Diagnostic ability and factors affecting accuracy of endoscopic ultrasound-guided fine needle aspiration for pancreatic solid lesions: Japanese large single center experience

The role of needle-based confocal laser endomicroscopy in the diagnosis of pancreatic neuroendocrine tumors

BACKGROUND/AIMS

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a highly accurate method for diagnosing pancreatic neuroendocrine tumors (PNETs); however, some PNETs are difficult to diagnose. Recently, the efficacy of needle-based confocal laser endomicroscopy (nCLE) in diagnosing solid pancreatic masses has been reported. However, the efficacy of nCLE in the diagnosis of PNETs remains unknown and only a small number of cases have been reported. Hence, this study aimed to evaluate the efficacy of nCLE in the diagnosis of PNETs.

METHODS

This single-center retrospective study evaluated 30 consecutive patients with suspected PNETs on contrast-enhanced computed tomography, who consented to nCLE combined with EUS-FNA and were diagnosed using EUS-FNA or surgical resection. The diagnostic criteria for PNETs using nCLE were based on the nesting and trabecular and glandular arrangement of tumor cell clusters surrounded by capillary vessels and fibrosis, as reported in previous studies.

RESULTS

The diagnosis using nCLE was classified into three categories: misdiagnosis in three cases (10%), non-diagnostic in six cases (20%), and diagnostic in 21 cases (70%). nCLE was able to diagnose PNET in one of the two cases with inconclusive EUS-FNA.

CONCLUSIONS

Although further development of the resolution and optimization of the diagnostic criteria are required, nCLE may constitute a useful diagnostic option in cases of inconclusive EUS-FNA for PNETs.

Endoscopic ultrasound-guided tissue acquisition for comprehensive genomic profiling

Advances in next-generation sequencing have made comprehensive genomic profiling (CGP) using tumor tissue specimens and liquid biopsy using blood samples feasible in routine clinical practice. In the context of pancreaticobiliary cancer, it is necessary to consider CGP in formulating individualized treatment strategies. Performing CGP with tumor tissue specimens requires a sufficient number of high-quality samples. EUS-guided tissue acquisition (EUS-TA) is expected to play a significant role in this regard, and endosonographers need to address this role. Here, we review the current status of EUS-TA for CGP focusing on pancreatic cancer and biliary tract cancer.

Current status of artificial intelligence analysis for the treatment of pancreaticobiliary diseases using endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography

Pancreatic and biliary diseases encompass a range of conditions requiring accurate diagnosis for appropriate treatment strategies. This diagnosis relies heavily on imaging techniques like endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography. Artificial intelligence (AI), including machine learning and deep learning, is becoming integral in medical imaging and diagnostics, such as the detection of colorectal polyps. AI shows great potential in diagnosing pancreatobiliary diseases. Unlike machine learning, which requires feature extraction and selection, deep learning can utilize images directly as input. Accurate evaluation of AI performance is a complex task due to varied terminologies, evaluation methods, and development stages. Essential aspects of AI evaluation involve defining the AI's purpose, choosing appropriate gold standards, deciding on the validation phase, and selecting reliable validation methods. AI, particularly deep learning, is increasingly employed in endoscopic ultrasonography and endoscopic retrograde cholangiopancreatography diagnostics, achieving high accuracy levels in detecting and classifying various pancreatobiliary diseases. The AI often performs better than doctors, even in tasks like differentiating benign from malignant pancreatic tumors, cysts, and subepithelial lesions, identifying gallbladder lesions, assessing endoscopic retrograde cholangiopancreatography difficulty, and evaluating the biliary strictures. The potential for AI in diagnosing pancreatobiliary diseases, especially where other modalities have limitations, is considerable. However, a crucial constraint is the need for extensive, high-quality annotated data for AI training. Future advances in AI, such as large language models, promise further applications in the medical field.

EUS-FNA versus EUS-FNB in Pancreatic Solid Lesions ≤ 15 mm

A small tumor size may impact the diagnostic performance of endoscopic ultrasound-guided tissue acquisition (EUS-TA) for diagnosing solid pancreatic lesions (SPLs). We aimed to compare the diagnostic yield of EUS-guided fine-needle aspiration (FNA) and biopsy (FNB) in SPLs with a diameter ≤ 15 mm. Consecutive patients who underwent EUS-TA for SPLs ≤ 15 mm between January 2015 and December 2022 in a tertiary referral center were retrospectively evaluated. The primary endpoint was diagnostic accuracy. The final diagnosis was based on surgical pathology or disease evolution after a minimum follow-up of 6 months. Inadequate samples were all considered false negatives for the study. Secondary outcomes included sample adequacy, factors impacting accuracy, and safety. We included 368 patients (52.4% male; mean age: 60.2 years) who underwent FNA in 72 cases and FNB in 296. The mean size of SPLs was 11.9 ± 2.6 mm. More than three passes were performed in 5.7% and 61.5% of patients in the FNB and FNA groups, respectively (p < 0.0001). FNB outperformed FNA in terms of diagnostic accuracy (89.8% vs. 79.1%, p = 0.013) and sample adequacy (95.9% vs. 86.1%, p < 0.001). On multivariate analysis, using FNA (OR: 2.10, 95% CI: 1.07-4.48) and a final diagnosis (OR: 3.56, 95% CI: 1.82-6.94) of benign conditions negatively impacted accuracy. Overall, the adverse event rate was 0.8%, including one pancreatitis in the FNA group and one pancreatitis and one bleeding in the FNB group, all mild and conservatively managed. EUS-TA for SPLs ≤ 15 mm has a high diagnostic yield and safety. This study suggests the superiority of FNB over FNA, with better performance even with fewer passes performed.

Avoid non-diagnostic EUS-FNA: a DNN model as a possible gatekeeper to distinguish pancreatic lesions prone to inconclusive biopsy

OBJECTIVE

This work aimed to explore the utility of CT radiomics with machine learning for distinguishing the pancreatic lesions prone to non-diagnostic ultrasound-guided fine-needle aspiration (EUS-FNA).

METHODS

498 patients with pancreatic EUS-FNA were retrospectively reviewed [Development cohort: 147 pancreatic ductal adenocarcinoma (PDAC); Validation cohort: 37 PDAC]. Pancreatic lesions not PDAC were also tested exploratively. Radiomics extracted from contrast-enhanced CT was integrated with deep neural networks (DNN) after dimension reduction. The receiver operating characteristic (ROC) curve, and decision curve analysis (DCA) were performed for model evaluation. And, the explainability of the DNN model was analyzed by integrated gradients.

RESULTS

The DNN model was effective in distinguishing PDAC lesions prone to non-diagnostic EUS-FNA (Development cohort: AUC = 0.821, 95% CI: 0.742-0.900; Validation cohort: AUC = 0.745, 95% CI: 0.534-0.956). In all cohorts, the DNN model showed better utility than the logistic model based on traditional lesion characteristics with NRI >0 (p < 0.05). And, the DNN model had net benefits of 21.6% at the risk threshold of 0.60 in the validation cohort. As for the model explainability, gray-level co-occurrence matrix (GLCM) features contributed the most averagely and the first-order features were the most important in the sum attribution.

CONCLUSION

The CT radiomics-based DNN model can be a useful auxiliary tool for distinguishing the pancreatic lesions prone to nondiagnostic EUS-FNA and provide alerts for endoscopists preoperatively to reduce unnecessary EUS-FNA.

ADVANCES IN KNOWLEDGE

This is the first investigation into the utility of CT radiomics-based machine learning in avoiding non-diagnostic EUS-FNA for patients with pancreatic masses and providing potential pre-operative assistance for endoscopists.

Safety and Diagnostic Yield of Endoscopic Ultrasound-Guided Fine-Needle Biopsy for Hypervascular Pancreatic Lesions

Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) is a common technique for diagnosing pancreatic lesions with high accuracy and a low incidence of procedural adverse events. However, occasional adverse events, particularly bleeding, may occur. Procedures for hypervascular lesions are considered important, but their risks are unknown. We aimed to evaluate the safety and diagnostic yield of EUS-FNB for hypervascular pancreatic solid lesions. This study included 301 patients with 308 solid pancreatic lesions who underwent EUS-FNB between May 2011 and December 2018. We performed propensity-score matching to balance clinical differences between hypervascular and hypovascular lesions and analyzed 52 lesions. We compared the safety and diagnostic performance of propensity score-matched cohorts. The sensitivity, specificity, and accuracy rates of EUS-FNB for hypervascular lesions were 94.7%, 100%, and 96.2%, and those for hypovascular lesions were 80.0%, 100%, and 84.6%, respectively. There was no difference in diagnostic performance between hypervascular and hypovascular lesions. Furthermore, adverse events occurred in only one patient (pancreatitis) in the hypovascular group. There were no significant differences in the occurrence of adverse events between hypervascular and hypovascular lesions (0% vs. 3.8%, p = 1.000). Therefore, EUS-FNB may be safe with a high diagnostic yield, even for hypervascular solid pancreatic lesions.

Diagnostic performance of endoscopic tissue acquisition for pancreatic ductal adenocarcinoma in the PREOPANC and PREOPANC-2 trials

BACKGROUND

Neoadjuvant treatment for pancreatic ductal adenocarcinoma (PDAC) has increased, necessitating histopathologic confirmation of cancer. This study evaluates the performance of endoscopic tissue acquisition (TA) procedures for borderline resectable and resectable PDAC.

METHODS

Pathology reports of patients included in two nationwide randomized controlled trials (PREOPANC and PREOPANC-2) were reviewed. The primary outcome was sensitivity for malignancy (SFM), considering both "suspicious for" and "malignant" as positive. Secondary outcomes were rate of adequate sampling (RAS) and diagnoses other than PDAC.

RESULTS

Overall, 892 endoscopic procedures were performed in 617 patients, including endoscopic ultrasonography (EUS)-guided TA in 550 (89.1%), endoscopic retrograde cholangiopancreatography (ERCP)-guided brush cytology in 188 (30.5%), and periampullary biopsies in 61 patients (9.9%). The SFM was 85.2% for EUS, 88.2% for repeat EUS, 52.7% for ERCP, and 37.7% for periampullary biopsies. The RAS ranged 94-100%. Diagnoses other than PDAC were other periampullary cancers in 24 (5.4%), premalignant disease in five (1.1%), and pancreatitis in three patients (0.7%).

CONCLUSIONS

EUS-guided TA of patients with borderline resectable and resectable PDAC included in RCTs had an SFM above 85% for both first and repeat procedures, meeting international standards. Two percent had false positive result for malignancy and 5% had other (non-PDAC) periampullary cancers.

Diagnostic Ability and Safety of Repeated Pancreatic Juice Cytology Using an Endoscopic Nasopancreatic Drainage Catheter for Pancreatic Ductal Adenocarcinoma: A Multicenter Prospective Study

Pathological examination is essential for the diagnosis and treatment of pancreatic ductal adenocarcinoma (PDAC). Moreover, a reliable pathological diagnosis is extremely important for improving prognosis, especially in early-stage PDAC. This study prospectively evaluated the usefulness of repeated pancreatic juice cytology (PJC) using an endoscopic nasopancreatic drainage (ENPD) catheter for the diagnosis of PDAC. We enrolled 82 patients suspected of having resectable PDAC, based on imaging studies, and judged the necessity for cytology. The diagnostic yield of up to six repeated PJCs and the incidence of complications, such as pancreatitis, was evaluated. A total of 60 patients were diagnosed with PDAC. The overall sensitivity and specificity were 46.7% and 95.5%, respectively. The cumulative positivity rate increased with the number of sampling sessions, reaching 58.3% in the sixth session. The sensitivity was significantly higher in the pancreatic head than in the pancreatic tail (p = 0.043). Additionally, it was 100% in four patients with a tumor size ≤10 mm. Pancreatitis occurred in six patients (7.3%), all of whom were treated conservatively. In the diagnosis of PDAC, repeated PJC using an ENPD catheter revealed a cumulative effect of sensitivity up to six times and an excellent diagnostic yield for small PDAC.

Efficacy of endoscopic ultrasound-guided tissue acquisition for solid pancreatic lesions 20 mm or less in diameter suspected as neuroendocrine tumors or requiring differentiation

BACKGROUND

For non-functioning pancreatic neuroendocrine tumors (pNETs) ≤ 20 mm, most guidelines consider follow-up observations as an option; however, the various treatment strategies are defined by size alone, even though the Ki-67 index is important for malignancy grading. Endoscopic ultrasound-guided tissue acquisition (EUS-TA) is the standard for the histopathological diagnosis of solid pancreatic lesions; however, recent results for small lesions remain unclear. Therefore, we examined the efficacy of EUS-TA for solid pancreatic lesions ≤ 20 mm suspected as pNETs or requiring differentiation and the non-increase rate in tumor size in follow-up cases.

METHODS

We retrospectively analyzed data of 111 patients (median age = 58 years) with lesions ≤ 20 mm suspected as pNETs or requiring differentiation who underwent EUS-TA. All patients underwent specimen evaluation by rapid onsite evaluation (ROSE).

RESULTS

EUS-TA led to a diagnosis of pNETs in 77 patients (69.4%) and tumors other than pNETs in 22 patients (19.8%). The histopathological diagnostic accuracy of EUS-TA was 89.2% (99/111) overall, 94.3% (50/53) for 10-20 mm lesions, and 84.5% (49/58) for ≤ 10 mm lesions, with no significant difference in diagnostic accuracy (p = 0.13). The Ki-67 index was measurable in all patients with a histopathological diagnosis of pNETs. Among 49 patients with a diagnosis of pNETs who were followed up, one patient (2.0%) showed tumor enlargement.

CONCLUSIONS

EUS-TA for solid pancreatic lesions ≤ 20 mm suspected as pNETs or requiring differentiation is safe and has adequate histopathological diagnostic accuracy, suggesting that follow-up observations of pNETs with a histological pathologic diagnosis are acceptable in the short term.

Clinicopathological study of surgically treated non-neoplastic diseases of the pancreas with special reference to autoimmune pancreatitis

PURPOSE

After the popularization of serum immunoglobulin G4 (IgG4) measurement and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in our institute, surgical resection for non-neoplastic diseases of the pancreas became less common. Although the incidence of such false-positive cases was clarified in the 10-year period after the introduction of these measures (2009-2018), these data were not compared with the 30 years before 2009 (1979-2008). This study was performed to determine the percentage of autoimmune pancreatitis (AIP) that was included during the latter period and how the numbers of false-positive cases differed between the two periods.

METHODS

From 1979 to 2008, 51 patients had clinical suspicion of pancreatic carcinoma (false-positive disease). Among these 51 patients, 32 non-alcoholic patients who had tumor-forming chronic pancreatitis (TFCP) were clinically, histologically, and immunohistochemically compared with 11 patients who had TFCP during the latter 10-year period.

RESULTS

Retrospective IgG4 immunostaining of false-positive TFCP revealed 14 (35.0%) cases of AIP in the former 30 years versus 5 (45.5%) in the latter 10 years. There were 40 (5.9%) cases of TFCP among 675 patients in the former 30 years and 11 (0.9%) among 1289 patients in the latter 10 years.

CONCLUSIONS

When the TFCP ratio of pancreatic resections and the AIP ratio of false-positive TFCPs were compared between the two periods, the TFCP ratio was 5.9% versus 0.9% and the AIP ratio was 35.0% versus 45.5%, respectively. It can thus be speculated that IgG4 measurement and EUS-FNA are absolutely imperative for the diagnosis of TFCP.

Role of Endoscopic Ultrasound-Guided Fine Needle Aspiration (EUS-FNA) in the Diagnosis of Suspicious Malignant Esophageal Strictures

(1) Background: The accurate diagnosis of esophageal strictures is quite critical for optimizing medical intervention. However, the diagnosis of suspicious malignant esophageal strictures with intact mucosa appearance and negative biopsy results is challenging. This study aimed to evaluate the role of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) in the diagnosis of suspicious esophageal strictures. (2) Methods: We retrospectively analyzed the cases with suspicious malignant esophageal strictures that underwent EUS-FNA, with or without rapid on-site evaluation (ROSE), in our hospital from April 2017 to September 2022. Their clinical manifestations, imaging examinations, gastroscopic examinations, EUS-FNA results, and therapeutic strategies were retrospectively recorded and analyzed. (3) Results: A total of 23 patients (15 male and 8 female) were enrolled in this study. Based on EUS-FNA results, 18 patients were diagnosed with malignancies, including 16 cases of primary esophageal cancer (13 squamous carcinomas and 3 adenocarcinomas), 1 case of mediastinal cancer, and 1 case of metastatic esophageal cancer; 1 case of tuberculosis was also confirmed by EUS-FNA. Among 4 cases of ambiguous diagnosis with EUS-FNA, 1 was diagnosed with an esophageal glomus tumor after surgical removal, and 2 patients survived for several years without medical intervention, which hinted at the possibility of benign esophageal strictures. No major complications, including bleeding or perforation, were observed. (4) Conclusions: EUS-FNA may serve as a safe and effective diagnostic tool in suspicious malignant esophageal strictures with accurate specimen acquisition, especially for biopsy-negative cases.

Clinical Features and Prognostic Impact of Pancreatic Ductal Adenocarcinoma without Dilatation of the Main Pancreatic Duct: A Single-Center Retrospective Analysis

The presence of main pancreatic duct (MPD) dilatation is important for diagnosing pancreatic ductal adenocarcinomas (PDACs). However, we occasionally encounter PDAC cases without MPD dilatation. The objectives of this study were to compare the clinical findings and prognosis of pathologically diagnosed PDAC cases with and without MPD dilatation and to extract factors related to the prognosis of PDAC. The 281 patients pathologically diagnosed with PDAC were divided into two groups: the dilatation group (n = 215), consisting of patients with MPD dilatation of 3 mm or more, and the non-dilatation group (n = 66), consisting of patients with MPD dilatation less than 3 mm. We found that the non-dilatation group had more cancers in the pancreatic tail, more advanced disease stage, lower resectability, and worse prognoses than the dilatation group. Clinical stage and history of surgery or chemotherapy were identified as significant prognostic factors for PDAC, while tumor location was not. Endoscopic ultrasonography (EUS), diffusion-weighted magnetic resonance imaging (DW-MRI), and contrast-enhanced computed tomography had a high tumor detection rate for PDAC even in the non-dilatation group. Construction of a diagnostic system centered on EUS and DW-MRI is necessary for the early diagnosis of PDAC without MPD dilatation, which can improve its prognosis.

Artificial intelligence using deep learning analysis of endoscopic ultrasonography images for the differential diagnosis of pancreatic masses

BACKGROUND : There are several types of pancreatic mass, so it is important to distinguish between them before treatment. Artificial intelligence (AI) is a mathematical technique that automates learning and recognition of data patterns. This study aimed to investigate the efficacy of our AI model using endoscopic ultrasonography (EUS) images of multiple types of pancreatic mass (pancreatic ductal adenocarcinoma [PDAC], pancreatic adenosquamous carcinoma [PASC], acinar cell carcinoma [ACC], metastatic pancreatic tumor [MPT], neuroendocrine carcinoma [NEC], neuroendocrine tumor [NET], solid pseudopapillary neoplasm [SPN], chronic pancreatitis, and autoimmune pancreatitis [AIP]). METHODS : Patients who underwent EUS were included in this retrospective study. The included patients were divided into training, validation, and test cohorts. Using these cohorts, an AI model that can distinguish pancreatic carcinomas from noncarcinomatous pancreatic lesions was developed using a deep-learning architecture and the diagnostic performance of the AI model was evaluated. RESULTS : 22 000 images were generated from 933 patients. The area under the curve, sensitivity, specificity, and accuracy (95 %CI) of the AI model for the diagnosis of pancreatic carcinomas in the test cohort were 0.90 (0.84-0.97), 0.94 (0.88-0.98), 0.82 (0.68-0.92), and 0.91 (0.85-0.95), respectively. The per-category sensitivities (95 %CI) of each disease were PDAC 0.96 (0.90-0.99), PASC 1.00 (0.05-1.00), ACC 1.00 (0.22-1.00), MPT 0.33 (0.01-0.91), NEC 1.00 (0.22-1.00), NET 0.93 (0.66-1.00), SPN 1.00 (0.22-1.00), chronic pancreatitis 0.78 (0.52-0.94), and AIP 0.73 (0.39-0.94). CONCLUSIONS : Our developed AI model can distinguish pancreatic carcinomas from noncarcinomatous pancreatic lesions, but external validation is needed.

Current Status of the Diagnosis of Early-Stage Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) can be treated with surgery, chemotherapy, and radiotherapy. Despite medical progress in each field in recent years, it is still insufficient for managing PDAC, and at present, the only curative treatment is surgery. A typical pancreatic cancer is relatively easy to diagnose with imaging. However, it is often not recommended for surgical treatment at the time of diagnosis due to metastatic spread beyond the pancreas. Even if it is operable, it often recurs during postoperative follow-up. In the case of PDAC with a diameter of 10 mm or less, the 5-year survival rate is as good as 80% or more, and the best index for curative treatment is tumor size. The early detection of pancreatic cancer with a diameter of less than 10 mm or carcinoma in situ is critical. Here, we provide an overview of the current status of diagnostic imaging features and genetic tests for the accurate diagnosis of early-stage PDAC.

Usefulness of Adding Maspin Staining to p53 Staining for EUS-FNA Specimens of Pancreatic Ductal Adenocarcinoma

Background: Endoscopic ultrasound-guided puncture aspiration biopsy (EUS-FNA) of pancreatic ductal adenocarcinoma (PDAC) is highly diagnostic, but it is difficult to distinguish from benign disease. Our objective was to determine the usefulness of maspin staining, in addition to conventional p53 staining, in the diagnosis of PDAC by EUS-FNA. Methods: Of the patients who underwent EUS-FNA and were diagnosed with PDAC, we retrospectively identified 90 cases in which both maspin and p53 staining were performed. In addition, we identified 28 cases of benign pancreatic disease diagnosed using EUS-FNA and these were selected as a control group. For analysis of EUS-FNA specimens, Cohen’s Kappa (κ) coefficient and the prevalence and bias adjusted Kappa statistic (PABAK) were applied to assess the significance of sensitivity and specificity, comparing p53, maspin, p53+maspin. Results: The sensitivity and specificity of p53 staining were 48.9% and 100%. The κ coefficient was 0.31 (95%CI 0.18−0.44) (p < 0.01) and the PABAK coefficient was 0.22 (95%CI 0.03−0.40). The results for maspin staining were 88.9% and 92.9%. The κ coefficient was 0.72 (95%CI 0.54−0.90) (p < 0.01) and the PABAK coefficient was 0.78 (95%CI 0.64−0.88). The results for the combination of maspin and p53 staining were 94.4% and 92.2%. The κ coefficient was 0.82 (95%CI 0.64−1.00) (p < 0.01) and the PABAK coefficient was 0.86 (95%CI 0.74−0.94). Conclusion: Adding maspin staining to p53 staining showed high sensitivity and specificity. Our results demonstrated the usefulness of their combined use that might contribute to the improvement of tissue diagnostic performance of PDAC by EUS-FNA.

Early diagnosis of pancreatic cancer: What strategies to avoid a foretold catastrophe

While great strides in improving survival rates have been made for most cancers in recent years, pancreatic ductal adenocarcinoma (PDAC) remains one of the solid tumors with the worst prognosis. PDAC mortality often overlaps with incidence. Surgical resection is the only potentially curative treatment, but it can be performed in a very limited number of cases. In order to improve the prognosis of PDAC, there are ideally two possible ways: the discovery of new strategies or drugs that will make it possible to treat the tumor more successfully or an earlier diagnosis that will allow patients to be operated on at a less advanced stage. The aim of this review was to summarize all the possible strategies available today for the early diagnosis of PDAC and the paths that research needs to take to make this goal ever closer. All the most recent studies on risk factors and screening modalities, new laboratory tests including liquid biopsy, new imaging methods and possible applications of artificial intelligence and machine learning were reviewed and commented on. Unfortunately, in 2022 the results for this type of cancer still remain discouraging, while a catastrophic increase in cases is expected in the coming years. The article was also written with the aim of highlighting the urgency of devoting more attention and resources to this pathology in order to reach a solution that seems more and more unreachable every day.

Tumor Location in the Head/Uncinate Process and Presence of Fibrosis Impair the Adequacy of Endoscopic Ultrasound-Guided Tissue Acquisition of Solid Pancreatic Tumors

Simple Summary

Endoscopic ultrasound-guided tissue acquisition is the most accurate method to diagnose pancreatic tumors; nevertheless, this technique does not always bring adequate diagnostic accuracy. This study aimed to identify which factors can impair its adequacy. Pancreatic cytological and histological aspirates were retrospectively assessed according to two scores for grading the adequacy and the fibrosis of the specimens. The performance of the biopsies was lower when the tumor was located in the head/uncinate process of the pancreas, probably due to the higher fibrosis that we found in these sites. The specimens were less adequate also when <3 needle passes were performed and when the cell block was not done. We demonstrated the benefit to assess the presence of fibrosis in the specimens because it increased the risk of false negative results.

Abstract

Endoscopic ultrasound-guided tissue acquisition (EUS-TA) of solid pancreatic tumors shows optimal specificity despite fair sensitivity, with an overall suboptimal diagnostic yield. We aim to quantify the adequacy and accuracy of EUS-TA and assess predictive factors for success, focusing on the presence and degree of specimen fibrosis. All consecutive EUS-TA procedures were retrieved, and the specimens were graded for sample adequacy and fibrosis. The results were evaluated according to patients’ and tumor characteristics and the EUS-TA technique. In total, 407 patients (59% male, 70 [63–77] year old) were included; sample adequacy and diagnostic accuracy were 90.2% and 94.7%, respectively. Fibrosis was significantly more represented in tumors located in the head/uncinate process (p = 0.001). Tumor location in the head/uncinate (OR 0.37 [0.14–0.99]), number of needle passes ≥ 3 (OR 4.53 [2.22–9.28]), and the use of cell block (OR 8.82 [3.23–23.8]) were independently related to adequacy. Severe fibrosis was independently related to false negative results (OR 8.37 [2.33–30.0]). Pancreatic tumors located in the head/uncinate process showed higher fibrosis, resulting in EUS-TA with lower sample adequacy and diagnostic accuracy. We maintain that three or more needle passes and cell block should be done to increase the diagnostic yield.

Early detection of pancreatic tumors by advanced EUS imaging

The early detection of pancreatic ductal adenocarcinoma (PDAC) dramatically improves outcome. All available state-of-the-art imaging methods allow early detection with EUS being the best technique for exclusion of PDAC and detection of very early PDAC. Etiological differentiation of small SPL is important to guide individually tailored patients' management including radical surgery in resectable PDAC, medical (neoadjuvant or palliative intended) treatment in patients with non-resectable malignancy, pancreatic parenchyma saving strategies in some non-PDAC, and follow-up in particular in low-grade PanNEN or other small benign lesions. Multimodality EUS imaging including B-Mode assessment, elastography, contrast-enhancement and EUS-guided sampling is the most appropriate technique for diagnosis and risk assessment of small SPL. We present a review discussing modern (endoscopic) ultrasound imaging techniques including contrast enhanced ultrasound and elastography for the early detection and characterization of solid pancreatic lesions.

Optimal indication of endoscopic retrograde pancreatography-based cytology in the preoperative pathological diagnosis of pancreatic ductal adenocarcinoma

BACKGROUND

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is extremely useful for pathological diagnosis of pancreatic ductal adenocarcinoma (PDAC); however, puncturing is difficult in some cases, and there is a risk of needle tract seeding. This study evaluated the indications for endoscopic retrograde pancreatography-based (ERP)-based cytology for the preoperative diagnosis of PDAC.

METHODS

This study included 267 patients with PDAC who underwent preoperative ERP. The diagnostic performance of ERP-based cytology for PDAC was evaluated based on the sample collection method (pancreatic juice cytology [PJC] during ERP, brush cytology, PJC via endoscopic nasopancreatic drainage [ENPD] catheter), lesion site (pancreatic head, body/tail), and lesion size (≤10 mm, 10-20 mm, >20 mm), and compared with the diagnostic performance of EUS-FNA.

RESULTS

The overall sensitivity of ERP-based cytology was 54.9%; sensitivity by the sampling method was 34.7% for PJC during ERP, 65.8% for brush cytology, and 30.8% for PJC via an ENPD catheter. The sensitivity of EUS-FNA was 85.3%. Brush cytology and PJC via an ENPD catheter were performed more often in pancreatic body/tail lesions than in head lesions (P = 0.016 and P < 0.001, respectively), and the overall sensitivity of ERP-based cytology was better for body/tail lesions (63.2% vs. 49.0%, P = 0.025). The sensitivities of ERP-based cytology and EUS-FNA in diagnosing PDAC ≤10 mm were 92.3% and 33.3%, respectively. Post-ERP pancreatitis was observed in 22 patients (8.2%) and significantly less common with ENPD catheters (P = 0.002).

CONCLUSIONS

ERP-based cytology may be considered the first choice for pathological diagnosis of PDAC ≤10 mm and in the pancreatic body/tail.

Endoscopic ultrasonography‐guided tissue acquisition for small solid pancreatic lesions: Does the size matter?

Endoscopic ultrasonography‐guided tissue acquisition (EUS‐TA) is now an established technique to obtain the pathological diagnosis of solid pancreatic lesions (SPLs), but the diagnosis of small SPLS by EUS‐TA can still be difficult. We conducted a literature review and a meta‐analysis on the diagnostic yield of EUS‐TA according to the tumor size. In a meta‐analysis of 33 studies with 6883 cases, a pooled odds ratio (OR) of sensitivity was significantly higher in SPLs of >20 mm (OR 1.64, p = 0.02) and in SPLs of >10 mm (OR 3.05, p = 0.01), but not in SPLs of >30 mm (OR 1.18, p = 0.46). The meta‐analysis of accuracy also showed a similar trend: OR of 1.59 in SPLs of >20 mm (p < 0.01) and OR of 3.27 in SPLs of >10 mm (p < 0.01) and OR of 1.03 in SPLs of >30 mm (p = 0.87). The use of a 25‐gauge needle tended to improve sensitivity in small SPLs, though not statistically significant: OR of 1.25 and 2.82 in studies with and without a 25‐gauge needle (p = 0.08). The use of fine needle biopsy needles, slow pull method, and rapid on‐site evaluation did not significantly improve sensitivity in small SPLs. EUS‐TA for small SPLs, especially neuroendocrine neoplasms, is reported to have a high risk of adverse events. In summary, the diagnostic yield and safety of EUS‐TA for small (<20 mm) SPLs still needs improvement, and the best needle and technique for small SPLs should be further investigated.

New image‐processing technology for endoscopic ultrasound‐guided fine‐needle aspiration biopsy specimen evaluation in patients with pancreatic cancer

Objectives

Methods

Results

Conclusion

The diagnostic performance of combined conventional cytology with smears and cell block preparation obtained from endoscopic ultrasound-guided fine needle aspiration for intra-abdominal mass lesions

BACKGROUND/AIM

Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is the primary method for tissue acquisition of intra-abdominal masses. However, the main limitation of cytology alone is the lack of tissue architecture and inadequate samples. This study aimed to evaluate the diagnostic performance of combined conventional cytology and cell block preparation obtained from EUS-FNA of intra-abdominal masses without Rapid On-site Evaluation (ROSE).

METHODS

Cytologic smears and cell block slides of 166 patients undergoing EUS-FNA during 2010-2015 were reviewed by an experienced cytopathologist blinded to clinical data.

RESULTS

125 patients had neoplastic lesions. Pancreatic adenocarcinoma was the most common etiology (35.5%), followed by lymph node metastasis (27.7%). The mean mass size was 2.5±1.3 cm. The mean number of passes was 1.9±1.28. Tissue adequacy for conventional cytology and cell block preparation was 78.9% and 78.1%, respectively. Factors associated with tissue adequacy were assessed. For cytology, lesions of > 2.1 cm, masses in the pancreatic body or tail, malignancy, and pancreatic cancer were positively associated with adequate cellularity. For cell block preparation, lesions of > 3 cm and malignancy were associated with increased tissue adequacy. The conventional cytology alone had a sensitivity of 68.5%, a specificity of 95.7%, and an area under the receiver operating characteristics (AUROC) of 0.821. The cell block preparation alone had a sensitivity of 65.4%, a specificity of 96%, and an AUROC of 0.807. The combined conventional cytology and cell block preparation performed significantly better than either method alone (p<0.05), as demonstrated by an increased AUROC of 0.853. Furthermore, cell block detected malignancy in 9.3% of cases where the cytologic smears failed to identify malignant cells.

CONCLUSIONS

The combined conventional cytology and cell block preparation increased the diagnostic accuracy of EUS-FNA compared to either method alone. This approach should be implemented in routine practice, especially where ROSE is unavailable.

Tissue harmonic versus contrast-enhanced harmonic endoscopic ultrasonography for the diagnosis of pancreatic tumors: Prospective multicenter study

OBJECTIVES

This prospective multicenter study aimed to assess and compare the accuracy of tissue harmonic endoscopic ultrasonography (TH-EUS) and contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) for differentiating pancreatic carcinoma from other pancreatic tumors.

METHODS

Consecutive patients with solid pancreatic tumors were prospectively enrolled between August 2013 and December 2014. To assess the accuracy of TH-EUS and CH-EUS, we compared four parameters of TH-EUS (fuzzy edge, irregular periphery, hypoechogenicity, and heterogeneous internal echogenicity) and four parameters of CH-EUS (hypoenhancement and heterogeneous enhancement in the early and late phases, respectively) to investigate which parameter of each method was most suitable to diagnose pancreatic carcinomas. Interobserver agreement and the diagnostic ability of pancreatic carcinoma using TH-EUS and CH-EUS were assessed and compared.

RESULTS

A total of 204 patients were enrolled. For the diagnosis of pancreatic carcinoma, interobserver agreement by experts and nonexperts was 0.33-0.50 and 0.35-0.50 for TH-EUS, respectively, and 0.72-0.74 and 0.20-0.54 for CH-EUS, respectively. Irregular periphery was the most accurate diagnostic parameter among TH-EUS findings for differentiating pancreatic carcinomas, with sensitivity, specificity, and accuracy of 95.0%, 42.9%, and 78.9%, respectively. Late phase hypoenhancement was the most accurate diagnostic parameter among CH-EUS findings for differentiating pancreatic carcinomas, with sensitivity, specificity, and accuracy of 90.8%, 74.6%, and 85.8%, respectively. The accuracy of CH-EUS (late phase hypoenhancement) for diagnosis of pancreatic carcinoma was significantly higher than that of TH-EUS (irregular periphery) (p < 0.001).

CONCLUSION

In comparison with TH-EUS, CH-EUS increased the diagnostic ability and reproducibility for the diagnosis of pancreatic carcinoma. UMIN (000011124).

Evaluation of preoperative diagnostic methods for resectable pancreatic cancer: a diagnostic capability and impact on the prognosis of endoscopic ultrasound-guided fine needle aspiration

BACKGROUND

A pathological diagnosis of pancreatic cancer should be performed as much as possible to determine the appropriate treatment strategy, but priorities and algorithms for diagnostic methods have not yet been established. In recent years, the endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has become the primary method of collecting tissues from pancreatic disease, but the effect of EUS-FNA on surgical results and prognosis has not been clarified.

AIMS

To evaluate the diagnostic ability of EUS-FNA and its effect on the preoperative diagnosis, surgical outcome, and prognosis of pancreatic cancer.

METHODS

Between January 2005 and June 2017, 293 patients who underwent surgical resection for pancreatic cancer were retrospectively evaluated. The outcomes of interest were the diagnostic ability of EUS-FNA and its influence on the surgical results and prognosis.

RESULTS

The diagnostic sensitivity of EUS-FNA was 94.4%, which was significantly higher than that of endoscopic retrograde cholangiopancreatography (ERCP) (45.5%) (p < 0.001). The adverse event rate in ERCP was 10.2%, which was significantly higher than EUS-FNA (1.3%) (p = 0.001). Patients were divided into FNA group (N = 160) and non-FNA group (N = 133) for each preoperative diagnostic method. In the study of surgical curability R0 between the two groups, there was no significant difference in FNA group (65.0% [104/160]) and non-FNA group (64.7% [86/133], p = 1.000). In the prognostic study, 256 patients with curative R0 or R1 had a recurrence rate was 54.3% (70/129) in the FNA group and 57.4% (73/127) in the non-FNA group. Moreover peritoneal dissemination occurred in 34.3% (24/70) in the FNA group and in 21.9% (16/73) in the non-FNA group, neither of which showed a significant difference. The median survival times of the FNA and non-FNA groups were 955 days and 799 days, respectively, and there was no significant difference between the two groups (log-rank p = 0.735). In the Cox proportional hazards model, factors influencing prognosis, staging, curability, and adjuvant chemotherapy were the dominant factors, but the preoperative diagnostic method (EUS-FNA) itself was not.

CONCLUSIONS

EUS-FNA is a safe procedure with a high diagnostic ability for the preoperative examination of pancreatic cancer. It was considered the first choice without the influence of surgical curability, postoperative recurrence, peritoneal dissemination and prognosis.

Advanced Endoscopic Techniques for the Diagnosis of Pancreatic Cancer and Management of Biliary and GastricOutlet Obstruction

Following high-quality imaging studies for staging, endoscopic ultrasound examination fine needle aspiration/biopsy is the preferred modality for tissue diagnosis of pancreatic cancer. Endoscopic retrograde cholangiopancreatography with metal stent placement is used for palliation of malignant biliary obstruction. Metal stents can be placed in patients with resectable pancreatic cancer in whom surgery is going to be delayed. For palliation of gastric outlet obstruction, endoscopic enteral stenting is often selected because of its less invasiveness. Endoscopic ultrasound-guided biliary drainage for malignant biliary obstruction or gastrojejunostomy for gastric outlet obstruction are emerging less invasive techniques as compared with palliative surgery.

Effectiveness of Menghini-Type Needles for Endoscopic Ultrasound-Guided Fine-Needle Aspiration of Pancreatic Masses

BACKGROUND

Cutting needles are thought to be effective as biopsy needles. A few types of cutting needles are available for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), and the Menghini-type needle is an end-type cutting needle.

AIMS

A prospective randomized controlled trial was conducted to compare the results of EUS-FNA using a Menghini-type needle (needle M) versus a conventional needle (needle S).

METHODS

The main eligibility criteria were as follows: patients with a pancreatic mass referred for EUS-FNA, ≥ 20 years old, and a performance status < 4. The primary outcome was the sample quality. The secondary outcomes were factors associated with the sample quality, diagnostic accuracy, and adverse events.

RESULTS

A total of 97 patients were enrolled in this study. The sample quality for total puncture with needle M (92.8%) was significantly higher than that with needle S (81.4%) (p = 0.0305). The tumor size (p = 0.033) and type of needle (p = 0.031) were significant factors associated with adequate tissue collection in univariate and multivariate analyses (odds ratio [OR] 2.71; 95% confidence interval [CI] 1.12-6.54; p = 0.027 for tumor size, and OR 2.93; 95% CI 1.23-8.21; p = 0.0153 for type of needle). The diagnostic accuracy of each needle was 88.7% (86/97) with needle M and 73.2% (71/97) with needle S. Adverse events occurred in 2 of the 97 patients (0.02%).

CONCLUSION

A Menghini-type needle was able to obtain core tissue for histology more effectively than a conventional aspiration needle.

TRIAL REGISTRATION NUMBERS

UMIN registration number of 000020668.

Diagnostic Performance of EUS-Guided Sampling in Indeterminate Radiological Diagnosis of Pancreatic Disease and Intra-Abdominal Lymphadenopathy

BACKGROUND

Endoscopic ultrasound (EUS)-guided sampling has been widely used for pathologic diagnosis of pancreatic lesions and intra-abdominal lymphadenopathy. However, its effectiveness for diagnostic decision making in indeterminate radiological diagnosis has not been well determined.

MATERIALS AND METHODS

From March 2012 to October 2015, 98 consecutive patients who underwent EUS-guided FNA for solid intra-abdominal lesions were retrospectively analyzed (100 procedures). The purpose of EUS-guided sampling was classified as (1) confirmation of a high-confidence radiological diagnosis (High-confidence group) or (2) decision making in the differential diagnostic dilemma for indeterminate radiological diagnosis (Indeterminate group). The accuracies of EUS-guided sampling according to the purpose were analyzed and then compared.

RESULTS

Of the 100 procedures, 22 procedures (22%) came under the Indeterminate group, whereas 78 came under the High-confidence group. The accuracies did not differ between the Indeterminate and the High-confidence groups (86.4% vs. 88.5%, p = 1.000). Clinical conditions that required EUS-guided sampling for indeterminate radiological diagnosis were (1) pancreatic cancer vs. benign disease (n = 8; e.g., pancreatic cancer vs. mass-forming pancreatitis), (2) recurrence of previous/pre-existing cancer vs. benign disease (n = 5; e.g., recurrent gastric cancer vs. reactive lymph node), (3) pathologic differentiation of presumed malignancy (n = 6; e.g., lymphadenopathies in the previous history of esophageal cancer and colon cancer), or (4) miscellaneous (n = 3; e.g., tuberculous lymphadenopathy vs. other condition).

CONCLUSIONS

EUS-guided sampling demonstrated an accuracy of 86.4% in the clinical setting of indeterminate radiological diagnosis, which was not different from that of the confirmation of high-confidence diagnosis.

Nanotechnology for Cancer Imaging: Advances, Challenges, and Clinical Opportunities

Nanoparticle (NP) imaging applications have the potential to improve cancer diagnostics, therapeutics, and treatment management. In biomedical research and clinical practice, NPs can serve as labels or labeled carriers for monitoring drug delivery or serve as imaging agents for enhanced imaging contrast, as well as providing improved signal sensitivity and specificity for in vivo imaging of molecular and cellular processes. These qualities offer exciting opportunities for NP-based imaging agents to address current limitations in oncologic imaging. Despite substantial advancements in NP design and development, very few NP-based imaging agents have translated into clinics within the past 5 years. This review highlights some promising NP-enabled imaging techniques and their potential to address current clinical cancer imaging limitations. Although most examples provided herein are from the preclinical space, discussed imaging solutions could offer unique in vivo tools to solve biologic questions, improve cancer treatment effectiveness, and inspire clinical translation innovation to improve patient care. Keywords: Molecular Imaging-Cancer, Molecular Imaging-Nanoparticles, Molecular Imaging-Optical Imaging, Metastases, Oncology, Surgery, Treatment Effects.

Endoscopic ultrasound elastography for small solid pancreatic lesions with or without main pancreatic duct dilatation

BACKGROUND

/Objectives: Endoscopic ultrasound elastography (EUS-EG) is useful for diagnosis of small solid pancreatic lesions (SPLs), particularly in excluding pancreatic cancer (PC), but its dependence on main pancreatic duct dilatation (MPDD) has not been examined. We aimed to investigate EUS-EG for diagnosis of small SPLs with and without MPDD.

METHODS

Patients with pathologically diagnosed SPLs of ≤20 mm were included and retrospectively analyzed. Using the blue:green ratio, an EUS-EG image was classified as blue-dominant, equivalent, or green-dominant. Using multiple EUS-EG images per patient, a lesion with a greater number of blue-dominant than green-dominant images was classified as stiff, and the others as soft. EUS-EG images in random order were judged by three raters. Considering stiff SPLs as PC, diagnostic performance of EUS-EG was examined for SPLs with and without MPDD.

RESULTS

Of 126 cases analyzed, 65 (52%) were diagnosed as PC, and 63 (50%) had MPDD. A total of 1077 EUS-EG images were examined (kappa coefficient = 0.783). Lesions were classified as stiff in 91 cases and soft in 35 (kappa coefficient = 0.932). The ratio of stiff to soft lesions was significantly higher in PC than in non-PC (62:3 vs. 29:32, P < 0.001). The sensitivity, specificity, and negative predictive value of a stiff lesion with vs. without MPDD for diagnosis of PC were 94%, 23%, and 50% vs. 100%, 60%, and 100%, respectively.

CONCLUSIONS

Using the EUS-EG stiffness classification for small SPLs, PC can be excluded with high confidence and concordance for a soft lesion without MPDD.

Role of Endoscopic Ultrasonography and Endoscopic Retrograde Cholangiopancreatography in the Diagnosis of Pancreatic Cancer

Pancreatic cancer has the poorest prognosis among all cancers, and early diagnosis is essential for improving the prognosis. Along with radiologic modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), endoscopic modalities play an important role in the diagnosis of pancreatic cancer. This review evaluates the roles of two of those modalities, endoscopic ultrasonography (EUS) and endoscopic retrograde cholangiopancreatography (ERCP), in the diagnosis of pancreatic cancer. EUS can detect pancreatic cancer with higher sensitivity and has excellent sensitivity for the diagnosis of small pancreatic cancer that cannot be detected by other imaging modalities. EUS may be useful for the surveillance of pancreatic cancer in high-risk individuals. Contrast-enhanced EUS and EUS elastography are also useful for differentiating solid pancreatic tumors. In addition, EUS-guided fine needle aspiration shows excellent sensitivity and specificity, even for small pancreatic cancer, and is an essential examination method for the definitive pathological diagnosis and treatment decision strategy. On the other hand, ERCP is invasive and performed less frequently for the purpose of diagnosing pancreatic cancer. However, ERCP is essential in cases that require evaluation of pancreatic duct stricture that may be early pancreatic cancer or those that require differentiation from focal autoimmune pancreatitis.

Evaluation of endoscopic ultrasound-guided fine-needle biopsy for preoperative pancreatic solid lesions

OBJECTIVES

Obtaining an accurate preoperative diagnosis is crucial. This study aimed to evaluate the diagnostic accuracy and utility of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) for preoperative pancreatic solid lesions.

MATERIALS AND METHODS

We retrospectively assessed all patients who underwent endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) or EUS-FNB to evaluate solid pancreatic lesions preoperatively at our center between July 2013 and June 2020. We enrolled 71 patients who underwent EUS-FNA using a 22 G conventional needle (FNA group) and 34 patients who underwent EUS-FNB using a 22 G Franseen needle (FNB group). Overall, 105 patients were analyzed. We employed propensity-matched analysis and adjusted the confounders.

RESULTS

No procedural adverse events were encountered. Both groups showed no significant differences in the procedure time, technical success rate, and rate of operator changes from trainee to expert. Regarding diagnostic accuracy, the FNB group (88.2%; 30/34) was higher but not significantly different from the FNA group (85.3%; 29/34) (p > .99). Furthermore, the FNB group (median 2, IQR;2-3) had a significantly lower number of punctures than the FNA group (median 3, IQR; 2-4) (p = .01).

CONCLUSIONS

The FNB needle provides higher diagnostic accuracy and requires significantly fewer punctures than conventional needles even at facilities with no available rapid on-site evaluation. Thus, using the FNB needle can be useful for preoperative pancreatic solid lesions.

Effectiveness of introducing a 20-gauge core biopsy needle with a core trap in EUS-FNA/B for diagnosing pancreatic cancer

Background

Endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/B) is a standard method for pathological diagnosis of pancreatic solid lesions. The EchoTip ProCore 20G® (PC20), a 20-gauge biopsy needle with a forward-bevel core trap, has been available in Japan since 2015.

Methods

We compared the efficacy of the PC20 with that of the EchoTip ProCore 22G® (PC22) and Acquire 22G® (AC22) in EUS-FNA/B for diagnosing pancreatic cancer. This retrospective study included 191 patients with pancreatic cancer who underwent EUS-FNA/B using the PC20, PC22, or AC22 at our facility from April 2013 to October 2019. We investigated the patients’ clinical characteristics and the diagnostic accuracy and safety of each needle.

Results

A sufficient stroke length of puncture was secured in all patients. The maximum length under EUS was shorter with the AC22 (22.1 ± 2.2 mm) than PC20 (30.6 ± 0.7 mm, p < 0.01) and PC22 (30.3 ± 0.8 mm, p < 0.01). The histological accuracy was 96.4% with the PC20 but only 58.8% with the PC22 (adjusted p (p-adj) < 0.0001) and 75.0% with the AC22 (p-adj = 0.06). The diagnostic accuracy of the combination of histology and cytology was 96.4% with the PC20, while it was 72.1% with the PC22 (p-adj < 0.0001) and 91.7% with the AC22 (p-adj > 0.99). One patient (0.9%) in the PC20 group developed mild pancreatitis, but no adverse events occurred with the other needles.

Conclusions

The PC20 showed better diagnostic capability than the PC22. The diagnostic efficacy was similar between the PC20 and AC22. The high histological accuracy of the PC20 could be advantageous for lesions in which histological assessment is critical.

Current status of artificial intelligence analysis for endoscopic ultrasonography

Endoscopic ultrasonography (EUS) is an essential diagnostic tool for various types of pancreatic diseases such as pancreatic tumors and chronic pancreatitis; however, EUS imaging has low specificity for the diagnosis of pancreatic diseases. Artificial intelligence (AI) is a mathematical prediction technique that automates learning and recognizes patterns in data. This review describes the details and principles of AI and deep learning algorithms. The term AI does not have any definite definition; almost all AI systems fall under narrow AI, which can handle single or limited tasks. Deep learning is based on neural networks, which is a machine learning technique that is widely used in the medical field. Deep learning involves three phases: data collection and annotation, building the deep learning architecture, and training and ability validation. For medical image diagnosis, image classification, object detection, and semantic segmentation are performed. In EUS, AI is used for detecting anatomical features, differential pancreatic tumors, and cysts. For this, conventional machine learning architectures are used, and deep learning architecture has been used in only two reports. Although the diagnostic abilities in these reports were about 85-95%, these were exploratory research and very few reports have included substantial evidence. AI is increasingly being used for medical image diagnosis due to its high performance and will soon become an essential technique for medical diagnosis.

Diagnostic Fine-Needle Biopsy of Small Solid Pancreatic Lesions Using a Franseen Needle during Endoscopic Ultrasound Examination

BACKGROUND AND AIM

During endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNB), Franseen needles can help collect sufficient tissue to permit histopathological assessment. However, its efficacy might be limited by the size of the targeted lesion. This study aimed to evaluate the feasibility of histopathological assessment of small solid pancreatic lesions using a 22-gauge Franseen needle during EUS-FNB.

METHODS

This retrospective study evaluated data from all patients who underwent EUS-FNB using a Franseen needle for solid pancreatic lesions at the University of Toyama Hospital between June 2018 and April 2020.

RESULTS

The study included 159 patients who had 152 malignant lesions and 7 benign lesions. The malignant lesions included pancreatic cancers (n = 134), neuroendocrine neoplasms (n = 15), metastatic tumors (n = 2), and a solid pseudopapillary neoplasm (n = 1). The diagnostic accuracy of EUS-FNB (combining histology and cytology) was 98.7%. However, the histopathological diagnosis was only confirmed for 64.3% of small lesions (<10 mm), relative to 97.2% for larger lesions. Multivariate analysis also revealed that lesion size of <10 mm predicted a less accurate histopathological diagnosis (odds ratio: 6.97, 95% confidence interval: 1.02-47.67; p = 0.041). Further analyses revealed a failed histological diagnosis in 4 patients with lesions of <5 mm in size and accurate diagnoses in 9 out of 10 patients with lesions of 5-10 mm in size.

CONCLUSIONS

The diagnostic accuracy for small lesions (<10 mm), especially for lesions of <5 mm, based on histological examination alone, was significantly lower than that for others (>10 mm). Furthermore, multivariate analysis revealed that only lesion size was an independent predictor of histopathological diagnosis accuracy.

Efficacy of EUS-guided FNB using a Franseen needle for tissue acquisition and microsatellite instability evaluation in unresectable pancreatic lesions

Background

The efficacy of immune checkpoint blockade in the treatment of microsatellite instability (MSI)-high tumors was recently reported. Therefore, the acquisition of histological specimens is desired in cases of unresectable solid pancreatic lesions (UR SPLs). This study investigated the efficacy of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) using a Franseen needle for UR SPL tissue acquisition and MSI evaluation.

Methods

A total of 195 SPL patients who underwent EUS-guided fine-needle aspiration (EUS-FNA) or EUS-FNB (EUS-FNAB) between January 2017 and March 2020 were enrolled in this study. Among them, 89 SPL patients (FNB: 28, FNA: 61) underwent EUS-FNAB using a 22-G needle (UR SPLs: 58, FNB: 22, FNA: 36) (UR SPLs after starting MSI evaluation: 23, FNB: 9, FNA: 14).

Results

The puncture number was significantly lower with FNB than with FNA (median (range): 3 (2–5) vs 4 (1–8), P <  0.01, UR SPLs: 3 (2–5) vs 4 (1–8), P = 0.036). Histological specimen acquisition was more commonly achieved with FNB than with FNA (92.9% (26/28) vs 68.9% (42/61), P = 0.015, UR SPLs: 100% (22/22) vs 72.2% (26/36), P <  0.01). The histological specimen required for MSI evaluation was acquired more often with FNB than with FNA (88.9% (8/9) vs 35.7% (5/14), P = 0.03).

Conclusions

EUS-FNB using a Franseen needle is efficient for histological specimen acquisition and sampling the required amount of specimen for MSI evaluation in UR SPL patients.

Comparison of EUS-guided conventional smear and liquid-based cytology in pancreatic lesions: A systematic review and meta-analysis

Background and study aims  Endoscopic ultrasound (EUS)-guided fine-needle aspiration (EUS-FNA) has limitations of inadequate sampling and false-negative results for malignancy. It has been performed using conventional smear (CS) cytology with rapid on-site evaluation (ROSE) with reasonable diagnostic accuracy. An alternative to ROSE is liquid-based cytology (LBC). Commonly used LBC techniques include precipitation-based (SurePath™) and filtration-based (ThinPrep ^® , CellPrep ^® ). Data regarding the diagnostic efficacy of LBC compared with CS are limited. Methods  Multiple databases were searched through March 2020 to identify studies reporting diagnostic yield of EUS-guided CS and LBC in pancreatic lesions. Pooled diagnostic odds and rates of performance for the cytologic diagnoses of benign, suspicious, and malignant lesions were calculated. Diagnostic efficacy was evaluated by pooled rates of accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Results  Nine studies with a total of 1308 patients were included in our final analysis. Pooled diagnostic odds of CS cytology were 1.69 (CI 1.02-2.79) and 0.39 (CI 0.19-0.8) for malignant lesions when compared to filtration-based and precipitation-based LBC techniques, respectively. For CS, precipitation-based and filtration-based LBC, pooled diagnostic accuracy was 79.7 %, 85.2 %, 77.3 %, sensitivity was 79.2 %, 83.6 %, 68.3 %, and specificity was 99.4 %, 99.5 %, 99.5 %, respectively. Conclusions  The precipitation-based LBC technique (SurePath™) had superior diagnostic odds for malignant pancreatic lesions compared with CS cytology in the absence of ROSE. It showed superior accuracy and sensitivity, but comparable specificity and PPV. Diagnostic odds of CS cytology in the absence of ROSE were superior to the filtration-based LBC technique (ThinPrep ^® , Cellprep ^® ) for diagnosing malignant pancreatic lesions.

Optimizing cytological specimens of EUS-FNA of solid pancreatic lesions: A pilot study to the effect of a smear preparation training for endoscopy personnel on sample quality and accuracy

BACKGROUND

In the absence of rapid on-side pathological evaluation, endoscopy staff generally "smears" endoscopic ultrasound guided fine needle aspiration (EUS-FNA) specimens on a glass slide. As this technique is vulnerable to preparation artifacts, we assessed if its quality could be improved through a smear-preparation-training for endoscopy staff.

METHODS

In this prospective pilot study, 10 endosonographers and 12 endoscopy nurses from seven regional EUS-centers in the Netherlands were invited to participate in a EUS-FNA smear-preparation-training. Subsequently, post training slides derived from solid pancreatic lesions were compared to pre-training "control" slides. Primary outcome was to assess if the training positively affects smear quality and, consequently, diagnostic accuracy of EUS-FNA of solid pancreatic lesions.

RESULTS

Participants collected and prepared 71 cases, mostly pancreatic head lesions (48%). Sixty-eight controls were selected from the pretraining period. The presence of artifacts was comparable for smears performed before and after training (76% vs 82%, P = .36). Likewise, smear cellularity (≥50% target cells) before and after training did not differ (44% (30/68) vs 49% (35/71), P = .48). Similar, no difference in diagnostic accuracy for malignancy was detected (P = .10).

CONCLUSION

In this pilot EUS-FNA smear-preparation-training for endoscopy personnel, smear quality and diagnostic accuracy were not improved after the training. Based on these results, we plan to further study other training programs and possibilities.

Current Status of Needles in the Optimization of Endoscopic Ultrasound-Guided Procedures

Endoscopic ultrasound (EUS) is among the most important tools for the evaluation of gastrointestinal tumors and affected areas around the gastrointestinal tract. It enables the acquisition of material from abnormal lesions via the gastrointestinal wall for tissue confirmation via endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). EUS-FNA has played a vital role in oncological care and has become the standard method for tissue sampling. The choice of needle type is an important factor determining tissue acquisition and has been evaluated by many researchers. New needles are introduced into the market almost every year, and opinions vary regarding proper needle selection. While there are diverse opinions but no definitive recommendations about the use of one particular device, fine-needle biopsy needles may provide detailed information on a tissue’s architecture based on greater sample yields. This permits additional analyses, including genetic sequencing and phenotyping, thereby enabling the provision of more personalized treatment plans. Furthermore, other EUS-guided procedures have been developed, including interventional EUS and through-the-needle devices. Given the continued attempts to improve the diagnostic ability and therapeutic techniques, we review in detail the available types of puncture needles to provide guidance on the selection of the appropriate needle types.

Factors affecting the accuracy of endoscopic ultrasound-guided fine needle aspiration for the diagnosis of small (≤20 mm) pancreatic lesions

To explore the diagnostic value of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for small, solid or semi-solid pancreatic lesions (≤20 mm) and the factors affecting its accuracy.

METHODS

Altogether 92 patients with small, solid or semi-solid pancreatic lesions who underwent EUS-FNA at the Nanjing Drum Tower Hospital from November 2009 to January 2019 were retrospectively analyzed. Univariate and multivariate analyses were used to determine the factors affecting the accuracy of EUS-FNA for detecting these lesions.

RESULTS

Among the 92 cases, 56 (60.9%) were diagnosed as having malignant lesions and 36 (39.1%) as benign lesions, respectively. The overall sensitivity, specificity and accuracy of EUS-FNA for the diagnosis of small, solid or semi-solid pancreatic lesions were 71.4%, 100% and 82.6%, respectively. When considering the impact of the presence of a tissue core on the diagnosis, the sensitivity, specificity, and accuracy of EUS-FNA with tissue core compared with those based on cytology alone were 77.3% vs 50.0%; 100% vs 100%; and 86.8% vs 62.5%, respectively. The multivariate analysis showed that larger tumor size (>15-20 mm) (odds ratio [OR] 4.200, 95% confidence interval [CI] 1.21-14.53, P = 0.023) and histologic diagnosis based on tissue core (OR 4.593, 95% CI 1.03-20.47, P = 0.046) were related to a higher accuracy of EUS-FNA. Adverse events were observed in three patients, all were treated conservatively and recovered within 3 days.

CONCLUSIONS

EUS-FNA is effective and safe for diagnosing small pancreatic lesions. Tumor size and presence of tissue core are related to higher accuracy of the EUS-FNA.

Comparison between Conventional Smear and Liquid-Based Preparation in Endoscopic Ultrasonography-Fine Needle Aspiration Cytology of Pancreatic Lesions

The present study aimed to compare the diagnostic accuracy between conventional smear (CS) and liquid-based preparation (LBP) in endoscopic ultrasonography-fine needle aspiration cytology (EUS-FNAC) of pancreatic lesions. Using 31 eligible studies, the diagnostic accuracy of cytologic examination in CS and LBP was evaluated through a conventional meta-analysis and diagnostic test accuracy review. Overall concordance rates were 82.8% (95% confidence interval [CI], 79.8–85.5%) and 94.0% (95% CI, 84.4–97.8%) in CS and LBP, respectively. CS with rapid on-site evaluation (ROSE) showed a higher concordance rate than CS without ROSE. In CS, the pooled sensitivity and specificity were 89.8% (95% CI, 85.2–93.1%) and 95.0% (95% CI, 90.0–97.6%), respectively. The diagnostic odds ratio (OR) and area under curve (AUC) of the summary receiver operating characteristic (SROC) curve were 90.32 (95% CI, 43.85–147.11) and 0.945, respectively. In LBP, the pooled sensitivity and specificity were 80.9% (95% CI, 69.7–88.7%) and 99.9% (95% CI, 1.5–100.0%), respectively. The diagnostic OR and AUC of the SROC curve were 57.21 (95% CI, 23.61–138.64) and 0.939, respectively. Higher concordance rates were found in CS with ROSE and LBP in EUS-FNAC of pancreatic lesions. Regardless of the cytologic preparation method, EUS-FNAC is a useful and accurate diagnostic tool for pancreatic lesions.

Comparison of prognosis between observation and surgical resection groups with small sporadic non-functional pancreatic neuroendocrine neoplasms without distant metastasis

BACKGROUND

The treatment of small (≤ 2 cm), sporadic localized non-functional pancreatic neuroendocrine neoplasms (PNENs) is often controversial. This study aimed to investigate the clinical outcomes with observation and surgical resection in small PNENs.

METHODS

Seventy-five patients with small localized sporadic non-functional PNENs ≤ 2 cm, who underwent observation or surgical resection, were retrospectively reviewed. Changes in tumor size during follow-up in the observation group were also investigated.

RESULTS

The median age of the cohort was 61 (range 35-81) years. The tumor grades were G1, G2, and unknown, in 61 (81.3%), 8 (10.7%), and 6 (8.0%) patients, respectively. The mean follow-up periods in the observation (n = 23) and surgical resection groups (n = 52) were 52.3 (range 6.8-133.3) months and 73.0 (range 9.1-179.9) months, respectively. The median overall survival was not reached. During follow-up, no patient died of PNENs, two died of other diseases, three had lymph node metastases, and one experienced recurrence after surgical resection. There was no significant difference in overall survival between the observation and surgical resection groups (hazard ratio: 0.031, P = 0.417). The mean change in tumor size in the observation group was + 0.30 mm (range - 1.6 to + 3.0 mm). No deaths, tumor progression, lymph node metastases, distant metastases, or recurrence were noted in patients with PNENs ≤ 1 cm (n = 36).

CONCLUSIONS

The prognosis of small localized PNENs is good. Observation may be an alternative to surgery in high-risk patients and those with small G1 tumors, particularly those measuring ≤ 1 cm.

Comparison of liquid-based cytology with conventional smear cytology for EUS-guided FNA of solid pancreatic masses: a prospective randomized noninferiority study

BACKGROUND AND AIMS

There are limited data on the efficacy of liquid-based cytology (LBC) for EUS-guided FNA specimens. We aimed to evaluate the diagnostic efficacy of LBC for solid pancreatic neoplasms compared with conventional smears (CSs).

METHODS

In this randomized, crossover, noninferiority trial, we randomly assigned (1:1) patients with suspected pancreatic cancer to the LBC group or the CS group. Aspirates from the first needle pass were processed by one method, aspirates from the second pass by the other method, and specimens from the last pass were processed as core biopsy samples. The primary endpoint was the diagnostic efficacy of each method, with the final diagnosis as the gold standard. A noninferiority margin of -10% was assumed.

RESULTS

Of 170 randomized patients, 165 were classified as malignant and 5 as benign. Unsatisfactory samples were less frequent in the LBC group (1.78%) compared with the CS group (5.33%). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of LBC versus CS were 88.0% versus 83.8% (P = .276), 87.7% versus 83.2% (P = .256), 100% versus 100% (P = .999), 100% versus 100% (P = .999), and 16.7% versus 16.1% (P = .953), respectively. A bloody background was significantly more frequent in the CS group (CS, 85.2%; LBC, 1.8%; P < .001), whereas the nuclear features were similar for both groups.

CONCLUSIONS

The diagnostic usefulness of LBC was comparable with that of CS. The cytomorphologic features did not differ significantly between the 2 methods, and the reduced bloody backgrounds allowed better visibility in the LBC method. (Clinical trial registration number: NCT03606148.).

Features of chronic pancreatitis by endoscopic ultrasound influence the diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration of small pancreatic lesions

BACKGROUND AND AIM

In chronic pancreatitis (CP) patients, diagnosis of small pancreatic lesions by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is challenging. Thus, the aim of the present study was to investigate whether CP influences the diagnostic ability of EUS-FNA for pancreatic lesions ≤10 mm.

METHODS

One hundred and seventeen patients who underwent EUS-FNA for pancreatic lesions ≤10 mm in size were enrolled. Patients were classified into two groups based on features of CP observed by EUS (EUS-CP features) in accordance with the Rosemont classification. The CP group was defined as cases consistent with CP or suggestive of CP, and the non-CP group was defined as cases indeterminate for CP or normal. Factors influencing the diagnostic accuracy of EUS-FNA and CP status in pancreatic tumors were also investigated.

RESULTS

Diagnostic ability of EUS-FNA (overall cases, non-CP vs CP) had sensitivity (80.4%, 96.7% vs 57.1%; P < 0.001), specificity (100%, 100% vs 100%; P > 0.05), and accuracy (91.5%, 98.6% vs 80.4%; P = 0.001). In multivariate analysis of factors influencing the accuracy of EUS-FNA, CP significantly lowered the accuracy (P = 0.048; odds ratio [OR] = 9.21). Among pancreatic cancer patients, the number of CP patients was significantly higher than the number of patients with benign lesions (P = 0.023). In multivariate analysis, lobularity without honeycombing was more frequently observed in cases of pancreatic cancer (P = 0.018; OR, 12.65).

CONCLUSION

Endoscopic ultrasound-guided FNA offers high accuracy for small pancreatic lesions ≤10 mm. However, in cases with CP, the diagnostic ability of EUS-FNA is significantly reduced.

Diagnostic yield and agreement on fine-needle specimens from solid pancreatic lesions : comparing the smear technique to liquid-based cytology

Background and study aims  The traditional "smear technique" for processing and assessing endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is sensitive to artifacts. Processing and evaluation of specimens collected in a liquid medium, liquid-based cytology (LBC) may be a solution. We compared the diagnostic value of EUS-FNA smears to LBC in pancreatic solid lesions in the absence of rapid on-site evaluation (ROSE). Patients and methods  Consecutive patients who required EUS-FNA of a solid pancreatic lesion were included in seven hospitals in the Netherlands and followed for at least 12 months. Specimens from the first pass were split into two smears and a vial for LBC (using ThinPrep and/or Cell block). Smear and LBC were compared in terms of diagnostic accuracy for malignancy, sample quality, and diagnostic agreement between three cytopathologists. Results  Diagnostic accuracy for malignancy was higher for LBC (82 % (58/71)) than for smear (66 % (47/71), P  = 0.04), but did not differ when smears were compared to ThinPrep (71 % (30/42), P  = 0.56) or Cell block (62 % (39/63), P  = 0.61) individually. Artifacts were less often present in ThinPrep (57 % (24/42), P  = 0.02) or Cell block samples (40 % (25/63), P  < 0.001) than smears (76 % (54/71)). Agreement on malignancy was equally good for smears and LBC (ĸ = 0.71 versus ĸ = 0.70, P  = 0.98), but lower for ThinPrep (ĸ = 0.26, P  = 0.01) than smears. Conclusion  After a single pass, LBC provides higher diagnostic accuracy than the conventional smear technique for EUS-FNA of solid pancreatic lesions in the absence of ROSE. Therefore, LBC, may be an alternative to the conventional smear technique, especially in centers lacking ROSE.

Value of endoscopy for early diagnosis of pancreatic carcinoma

Despite recent advances in diagnostic imaging modalities, most cases of pancreatic carcinoma are discovered at an unresectable stage, resulting in poor prognosis. Early diagnosis is essential to ensure curative treatment and improve the prognosis of pancreatic carcinoma. Imaging modalities with high diagnostic ability are necessary for the early diagnosis of pancreatic carcinoma. Endoscopic ultrasonography is a reliable and efficient diagnostic modality because it provides superior spatial resolution and should be incorporated into screening programs in patients at high risk of pancreatic carcinoma. Endoscopy facilitates cytopathological diagnosis based on samples collected via endoscopic ultrasonography-guided fine-needle aspiration and endoscopic retrograde cholangiopancreatography. Cytodiagnosis with endoscopic naso-pancreatic drainage is useful in patients with carcinoma in situ. In this review, we highlight the potential role of endoscopy in the early diagnosis of pancreatic carcinoma. We provide an overview of the endoscopy tools used for the diagnosis of pancreatic carcinoma, discuss the diagnostic ability of these tools for small carcinomas and carcinomas in situ, and propose a strategy for endoscopy-based screening of early pancreatic carcinoma.

On-site stereomicroscope quality evaluations to estimate white core cutoff lengths using EUS-FNA biopsy sampling with 22-gauge needles

BACKGROUND AND AIMS

Although rapid on-site cytologic evaluation (ROSE) during EUS-guided FNA biopsy (EUS-FNAB) sampling may improve accuracy of pathologic analyses, cytopathologists are not widely available. We calculated the cutoff lengths required for accurate pathologic diagnoses from stereomicroscopically visible white cores (SVWCs) sampled using 22-gauge needles.

METHODS

Overall, 118 patients with mediastinal or upper abdominal solid masses requiring pathologic diagnoses were included. EUS-FNAB sampling was performed using 22-gauge needles. SVWCs were isolated and measured using stereomicroscopy, and the utility of calculated cutoff lengths in diagnosis was investigated.

RESULTS

The procedure success and SVWC sampling rates were both 100%, and the median SVWC length was 10 mm. Pathologic examination identified 75, 31, and 12 patients with pancreatic neoplasms (PNs), subepithelial lesions (SELs), and other lesions, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for diagnosing malignancy using EUS-FNAB sampling were 93.1%, 100%, 100%, 69.6%, and 94%, respectively. The final diagnostic accuracy in the entire cohort, PNs, and SELs was 92.4%, 90.7%, and 93.5%, respectively. Receiver operating characteristic curves demonstrated the overall SVWC cutoff length to be 11 mm (11 mm for PNs, 3.5 mm for SELs). The overall sensitivity according to SVWC cutoff length was 91.4% (87.6% for PNs, 98.8% for SELs). Compared with cutoff length, multivariate analysis confirmed SVWC length to be a stronger independent factor for tissue diagnosis in both groups.

CONCLUSIONS

Diagnosis improved significantly with SVWC cutoff lengths ≥11 mm. This may be a useful index for endoscopists, particularly where ROSE is unavailable. (Clinical trial registration number: UMIN000023013.).

Does endoscopic ultrasound-guided fine needle biopsy using a Franseen needle really offer high diagnostic accuracy? A propensity-matched analysis

Background and study aims  This study aimed to investigate the diagnostic accuracy and utility of endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) performed using a Franseen needle on solid pancreatic lesions. Patients and methods  This study included 132 consecutive lesions sampled by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) using a 22-G conventional needle and 95 consecutive lesions evaluated by EUS-FNB using a 22-G Franseen needle to evaluate solid pancreatic lesions at our medical center between July 2013 and November 2018. We used propensity-matched analysis with adjustment for confounders. Patient data were analyzed retrospectively. Results  Diagnostic accuracy was higher in the Franseen needle group (Group F; 91.6 %, 87 /95) than in the conventional needle group (Group C; 86.3 %, 82 /95), showing no significant difference ( P  = 0.36). In Group F, diagnostic accuracies for pancreatic head lesions and lesions sampled by transduodenal puncture were 98.0 % (48/49) and 97.9 % (46/47), respectively. These values were significantly higher than values in Group C ( P  = 0.013, 0.01). Group F displayed a significantly lower number of punctures. In terms of differentiating benign from malignant lesions, Group C showed 85.1 % sensitivity (74/87), 100 % specificity (8/8), 100 % positive predictive value (74/74), and 38.1 % negative predictive value (8/21), compared to values of 90.1 % (73/81), 100 % (14/14), 100 % (73/73), and 63.6 % (14/22), respectively, in Group F. Sensitivity and negative predictive value were better in Group F. Conclusions  Franseen needles for EUS-FNB of solid pancreatic lesions offer similar puncture performance at different lesion sites while requiring fewer punctures than conventional needles.

Modern ultrasound imaging of pancreatic tumors

In patients with solid pancreatic lesions (SPLs), the differential diagnosis must be evaluated to determine whether radical surgery, pancreatic parenchyma-saving strategies, or follow-up is indicated. Contrast-enhanced (endoscopic) ultrasonography and elastography facilitate the further characterization of SPLs. The majority of cases of pancreatic ductal adenocarcinoma exhibit hypoenhancement with contrast-enhanced ultrasonography. Elastographically soft SPLs are benign with very few exceptions, whereas stiffer SPLs can be malignant or benign. This article reviews the current use of modern ultrasound imaging techniques, including contrast-enhanced ultrasonography and elastography, for the detection and characterization of SPLs. In particular, the unexcelled diagnostic potential of multiparametric endoscopic ultrasonography to detect and characterize small SPLs is highlighted.

Endoscopic ultrasonography for pancreatic solid lesions

The incidence and mortality rates of pancreatic cancer, which has a poor prognosis, are rising rapidly. Endoscopic ultrasonography (EUS) provides superior spatial resolution compared with other imaging modalities such as transabdominal ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), and it is considered among the most reliable and efficient diagnostic modalities for pancreatic diseases. In this review, we show that EUS is useful for detection of pancreatic solid lesions and staging of pancreatic cancer. EUS also plays an important role in screening patients with high-risk factors for pancreatic cancer. Although EUS is useful for detection of small pancreatic lesions, pancreatic lesions are difficult to characterize using this modality, because most pancreatic solid lesions appear hypoechoic on EUS. From this point of view, contrast-enhanced harmonic EUS (CH-EUS) plays an important role in the differential diagnosis of pancreatic lesions. EUS and CH-EUS are also useful for staging pancreatic cancer. Moreover, EUS-guided fine-needle aspiration (EUS-FNA) is superior to other modalities in terms of cytopathological diagnosis. Although EUS-FNA has a high diagnostic ability for pancreatic cancer, the combination of EUS-FNA and CH-EUS improves the diagnostic ability by decreasing the number of false-negative cases. Thus, conventional EUS, EUS-FNA, and CH-EUS are essential in clinical practice for the diagnosis of pancreatic solid lesions.