endoscopic ultrasound (EUS) is the most sensitive imaging modality for diagnosing pancreatic disorders, it can demonstrate subtle alterations in the pancreatic parenchymal and ductal structure even before traditional imaging and functional testing demonstrate any abnormality. In spite of this fact and abundant literature, the exact role of EUS in the diagnosis of chronic pancreatitis (CP) is still not established. The EUS features to diagnose CP have evolved over a period from a pure qualitative approach to more advanced and complicated scoring systems incorporating multiple parenchymal and ductal EUS features. The rosemont criteria have attempted to define precisely each EUS criterion and thus have good inter-observer agreement. However, initial studies have failed to demonstrate any significant improvement in the inter-observer variability and further validation studies are needed to define the exact role of these criteria. The measurement of strain ratio using quantitative EUS elastography and thus allowing quantification of pancreatic fibrosis seems to be a promising new technique.

Role of diagnostic and therapeutic endoscopic ultrasonography in benign pancreatic diseases

Standard imaging of pancreas is generally obtained by computed tomography and magnetic resonance imaging. However endoscopic ultrasound (EUS) has become an indispensable tool for the diagnosis of various pancreatic diseases. Because of the close proximity of the EUS probe to the pancreas, EUS provides excellent images of the pancreas. In this review, we discuss the role of EUS in the clinical management of patients with benign pancreatic diseases, i.e., various forms of pancreatitis.

Current options for the diagnosis of chronic pancreatitis

The diagnostic options for chronic pancreatitis have evolved over recent years. The previous gold standard references for structural imaging and exocrine pancreatic function testing have both been supplanted and redesigned. Endoscopic retrograde pancreatography has now been overtaken by endoscopic ultrasound and magnetic resonance cholangiopancreatography, whilst the old technique for Dreiling tube pancreatic function testing has now been replaced by the endoscopic pancreatic function test. New advances in endoscopic ultrasound elastography have also extended the options for evaluating pancreatic masses to differentiate mass-forming chronic pancreatitis from malignancy. Genetic contribution to chronic pancreatitis is also now more widely recognized than ever before.

Reported findings on endoscopic ultrasound examinations for chronic pancreatitis: toward establishing an endoscopic ultrasound quality benchmark

OBJECTIVES

Endoscopic ultrasound (EUS) quality benchmarks for pancreatic disease previously focused on maintaining thresholds of diagnostic accuracy for fine-needle aspiration and measuring complications. We aimed to evaluate quality indicators when performing EUS specifically for the diagnosis of chronic pancreatitis (CP).

METHODS

Using a single-center EUS database, we identified patients who underwent an EUS since 2001 specifically for the indication of (1) suspected CP, (2) exclusion of CP, or (3) established CP. Each EUS report was evaluated for the number of parenchymal and ductal criteria as per minimal standards terminology criteria.

RESULTS

Two hundred eighty-six EUS examinations performed by 4 endosonographers were included. The mean number of reported evaluated parenchymal criteria was 2.44 (median, 2), and that of ductal criteria was 2.41 (median, 2). There was a difference among endosonographers in terms of mean number of total criteria reported evaluated (P < 0.001): endosonographer 1 = 3.9 (n = 174 examinations), endosonographer 2 = 6.8 (n = 86 examinations), endosonographer 3 = 6.2 (n = 13 examinations), and endosonographer 4 = 2.5 (n = 11 examinations). However, there was no difference between endosonographers in the number of total (parenchymal and ductal) criteria found.

CONCLUSIONS

There was a discrepancy among endosonographers when reporting which EUS findings were evaluated in patients undergoing EUS specifically to diagnose CP.

Clinical role of contrast-enhanced harmonic endoscopic ultrasound in differentiating solid lesions of the pancreas: a single-center experience in Korea

Background/Aims

The differential diagnosis of pancreatic solid lesions remains challenging. The aim of this study was to investigate the accuracy of contrast-enhanced harmonic endoscopic ultrasound (CEH-EUS) in differentiating pancreatic cancer from benign lesions.

Methods

We prospectively evaluated 37 patients with pancreatic solid lesions. After intravenous injection of a contrast agent (SonoVue), CEH-EUS was performed using a radial echoendoscope. Pancreatic solid lesions were classified into three vascular patterns (hyperintense, isointense, and hypointense) on the basis of CEH-EUS imaging, and these patterns were compared to the histological diagnosis.

Results

The lesions were hypervascular (n=6), isovascular (n=3), or hypovascular (n=28). Histological diagnosis was confirmed by EUS-FNA in 26 patients (22 adenocarcinomas, two focal pancreatitis, one pancreatic neuroendocrine tumor [NET], and one pancreatic tuberculosis); by surgery in 10 patients (four adenocarcinomas, three pancreatic NETs, two invasive intraductal papillary mucinous neoplasms, and one acinar cell carcinoma); and by both methods in one patient. Among pancreatic carcinomas, 28 out of 30 lesions (93%) had persistent hypovascular signals in the early and late phase, which indicates a sensitivity and diagnostic accuracy of 93% and 92%, respectively for the diagnosis of pancreatic cancer.

Conclusions

CEH-EUS was useful for characterization of pancreatic solid masses with high sensitivity and accuracy.

A comparison of electronic radial and curvilinear endoscopic ultrasonography in the detection of pancreatic malignant tumor

OBJECTIVE

There is no comparative study of electronic radial endoscopic ultrasonography (ER-EUS) and electronic curvilinear EUS (EC-EUS). The aim of this study was to compare the accuracy of ER-EUS and EC-EUS for detecting pancreatic malignancies.

METHODS

This was a retrospective review of the patients who had EUS assessment from September 2008 to December 2011 for suspicious pancreatic tumors. Sensitivity, specificity, and area under the ROC curve to detect pancreatic malignancies were calculated and compared between the ER-EUS and EC-EUS cohort. The final diagnosis of pancreatic malignancy was based on pathology, or the consensus of patient's clinical course and multimodal imaging tests.

RESULTS

Two hundred twenty-one patients were included and divided into two cohorts: ER-EUS (n = 139) and EC-EUS (n = 82) cohorts. With propensity score matching method, 70 cases in each cohort were selected for the comparison. There was no significant difference in sensitivity, specificity, and area under the ROC curve to detect pancreatic malignancy between ER-EUS and EC-EUS cohort (88.5 vs. 100%, 88.6 vs. 90.9%, 0.8855 vs. 0.9545).

CONCLUSION

ER-EUS and EC-EUS provided similar accuracy for the detection of pancreatic malignancies. In view of similar diagnostic results of ER-EUS and EC-EUS for the detection of pancreatic malignancy, and the advantage of being able to perform FNA with EC-EUS, EC-EUS may be the preferred choice.

A convex EUS is useful to diagnose vascular invasion of cancer, especially hepatic hilus cancer

Endoscopic ultrasonography (EUS) has become an indispensable diagnostic procedure pairing endoscopy with transluminal high frequency ultrasonography. EUS provides images with a high resolution such that the depth of tumor invasion can be accurately determined. It also sees lesions outside of gastrointestinal tract, particularly those in pancreas, biliary system and periluminal lymph nodes. The most important limitation of EUS was lack of specificity, that is, the differentiation between benign and malignant lesions. In 1992, EUS-guided fine needle aspiration (EUS-FNA) was introduced with the sampling of a lesion in the pancreatic head using a convex EUS. Since then the indications of EUS-FNA have been expanded to include a variety of therapeutic uses. In addition, a convex EUS probe can also be used for detailed evaluation of the pancreatobiliary system, in lieu of a radial EUS. The vascular structures surrounding liver, biliary system and pancreas can be showed by a convex EUS system very clearly and easily compared with the more familiar radial EUS images. So we think a convex EUS is very useful for not only EUS-FNA but also screening and close examination for cancer with vascular invasion.

Update on the role of endoscopic ultrasound in chronic pancreatitis

Chronic pancreatitis (CP) remains an important healthcare problem that adversely affects quality of life. Endoscopic ultrasound (EUS) is a preferred test for the diagnosis of early CP. The Rosemont classification strictly defines and assigns weighting to the previously described ductal and parenchymal criteria. Recent histological correlation studies have improved our understanding of the accuracy of EUS criteria. Digital imaging analysis and complementary functional testing may complement endosonographic diagnosis. EUS-directed celiac plexus blockade and ductal access techniques have expanded the therapeutic armamentarium for pain management in CP.

Endoscopic ultrasound in chronic pancreatitis: Where are we now?

Endoscopic ultrasonography (EUS) is well suited for assessment of the pancreas due to its high resolution and the proximity of the transducer to the pancreas, avoiding air in the gut. Evaluation of chronic pancreatitis (CP) was an early target for EUS, initially just for diagnosis but later for therapeutic purposes. The diagnosis of CP is still accomplished using the standard scoring based on nine criteria, all considered to be of equal value. For diagnosis of any CP, at least three or four criteria must be fulfilled, but for diagnosis of severe CP at least six criteria are necessary. The Rosemont classification, more restrictive, aims to standardize the criteria and assigns different values to different features, but requires further validation. EUS-fine needle aspiration (EUS-FNA) is less advisable for diagnosis of diffuse CP due to its potential side effects. Elastography and contrast-enhanced EUS are orientation in differentiating a focal pancreatic mass in a parenchyma with features of CP, but they cannot replace EUS-FNA. The usefulness of EUS-guided celiac block for painful CP is still being debated with regard to the best technique and the indications. EUS-guided drainage of pseudocysts is preferred in non-bulging pseudocysts or in the presence of portal hypertension. EUS-guided drainage of the main pancreatic duct should be reserved for cases in which endoscopic retrograde cholangiopancreatography has failed owing to difficult cannulation of the papilla or difficult endotherapy. It should be performed only by highly skilled endoscopists, due to the high rate of complications.

Endoscopic ultrasound for the diagnosis of chronic pancreatitis

Endoscopic ultrasound (EUS) has become a well accepted test for the diagnosis of chronic pancreatitis. Advantages include its ability to detect subtle and severe changes of the pancreatic duct and parenchyma, and its relative safety compared with endoscopic retrograde cholangiopancreatography. Limitations include inter- and intra-observer variability, operator dependence, and an incomplete understanding of its true accuracy. The Rosemont classification has recently been proposed as a weighted, standardized method that may improve EUS chronic pancreatitis scoring. This paper reviews the published evidence regarding the accuracy of EUS in chronic pancreatitis diagnosis, and enumerates the emerging technologies that have been recently studied which may ultimately improve endosonographic imaging of the pancreas.