Differential EUS findings in focal type 1 autoimmune pancreatitis and pancreatic cancer: A proof-of-concept study

The Role of Endoscopic Ultrasound and Ancillary Techniques in the Diagnosis of Autoimmune Pancreatitis: A Comprehensive Review

Autoimmune pancreatitis (AIP) is a unique form of chronic pancreatitis with a multifactorial pathogenesis. Historically, it has been classified as type 1 and type 2, according to its clinical and histological features. The diagnosis of AIP is challenging and relies on a combination of clinical, histopathologic, serologic, and imaging characteristics. In the available guidelines, the imaging hallmarks of AIP are based on cross-sectional imaging and cholangiopancreatography retrograde endoscopic findings. Endoscopic ultrasound (EUS) is generally used for pancreatic tissue acquisition to rule out pancreatic cancer and diagnose AIP with limited accuracy. Several papers reported the reliability of EUS for providing informative morphologic features of AIP. Nowadays, the improvement in the resolution of EUS conventional images and the development of new ancillary technologies have further increased the diagnostic yield of EUS: contrast-enhanced EUS and EUS elastography are non-invasive and real-time techniques that strongly support the diagnosis and management of pancreatic diseases. In this review article, we will present the role of conventional EUS and ancillary diagnostic techniques in the diagnosis of AIP to support clinicians and endosonographers in managing this condition.

Quantitative evaluation of endobronchial ultrasound elastography in the diagnosis of benign and malignant mediastinal and hilar lymph nodes

OBJECTIVE

To compare the diagnostic value of different quantitative methods of endobronchial ultrasound elastography in benign and malignant mediastinal and hilar lymph nodes.

METHODS

This retrospective study included patients who underwent endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for mediastinal and hilar lymph node enlargement in our hospital between January 2019 and August 2022. We compared different quantitative elastography parameters [red area ratio (RAR, lymph node red area/lymph node area), green area ratio (GAR, lymph node green area/lymph node area), blue area ratio (SAR, lymph node blue area/lymph node area), mixed area ratio (MAR, lymph node green area/lymph node area), blue-green lymph node area/lymph node area), strain rate ratio (SR), strain rate in the target lymph node (LPA), ratio of blue area to total lymph node area outside the center of the target lymph node (PAR), and average grey value (MGV)], in order to find the best quantitative evaluation method.

RESULTS

A total of 244 patients (346 lymph nodes) were included in this study. All quantitative elastography parameters were statistically significant for the differentiation of benign and malignant lesions except the average grey value of the target lymph nodes. The area under the receiver operating characteristic curve of SAR was 0.872 (95% confidence interval: 0.83-0.91), the cutoff value was 0.409, and the sensitivity, specificity, positive and negative predictive values were 85.4%, 78.0%, 80.4%, and 83.4%, respectively.

CONCLUSION

Compared with other types of quantitative analysis, SAR has a higher predictive significance for benign and malignant lymph nodes.

Can serum immunoglobulin G4 levels and age serve as reliable predictors of relapse in autoimmune pancreatitis?

We are writing in response to the paper published in the World Journal of Gastroenterology by Zhou et al. The authors identified higher serum immunoglobulin (Ig) G4 levels and age over 55 years as independent risk factors for disease relapse. Despite notable strengths, it is crucial to address potential biases. Firstly, the cohort study included 189 patients with autoimmune pancreatitis (AIP) type 1 (with higher IgG4 seropositivity and higher relapse) and 24 with type 2 (with lower IgG4 seropositivity and lower relapse). Consequently, most, if not all, AIP type 2 patients were assigned to the normal group, possibly inflating the association of higher serum IgG4 levels with relapse and potentially exaggerating the association of older age with relapse. Secondly, the authors did not provide sufficient details regarding AIP diagnosis, such as the ratio of definitive vs probable cases and the proportion of biopsies. In cases where histological evidence is unavailable or indeterminate, AIP type 2 may be misdiagnosed as definitive type 1, and type 1 may also be misdiagnosed as probable type 2, particularly in cases with normal or mildly elevated serum IgG4 levels. Lastly, in this retrospective study, approximately one-third of the consecutive patients initially collected were excluded for various reasons. Accordingly, the impact of non-random exclusion on relapse outcomes should be carefully considered. In conclusion, the paper by Zhou et al offers plausible, though not entirely compelling, evidence suggesting a predictive role of elevated serum IgG4 levels and advanced age in AIP relapse. The foundation for future investigations lies in ensuring a reliable diagnosis and accurate disease subtyping, heavily dependent on obtaining histological specimens. In this regard, endoscopic ultrasound-guided fine-needle biopsy emerges as a pivotal component of the diagnostic process, contributing to mitigating biases in future explorations of the disease.

Diagnostic Differentiation between Pancreatitis and Pancreatic Cancer: A Scoping Review

Pancreatitis, encompassing acute and chronic forms, and pancreatic cancer pose significant challenges to the exocrine tissue of the pancreas. Recurrence rates and complications following acute pancreatitis episodes can lead to long-term risks, including diabetes mellitus. Chronic pancreatitis can develop in approximately 15% of cases, regardless of the initial episode's severity. Alcohol-induced pancreatitis, idiopathic causes, cigarette smoking, and hereditary pancreatitis contribute to the progression to chronic pancreatitis. Chronic pancreatitis is associated with an increased risk of pancreatic cancer, with older age at onset and smoking identified as risk factors. This scoping review aims to synthesise recent publications (2017-2022) on the diagnostic differentiation between pancreatitis and pancreatic cancer while identifying knowledge gaps in the field. The review focuses on biomarkers and imaging techniques in individuals with pancreatitis and pancreatic cancer. Promising biomarkers such as faecal elastase-1 and specific chemokines offer non-invasive ways to assess pancreatic insufficiency and detect early biomarkers for chronic pancreatitis. Imaging techniques, including computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasound (EUS), and positron emission tomography (PET), aid in differentiating between chronic pancreatitis and pancreatic cancer. However, accurately distinguishing between the two conditions remains a challenge, particularly when a mass is present in the head of the pancreas. Several knowledge gaps persist despite advancements in understanding the association between pancreatitis and pancreatic cancer, including the correlation between histopathological grading systems, non-invasive imaging techniques, and biomarkers in chronic pancreatitis to determine the risk of progression to pancreatic cancer, as well as differentiating between the two conditions. Further research is necessary to enhance our understanding of these aspects, which can ultimately improve the diagnosis and management of pancreatitis and pancreatic cancer.

Applications and Prospects of Artificial Intelligence-Assisted Endoscopic Ultrasound in Digestive System Diseases

Endoscopic ultrasound (EUS) has emerged as a widely utilized tool in the diagnosis of digestive diseases. In recent years, the potential of artificial intelligence (AI) in healthcare has been gradually recognized, and its superiority in the field of EUS is becoming apparent. Machine learning (ML) and deep learning (DL) are the two main AI algorithms. This paper aims to outline the applications and prospects of artificial intelligence-assisted endoscopic ultrasound (EUS-AI) in digestive diseases over the past decade. The results demonstrated that EUS-AI has shown superiority or at least equivalence to traditional methods in the diagnosis, prognosis, and quality control of subepithelial lesions, early esophageal cancer, early gastric cancer, and pancreatic diseases including pancreatic cystic lesions, autoimmune pancreatitis, and pancreatic cancer. The implementation of EUS-AI has opened up new avenues for individualized precision medicine and has introduced novel diagnostic and treatment approaches for digestive diseases.

Evaluating the role of endoscopic ultrasound in pancreatitis

INTRODUCTION

Endoscopic ultrasound (EUS) provides high-resolution images of both pancreatic parenchyma and duct and therefore is an integral component of evaluating and treating patients with pancreatitis and its complications. The development of enhanced EUS imaging techniques and newer EUS-specific accessories has expanded the diagnostic and therapeutic role of EUS in patients with acute and chronic pancreatitis (CP).

AREAS COVERED

This review discusses the current diagnostic and therapeutic role of EUS in acute pancreatitis (AP), CP, and autoimmune pancreatitis (AIP).

EXPERT OPINION

EUS plays a vital role in patients with AP by confirming the presence of common bile duct (CBD) stones in patients with acute biliary pancreatitis and intermediate probability of CBD stones. It plays an important role in the etiological evaluation of patients with idiopathic acute and recurrent pancreatitis. EUS is also an essential modality for diagnosing and managing pancreatico-biliary as well as gastroduodenal complications associated with CP. EUS-guided FNB using newer generation core biopsy needles has made possible accurate diagnosis of AIP by providing tissue samples with preserved architecture.