Imaging of pancreas divisum by linear-array endoscopic ultrasonography

Superiority of linear-array EUS over MRCP in diagnosing pancreas divisum: evidence from a multicenter retrospective study in Oriental cohorts (with video)

BACKGROUND AND AIMS

Pancreas divisum (PD) is the most common developmental anatomic variant of pancreatic duct. The published data on the accuracy of the detection of PD by means of linear-array endoscopic ultrasound (L-EUS) is limited. This study aimed to assess the diagnostic accuracy of L-EUS compared with magnetic resonance cholangiopancreatography (MRCP) for identifying PD.

METHODS

Patients who underwent L-EUS for pancreaticobiliary indications and subsequently received endoscopic retrograde pancreatograghy (ERP) treatment were retrospectively evaluated from January 2019 to July 2023.

RESULTS

A total of 1378 patients from 3 tertiary centers were included, of which 120 were diagnosed with PD, as confirmed with the use of ERP, yielding an endoscopic detection rate of 8.7%. L-EUS exhibited a high sensitivity of 90.8% (95% confidence interval [CI], 85.7%-96.0%) and an overall accuracy of 99% (95% CI, 98.5%-99.5%) for the diagnosis of PD. These figures were significantly superior to those of MRCP, which showed a sensitivity of 48.4% (95% CI, 38.1%-58.6%) and an accuracy of 95.4% (95% CI, 93.5%-96.3%) (P < .001). Furthermore, the area under the receiver operating characteristic curve (AUC) for PD diagnosis was notably higher for L-EUS (95.7%) compared with MRCP (74.1%) (P < .001). Consistency testing revealed that L-EUS had an excellent kappa value of 0.934, compared with the reference standard of 0.621. Univariate logistic regression analysis identified the presence of pancreatic duct stones, chronic pancreatitis, and severe pancreatitis as potential factors leading to diagnostic failure in detecting PD with the use of L-EUS. Subsequent multivariate logistic regression analysis confirmed that the presence of pancreatic duct stones (odds ratio [OR], 5.627; 95% CI, 1.391-22.765) and severe pancreatitis (OR, 12.818; 95% CI, 2.280-72.061) were significantly associated with increased odds of L-EUS diagnostic failure for PD.

CONCLUSIONS

Our study conclusively demonstrates that L-EUS significantly outperforms MRCP in diagnosing PD. L-EUS exhibits markedly higher sensitivity and AUC values. However, its diagnostic reliability decreases in the presence of pancreatic duct stones or severe pancreatitis.

Endoscopic Ultrasound in Pancreatic Duct Anomalies

Embryological development of the pancreas is a complex phenomenon and, therefore, it can have multiple developmental aberrations. Fortunately, the majority of these pancreatic ductal anomalies are asymptomatic with no clinical relevance and are incidentally detected during diagnostic cross-sectional imaging or endoscopic retrograde cholangiopancreatography (ERCP) or autopsy. Occasionally, pancreatic duct anomalies can result in symptoms like abdominal pain or recurrent pancreatitis. Also, an accurate pre-operative diagnosis of ductal anomalies can prevent inadvertent duct injury during surgery. Conventionally, ERCP had been used for an accurate diagnosis of pancreatic duct anomalies. However, because it is invasive and associated with a risk of pancreatitis, it has been replaced with magnetic resonance cholangiopancreatography (MRCP). MRCP has demonstrated high sensitivity and specificity for the diagnosis of ductal anomalies, which can be further improved with the use of secretin-enhanced MRCP. Endoscopic ultrasound (EUS) is a new diagnostic and interventional tool in the armamentarium of endoscopists and has demonstrated promising results in the detection of pancreatic duct variations and anomalies. Along with the visualization of the course and configuration of the pancreatic duct, EUS can also visualize changes in the pancreatic parenchyma, thereby helping with an early diagnosis of any co-existent pancreatic disease. Absence of the stack sign and crossed duct sign are important EUS features to diagnose pancreas divisum. EUS can also help with the diagnosis of other congenital ductal anomalies like annular pancreas, ansa pancreatica, and anomalous pancreaticobiliary union, although the published experience is limited.

Diagnostic Endoscopic Ultrasound in Pancreatology: Focus on Normal Variants and Pancreatic Masses

Background

Endoscopic ultrasound (EUS) is a main tool in gastroenterology for both diagnosis and exclusion of pancreatic pathology. It allows minimally invasive assessment of various diseases or anatomic variations affecting the pancreas also with the help of new Doppler technologies, elastography, contrast-enhanced imaging including post hoc image processing with quantification analyses, three-dimensional reconstruction, and artificial intelligence. EUS also allows interventional direct access to the pancreatic parenchyma and the retroperitoneal space, to the pancreatic duct, pancreatic masses, cysts, and vascular structures.

Summary

This review aimed to summarize new developments of EUS in the field of pancreatology. We highlight the role of EUS in evaluating pancreatic pathology by describing normal anatomic variants like pancreas divisum, pancreatic lipomatosis, pancreatic fibrosis in the elderly and characterizing pancreatic masses, both in the context of chronic pancreatitis and within healthy pancreatic parenchyma. EUS is considered the optimal imaging modality for pancreatic masses of uncertain dignity and allows both cytological diagnosis and histology, which is essential not only for neoplastic conditions but also for tailoring therapy for benign inflammatory conditions.

Key Messages

EUS plays an indispensable role in pancreatology and the development of new diagnostic and interventional approaches to the retroperitoneal space and the pancreas exponentially increased over the last years. The development of computer-aided diagnosis and artificial intelligence algorithms hold the potential to overcome the obstacles associated with interobserver variability and will most likely support decision-making in the management of pancreatic disease.

Anatomical pancreatic variants in intraductal papillary mucinous neoplasm patients: a cross-sectional study

Background

No previous studies have examined the possible relationship between intraductal papillary mucinous neoplasm (IPMN) and the developmental ductal variations of the pancreas, such as an ansa pancreatica and a meandering main pancreatic duct (MMPD).

Methods

This retrospective cross-sectional study enrolled 214 patients, 108 with IPMN disease and 106 subjects from a community at the tertiary care unit. The main pancreatic duct (MPD) was evaluated in the head of the pancreas by its course, which were non-MMPD: descending, vertical, and sigmoid, or MMPD including loop types, reverse-Z subtypes, and an N-shape, which was identified for the first time in this study. IPMN patients were also evaluated for worrisome features (WF) or high-risk stigmata (HRS), and the extent of IPMN cysts.

Results

Among IPMN patients, 18.4% had MMPD, which we observed in only 3.0% of the control group (P < 0.001). Patients with MMPD were more likely to belong to the IPMN group compared with non-MMPD patients [odds ratio (OR) 6.4, 95% confidence interval (CI) 2.2–24.9]. Compared with a descending shape MPD, IPMN patients with an N-shaped MPD were more likely to have a cystic mural nodule (OR 5.9, 95% CI 1.02–36.0). The presence of ansa pancreatica associated with more extent IPMN disease (OR 12.8, 95% CI 2.6–127.7).

Conclusions

IPMN patients exhibited an MMPD more often than control patients. Ansa pancreatica associated with multiple cysts. Furthermore, an N-shape in IPMN patients associated with cystic mural nodules, suggesting that this shape serves as a risk factor for more severe IPMN.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02465-w.

[Pancreas divisum and pancreatitis]

CLINICAL/METHODOLOGICAL ISSUE

Diagnostic and clinical relevance of pancreas divisum.

STANDARD RADIOLOGICAL METHODS

Ultrasonography (US), magnetic resonance cholangiopancreatography (MRCP), magnetic resonance imaging (MRI), computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP).

PERFORMANCE

Pancreas divisum is an anatomic variation of pancreatic duct system with an incidence in general population of about 10%. It can become symptomatic in approximately 5% of patients. MRI with MRCP is the method of choice to diagnose pancreas divisum.

ACHIEVEMENTS

MRCP is equal to ERCP in diagnosing pancreas divisum in routine clinical practice as it is noninvasive, offers the possibility to evaluate the adjacent tissues and has almost no contraindications.

PRACTICAL RECOMMENDATIONS

It is important to be familiar with the anatomy of the pancreatic duct system in order to plan interventional procedures for symptomatic patients in due time.

Identification and management of pancreas divisum

Introduction: Pancreas divisum is the most common congenital malformation of the pancreas with the majority asymptomatic. The etiological role, pathogenesis, clinical significance and management of pancreas divisum in pancreatic disease has not been clearly defined and our understanding is yet to be fully elucidated.Areas covered: This review describes the role of pancreas divisum in the development of pancreatic disease and the ambiguity related to it. In our attempt to offer clarity, a comprehensive search on PubMed, Ovid, Embase and Cochrane Library from inception to May 2019 was undertaken using key words "pancreas divisum", "idiopathic recurrent acute pancreatitis" and "chronic pancreatitis".Expert opinion: Current research fails to define a clear association between pancreas divisum and pancreatic disease. Though debatable, several studies do suggest a pathological role of pancreas divisum in pancreatic disease and a benefit of minor papilla therapy in the setting of acute recurrent pancreatitis. Surgical and endoscopic therapeutic modalities have not been directly compared. With the current data available, it would be imprudent to advise a definitive line of management for pancreatic disease associated with pancreas divisum and should involve a comprehensive discussion with the individual patient to define expectations before embarking on any medical and/or interventional therapy.

Acute management of pancreatitis: the key to best outcomes

Acute pancreatitis (AP) accounts for over 230 000 US and 28 000 UK hospital admissions annually. Abdominal pain is the most common presenting symptom in AP but may not reflect severity. The clinical challenge is identifying the 20% of patients in whom AP will be severe. We summarise the common aetiologies, the risk stratification strategies including the simplified Bedside Index for Severity in Acute Pancreatitis, acute management approaches in the initial presentation setting, conditions for using advance imaging and opinions on antibiotic use. Some warning signs of impending complications are also discussed.

Evaluation and management of acute pancreatitis

Acute pancreatitis (AP) is one of the most common gastrointestinal causes for hospi-talization in the United States. In 2015, AP accounted for approximately 390000 hospitalizations. The burden of AP is only expected to increase over time. Despite recent advances in medicine, pancreatitis continues to be associated with a substantial morbidity and mortality. The most common cause of AP is gallstones, followed closely by alcohol use. The diagnosis of pancreatitis is established with any two of three following criteria: (1) Abdominal pain consistent with that of AP; (2) Serum amylase and/or lipase greater than three times the upper limit of normal; and (3) Characteristics findings seen in cross-sectional abdominal imaging. Multiple criteria and scoring systems have been established for assessing severity of AP. The cornerstones of management include aggressive intravenous hydration, appropriate nutrition and pain management. Endoscopic retrograde cholangiopancreatography and surgery are important aspects in management of acute gallstone pancreatitis. We provide a comprehensive review of evaluation and management of AP.

Pancreas divisum: a reemerging risk factor for pancreatic diseases

Pancreas divisum (PD) is the most common developmental anatomic variant of pancreatic duct. The attention towards the PD has grown significantly since there are reports that this condition may cause acute relapsing pancreatitis, chronic pancreatitis and chronic abdominal pain syndrome. Furthermore, over the years, there have been multiple reports of PD associated with different types of tumors. There is evidence that PD can be associated with pancreatic tumors (up to 12.5% of cases). The golden standard for diagnosing PD is endoscopic retrograde cholangiopancreatography, but since it is an invasive procedure magnetic resonance cholangiopancreatography with secretin is a good alternative. In case the patient is symptomatic, endoscopic or surgical treatment should be performed. This review describes the key points of the pathophysiology, diagnostic modalities, risks of pancreatitis and tumors, as well as treatment options of PD.

Imaging of gall bladder by endoscopic ultrasound

Endoscopic ultrasonography (EUS) is considered a superior investigation when compared to conventional ultrasonography for imaging gall bladder (GB) lesions as it can provide high-resolution images of small lesions with higher ultrasound frequencies. Examination of GB is frequently the primary indication of EUS imaging. Imaging during EUS may not remain restricted to one station and multi-station imaging may provide useful information. This review describes the techniques of imaging of GB by linear EUS from three different stations. The basic difference of imaging between the three stations is that effective imaging from station 1 is done above the neck of GB, from station 2 at the level of the neck of GB and from station 3 below the level of the neck of GB.

Present status and perspectives of endosonography 2017 in gastroenterology

Endoscopic ultrasound has become an essential tool in modern gastroenterology and abdominal surgery. Compared with all other endoscopic methods, it has the most potential for innovation and its future looks bright. Thus, we compiled this summary of established and novel applications of endoscopic ultrasound methods to inform the reader about what is already possible and where future developments will lead in improving patient care further. This review is structured in four parts. The first section reports on developments in diagnostic endoscopic ultrasound, the second looks at semi-invasive endoscopic ultrasound, and the third discusses advances in therapeutic endoscopic ultrasound. An overview on the future prospects of endoscopic ultrasound methods concludes this article.

Role of endoscopic ultrasound in idiopathic pancreatitis

Recurrent acute pancreatitis (RAP) is defined based on the occurrence of two or more episodes of acute pancreatitis. The initial evaluation fails to detect the cause of RAP in 10%-30% of patients, whose condition is classified as idiopathic RAP (IRAP). Idiopathic acute pancreatitis (IAP) is a diagnostic challenge for gastroenterologists. In view of associated morbidity and mortality, it is important to determine the aetiology of pancreatitis to provide early treatment and prevent recurrence. Endoscopic ultrasound (EUS) is an investigation of choice for imaging of pancreas and biliary tract. In view of high diagnostic accuracy and safety of EUS, a EUS based management strategy appears to be a reasonable approach for evaluation of patients with a single/recurrent idiopathic pancreatitis. The most common diagnoses by EUS in IAP is biliary tract disease. The present review aims to discuss the role of EUS in the clinical management and diagnosis of patients with IAP. It elaborates the diagnostic approach to IAP in relation to EUS and other different modalities. Controversial issues in IAP like when to perform EUS, whether to perform after first episode or recurrent episodes, comparison among different investigations and the latest evidence significance are detailed.