Feasibility and usefulness of endoscopic ultrasonography-guided shear-wave measurement for assessment of autoimmune pancreatitis activity: a prospective exploratory study

Diagnostic accuracy of endoscopic ultrasonographic shear wave elastography for assessing early chronic pancreatitis using the Japanese diagnostic criteria 2019

Background and Aim

Endoscopic ultrasound shear wave elastography (EUS-SWE) can facilitate an objective evaluation of pancreatic fibrosis. Although it is primarily applied in evaluating chronic pancreatitis, its efficacy in assessing early chronic pancreatitis (ECP) remains underinvestigated. This study evaluated the diagnostic accuracy of EUS-SWE for assessing ECP diagnosed using the Japanese diagnostic criteria 2019.

Methods

In total, 657 patients underwent EUS-SWE. Propensity score matching was used, and the participants were classified into the ECP and normal groups. ECP was diagnosed using the Japanese diagnostic criteria 2019. Pancreatic stiffness was assessed based on velocity (Vs) on EUS-SWE, and the optimal Vs cutoff value for ECP diagnosis was determined. A practical shear wave Vs value of ≥50% was considered significant.

Results

Each group included 22 patients. The ECP group had higher pancreatic stiffness than the normal group (2.31 ± 0.67 m/s vs. 1.59 ± 0.40 m/s, p < 0.001). The Vs cutoff value for the diagnostic accuracy of ECP, as determined using the receiver operating characteristic curve, was 2.24m/s, with an area under the curve of 0.82 (95% confidence interval: 0.69-0.94). A high Vs was strongly correlated with the number of EUS findings (rs = 0.626, p < 0.001). Multiple regression analysis revealed that a history of acute pancreatitis and ≥2 EUS findings were independent predictors of a high Vs.

Conclusions

There is a strong correlation between EUS-SWE findings and the Japanese diagnostic criteria 2019 for ECP. Hence, EUS-SWE can be an objective and invaluable diagnostic tool for ECP diagnosis.

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.

Autoimmune pancreatitis: Cornerstones and future perspectives

Autoimmune pancreatitis (AIP) is an autoimmune subtype of chronic pancreatitis resulting from the aberrant immune response against the pancreas, leading to inflammation and fibrosis. Although AIP is rare, its incidence is increasing and is often misdiagnosed as other pancreatic diseases. AIP is commonly classified into two types. Type 1 AIP (AIP-1) is typically associated with elevated serum immunoglobulin G4 (IgG4) levels and systemic manifestations, while type 2 AIP is typically a more localized form of the disease, and may coexist with other autoimmune disorders, especially inflammatory bowel diseases. Additionally, there is emerging recognition of a third type (type 3 AIP), which refers to immunotherapy-triggered AIP, although this classification is still gaining acceptance in medical literature. The clinical manifestations of AIP mainly include painless jaundice and weight loss. Elevated serum IgG4 levels are particularly characteristic of AIP-1. Diagnosis relies on a combination of clinical, laboratory, radiological, and histological findings, given the similarity of AIP symptoms to other pancreatic disorders. The mainstay of treatment for AIP is steroid therapy, which is effective in most cases. Severe cases might require additional imm-unosuppressive agents. This review aims to summarize the current knowledge of AIP, encompassing its epidemiology, etiology, clinical presentation, diagnosis, and treatment options. We also address the challenges and controversies in diagnosing and treating AIP, such as distinguishing it from pancreatic cancer and managing long-term treatment, highlighting the need for increased awareness and knowledge of this complex disease.

The diagnostic accuracy of endoscopic ultrasound-shear wave elastography in multiple pancreatic regions for chronic pancreatitis based on the Rosemont criteria

PURPOSE

Although endoscopic ultrasound (EUS) has been widely used for diagnosing chronic pancreatitis (CP), the assessment of fibrosis using the Rosemont criteria (RC) is generally subjective. Shear wave elastography using EUS (EUS-SWE) has been advocated as an objective approach to evaluating pancreatic fibrosis; however, it is unknown which pancreatic region should be selected for measurement. This study aims to compare the diagnostic accuracy in diagnosing CP by measurement site.

METHODS

Fifty patients with CP or suspected CP who underwent EUS-SWE were retrospectively analyzed. As per the RC, they were classified into two groups: CP and non-CP. Pancreatic stiffness was evaluated by measuring the velocities of the shear wave (Vs) in addition to determining the relevant cutoff value of Vs for diagnosing CP. The correlation between Vs and RC, and the RC factors affecting pancreatic stiffness were evaluated.

RESULTS

In the CP group, the Vs were notably higher in all regions (P < 0.001). The Vs for diagnostic accuracy of CP were highest in the body [area under the curve (AUC): 0.87]. A significant correlation was seen between the number of RC and Vs in all regions, with the correlation coefficient being highest in the pancreatic body (rs = 0.55). Multivariate analysis revealed that lobularity with honeycombing was an independent factor for pancreatic stiffness (P = 0.02).

CONCLUSION

The pancreatic body is a suitable region for assessing pancreatic stiffness using EUS-SWE. Additionally, quantifying Vs is a valuable objective indicator for diagnosing CP.

Focal Type 2 Autoimmune Pancreatitis Mimicking Pancreatic Cancer: Treatment with Neoadjuvant Chemotherapy and Surgery

A 51-year-old man was referred to our hospital for the further examination of main pancreatic duct interruption. Imaging findings showed a 25-mm-diameter mass lesion located in the pancreatic head. Endoscopic ultrasonography (EUS)-guided fine-needle aspiration (FNA) was performed on the mass. Cytology suggested adenocarcinoma, but the histological diagnosis was not confirmed. We made a comprehensive diagnosis of resectable pancreatic cancer. The mass shrank after preoperative adjuvant chemotherapy, and the patient underwent surgery. The final pathological diagnosis was type 2 autoimmune pancreatitis (AIP). Two years after surgery, AIP had not recurred in the remaining pancreas.

Release of liposomally formulated near-infrared fluorescent probes included in giant cluster vesicles by ultrasound irradiation

Detection of tumors and regional lymph nodes during surgery has been proposed in the diagnosis of lymphatic metastasis and the surgical treatment of malignant diseases. Giant cluster vesicles (GCVs), including liposomally formulated indocyanine green (LP-ICG) derivatives, are a possible candidate for agents to realize the two contradictory properties, i.e., retention in tissue for lesion-marking and trace for sentinel lymph nodes (SLNs) identification. We attempted to release the LP-ICG derivatives from GCVs using ultrasound contrast agents (UCAs) under ultrasound irradiation. An absorption spectrophotometer quantitatively evaluated the amounts of released LP-ICG derivatives. As a result, we demonstrated that it depended on conditions for sound pressure, burst length, and number density of UCAs, and had a sound pressure threshold independent of burst length and number density of UCAs. The results will aid to determine appropriate conditions to maximize the released amount of LP-ICG derivatives while keeping safety.

Diagnosing chronic pancreatitis by endoscopic ultrasound assessing the association between ultrasound and pathological findings: A narrative review

Endoscopic ultrasound (EUS) is widely recognized for its non‐invasiveness and for its usefulness in chronic pancreatitis (CP) diagnosis, including early CP. Although it is desirable to obtain a definitive diagnosis of CP by tissue sampling with EUS‐guided fine needle aspiration, histopathological changes in CP are heterogeneous in terms of the extent and the distribution of lesions. Therefore, histopathological diagnosis of appropriate tissue sampling by EUS‐fine needle aspiration is expected to be difficult. Furthermore, it is virtually impossible to match EUS images with pathological sections, making direct contrast between EUS findings and pathology difficult. This narrative review presents a discussion of the diagnosis of CP/early CP by EUS, particularly assessing the association between ultrasound and pathological findings. Recently, the histological corroboration and correlation of EUS findings related to CP have been clarified by surgical specimens, including those obtained from animal studies. Furthermore, remarkable advances have occurred in the objective and quantitative diagnosis of pancreatic fibrosis by EUS‐elastography. Future technological advances in EUS are expected to improve the accuracy of diagnosis of pancreatic fibrosis at earlier stages.

IgG4-related autoimmune liver disease

The term IgG4-related autoimmune liver disease (AILD) refers to hepato-biliary manifestations of Immunoglobin G4-related disease (IgG4-RD) including IgG4-related sclerosing cholangitis and IgG4-related pseudotumor. The association of some forms of autoimmune hepatitis to IgG4-RD remains controversial. Although autoimmune phenomena have not been clearly observed in IgG4-AILD, perturbation of the adaptive immune system and activation of the humoral response represent established pathophysiological hallmarks and potential therapeutic targets. Clinical manifestations of IgG4-AILD are virtually indistinguishable from bile duct cancer or primary sclerosing cholangitis and are due to mass forming lesions and thickening of the biliary tract that progressively lead to biliary ducts obstruction. There are no current reliable biomarkers for IgG4-AILD and diagnosis should rely on the integration of clinical, serological, radiological, and histological findings. In analogy to most IgG4-RD manifestations, and in contrast to its major mimickers, IgG4-AILD promptly responds to glucocorticoids but frequently relapses, thus requiring long-term maintenance therapy to avoid progressive fibrosclerotic disease and liver cirrhosis. Accumulating evidence on the efficacy of B-cell depletion therapy in patients with systemic IgG4-RD is gradually changing the treatment paradigm of IgG4-AILD and biologics will be increasingly used also for gastroenterological manifestations of IgG4-RD to spare glucocorticoids and traditional immunosuppressive agents. Looking ahead, identification of reliable biomarkers and of mini-invasive strategies to obtain informative biopsies from the biliary tree represent unavoidable priorities to optimize diagnosis and management of IgG4-AILD.

Endoscopic Ultrasound Guided Shear Wave Elastography Is Safe With High Feasibility and Reproducibility When Used in the Pancreas: Findings From a Prospective Cohort

OBJECTIVES

The aim of this study was to assess the safety, feasibility, and reproducibility of endoscopic ultrasound shear wave elastography (EUS-SWE) in the pancreas.

METHODS

This is a prospective registry of consecutive patients undergoing clinically indicated EUS. Ten readings of SWE velocities (Vs [distance/time, m/s]) were obtained in the head (HOP), body, and tail of pancreas to quantify tissue stiffness. Each Vs score was accompanied by a reliability measurement VsN (%) with VsN >50% considered reliable. Safety was evaluated by perioperative complications rate. Feasibility was determined by technical success of obtaining measurements. Reproducibility was evaluated using intraclass correlation coefficient analysis.

RESULTS

Total of 3320 EUS-SWE measurements were performed on 117 patients without perioperative complications. Measurement success rate was 100% across all locations. Reliable measurements were more common in the HOP (953/1120 [85.1%]) followed by body (853/1130 [75.5%]) and tail of pancreas (687/1070 [64.2%]) (P < 0.001). The analysis showed good reproducibility in all locations (intraclass correlation coefficient range, 0.80-0.89).

CONCLUSIONS

Endoscopic ultrasound-SWE is safe, has 100% technical success rate, and is highly reproducible when used in the pancreas. Our study suggests that SWE measurements in the HOP offer the highest reliability, likely because of large study area and less respiratory artifact.

Comparative accuracy of endosonographic shear wave elastography and transcutaneous liver stiffness measurement: a pilot study

BACKGROUND AND AIMS

Vibration-controlled transient elastography (VCTE) is a validated test for assessing liver fibrosis but may be unreliable in select patients, including those with morbid obesity. The limitations of VCTE may be overcome by EUS-guided shear wave elastography (EUS-SWE).

METHODS

This single-center, prospective, nonrandomized tandem study compared the diagnostic accuracy of EUS-SWE and VCTE in consecutive patients undergoing liver biopsy sampling because of unreliable noninvasive testing. EUS-SWE of the left and right lobes were separately performed and then compared with VCTE. Liver elasticity cutoffs for different stages of fibrosis were estimated in 3 ways: optimized sensitivity and specificity using the Youden index; and with sensitivity and specificity fixed at 90% each, Diagnostic accuracy for fibrosis was compared with liver histology using the area under the receiver-operating characteristic curve (AUROC). The primary outcome was the diagnostic accuracy of EUS-SWE for advanced fibrosis. Secondary outcomes were diagnostic accuracy of VCTE, EUS-SWE for left and right hepatic lobes for significant/advanced fibrosis, and cirrhosis.

RESULTS

Forty-two patients (39 men, aged 54.5 ± 12.1 years) underwent EUS-SWE, VCTE, and liver biopsy sampling. The cross-validated AUROCs for advanced fibrosis were as follows: VCTE, .87 (95% confidence interval [CI], .76-.97); EUS-SWE left lobe, .8 (95% CI, .64-.96); and EUS-SWE right lobe, .78 (95% CI, .62-.95). The corresponding AUROCs for cirrhosis were as follows: VCTE, .9 (95% CI, .83-.97); EUS-SWE left lobe, .96 (95% CI, .9-1); and EUS-SWE right lobe, .9 (95% CI, .8-1). VCTE was unreliable in 8 patients who successfully underwent EUS-SWE. There was no statistically significant difference in the AUROCs for EUS-SWE and VCTE.

CONCLUSIONS

EUS-SWE correlates well with liver histology and is a safe and reliable diagnostic test for assessing liver fibrosis with accuracy comparable with VCTE. (Clinical trial registration number: NCT04533932.).

Ultrasound Shear Wave Elastography of Normal Pancreas in Adult Subjects

Background and Purpose Transabdominal ultrasound (US)-based shear wave elastography (SWE) provides an attractive method of estimating pancreatic stiffness. There is limited data on the SWE values of the healthy pancreas in Indian subjects. The current study aimed to evaluate SWE of the normal pancreas.

Methods We performed a study from January 2019 to March 2019. We included adult patients who presented for the US of the upper abdomen for vague abdominal symptoms, unrelated to the pancreas. The SWE values were obtained from the pancreatic head and body. The association of pancreatic SWE with age, gender, fatty liver, chronic liver disease, and cholelithiasis was recorded.

Results During the study period, 205 subjects underwent SWE of the pancreas. The mean age of subjects was 41.3 (standard deviation [SD] 15.3) years. There were 93 males and 112 females. The mean SWE value in the head of the pancreas was 8.98 (SD 2.46 kPa), and that in the body region was 8.67 (SD 2.67 kPa). There was a positive correlation of SWE with age. The SWE of the pancreatic body was significantly higher in patients who had a fatty liver on US (p < 0.05). There was no significant association of SWE of the pancreas with gender, presence of chronic liver disease, or gallstones.

Conclusion The normal values of pancreatic SWE are correlated with age and fatty change in the liver.

Two-dimensional shear wave elastography of the pancreas: measurement success rate, repeatability, and factors affecting measurement values

PURPOSE

We aimed to evaluate the success rate, repeatability, and factors affecting the measurement values of two-dimensional ultrasonic shear wave elastography (2D-SWE) for measuring pancreatic stiffness.

METHODS

This prospective study recruited 100 healthy participants. 2D-SWE was performed on the pancreatic head, body, and tail. We compared the success rates of pancreatic stiffness measurements of different body positions and ultrasonic scans, with and without probe pressurization, as well as the effects of sex, age, body mass index (BMI), and region of interest (ROI) depth on measurement values. Intra- and inter-operator repeatabilities were assessed in 20 participants. The influence of ROI depth was verified using a tissue-like phantom.

RESULTS

The median 2D-SWE measurements of the pancreatic head, body, and tail were 1.44, 1.45, and 1.56 m/s, respectively. The success rates for the pancreatic head and body were significantly higher than that of the tail. The success rate for the semi-recumbent position was higher than that of the supine position (P < 0.001). The intra-operator values for same-day and inter-operator reliability were excellent. Univariate analyses showed that probe pressurization, age, BMI, and ROI depth were correlated with pancreatic shear wave velocity (SWV) (P < 0.05); only ROI depth had a significant effect on SWV values. The inclusion phantom showed that the SWV value increased as the ROI depth increased.

CONCLUSIONS

2D-SWE had a high success rate and good repeatability for measuring pancreatic head and body stiffness. The ROI depth was the main factor affecting pancreatic SWV, which increased with ROI depth.

Current status of the diagnosis of chronic pancreatitis by ultrasonographic elastography

Chronic pancreatitis (CP) is pathologically characterized by the loss of exocrine pancreatic parenchyma, irregular fibrosis, cellular infiltration, and ductal abnormalities. Diagnosing CP objectively is difficult because standard diagnostic criteria are insufficient. The change of parenchymal hardness is the key factor for the diagnosis and understanding of the severity of CP. The ultrasonography (US) or endoscopic ultrasonography (EUS) elastography have been used to diagnose pancreatic diseases. Both strain elastography (SE) and shear wave elastography are specific diagnostic techniques for measuring tissue hardness. Most previous studies were conducted with SE. There are three methods of interpreting SE; the method of recognizing the patterns in SE distribution images in the region of interest, the method of using strain ratio to compare the hardness of adipose tissue or connective tissue with that of the lesion, and the method of evaluating the hardness distribution of a target by histogram analysis. These former two methods have been used primarily for neoplastic diseases, and histograms analysis has been used to assess hardness distribution in the evaluation of CP. Since the hardness of the pancreas increases with aging, it is necessary to consider the age in the diagnosis of pancreatic disorders using US or EUS elastography.

Imaging diagnosis of autoimmune pancreatitis using endoscopic ultrasonography

The diagnosis of autoimmune pancreatitis (AIP) is challenging and should be achieved through the comprehensive evaluation of clinical, radiological, serological, and pathological evidence, as there is currently no single reliable diagnostic modality. Endoscopic ultrasonography (EUS) can reveal pancreatic parenchymal and ductal features in much more detail than any other existing imaging modality. In this article, we focused on three applications of EUS, i.e., conventional EUS imaging, EUS elastography (EUS-EG), and contrast-enhanced harmonic EUS (CEH-EUS), for the diagnosis of AIP. Diffuse hypoechoic areas, diffuse enlargement, bile duct wall thickening, and peripancreatic hypoechoic margins on conventional EUS are characteristic features of AIP, and the frequencies of these findings are significantly higher in AIP than in pancreatic cancer (PC). EUS-EG of the pancreatic parenchyma in AIP showed homogenous stiffness and that the elasticity of the pancreas may change after steroid therapy. CEH-EUS revealed focal or diffuse iso-enhancement in most AIP cases and hypo-enhancement in most PC cases. However, some AIP cases show a contrast enhancement pattern similar to that of PC. It should be noted that EUS findings of AIP may differ depending on its stage or disease activity. Differentiation from PC has become an increasingly important issue in the process of diagnosing AIP, and EUS, including elastography and contrast enhancement, could be a promising imaging modality for this purpose.

Role of transabdominal ultrasound in the diagnosis of autoimmune pancreatitis

The most important thing in the diagnosis of autoimmune pancreatitis (AIP) is to suspect the possibility of AIP. In the acute phase, diffuse pancreatic enlargement is a highly specific finding of AIP compared to focal enlargement. Though the sensitivity is low, high-frequency transducers can detect the capsule-like rim sign and penetrating duct sign. Those findings are characteristic of AIP and useful for differential diagnosis with pancreatic carcinoma. In focal AIP, both contrast-enhanced US showing iso/hypervascularity and elastography showing increased stiffness not only in the focal enlargement but also in the surrounding parenchyma are also useful for differential diagnosis. Furthermore, changes over time after the two-week steroid trial, such as resolution or measurable reduction in parenchymal enlargement and a decrease in the mean shear-wave velocity on elastography, are also cardinal features of AIP. Since AIP is a pancreatic manifestation in immunoglobulin G4-related disease, evaluation of other organs, including the biliary tract and salivary glands, is particularly useful in focal AIP. A characteristic US finding of bile ducts is three-layered (high-low-high pattern) wall thickening with a markedly thickened middle layer. US can also detect wall thickening of bile ducts, which show no abnormalities on cholangiography. These findings are useful for differential diagnosis with cholangiocarcinoma. Multiple hypoechoic areas in submandibular glands are characteristic US findings of sialadenitis in type 1 AIP, and the sensitivity is higher than that of physical examination. US can further contribute to the diagnosis of AIP by employing elastography and contrast-enhanced US in addition to high-frequency transducers.

Impact of endoscopic ultrasound elastography in pancreatic lesion evaluation

Pancreatic malignancy still becomes a major global problem and is considered as one of the most lethal cancers in the field of gastroenterology. Most patients come in the late stage of the disease due to organ’s location, and until now the treatment result is still far away from satisfaction. Early detection is still the main key for good, prolonged survival. However, discerning from other types of tumor sometimes is not easy. Endoscopic ultrasound (EUS) is still the best tool for pancreatic assessment, whereas fine-needle aspiration biopsy (FNAB) is considered as the cornerstone for further management of pancreatic malignancy. Several conditions have become a concern for EUS-FNAB procedure, such as risk of bleeding, pancreatitis, and even needle track-seeding. Recently, an artificial intelligence innovation, such as EUS elastography has been developed to improve diagnostic accuracy in pancreatic lesions evaluation. Studies have shown the promising results of EUS elastography in improving diagnostic accuracy, as well as discerning from other tumor types. However, more studies are still needed with further considerations, such as adequate operator training, expertise, availability, and its cost-effectiveness in comparison to other imaging options.

Recent Advances in Endosonography-Elastography: Literature Review

Ultrasonographic elastography is a modality used to visualize the elastic properties of tissues. Technological advances in ultrasound equipment have supported the evaluation of elastography (EG) in endosonography (EUS). Currently, the usefulness of not only EUS-strain elastography (EUS-SE) but also EUS-shear wave elastography (EUS-SWE) has been reported. We reviewed the literature on the usefulness of EUS-EG for various diseases such as chronic pancreatitis, pancreatic solid lesion, autoimmune pancreatitis, lymph node, and gastrointestinal and subepithelial lesions. The importance of this new diagnostic parameter, "tissue elasticity" in clinical practice might be applied not only to the diagnosis of liver fibrosis but also to the elucidation of the pathogeneses of various gastrointestinal diseases, including pancreatic diseases, and to the evaluation of therapeutic effects. The most important feature of EUS-EG is that it is a non-invasive modality. This is an advantage not found in EUS-guided fine needle aspiration (EUS-FNA), which has made remarkable progress in the field of diagnostics in recent years. Further development of artificial intelligence (AI) is expected to improve the diagnostic performance of EUS-EG. Future research on EUS-EG is anticipated.

Diagnostic performance of endoscopic ultrasonography-guided elastography for solid pancreatic lesions: Shear-wave measurements versus strain elastography with histogram analysis

BACKGROUND AND AIMS

Endoscopic ultrasound (EUS) elastography (EUS-EG) is a minimally invasive diagnostic method for evaluating tissue elasticity. The aim of this study was to evaluate the feasibility of newly developed EUS shear-wave measurement (EUS-SWM) and to compare diagnostic performance between EUS-SWM and the conventional strain elastography (SE) for the measurement of elasticity of solid pancreatic lesions (SPLs).

METHODS

From December 2017 until August 2019, we retrospectively reviewed 64 consecutive cases with SPLs who underwent both EUS-SWM and SE. EUS-SWM was used to measure the shear-wave velocity, Vs (m/s), and the unique measurement reliability index, VsN (%), in the target lesion. SE images were assessed by strain histogram (SH) analysis, and the mean strain value of the elasticity index was measured. We evaluated the diagnostic performance of EUS-SWM and SE with SH to characterize the SPLs.

RESULTS

The Vs (m/s) values of SPLs were 2.19 for pancreatic cancer (PC), 1.31 for pancreatic neuroendocrine neoplasm (PanNEN), 2.56 for mass-forming pancreatitis (MFP) and 1.58 for metastatic tumors. Vs showed no significant difference based on the disease. The mean strain values were 45.5 for PC, 47.3 for PanNEN, and 74.5 for MFP. In the comparison of tissue elasticity between PC and MFP, Vs showed no significant difference (P = 0.5687); however, the mean strain value was significantly lower in PC cases (45.4 vs 74.5: P = 0.0007).

CONCLUSION

Endoscopic ultrasound SWM tended to be unstable for the measurement of elasticity of SPLs, and conventional SE with SH was superior for their characterization.

Imaging diagnosis of autoimmune pancreatitis: computed tomography and magnetic resonance imaging

Autoimmune pancreatitis (AIP) is a pancreatic phenotype of IgG4-related systemic disease. Since its first description in the literature, characteristic imaging features have gradually become known to many clinicians encompassing various specialties in the past quarter century. CT and MRI have been the workhorses for imaging diagnosis of AIP. Typical features include sausage-like swelling of the focal or entire pancreas, duct-penetrating sign, a capsule-like rim of the affected lesions, and homogeneous delayed enhancement or enhanced duct sign after contrast administration, as well as characteristic combined findings reflecting coexisting pathologies in the other organs as a systemic disease. In this review, recent and future developments in CT and MRI that may help diagnose AIP are discussed, including restricted diffusion and perfusion and increased elasticity measured using MR.

Do we need elastography for EUS?

We recently introduced a series of papers “What should be known prior to performing EUS exams.” In Part I, the authors discussed which clinical information and whether other imaging modalities are needed before embarking EUS examinations. In Part II, technical controversies on how EUS is performed were discussed from different points of view. In this article, important practical issues regarding EUS elastography will be raised and controversially discussed from very different points of view.

Steroid Therapy and Steroid Response in Autoimmune Pancreatitis

Autoimmune pancreatitis (AIP), a unique subtype of pancreatitis, is often accompanied by systemic inflammatory disorders. AIP is classified into two distinct subtypes on the basis of the histological subtype: immunoglobulin G4 (IgG4)-related lymphoplasmacytic sclerosing pancreatitis (type 1) and idiopathic duct-centric pancreatitis (type 2). Type 1 AIP is often accompanied by systemic lesions, biliary strictures, hepatic inflammatory pseudotumors, interstitial pneumonia and nephritis, dacryoadenitis, and sialadenitis. Type 2 AIP is associated with inflammatory bowel diseases in approximately 30% of cases. Standard therapy for AIP is oral corticosteroid administration. Steroid treatment is generally indicated for symptomatic cases and is exceptionally applied for cases with diagnostic difficulty (diagnostic steroid trial) after a negative workup for malignancy. More than 90% of patients respond to steroid treatment within 1 month, and most within 2 weeks. The steroid response can be confirmed on clinical images (computed tomography, ultrasonography, endoscopic ultrasonography, magnetic resonance imaging, and 18F-fluorodeoxyglucose-positron emission tomography). Hence, the steroid response is included as an optional diagnostic item of AIP. Steroid treatment results in normalization of serological markers, including IgG4. Short- and long-term corticosteroid treatment may induce adverse events, including chronic glycometabolism, obesity, an immunocompromised status against infection, cataracts, glaucoma, osteoporosis, and myopathy. AIP is common in old age and is often associated with diabetes mellitus (33-78%). Thus, there is an argument for corticosteroid therapy in diabetes patients with no symptoms. With low-dose steroid treatment or treatment withdrawal, there is a high incidence of AIP recurrence (24-52%). Therefore, there is a need for long-term steroid maintenance therapy and/or steroid-sparing agents (immunomodulators and rituximab). Corticosteroids play a critical role in the diagnosis and treatment of AIP.

Role of transabdominal ultrasonography in the diagnosis of pancreatic cystic lesions

Pancreatic cystic lesions (PCLs) are incidental findings that are being increasingly identified because of recent advancements in abdominal imaging technologies. PCLs include different entities, with each of them having a peculiar biological behavior, and they range from benign to premalignant or malignant neoplasms. Therefore, accurate diagnosis is important to determine the best treatment strategy. As transabdominal ultrasonography (US) is noninvasive, inexpensive, and widely available, it is considered to be the most appropriate imaging modality for the initial evaluation of abdominal diseases, including PCLs, and for follow-up assessment. We present a review of the possibilities and limits of US in the diagnosis of PCLs, the technical development of US, and the ultrasonographic characteristics of PCLs.