Combination of EUS-FNA and elastography (strain ratio) to exclude malignant solid pancreatic lesions: A prospective single-blinded study

Role of contrast-enhanced harmonic endoscopic ultrasonography (EUS) and EUS elastography in pancreatic lesions

Pancreatic cancers have a poor prognosis, and their incident rates have risen. Endoscopic ultrasonography (EUS) is an efficient and reliable diagnostic modality for pancreatic lesions, providing high spatial resolution. However, while EUS helps to detect minor pancreatic lesions, nearly all solid pancreatic lesions are hypoechoic, which creates difficulty in making differential diagnoses of pancreatic lesions. When diagnosing pancreatic lesions, the performance of image-enhanced EUS techniques is essential, such as EUS elastography or contrast-enhanced harmonic EUS (CH-EUS). CH-EUS diagnosis is based on assessing the vascularity of lesions, whereas tissue elasticity is measured via EUS elastography. Elastography is either strain or shear-wave, depending on the different mechanical properties being evaluated. The usefulness of enhanced EUS techniques is demonstrated in this review for the differential diagnosis of pancreatic lesions, including solid and cystic lesions, and pancreatic cancer staging.

Contrast Enhanced EUS for Predicting Solid Pancreatic Neuroendocrine Tumor Grade and Aggressiveness

Pancreatic neuroendocrine tumor (PNET) behavior assessment is a daily challenge for physicians. Modern PNET management varies from a watch-and-wait strategy to surgery depending on tumor aggressiveness. Therefore, the aggressiveness definition plays a pivotal role in the PNET work-up. The aggressiveness of PNETs is mainly based on the dimensions and histological grading, with sometimes a lack of specificity and sensibility. In the last twenty years, EUS has become a cornerstone in the diagnostic phase of PNET management for its high diagnostic yield and the possibility of obtaining a histological specimen. The number of EUS applications in the PNET work-up has been rapidly increasing with new and powerful possibilities. The application of contrast has led to an important step in PNET detection; in recent years, it has been gaining interesting applications in aggressiveness assessment. In this review, we underline the latest experiences and opportunities in the behavior assessment of PNETs using contact-enhanced EUS and contested enhanced harmonic EUS with a particular focus on the future application and possibility that these techniques could provide.

Shear-wave versus strain elastography in endoscopic ultrasound for the diagnosis of chronic pancreatitis

BACKGROUND

/Objectives: Endoscopic ultrasound (EUS) elastography is a non-invasive diagnostic method for evaluating tissue elasticity. The aims of this study were to compare shear-wave elastography (SWE) and conventional strain elastography (SE) in determination of the diagnosis and degree of chronic pancreatitis (CP).

METHODS

Forty-nine patients who underwent computed tomography (CT), EUS-SWE, EUS-SE, and pancreatic exocrine function testing between January 2019 and January 2022 were prospectively evaluated. CP was diagnosed according to Japan Pancreatic Society criteria (JPSC) 2019, Rosemont criteria (RC), CT findings, and pancreatic exocrine dysfunction. The cut-off values, sensitivity, and specificity for CP diagnosed according to the four criteria were calculated for EUS-SWE and EUS-SE. Relationships between values measured by either of the EUS elastography methods and the number of EUS features were also assessed.

RESULTS

EUS-SWE values were positively correlated with the severity grades of RC and JPSC, but EUS-SE values were not. EUS-SWE was significantly better than EUS-SE for diagnosing CP defined according to CT findings (area under the receiver operating characteristics curve [AUROC]: 0.77 vs. 0.61, P < 0.001), RC (AUROC: 0.85 vs. 0.56, P < 0.001), JPSC 2019 (AUROC: 0.83 vs. 0.53, P < 0.001), and exocrine dysfunction (AUROC: 0.78 vs. 0.61, P < 0.001). EUS-SWE values were positively correlated with the number of EUS features, but EUS-SE values were not.

CONCLUSIONS

EUS-SWE provides objective assessment for diagnosing and assessing the degree of CP defined according to the criteria of CT findings, RC, JPSC, or exocrine dysfunction, and it can be considered a non-invasive diagnostic tool for CP and exocrine dysfunction.

Endoscopic ultrasound elastography for malignant pancreatic masses and associated lymph nodes: Critical evaluation of strain ratio cutoff value

BACKGROUND

Endoscopic ultrasound (EUS) can detect small lesions throughout the digestive tract; however, it remains challenging to accurately identify malignancies with this approach. EUS elastography measures tissue hardness, by which malignant and nonmalignant pancreatic masses (PMs) and lymph nodes (LNs) can be differentiated. However, there is currently little information regarding the strain ratio (SR) cutoff in Hispanic populations.

AIM

To determine the diagnostic accuracy of EUS elastography for PMs and LNs with an SR cutoff value in Hispanics.

METHODS

A retrospective study of patients who underwent EUS elastography for PMs between December 2013 and December 2014. A qualitative (analysis of color maps) and quantitative (SR) analysis of PMs and their associated LNs was performed. The accuracy of EUS elastography in identifying malignant PMs and LNs and cutoff value for SR were analyzed. A PM and/or its associated LNs were considered malignant based on histopathological findings from fine-needle aspiration biopsy samples.

RESULTS

A sample of 121 patients was included, 45.4% of whom were female. 69 (57.0%) PMs were histologically malignant, with a median SR of 50.4 vs 33.0 for malignant vs nonmalignant masses (P < 0.001). EUS evaluation identified associated LNs in 43/121 patients (35.5%), in whom 22/43 (51.2%) patients had histologically confirmed malignant diagnosis, with a median SR of 30 vs 40 for malignant vs nonmalignant LNs (P = 0.7182). In detecting malignancy in PMs, an SR cutoff value of > 21.5 yielded a sensitivity of 94.2%, while a cutoff value of > 121 yielded a specificity of 96.2.2%. There were significant differences in the Giovannini scores, a previously established elastic score system, between the patients grouped by their final histology results (P < 0.001). For LNs, SR cutoff values of > 14.0 and > 155 yielded a sensitivity of 90.9% and a specificity of 95.2%, respectively, in detecting malignancy.

CONCLUSION

EUS elastography is a helpful technique for the diagnosis of solid PMs and their associated LNs. The proposed SR cutoff values have a high sensitivity and specificity for the detection of malignancy.

The expanding role of endoscopic ultrasound elastography

Endoscopic ultrasound (EUS) is an invaluable tool for assessing various GI diseases. However, using just the conventional B-mode EUS imaging may not be sufficient to accurately delineate the lesion's character. Using the principle of stress-induced tissue strain, EUS elastography (EUS-E) can help in the real-time sonographic assessment of the level of tissue stiffness or hardness of any organ of interest during a routine EUS procedure. Thus, EUS-E can better characterize the lesion's nature and highlight the more suspicious areas within an individual lesion. The most commonly studied lesions with EUS-E are the pancreatic lesions, namely, chronic pancreatitis, pancreatic cancer, and lymph nodes. However, EUS-E is gradually expanding its use for lesion characterization of the liver, bile duct, adrenals, gastrointestinal tract, and even therapy response. Moreover, the use of EUS-E along with other image enhancement techniques such as harmonic EUS and contrast-enhanced EUS can improve the accuracy of the diagnosis. However, several technical aspects need to be standardized before EUS-E can be truly used as a tool for "virtual biopsy". This review focuses on the various technical aspects of the use of EUS-E, it is established and expanding indications and an extensive outline of the various studies on EUS-E. We also discuss the current pitfalls and future trends in EUS-E.

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.

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.

Endoscopic Ultrasound-Guided Fine-Needle Aspiration (EUS-FNA) with Image Enhancement

Although endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is useful in the differential diagnosis of solid pancreatic lesions, lymph nodes, and liver lesions, inadequate sampling may result in an incorrect pathological diagnosis. The accuracy of EUS for the evaluation of pancreatobiliary lesions may be increased by image enhancement technologies, including contrast-enhanced harmonic (CH)-EUS and EUS-elastography. These methods can provide information that complement EUS-FNA for the diagnosis and staging of pancreatobiliary cancer, and can help to identify the EUS-FNA target, reducing the requirement for repeat FNA.

Endoscopic ultrasonography elastography in the diagnosis of intrapancreatic ectopic spleen: A case report

BACKGROUND

Intrapancreatic accessory spleen (IPAS) mimics a pancreatic neoplasm on imaging studies, and due to the lack of radiological diagnostic criteria, patients undergo unnecessary distal pancreatectomies. Endoscopic ultrasonography (EUS) is a reliable and efficient diagnostic modality for pancreatic diseases. However, no EUS criteria have been established for IPAS. We present the EUS-elastography image of IPAS, which may minimize the chance of misdiagnosis in the future.

CASE SUMMARY

A 50-year-old man was referred for an EUS evaluation after computed tomography showed a hypervascular enhanced mass in the tail of the pancreas, which indicated a neuroendocrine neoplasm. EUS elastography demonstrated that the lesion of interest covered no more than 25% of the region of interest. The patient underwent distal pancreatectomy. However, the resected tissue was evaluated, and the patient was finally diagnosed with IPAS.

CONCLUSION

IPAS should be considered in patients with suspected pancreatic neuroendocrine tumors of the pancreatic tail before surgery is performed. The differentiation between IPAS and pancreatic neuroendocrine tumors can be demonstrated using EUS-elastography.

Protein Signatures and Tissue Diagnosis of Pancreatic Cancer

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration fails to diagnose up to 25% of patients with pancreatic ductal adenocarcinoma (PDAC). Proteomics can help to overcome this clinical dilemma. We hypothesized that soluble protein signatures can differentiate PDAC from benign tissues.

STUDY DESIGN

Tissues were obtained from resected surgical specimens, lysed, and homogenates collected for analysis with a 41-protein multiplex assay. Analyte concentrations were normalized to total protein. Statistical analysis was performed to evaluate for differences in PDAC vs benign tissue.

RESULTS

Tissues were obtained from 159 patients, 82 patients with PDAC naïve to therapy and 77 with benign pancreatic pathology. Fourteen analytes had a receiver operating characteristic curve area of >0.75 for predicting PDAC vs benign tissue. A recursive partitioning model using only 2 analytes, interleukin 1 receptor antagonist and transforming growth factor-α, provided an accuracy, sensitivity, and specificity of 91.2%, 90.2%, and 92.2%, respectively. A penalized logistic regression model found 12 analytes that provide diagnostic value to a protein signature. The mean area under the receiver operating characteristic after 50 tenfold cross-validations was 0.951. Accuracy, sensitivity, and specificity of this model were 91.2%, 87.8%, and 94.8%, respectively. Applying the scenario of 80% disease prevalence in patients undergoing endoscopic ultrasound with fine-needle aspiration for a pancreatic head mass, positive predictive value is 98.5% (95% CI 93.0% to 99.7%) and negative predictive value is 66.0% (95% CI 54.9% to 75.6%).

CONCLUSIONS

Protein signatures from pancreatic specimens can differentiate PDAC from benign tissue. Additional work to validate these findings in a unique sample set is warranted.

Quantitative Elastography Versus Fine-needle Aspiration by Endoscopic Ultrasound for the Assessment of Pancreatic Solid Masses

BACKGROUND AND AIMS

Pancreatic solid masses (PSM) are difficult to assess; endoscopic ultrasound with fine-needle aspiration (FNA) enables tissue acquisition, but has high false-negative rates. Quantitative elastography (QE) predicts diagnosis on the basis of the strain ratio (SR). We aimed to compare both methods to evaluate PSM.

MATERIALS AND METHODS

This prospective study, carried out between January and December 2016, included suspected PSM cases; those with advanced disease and cystic components were excluded. Both procedures were performed; histologic information was obtained for the final diagnoses. Diagnostic tests and receiver-operating characteristic curve were calculated. P<0.05 was considered statistically significant.

RESULTS

We included 134 patients (53% women; mean, 53±16.2 y). The median tumor size was 30 (10 to 78) mm, with 69.4% and 30.6% malignant and benign tumors (median SR: 19.5 vs. 7.5; P=0.000), respectively, and 87% were pancreatic adenocarcinoma. QE with SR cutoff ≥10 showed similar parameters to FNA in both PSM types: sensitivity, 94% in both; specificity, 85% versus 87%; positive predictive value, 93% versus 94%; negative predictive value, 87% in both; and accuracy, 92% for malignant and sensitivity, 85% versus 87%; specificity, 94% in both; positive predictive value, 87% in both; negative predictive value, 93% versus 94%; and accuracy, 92% for benign. The area under the curve was 0.96 (P<0.000; 95% confidence interval, 0.940-0.995). New classifications on the basis of positive likelihood ratio were grouped as follows: A ≤8.7 (benign tumor); B >8.7 to <15.5 (indeterminate); and C ≥15.5 (malignant).

CONCLUSIONS

QE has similar capacity to FNA in PSM evaluation. However, the former can be used potentially as a substitute of the latter in certain cases on the basis of these new SR cutoff-based classifications.

Elastography of the Pancreas, Current View

Ultrasound elastography (USE) of the pancreas allows pancreatic tissue stiffness assessment by virtual palpation. Two main types of USE are used. For the pancreas strain elastography applying by endoscopic ultrasound has been established for the characterisation of small solid pancreatic lesions (SPL). In larger SPL >30 mm the results are less convincing mainly due to the heterogenicity of the lesions but also by concomitant changes of the surrounding pancreatic parenchyma. The current role of shear wave elastography has to be determined. This article reviews the current use of elastography of the pancreas.

Feasibility and reproducibility of liver and pancreatic stiffness in patients with alcohol-related liver disease

BACKGROUND

To date no studies evaluated liver stiffness and pancreatic stiffness by shear-wave elastography, in alcoholic liver disease setting.

AIMS

To assess feasibility and reproducibility of Shear-wave elastrography in measuring liver and pancreatic stiffness in alcoholic liver disease and investigate the correlation among liver and pancreatic stiffness and clinical data.

METHODS

Liver and pancreatic stiffness were measured by elastography (2 examiners) in patients with alcoholic liver disease and in healthy volunteers, for reference values. Effect of clinical data was evaluated on log-transformed pancreatic or liver stiffness, using univariate and multivariate linear regression model.

RESULTS

87 patients and 46 healthy volunteers enrolled. Both the stiffness values were higher in patients than healthy volunteers (p < 0.001). For liver stiffness: no failure measurements found, the Intraclass correlation coefficient (between 2 examiners) was 0.72 and the variables significantly correlated at multivariate analysis were cirrhosis (p < 0.0001) and steatosis (p = .007). For pancreatic stiffness: 2 failures found, with ICC 0.40 and the only variable significantly correlated at multivariate analysis was liver cirrhosis (p = .005).

CONCLUSIONS

Shear-wave elastography feasibility was good for liver and pancreatic stiffness. Reproducibility was good for liver stiffness, whereas fair for pancreatic one. Both the stiffness correlated with alcoholic liver disease severity. Elastography could be a useful tool to detect and monitor alcohol-related liver and pancreatic damage.

Diagnostic Efficacy of Endoscopic Ultrasound Elastography in Differentiating Solid Pancreatic Lesions: A Single-Center Experience

Background/Aims

Endoscopic ultrasound (EUS) has a limited ability to determine the nature of solid pancreatic lesions (SPLs). Most recent ultrasound processors are provided with elastography software, which allows quantification of the tissue hardness. The aim of this study is to evaluate the effectiveness of the elasticity score (ES) and strain ratio (SR) in the differentiation of benign pancreatic lesions from malignant pancreatic lesions.

Methods

The study had a retrospective design; it included 97 patients with SPLs and 19 patients with inflammatory lesions. The ES and SR were determined during the examination; finally, EUS-guided fine needle aspiration was performed.

Results

In this 2-year study, 116 patients were enrolled (97 with malignant lesions and 19 with benign lesions). There were 69 men and 47 women. Their median age was 55.9 years. A cut-off point was detected at SR of 7.75 with a specificity of 99.9%, sensitivity of 90.7%, positive predictive value (PPV) of 99.9%, negative predictive value (NPV) of 67.9%, and accuracy of 92.2%. After adding the ES to the SR, the cut-off point at 7.75 resulted in a specificity of 94.6%, sensitivity of 99%, PPV of 98%, NPV of 98.5%, and accuracy of 97%.

Conclusions

The use of the ES combined with the SR increases the accuracy of differentiation between benign and malignant SPLs and is an effective method for the evaluation of pancreatic masses.

Impact of endoscopic ultrasonography on diagnosis of pancreatic cancer

Accumulated evidence has revealed that endoscopic ultrasonography (EUS) has had a great impact on the clinical evaluation of pancreatic cancers. EUS can provide high-resolution images of the pancreas with a quality regarded as far surpassing that achieved on transabdominal ultrasound (US), computed tomography (CT), or magnetic resonance imaging (MRI). EUS is particularly useful for the detection of small pancreatic lesions, while EUS and its related techniques such as contrast-enhanced EUS (CE-EUS), EUS elastography, and EUS-guided fine needle aspiration (EUS-FNA) are also useful in the differential diagnosis of solid or cystic pancreatic lesions and the staging (T-staging, N-staging, and M-staging) of pancreatic cancers. In the diagnosis of pancreatic lesions, CE-EUS and EUS elastography play a complementary role to conventional EUS. When sampling is performed using EUS-FNA, CE-EUS and EUS elastography provide information on the target lesions. Thus, conventional EUS, CE-EUS, EUS elastography, and EUS-FNA are essential in the clinical investigation of pancreatic cancer.

Endoscopic ultrasound elastography in the diagnosis of pancreatic masses: A meta-analysis

BACKGROUND AND AIMS

Endoscopic ultrasound (EUS) elastography is a novel non-invasive technique that can be used for distinguishing benign from malignant pancreatic masses. However, the studies have reported widely varied sensitivities and specificities. A meta-analysis was performed to assess the performance of EUS elastography for the differentiation of benign and malignant pancreatic masses.

METHODS

All the eligible studies were searched by PubMed, Medline, Embase, and the Cochrane Library. Sensitivity, specificity, positive likelihood ratio (LR), negative LR, and area under the curve (AUC) were calculated to examine the accuracy.

RESULTS

A total of nineteen studies which included 1687 patients were analyzed. The pooled sensitivity and specificity for the diagnosis of malignant pancreatic masses were 0.98 (95% confidence interval [CI] 0.96-0.99) and 0.63 (95% CI 0.58-0.69) for qualitative EUS elastography, 0.95 (95% CI 0.93-0.97) and 0.61 (95% CI 0.56-0.66) for quantitative EUS elastography, respectively. The positive and negative LR were 2.60 (95% CI 1.84-3.66) and 0.05 (95% CI 0.02-0.10) for qualitative EUS elastography, 2.64 (95% CI 1.82-3.82) and 0.10 (95% CI 0.06-0.16) for quantitative EUS elastography, respectively. The summary diagnostic odds ratio (DOR) and the AUC were 60.59 (95% CI 28.12-130.56) and 0.91 (Q* = 0.842) for qualitative EUS elastography, 30.09 (95% CI 15.40-58.76) and 0.93 (Q* = 0.860) for quantitative EUS elastography.

CONCLUSIONS

Our meta-analysis shows that both qualitative and quantitative EUS elastography have high accuracy in the detection of malignant pancreatic masses, which could be used as a valuable complementary method to EUS-FNA for the differentiation of pancreatic masses in the future.

Endoscopic ultrasound (EUS) elastography and strain ratio, could it help in differentiating malignant from benign pancreatic lesions?

Evaluating the role of endoscopic ultrasound (EUS) elastography and strain ratio in differentiation between malignant and benign pancreatic lesions.Three hundred twenty-five patients with solid pancreatic lesions were enrolled in this prospective study from 2014 to 2017. EUS real-time elastography scoring and strain ratio were done to all patients and compared to the final diagnosis to assess its sensitivity, specificity, positive and negative predictive values (PPV and NPV) in differentiating malignant from benign lesions.A cut-off value of 4.2 we had sensitivity of 95%, specificity of 63%, PPV of 89%, NPV of 81%, and accuracy of 87%. Another cut-off value of 10.9 showed a sensitivity of 75%, specificity of 88%, PPV of 95%, NPV of 54%, and accuracy of 79%. Adding the elastography to the better cut-off value gave a sensitivity of 97%, specificity of 63%, PPV of 89%, NPV of 88%, and accuracy of 89%.Real-time elastography and strain ration are valuable in differentiating malignant from pancreatic lesions.

EUS elastography (strain ratio) and fractal-based quantitative analysis for the diagnosis of solid pancreatic lesions

BACKGROUND AND AIMS

EUS elastography is useful in characterizing solid pancreatic lesions (SPLs), and fractal analysis-based technology has been used to evaluate geometric complexity in oncology. The aim of this study was to evaluate EUS elastography (strain ratio) and fractal analysis for the characterization of SPLs.

METHODS

Consecutive patients with SPLs were prospectively enrolled between December 2015 and February 2017. Elastographic evaluation included parenchymal strain ratio (pSR) and wall strain ratio (wSR) and was performed with a new compact US processor. Elastographic images were analyzed using a computer program to determine the 3-dimensional histogram fractal dimension. A composite cytology/histology/clinical reference standard was used to assess sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating curve.

RESULTS

Overall, 102 SPLs from 100 patients were studied. At final diagnosis, 69 (68%) were malignant and 33 benign. At elastography, both pSR and wSR appeared to be significantly higher in malignant as compared with benign SPLs (pSR, 24.5 vs 6.4 [P < .001]; wSR, 56.6 vs 15.3 [P < .001]). When the best cut-off levels of pSR and wSR at 9.10 and 16.2, respectively, were used, sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating curve were 88.4%, 78.8%, 89.7%, 76.9%, and 86.7% and 91.3%, 69.7%, 86.5%, 80%, and 85.7%, respectively. Fractal analysis showed a significant statistical difference (P = .0087) between the mean surface fractal dimension of malignant lesions (D = 2.66 ± .01) versus neuroendocrine tumor (D = 2.73 ± .03) and a statistical difference for all 3 channels red, green, and blue (P < .0001).

CONCLUSIONS

EUS elastography with pSR and fractal-based analysis are useful in characterizing SPLs. (Clinical trial registration number: NCT02855151.).

Diagnostic accuracy of fine-needle aspiration of solid pancreatic lesions guided by endoscopic ultrasound elastography

Background:

Real-time elastography (RTE) may increase the diagnostic accuracy of fine-needle aspiration guided by endoscopic ultrasound. The aim of this study was to establish the diagnostic accuracy, sensitivity, and specificity of this combined methodological approach in a cohort of patients with solid pancreatic masses.

Methods:

We reviewed data from 54 patients with solid pancreatic lesions referred to our institution between January 2014 and June 2015. RTE, assessed in terms of strain ratio, was performed both qualitatively and semi-quantitatively, and a 25G needle was inserted into the most suspicious part of the lesion. Sensitivity, specificity, diagnostic accuracy, positive and negative predictive values were calculated.

Results:

The median lesion size was 35 mm (interquartile range: 25-43 mm). A diagnosis of adenocarcinoma was confirmed in 85.1% of cases. RTE, with a strain ratio cutoff of 4.21, showed a sensitivity of 86.9%, a specificity of 75%, and diagnostic accuracy of 85.1%. The diagnostic accuracy, sensitivity, and specificity of the combined methodology were 94.4%, 93.4%, and 100%, respectively. The positive predictive value was 100%, the negative predictive value 72.7% and the negative likelihood ratio 6.5. No severe adverse events were registered.

Conclusion:

The combination of RTE with endoscopic ultrasound-guided fine-needle aspiration appears to be an efficient and safe technique for the characterization of solid pancreatic masses.

Assessment of the Pancreas with Strain Elastography in Healthy Children: Correlates and Clinical Implications

Background

To determine strain index (SI) values at various locations in the pancreas and to investigate the relationship between age, gender, body weight, height, body mass index (BMI), and elasticity values of the pancreas in healthy children.

Material/Methods

This cross-sectional trial was performed in 147 healthy children who underwent transabdominal ultrasonography for strain elastography of the pancreas. A convex, 3.5–5-MHz probe was used to obtain the images. Baseline descriptive data including age (months), body weight (kg), height (cm), and BMI (kg/m2) were noted. Strain index values were calculated for the head, body, and tail of the pancreas, and a mean value was obtained. The relationship between demographic variables and SI values was assessed. Correlation between variables with normal distribution was evaluated with Pearson’s correlation coefficient and Spearman’s rho.

Results

The average SI values in girls and boys were 1.30±0.34 and 1.32±0.22, respectively. There was no significant difference between SI values measured in the head, trunk, and tail of the pancreas (p=0.594). The average SI value did not differ between girls and boys (p=0.751). Correlation analysis revealed that SI was positively associated with age (p=0.005), body weight (p=0.004), height (p=0.003), and BMI (p=0.005).

Conclusions

This study determined normal elasticity values of the pancreas in healthy children. SI values of pancreas change with age, body weight, height, and BMI in the pediatric population. Information obtained from healthy children can serve as a baseline against which pancreatic diseases can be examined.

Endoscopic ultrasound elastography for solid pancreatic lesions

Elastography is one of technologies assisting diagnosis of solid pancreatic lesions (SPL). This technology has been previously used for measuring the stiffness of various organs based on a principle of “harder the lesions, higher chance for malignancy”. Two elastography techniques; strain and shear wave elastography, are available. For endoscopic ultrasound (EUS), only the former is existing. To interpret results of EUS elastography for SPL, 3 methods are used: (1) pattern recognition; (2) strain ratio; and (3) strain histogram. Based on results of existing studies, these 3 techniques provide high sensitivity but low to moderate specificity and accuracy rate. This review will summarize all available information in order to update current situation of using elastography for an evaluation of SPLs to readers.

Point shear-wave elastography in chronic pancreatitis: A promising tool for staging disease severity

BACKGROUND

Objectives: ElastPQ^®-pSWE is an ultrasound technique developed to stage disease severity in patients with chronic liver diseases. Little data is available about its application to the pancreas. We aimed to assess the feasibility and reproducibility of pancreatic stiffness (PS) measurements in patients with chronic pancreatitis and their relationship with clinical and laboratory data.

MATERIAL AND METHODS

52 consecutive patients with chronic pancreatitis (CP) (40 males; median age 60 years) underwent hepatic and pancreatic pSWE. Liver stiffness was measured by transient elastography, 42 healthy subjects being controls (25 males; median age 54 years). Pancreatic pSWE inter-observer agreement was analyzed by intraclass correlation coefficient (ICC). The effects of clinical, laboratory and US data on PS measurements were evaluated by linear regression.

RESULTS

pSWE was feasible in all the CP patients, but one. Pancreatic stiffness was significantly higher in CP patients than healthy controls (4.3 ± SD 2.4 vs. 2.8 ± SD 1.1 kPa, respectively, p = 0.001). Significantly higher values in the CP group were observed in patients with longer disease duration (>10 vs. ≤10 years) (5.8 ± SD 4 vs. 3.9 ± SD 1.5 kPa, respectively, p = 0.01), on chronic analgesic drugs (6.0 vs. 3.5 kPa, p < 0.05) and with lower body weight (p < 0.05, r = -0.38). At multivariate analysis all the three variables resulted independently associated to the pancreatic stiffness value. The ICC for PS was 0.77.

CONCLUSIONS

ElastPQ^®-pSWE is promising and reproducible in assessing pancreatic stiffness, which mainly reflects disease length and severity. Accordingly, its use is of potential value in stratifying CP patients by identifying those with a more serious degree of disease.

New Imaging Techniques: Endoscopic Ultrasound-Guided Elastography

Endoscopic ultrasound (EUS) is a major imaging method in the management of several diseases of the gastrointestinal tract and surrounding structures. Elastography is a novel technique providing additional information to standard B-mode imaging on the tissue stiffness. Elastography can be performed under EUS guidance. This method has proven to be an accurate and additional tool in the evaluation of pancreatic diseases and lymph nodes analysis. Possible uses include the study of liver lesions, subepithelial masses, and many more. This article reviews current knowledge and future perspectives.

Real time endoscopic ultrasound elastography and strain ratio in the diagnosis of solid pancreatic lesions

AIM

To evaluate the accuracy of the elastography score combined to the strain ratio in the diagnosis of solid pancreatic lesions (SPL).

METHODS

A total of 172 patients with SPL identified by endoscopic ultrasound were enrolled in the study to evaluate the efficacy of elastography and strain ratio in differentiating malignant from benign lesions. The semi quantitative score of elastography was represented by the strain ratio method. Two areas were selected, area (A) representing the region of interest and area (B) representing the normal area. Area (B) was then divided by area (A). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated by comparing diagnoses made by elastography, strain ratio and final diagnoses.

RESULTS

SPL were shown to be benign in 49 patients and malignant in 123 patients. Elastography alone had a sensitivity of 99%, a specificity of 63%, and an accuracy of 88%, a PPV of 87% and an NPV of 96%. The best cut-off level of strain ratio to obtain the maximal area under the curve was 7.8 with a sensitivity of 92%, specificity of 77%, PPV of 91%, NPV of 80% and an accuracy of 88%. Another estimated cut off strain ratio level of 3.8 had a higher sensitivity of 99% and NPV of 96%, but with less specificity, PPV and accuracy 53%, 84% and 86%, respectively. Adding both elastography to strain ratio resulted in a sensitivity of 98%, specificity of 77%, PPV of 91%, NPV of 95% and accuracy of 92% for the diagnosis of SPL.

CONCLUSION

Combining elastography to strain ratio increases the accuracy of the differentiation of benign from malignant SPL.

Endoscopic ultrasound guided fine needle aspiration versus endoscopic ultrasound guided fine needle biopsy in sampling pancreatic masses: A meta-analysis

BACKGROUND

The comparison between endoscopic ultrasound guided fine needle aspiration (EUS-FNA) and endoscopic ultrasound guided fine needle biopsy (EUS-FNB) for the diagnosis of pancreatic masses is still controversial. Many factors can affect the final results.

METHODS

Databases, such as PubMed, EMBASE, Cochrane Library, and Science Citation Index updated from 2000 to 2016 were searched to include eligible articles. In the meta-analysis, the main outcome measurements were the diagnostic accuracy, number of needle passes, specimen adequacy, the rate of complications, and technical success.

RESULTS

Eight randomized controlled trials (RCTs) were identified, and a total of 921 cases were included in the meta-analysis. The diagnostic accuracy was not significantly different between the FNA and FNB groups. The specimen adequacy was higher in the FNB group compared with the FNA group. The number of needle passes to obtain sufficient tissue was lower in the FNB group. The rate of adverse events and technical success did not significantly differ between the 2 groups. But, the forest plot showed a trend toward lower technical success rate and a trend toward higher diagnostic accuracy in the FNB group, compared with FNA.

CONCLUSION

We provide the evidence that FNB is comparable to FNA in terms of diagnostic accuracy, adverse events, and technical success. FNB gives higher specimen adequacy than that of FNA, despite performance of fewer needle passes.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.

Imaging in pancreatic disease

Pancreatic diseases, chronic pancreatitis, pancreatic cancer and diabetes mellitus, taken together, occur in >10% of the world population. Pancreatic diseases, as with other diseases, benefit from early intervention and appropriate diagnosis. Although imaging technologies have given clinicians an unprecedented toolbox to aid in clinical decision-making, advances in these technologies and development of molecular-based diagnostic tools could enable physicians to identify diseases at an even earlier stage and, thereby, improve patient outcomes. In this Review, we discuss and identify gaps in the use of imaging techniques for the early detection and appropriate treatment stratification of various pancreatic diseases, including diabetes mellitus, acute and chronic pancreatitis and pancreatic cancer. Imaging techniques discussed are MRI, CT, PET and ultrasonography. Additionally, the identification of new molecular targets for imaging and the development of contrast agents that are able to give molecular information in noninvasive radionuclear imaging and ultrasonography are emerging areas of innovation that could lead to increased diagnostic accuracy and improved patient outcomes.

Endoscopic ultrasound-guided techniques for diagnosing pancreatic mass lesions: Can we do better?

The diagnostic approach to a possible pancreatic mass lesion relies first upon various non-invasive imaging modalities, including computed tomography, ultrasound, and magnetic resonance imaging techniques. Once a suspect lesion has been identified, tissue acquisition for characterization of the lesion is often paramount in developing an individualized therapeutic approach. Given the high prevalence and mortality associated with pancreatic cancer, an ideal approach to diagnosing pancreatic mass lesions would be safe, highly sensitive, and reproducible across various practice settings. Tools, in addition to radiologic imaging, currently employed in the initial evaluation of a patient with a pancreatic mass lesion include serum tumor markers, endoscopic retrograde cholangiopancreatography, and endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). EUS-FNA has grown to become the gold standard in tissue diagnosis of pancreatic lesions.

The endoscopist's role in the diagnosis and management of pancreatic cancer

Pancreatic cancer remains one of the most lethal malignancies with little improvement in survival over the past several decades in spite of advances in imaging, risk factor identification, surgical technique and chemotherapy. This disappointing outcome is mainly due to failures to make an early diagnosis. In fact, the majority of the patients present with inoperable advanced stages of the disease. Though some of the new tumor markers are promising, we are still in search of the one that has a high sensitivity and accuracy, yet is inexpensive and easy to obtain. The paradigm of management has shifted from up-front surgery followed by adjuvant chemotherapy to neoadjuvant chemoradiation followed by surgery, especially for borderline resectable cancers and even for some resectable cancers. In this article, we will critically assess the limitations of tumor markers and review the advancements in endoscopic techniques in the management of pancreatic cancer.