Power Doppler endoscopic ultrasonography for the differential diagnosis between pancreatic cancer and pseudotumoral chronic pancreatitis

Endoscopic ultrasonography for microvascular imaging without contrast enhancement in the differential diagnosis of pancreatic lesions

OBJECTIVES

Detective flow imaging endoscopic ultrasonography (DFI-EUS) is a recent imaging modality developed for detecting fine vessels without the need for ultrasound contrast agents. The aim of the present study was to evaluate the utility of DFI-EUS for solid pancreatic lesions and to compare the diagnostic ability for pancreatic cancer (PC) between DFI-EUS, directional power Doppler (eFLOW) EUS, and contrast-enhanced harmonic (CH)-EUS.

METHODS

Patients with a pancreatic lesion who underwent DFI-EUS, eFLOW-EUS, and CH-EUS between March 2019 and November 2023 were retrospectively enrolled. Final diagnoses were confirmed by pathologic examination of EUS-guided tissue acquisition and/or resected specimens. Lesions were categorized into the three patterns of poor, mild, and rich vascularity on DFI-EUS and eFLOW-EUS, and hypo-, iso-, and hypervascular on CH-EUS. PC was defined as a poor pattern on DFI-EUS and eFLOW-EUS, and a hypovascular pattern on CH-EUS.

RESULTS

The final diagnoses of 90 examined tumors were PC (n = 57), inflammatory mass (n = 6), autoimmune pancreatitis (n = 13), neuroendocrine tumor (n = 9), and others (n = 5). The sensitivity, specificity, and accuracy for diagnosis of PC were 93%, 82%, and 88%, respectively, on DFI-EUS, 97%, 42%, and 77% on eFLOW-EUS, and 95%, 89%, and 92% on CH-EUS. The accuracy of DFI-EUS was significantly superior to eFLOW-EUS (P = 0.005), but no significant difference was found between DFI-EUS and CH-EUS.

CONCLUSION

DFI-EUS is more sensitive for depicting vasculature than eFLOW-EUS, and has higher diagnostic sensitivity for PC. Evaluation of vascularity on DFI-EUS is useful for the differential diagnosis of pancreatic lesions without the need for intravenous contrast agent.

Advances in Endoscopic Ultrasonography-Based Diagnosis of Pancreatic Lesions: Narrative Review

Pancreatic cancer is the fourth deadliest cancer in the U [...].

Discriminating chronic pancreatitis from pancreatic cancer: Contrast-enhanced EUS and multidetector computed tomography in direct comparison

BACKGROUND AND OBJECTIVES

To compare the ability of multidetector computed tomography (MDCT) and contrast-enhanced EUS to discriminate chronic pancreatitis (CP) from pancreatic ductal adenocarcinoma (PDAC).

SUBJECTS AND METHODS

A total of 215 patients (age: 62 ± 15 years, sex: f/m 80/135) were included in this retrospective study. All patients were examined by conventional endoscopic B-mode and contrast-enhanced high mechanical index EUS (CEHMI-EUS). CELMI-EUS was performed in 159 patients and endoscopic sonoelastography (ESE) in 210 patients. MDCT was carried out in 131 patients as part of their clinical work-up. Radiological reports were retrospectively analyzed. Final diagnosis was achieved by biopsy and evaluation of cytological specimens collected was performed by EUS-FNA, surgery, or follow-up of 12 months or more in patients with benign findings. In a subgroup of 100 patients, all diagnostic five methods were performed, and head-to-head analysis was performed.

RESULTS

Sensitivity and specificity for MDCT were 89% and 70% and for CEHMI-EUS were 96% and 91%, respectively. Sensitivities and specificities for EUS were 92% and 63% for B-Mode EUS, 96% and 38% for ESE, and 82% and 76% for CELMI-EUS, respectively. In the head-to-head analysis, each modality had shown lower numbers for specificity than shown in the overall group analysis because of high drop-out rate. EUS-FNA for PDAC had a sensitivity of 96% and a specificity of 100%.

CONCLUSIONS

Contrast-enhanced EUS is a reliable tool in discriminating PDAC from CP.

Clinical Value of Contrast-Enhanced Harmonic Endoscopic Ultrasonography in the Differential Diagnosis of Pancreatic and Gallbladder Masses

Background/Aims

Recent studies have revealed that contrast-enhanced harmonic endoscopic ultrasonography (CEH-EUS) is beneficial in the differential diagnosis of malignant neoplasms of the pancreas and gallbladder from benign masses, in terms of the evaluation of microvasculature and real-time perfusion. In this study, we aimed to prove the clinical value of CEH-EUS in the differential diagnosis of pancreatic and gallbladder masses by direct comparison with that of conventional EUS.

Methods

We reviewed the sonographic images and medical information of 471 patients who underwent conventional EUS and CEH-EUS for the diagnosis of pancreatic and gallbladder masses at a single medical center (Severance Hospital, Seoul, Korea) between March 2010 and March 2016.

Results

The enhancement pattern of CEH-EUS of the pancreatic solid masses showed higher sensitivity and specificity in differentiating pancreatic adenocarcinoma and neuroendocrine tumors (82.0% and 87.9% for pancreatic adenocarcinoma and 81.1% and 90.9% for neuroendocrine tumors, respectively), and the area under the receiver operating characteristic curves was higher than that of conventional EUS. The enhancement texture of CEH-EUS of the gallbladder masses showed a higher sensitivity in differentiating malignant masses than that of conventional EUS; however, the difference between the areas under the receiver operating characteristic curves was not statistically significant.

Conclusions

CEH-EUS can complement conventional EUS in the diagnosis of pancreatic and gallbladder masses, in terms of the limitations of the latter.

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.

The role of contrast-enhanced endoscopic ultrasound in pancreatic adenocarcinoma

Contrast-enhanced endoscopic ultrasound (CE-EUS) allows characterization, differentiation, and staging of focal pancreatic masses. The method has a high sensitivity and specificity for the diagnosis of pancreatic adenocarcinoma which is visualized as hypo-enhanced as compared to the rest of the parenchyma while chronic pancreatitis and neuroendocrine tumors are generally either iso-enhanced or hyper-enhanced. The development of contrast-enhanced low mechanical index harmonic imaging techniques used in real time during endoscopic ultrasound (EUS) allowed perfusion imaging and the quantification of intensity of the contrast signal through time-intensity curve analysis. Thus, contrast harmonic imaging-EUS has been used to differentiate pancreatic adenocarcinoma based on lower values of the peak enhancement. Future applications of CE-EUS in pancreatic adenocarcinoma include not only use of targeted contrast agents for early detection, tridimensional and fusion techniques for enhanced staging and resectability assessment but also novel applications of perfusion imaging for monitoring ablative therapy, improved local detection through EUS-guided sampling of portal vein flow or enhanced drug delivery through sonoporation and ultrasound-induced release of the drugs locally.

Key endoscopic ultrasound features of pancreatic ductal adenocarcinoma smaller than 20 mm

BACKGROUND AND STUDY AIMS. Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis compared with other solid pancreatic tumors. Diagnosis of PDAC in the earliest possible stage is important to improve the prognosis. Although endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been the gold-standard modality for diagnosing pancreatic lesions, its diagnostic yield is not satisfactory for pancreatic tumors smaller than 20 mm. The purpose of this study was to determine the EUS findings that are useful for differentiating PDAC from other solid pancreatic tumors when the lesions are smaller than 20 mm. PATIENTS AND METHODS. We performed a retrospective review of 126 patients with pancreatic tumors smaller than 20 mm who had undergone EUS. According to the final pathological diagnoses, they were categorized into either the PDAC or non-PDAC group. We, then, compared the EUS findings between the two groups. RESULTS. Among the 126 patients, we diagnosed PDAC in 75 patients and non-PDAC in the remaining patients, including neuroendocrine tumor in 43 patients, intraductal papillary mucinous carcinoma in 3 patients, solid pseudopapillary neoplasm in 2 patients, and inflammatory pseudotumor in 3 patients. Of all EUS findings, three factors were significantly indicative of PDAC: an irregular tumor edge, main pancreatic duct dilation, and tumor location in the pancreatic head. The predicted probability for PDAC was 80%, 92.6%, and 74.1%, respectively. CONCLUSIONS. EUS could be a useful modality for differentiating PDAC from other solid pancreatic tumors, when the diagnostic yield of EUS-FNA is unsatisfactory, even for lesions smaller than 20 mm.

Differentiation of branch duct intraductal papillary mucinous neoplasms from serous cystadenomas of the pancreas using contrast-enhanced sonography

OBJECTIVES

The purpose of this study was to determine whether contrast-enhanced sonography can improve the ability to differentiate branch duct intraductal mucinous neoplasms from serous cystadenomas of the pancreas compared to conventional (unenhanced) sonography alone.

METHODS

Between March 2008 and May 2012, there were 20 patients with branch duct intraductal mucinous neoplasms and 25 with serous cystadenomas in our institute, for whom preoperative conventional and contrast-enhanced sonographic results were available. The final diagnosis was obtained by histopathology. Various conventional and contrast-enhanced sonographic characteristics were retrospectively evaluated by 2 radiologists in consensus. A receiver operating characteristic curve analysis was used to evaluate the diagnostic value of conventional and contrast-enhanced sonography for discriminating between the two entities.

RESULTS

Three conventional sonographic characteristics (microcysts, cysts with internal echoes, and main pancreatic duct dilatation) and 2 contrast-enhanced sonographic characteristics (communication between the lesion and main pancreatic duct and enhancement of mural nodules) significantly improved the ability to differentiate branch duct intraductal mucinous neoplasms from serous cystadenomas. The area under the receiver operating characteristic curve increased from 0.691 with conventional sonography to 0.859 with combined contrast-enhanced and conventional ultrasonography (P = .043).

CONCLUSIONS

In this series of patients, the addition of contrast-enhanced sonography to conventional sonography improved the ability to differentiate branch duct intraductal mucinous neoplasms from serous cystadenomas.

Advanced EUS imaging for early detection of pancreatic cancer

Endoscopic ultrasound (EUS)-fine needle aspiration remains the gold standard for diagnosing pancreatic malignancy. However, in a subset of patients, limitations remain in regards to image quality and diagnostic yield of biopsies. Several new devices and processors have been developed that allow for enhancement of the EUS image. Initial studies of these modalities do show promise. However, cost, availability, and overall incremental benefit to EUS-fine needle aspiration have yet to be determined.

Diagnostic accuracy of endoscopic ultrasound-guided fine-needle aspiration for solid pancreatic lesion: a systematic review

OBJECTIVE

To summarize EUS-FNA test performance in suspected pancreatic malignancy with meta-analysis.

METHOD

Two reviewers searched MEDLINE (PubMed and Ovid from January 2002 to January 2012) database to identify relevant studies. The reference lists of the trials were manually searched. Included studies used histopathology or clinical and morphological (CT and MRI and US) follow-up as the "gold standard" and provided sufficient data to construct a diagnostic 2 × 2 table. A statistical program of Meta-Disc was used to calculate the pooled sensitivity, specificity, positive LR, negative LR, DOR, and the SROC curve. Subgroup analysis and meta-regression were calculated to evaluate potential sources of heterogeneity.

RESULT

A total of 15 studies with 1860 patients were included for the analysis. The pooled sensitivity and specificity of EUS-FNA were 92 % (95 % CI = 91-93 %, p < 0.001, I (2) = 69.6 %) and 96 % (95 % CI = 93-98 %, p = 0.006, I (2) = 54.9 %), respectively. The positive LR and negative LR were 14.24 (95 % CI = 7.78-26.07) and 0.09 (95 % CI = 0.07-0.13), respectively. The area under the curve was 0.974. The subgroup analysis of six studies with rapid on-site evaluation (ROSE) showed a pooled sensitivity of 95 % (95 % CI = 93-96 %), with p value equal 0.622 and I (2) = 0. The sensitivity analysis of ten high-quality studies (a score of ≥4) showed a pooled sensitivity of 94 % (95 % CI = 93-96 %, p = 0.144, I (2) = 33.1 %), and the pooled specificity was 0.95 (95 % CI, 0.91-0.97).

CONCLUSION

EUS-FNA had overall excellent specificity and sensitivity in accurately diagnosing solid pancreatic masses. ROSE could help to improve the accuracy of diagnostic test.

Vascularisation pattern of chronic pancreatitis compared with pancreatic carcinoma: results from contrast-enhanced endoscopic ultrasound

Discriminating between focal chronic pancreatitis and pancreatic cancer is always a challenge in clinical medicine. Contrast-enhanced endoscopic ultrasound using Doppler techniques can uniquely reveal different vascularisation patterns in pancreatic tissue alterated by chronic inflammatory processes and even allows a discrimination from pancreatic cancer. This paper will describe the basics of contrast-enhanced high mechanical index endoscopic ultrasound (CEHMI EUS) and contrast enhanced low mechanical index endoscopic ultrasound (CELMI EUS) and explain the pathophysiological differences of the vascularisation of chronic pancreatitis and pancreatic carcinoma. Furthermore it will discuss how to use these techniques in daily clinical practice.

Characterization of small solid tumors in the pancreas: the value of contrast-enhanced harmonic endoscopic ultrasonography

OBJECTIVES

Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS), a novel technology, visualizes parenchymal perfusion in the pancreas. This study prospectively evaluated how accurately CH-EUS characterizes pancreatic lesions and compared its diagnostic ability with that of contrast-enhanced multidetector-row computed tomography (MDCT) and endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA).

METHODS

A total of 277 consecutive patients with pancreatic solid lesions that were detected by conventional EUS underwent CH-EUS for evaluation of vascularity. After infusing an ultrasound contrast, CH-EUS was performed by using an echoendoscope and a specific mode for contrast harmonic imaging. On the basis of the intensity of enhancement, the lesions were categorized into four patterns: nonenhancement, hypoenhancement, isoenhancement, and hyperenhancement. For comparison, all patients underwent MDCT. The ability of CH-EUS to differentiate ductal carcinomas from the other solid tumors, particularly small lesions (≤2 cm in diameter) was assessed, and compared with the differentiating abilities of MDCT and EUS-FNA.

RESULTS

In terms of reading the CH-EUS images, the κ-coefficient of the interobserver agreement test was 0.94 (P<0.001). CH-EUS-depicted hypoenhancement diagnosed ductal carcinomas with a sensitivity and specificity of 95.1% (95% confidence interval (CI) 92.7-96.7%) and 89.0% (95% CI 83.0-93.1%), respectively. For diagnosing small carcinomas by CH-EUS, the sensitivity and specificity were 91.2 % (95% CI 82.5-95.1%) and 94.4% (95% CI 86.2-98.1%), respectively. CH-EUS-depicted hypervascular enhancement diagnosed neuroendocrine tumors with a sensitivity and specificity of 78.9% (95% CI 61.4-89.7%) and 98.7% (95% CI 96.7-98.8%), respectively. Although CH-EUS and MDCT did not differ significantly in diagnostic ability with regard to all lesions, CH-EUS was superior to MDCT in diagnosing small (≤2 cm) carcinomas (P<0.05). In 12 neoplasms that MDCT failed to detect, 7 ductal carcinomas and 2 neuroendocrine tumors had hypoenhancement and hyperenhancement on CH-EUS, respectively. When CH-EUS was combined with EUS-FNA, the sensitivity of EUS-FNA increased from 92.2 to 100%.

CONCLUSIONS

CH-EUS is useful for characterizing conventional EUS-detected solid pancreatic lesions. EUS equipped with contrast harmonic imaging may play an important role in the characterization of small tumors that other imaging methods fail to depict and may improve the diagnostic yield of EUS-FNA.

New techniques and future perspective of EUS for the differential diagnosis of pancreatic malignancies: contrast harmonic imaging

Although endoscopic ultrasonography (EUS) has the advantage over other imaging methods in that it is possible to obtain high resolution images of the pancreas, it is limited in its ability to characterize pancreatic masses. Contrast-enhanced power Doppler ultrasonography suffers from several limitations such as blooming artifacts, poor spatial resolution, low sensitivity to slow flow and high sensitivity to motion artifacts. Recently, EUS system specific for contrast harmonic imaging has been developed. The use of this EUS system enabled us to observe images of microcirculation and parenchymal perfusion without Doppler-related artifacts in the pancreas. Contrast-enhanced harmonic EUS could diagnose pancreatic carcinomas as hypovascular masses with a high sensitivity (89-96%) and specificity (64-88%). Contrast-enhanced harmonic EUS also discriminates mural nodules from mucous clots in the intraductal papillary mucinous neoplasms.

Endoscopic ultrasonography and contrast-enhanced endoscopic ultrasonography

Endoscopic ultrasonography (EUS) is superior to all other imaging modalities in detecting small pancreatic cancers. However, its ability to characterize hypoechoic pancreatic masses is limited: most carcinomas, neuroendocrine tumors, and inflammatory pseudotumors are simply depicted as hypoechoic masses. Contrast enhancement helps EUS to characterize such hypoechoic masses. Intravenous ultrasound (US) agents increase the signal from the blood and, thus, act as amplifiers and improve visualization of blood flow in small vessels using Doppler US. Contrast-enhanced Doppler EUS can differentiate small pancreatic carcinomas that cannot be detected by other imaging modalities. The development of second-generation US contrast agents and an EUS system with a broad-band transducer enabled the visualization of microvessels and the parenchymal perfusion in the pancreas. This contrast-enhanced harmonic EUS has shown that most pancreatic cancers exhibit hypovascular heterogeneous enhancement with irregular network-like microvessels. Moreover, it can diagnose pancreatic cancers with a high sensitivity (89-92%).

Mesenteric venous collateral vessels mimicking cystic pancreatic neoplasm

We report an unusual case of intrapancreatic mesenteric venous collateral vessels following partial pancreatic surgical resection resembling pancreatic neoplasm upon greyscale sonographic and unenhanced CT examinations.

Contrast harmonic echo-endoscopic ultrasound improves accuracy in diagnosis of solid pancreatic masses

BACKGROUND & AIMS

Contrast harmonic echo (CHE) has been developed for endoscopic ultrasound (EUS). This new technique detects echo signals from microbubbles in vessels with very slow flow, without artifacts. We assessed whether CHE-EUS increases the accuracy of diagnosis of pancreatic solid lesions.

METHODS

At a tertiary-care EUS center, we examined 90 patients who were suspected of having pancreatic solid neoplasm. Radial and linear echoendoscopes were used with dedicated software for CHE. Sonovue (Bracco International BV, Amsterdam, The Netherlands) uptake, pattern, and washout were studied; data were compared for pancreatic lesions and adjacent parenchyma. The final diagnosis was obtained based on results of surgical pathology and/or EUS-fine needle aspiration (FNA) analyses.

RESULTS

The finding of a hypoenhancing mass with an inhomogeneous pattern was a sensitive and accurate identifier of patients with adenocarcinoma (96% and 82%, respectively) (49 of 51 patients with primary pancreatic adenocarcinoma had a hypoenhancing mass that was inhomogeneous and had fast washout). This finding was more accurate in diagnosis than the finding of a hypoechoic lesion using standard EUS (P < .000). Hyperenhancement specifically excluded adenocarcinoma (98%), although sensitivity was low (39%). Of neuroendocrine tumors, 11 of 13 were non-hypo-enhancing (9 hyperenhancing, 2 isoenhancing). Interestingly, CHE-EUS allowed detection of small lesions in 7 patients who had uncertain standard EUS findings because of biliary stents (n = 5) or chronic pancreatitis (n = 2). Targeted EUS-FNA was performed on these lesions.

CONCLUSIONS

Detection of a hypoenhancing and inhomogeneous mass accurately identified patients with pancreatic adenocarcinoma. CHE-EUS increased the detection of malignant lesions in difficult cases (patients with chronic pancreatitis or biliary stents) and helped guide EUS-FNA. A hyperenhancing pattern could be used to rule out adenocarcinoma.

Prospective, randomized comparison of mechanical and electronic radial endoscopic ultrasound systems: assessment of performance parameters and image quality

OBJECTIVE

Implementation of electronic image technology in endoscopic ultrasonography (EUS) should improve image quality, but systematic data are scarce. The purpose of this study was to compare the image quality and performance of an electronic and a mechanical radial echoendoscope.

MATERIAL AND METHODS

Eighty consecutive patients (42 M, mean age 56 years) in a tertiary referral center, without gross pathology (advanced tumors excluded), were prospectively randomized to EUS with the mechanical or electronic echoendoscope. Images from five standardized positions (pancreatobiliary and upper gastrointestinal (GI) tract) were taken by two examiners of differing experience. Time to acquire images was noted. Penetration depth was also measured. Image quality variables (overall quality, contrast, and structure discrimination) were assessed blindly on the basis of randomly shuffled images during three independent evaluations by the same experienced examiner (mean values were taken), using a visual analogue scale (VAS) from 1 (excellent) to 10 (inadequate).

RESULTS

Time needed to achieve visualization of the distal common bile duct (CBD) was significantly shorter with the electronic scope (49.7+/-8.6 versus 97.4+/-8.5 s; p<0.001). Image quality with the electronic scope was rated significantly better for all variables assessed, whereas EUS penetration depth was similar in both groups. There were no differences in examiner experience.

CONCLUSIONS

Electronic EUS provided better quality images according to the examiner's subjective assessment. An objective advantage was faster identification of the distal CBD.

Role of endoscopic ultrasound in the diagnosis and staging of pancreatic cancer

Early diagnosis of pancreatic cancer remains a difficult task, and multiple imaging tests have been proposed over the years. The aim of this review is to describe the current role of endoscopic ultrasound (EUS) for the diagnosis and staging of patients with pancreatic cancer. A detailed search of MEDLINE between 1980 and 2007 was performed using the following keywords: pancreatic cancer, endoscopic ultrasound, diagnosis, and staging. References of the selected articles were also browsed and consulted. Despite progress made with other imaging methods, EUS is still considered to be superior for the detection of clinically suspected lesions, especially if the results of other cross-sectional imaging modalities are equivocal. The major advantage of EUS is the high negative predictive value that approaches 100%, indicating that the absence of a focal mass reliably excludes pancreatic cancer. The introduction of EUS-guided fine needle aspiration allows a preoperative diagnosis in patients with resectable cancer, as well as a confirmation of diagnosis before chemoradiotherapy for those that are not. This comprehensive review highlighted the diagnostic capabilities of EUS including the newest refinements such as contrast-enhanced EUS, EUS elastography, and 3-dimensional EUS. The place of EUS-guided biopsy is also emphasized, including the addition of molecular marker techniques.

Endoscopic ultrasound in pancreatic disease--its influence on surgical decision-making. An update 2008

Endoscopic ultrasonography (EUS) was introduced about 25 years ago with the primary aim of better visualization of the pancreas as compared to transabdominal ultrasonography. This review discusses the current evidence in 2008 concerning the role of EUS in the clinical management of patients, with a special emphasis on its impact on surgical therapy. According to the literature, good indications are detection of common bile duct stones (e.g. in acute pancreatitis), the detection of small exo- and endocrine pancreatic tumors, the performance of fine-needle aspiration in pancreatic masses depending on therapeutic consequences. In other areas such as diagnosis of chronic pancreatitis and cystic pancreatic lesions, the contribution of EUS seems limited. Pancreatic cancer staging is discussed controversially due to conflicting evidence and certainly has lost grounds due to improvements in CT technology. Therapeutic EUS is, however, more widely accepted and may replace other techniques, e.g. in pancreatic cyst drainage and celiac plexus neurolysis; further techniques of interest are being developed.

Neural network analysis of dynamic sequences of EUS elastography used for the differential diagnosis of chronic pancreatitis and pancreatic cancer

BACKGROUND

EUS elastography is a newly developed imaging procedure that characterizes the differences of hardness and strain between diseased and normal tissue.

OBJECTIVE

To assess the accuracy of real-time EUS elastography in pancreatic lesions.

DESIGN

Cross-sectional feasibility study.

PATIENTS

The study group included, in total, 68 patients with normal pancreas (N = 22), chronic pancreatitis (N = 11), pancreatic adenocarcinoma (N = 32), and pancreatic neuroendocrine tumors (N = 3). A subgroup analysis of 43 cases with focal pancreatic masses was also performed.

INTERVENTIONS

A postprocessing software analysis was used to examine the EUS elastography movies by calculating hue histograms of each individual image, data that were further subjected to an extended neural network analysis to differentiate benign from malignant patterns.

MAIN OUTCOME MEASUREMENTS

To differentiate normal pancreas, chronic pancreatitis, pancreatic cancer, and neuroendocrine tumors.

RESULTS

Based on a cutoff of 175 for the mean hue histogram values recorded on the region of interest, the sensitivity, specificity, and accuracy of differentiation of benign and malignant masses were 91.4%, 87.9%, and 89.7%, respectively. The positive and negative predictive values were 88.9% and 90.6%, respectively. Multilayer perceptron neural networks with both one and two hidden layers of neurons (3-layer perceptron and 4-layer perceptron) were trained to learn how to classify cases as benign or malignant, and yielded an excellent testing performance of 95% on average, together with a high training performance that equaled 97% on average.

LIMITATION

A lack of the surgical standard in all cases.

CONCLUSIONS

EUS elastography is a promising method that allows characterization and differentiation of normal pancreas, chronic pancreatitis, and pancreatic cancer. The currently developed methodology, based on artificial neural network processing of EUS elastography digitalized movies, enabled an optimal prediction of the types of pancreatic lesions. Future multicentric, randomized studies with adequate power will have to establish the clinical impact of this procedure for the differential diagnosis of focal pancreatic masses.

Color-coded duplex endoscopic ultrasound of the adrenals

Imaging of the adrenals by endoscopic ultrasound (EUS) is a valuable technique for detection and localization of adrenal lesions, but endosonomorphological tumor distinction remains difficult. In this single-center study, the amount of blood flow in common adrenal lesions, such as adrenal adenomas, adrenal hyperplasia, and pheochromocytomas, was visualized by color-coded duplex EUS (CD-EUS) and was retrospectively analysed. Therefore, we reviewed our EUS database to evaluate and correlate the perfusion patterns of common adrenal lesions with histologically confirmed diagnosis, possible malignancy, and endosonomorphological features such as echogeneity, echostructure, and tumor size. CD-EUS was performed using an endosonoscope Pentax FG 32 UA with a longitudinal 7.5 MHz sector array and Hitachi EUB 525 ultrasound system. In 38 consecutive patients (male=19; female=19; age: mean 53+/-16 yr SD), perfusion patterns of 46 histologically confirmed adrenal, para- or extra-adrenal lesions of adrenal origin (adenoma: no.=20; nodular hyperplasia: no.=11; pheochromocytoma: no.=15; diameter 26+/-15 mm, range 6-70 mm) were analyzed and classified semiquantitatively as "not" (no.=24), "slightly" (no.=12), "moderately" (no.=4) or "highly" (no.=6) hypervascularized. Compared to adenomas (p=0.003) and nodular hyperplasia (p=0.047), pheochromocytomas showed a significantly higher grade of perfusion. There was no relationship between perfusion patterns and localization of pheochromocytomas (adrenal: 8; paraadrenal: 3; extra-adrenal: 4). Vascularization was not statistically associated with tumor echogeneity, echostructure, malignancy or tumor size. CD-EUS is an additional tool for adrenal endosonographic tumor distinction and seems to improve the endosonographic detection of pheochromocytomas by visualization of hypervascularization. As an overlap of perfusion patterns exists, CD-EUS findings must be interpreted in the context of clinical, laboratory and chemical results.

A novel perfusion imaging technique of the pancreas: contrast-enhanced harmonic EUS (with video)

BACKGROUND

Contrast-enhanced harmonic-imaging techniques have been unavailable for EUS because of the limited frequency bandwidth and acoustic power output of current echoendoscopes.

OBJECTIVE

To investigate the contrast harmonic imaging technique by using a prototype echoendoscope equipped with an adequate broad-band transducer that can detect harmonic signals from the US contrast agents.

DESIGN

Identification of optimal settings (study I) and preliminary clinical investigations (study II).

SETTING

Bethesda General Hospital Bergedorf.

PATIENTS

A total of 104 patients undergoing standard EUS examinations.

INTERVENTIONS

Contrast-enhanced harmonic EUS (CEH-EUS) was performed by using a prototype echoendoscope and extended pure harmonic detection mode, a specific mode for contrast harmonic imaging.

MAIN OUTCOME MEASUREMENTS

In study I, time-intensity curves for peak signal intensity were calculated after infusion of a contrast agent, SonoVue, and the changes in echo intensity were compared for different mechanical indices and interval times. In study II, intermittent and real-time continuous images of pancreatobiliary and gastroduodenal diseases obtained by CEH-EUS were evaluated in comparison with contrast-enhanced power-Doppler EUS (CED-EUS).

RESULTS

In study I, with the optimal mechanical index (0.4), homogeneous parenchymal perfusion images of the pancreas were obtained by intermittent imaging, and finely branching vessels of the pancreas were obtained with real-time continuous imaging. In study II, apparent perfusion and vessel images were observed in pancreatobiliary carcinomas, GI stromal tumors, and lymph-node metastases. CED-EUS failed to depict images of the fine vessels and parenchymal perfusion.

LIMITATIONS

The subjective nature of the findings, with a limited number of patients.

CONCLUSIONS

CEH-EUS successfully visualized parenchymal perfusion and microvasculature in the pancreas and may play an important role in the differential diagnosis of digestive diseases.