Differentiation of neuroendocrine tumors from other pancreatic lesions by echo-enhanced power Doppler sonography and somatostatin receptor scintigraphy

Enhancement patterns in the venous phase of contrast-enhanced ultrasounds: diagnostic value for patients with solid pancreatic lesions

Background

To observe and assess the diagnostic value of the venous phase enhancement patterns of contrast-enhanced ultrasounds (CEUS) in patients with solid pancreatic lesions that show iso- to hyperenhancement in the arterial phase of the CEUS.

Methods

Patients who underwent CEUS for pancreatic lesions in the Peking Union Medical College Hospital between April 2017 and August 2019 were identified from the dynamic CEUS imaging database in the hospital. A total of 57 patients with pathologically or clinically diagnosed pancreatic lesions were retrospectively included in this study, and the CEUS images from these patients were evaluated. The enhancement patterns in each phase were analyzed, and each lesion was classified as malignant or benign using a five-point scale of confidence based on morphology, boundary, vascular invasion, blood flow, and enhancement patterns in ultrasound (US) and CEUS images.

Results

Rapid washout in the venous phase of CEUS images was detected in 30 malignant lesions and 4 benign lesions with malignant potential. The specificity for determining malignancy was 77.8%. Continuous isoenhancement with normal pancreatic tissues in the venous phase achieved a high specificity of 95.0% for determining benign lesions. Early hyperenhancement in the arterial phase followed by slow washout in the venous phase showed high specificity of 98.1% for determining metastasis. The diagnostic confidence improved after reviewing CEUS scans (area under the receiver operating characteristic curve was 0.737 for baseline US and 0.910 for CEUS; P=0.056).

Conclusions

Enhancement patterns in the venous phase of CEUS images were beneficial in the differential diagnosis of solid pancreatic lesions with iso- to hyperenhancement in the arterial phase on CEUS.

CEUS of the pancreas: Still research or the standard of care

Contrast-enhanced ultrasonography (CEUS) improves the characterization of pancreatic masses. CEUS is in fact a safe and accurate imaging method to evaluate the vascularity of pancreatic lesions. CEUS should be performed when possible immediately after the ultrasound (US) detection of a pancreatic mass. CEUS is accurate in the characterization of ductal adenocarcinoma. The use of CEUS in studying pancreatic lesions found at US, especially in the same session of ultrasound examination, is therefore recommendable to promote faster diagnosis mainly of pancreatic ductal adenocarcinoma.

(18)F-FDG PET/CT can be used to detect non-functioning pancreatic neuroendocrine tumors

18F-Fluorodeoxyglucose positron emission tomo-graphy and computed tomography (18F-FDG PET/CT) has limited value in well-differentiated neuroendocrine tumors. The value of 18F-FDG PET/CT in non-functioning pancreatic neuroendocrine tumors, which are often poorly differentiated, malignant, and present at an advanced stage, was also thought to be limited. This study was performed to evaluate the clinical value of 18F-FDG PET/CT in assessing non-functioning pancreatic neuroendocrine tumors. From January 2010 to February 2014, a comparable large cohort of patients (31 cases) with non-functioning pancreatic neuroendocrine tumors from Shanghai Cancer Center underwent 18F-FDG PET/CT scans. Demographics and clinical characteristics were retrospectively collected and analyzed for all the patients. Twenty-eight of 31 (90.3%) patients with non-functioning endocrine pancreatic tumors had an elevated 18F-FDG uptake (SUVmax ≥2.5). In addition, 18F-FDG PET/CT visualized 38 of 42 (90.5%) distant metastatic lesions. The 18F-FDG uptake had significant association with tumor size (P=0.012) and TNM stage (P=0.004). The application of 18F-FDG PET/CT has changed the management of 8 cases (8/31, 25.8%). In conclusion, 18F‑FDG PET/CT plays an important role in detecting and staging non-functioning pancreatic neuroendocrine tumors.

Incidental intraoperative discovery of a pancreatic neuroendocrine tumor associated with chronic pancreatitis

Pancreatic neuroendocrine tumors are a rare entity with an incidence between 2 per million to 5 per 100,000. Association with pancreatitis (acute or chronic) is rare and is considered to be determined by the tumoral obstruction of pancreatic ducts, but sometimes occurs without any apparent relationship between them. Non-functional neuroendocrine pancreatic tumors are usually diagnosed when either very large or metastatic. Small ones are occasionally diagnosed when imagery is performed for other diagnostic reasons. Intraoperative discovery is even rarer and poses problems of differential diagnosis with other pancreatic tumors. Association with chronic pancreatitis is rare and usually due to pancreatic duct obstruction by the tumor. We describe the case of a patient with a small non-functioning neuroendocrine tumor in the pancreatic tail accidentally discovered during surgery for delayed traumatic splenic rupture associated with chronic alcoholic pancreatitis. The tumor of 1.5 cm size was well differentiated and confined to the pancreas, and was resected by a distal splenopancreatectomy.

CONCLUSIONS

Surgeons should be well aware of the rare possibility of a non-functional neuroendocrine tumor in the pancreas, associated with chronic pancreatitis, surgical resection being the optimal treatment for cure. Histopathology is of utmost importance to establish the correct diagnosis, grade of differentiation, malignancy and prognosis.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2114470176676003.

Pancreatic endocrine neoplasms: a current update on genetics and imaging

Pancreatic endocrine neoplasms are rare pancreatic tumours that may occur sporadically or as part of inherited syndromes such as multiple endocrine neoplasia-1 syndrome, von Recklinghausen disease, von Hippel-Lindau syndrome and tuberous sclerosis complex. Recent advances in the genetics and pathology of hereditary syndromes have provided valuable insights into the pathophysiology and biology of sporadic pancreatic endocrine neoplasms. Evolving molecular data on the biology of these neoplasms have the potential for diagnostic, therapeutic and prognostic use.

Tailored imaging of islet cell tumors of the pancreas amidst increasing options

Pancreatic islet cell tumors are neuroendocrine tumors, which can produce hormones and can arise as part of multiple endocrine neoplasia type 1 or von-Hippel-Lindau-disease, two genetically well-defined hereditary cancer syndromes. Currently, technical innovation improves conventional and specific molecular imaging techniques. To organize the heterogeneous results described for the imaging of these tumors, we distinguished three indications (1) imaging of a patient with hormone hypersecretion, (2) search for a pancreatic primary in case of proven neuroendocrine cancer of unknown primary, and (3) screening of asymptomatic mutation carriers. We searched for publications on imaging of islet cell tumors between 1995 and January 2010 and defined a Level of Evidence (LOE) for the applicability of each technique. For each technique, data were analyzed in a Forest plot and arranged per imaging indication and tumor subtype. LOEs are weak for all imaging techniques. Analyses indicate a prominent role for endoscopic ultrasound for all three indications.

Transabdominal contrast-enhanced ultrasonography of pancreatic cancer

Since its introduction, contrast-enhanced ultrasonography (CEUS) has significantly extended the value of ultrasonography (US). CEUS can be used to more accurately determine pancreatic lesions compared to conventional US or to characterize lesions already detectable by US. Thus, CEUS can aid in the differential diagnosis of pancreatic tumors. Using US contrast media, it is possible to visually detect microvessels in the majority of pancreatic ductal adenocarcinomas. Thus, the use of quantitatively evaluated transabdominal CEUS can help in the differentiation of patients with mass-forming pancreatitis from patients with pancreatic adenocarcinomas. In neuroendocrine pancreatic tumors, different enhancement patterns can be observed in relation to the tumor mass: larger ones show a rapid early enhancement sometimes combined with necrotic central structures, and smaller ones disclose a capillary-blush enhancement. Pseudocysts, the most widespread cystic lesions of the pancreas, are not vascularized. They do not show any signal in CEUS and remain entirely anechoic in all phases, while true cystic pancreatic tumors usually have vascularized septa and parietal nodules. In summary, CEUS is effective for differentiating solid pancreatic tumors in most cases. CEUS is safe and cost effective and can better discriminate solid from cystic pancreatic lesions, thereby directing further imaging modalities.

Molecular imaging of neuroendocrine tumors

Neuroendocrine tumors (NET) are a heterogeneous group of tumors that arise from neuroendocrine cells. These tumors may arise from various organs, including lung, thymus, thyroid, stomach, duodenum, small bowel, large bowel, appendix, pancreas, adrenal, and skin. Most are well differentiated and have the ability to produce biogenic amines and various hormones. NET usually occur sporadically but they also be associated with various familial syndromes. For the vast majority of NET, surgical resection is the treatment of choice whenever feasible. Localization of NET prior to surgery and for staging and follow-up relies on both anatomic and functional imaging modalities. In fact, the unique secretory characteristics of these tumors lend themselves to imaging by molecular imaging modalities, which can target specific metabolic pathways or receptors. Neuroendocrine cells have a variety of such target receptors and pathways for which radiopharmaceuticals have been developed, including [(123)I/(131)I]-metaiodobenzylguanidine (MIBG), [(111)In]pentetreotide, [(68)Ga] somatostatin analogs, [(18)F] fluorodeoxyglucose (FDG), [(11)C/(18)F] dihydroxyphenylalanine (DOPA), [(11)C] 5-hydroxytryptophan (5-HTP) (99m)Tc pentavalent dimercaptosuccinic acid ([(99m)Tc] (V) DMSA, and [(18)F] fluorodopamine (FDA). Here, we review the molecular imaging approaches for NET using various radiopharmaceuticals.

Contrast-enhanced and 3-dimensional endoscopic ultrasonography

Recent progress of the data processing applied to ultrasonographic (US) examination has made it possible to develop new software. The US workstation of the last generation thus incorporated in their center a computer allowing a precise treatment of the US image. This advancement has made it possible to work out new images such as 3-dimensional (3D) US, contrast harmonic US associated with the intravenous injection of contrast agents, and even more recently, elastography. These techniques, quite elaborate in percutaneous US at present, are to be adapted and evaluated with endoscopic US (EUS). The contribution of contrast agents of US to pancreatic EUS and then 3D EUS are successively approached in this article.

The place of endoscopic ultrasound in bilio-pancreatic pathology

The place of endoscopic ultrasound (EUS) in malignant pathology of the pancreas is two-fold: (1) EUS is the best examination for the diagnosis of small tumours (<3cm in diameter). Its sensitivity is greater than that of CT scan, percutaneous ultrasound or magnetic resonance imaging (MRI) and is equal to that of endoscopic retrograde cholangiopancreatography (ERCP) without sharing its invasive character; (2) EUS is also indicated in the assessment of locoregional extension of tumours judged resectable by tomodensitometric (TDM) (scanner) data. The performance of EUS seems to be greater than other imaging techniques for the diagnosis of vascular and lymph node invasion although recent studies report less good results than those of studies in 1992 to 1994, particularly for vascular involvement. Nevertheless, EUS cannot affirm the malignant or benign character of these pancreatic masses. The development over the last 20 years of linear sector-based EUS has enabled us to perform guided biopsies of such lesions. EUS-guided biopsy is today the best technique for obtaining the histology of a pancreatic mass, with a sensitivity of 85 to 87%. Furthermore, it also has a non-negligible impact on the deciding the treatment particularly in the case of adenocarcinomas (ADKP) not visible to TDM (scanners). This is currently of importance because trials are being developed of preoperative radio-chemotherapy for resectable lesions. probably in the next future, contrast-enhanced EUS (CE-EUS) and elastography will improve the results of EUS and will be necessary for a precise local staging before treatment.

Impact of high-resolution transabdominal ultrasound in the diagnosis of complications of Crohn's disease

OBJECTIVE

Crohn's disease is associated with intestinal complications such as strictures, fistulas and abscesses. As the management of the patients is influenced by the presence or absence of complication, sensitive diagnostic modalities to detect these complications are needed. The aim of this prospective study was to evaluate the diagnostic accuracy of high-resolution transabdominal ultrasound in the diagnosis of complications of Crohn's disease.

MATERIAL AND METHODS

From April 2003 to July 2009, 58 patients (31 women, 27 men; mean age 36.3 years, range 13-86 years) with known Crohn's disease were included in the study and investigated with high-resolution transabdominal ultrasound. The diagnosis of Crohn's disease was based on clinical, endoscopic, histological, radiological and operative findings. Patients with other forms of enteritis (e.g. infectious) were excluded from the study. Twenty of the 58 patients were investigated on a second occasion with other symptoms than at the first admission. The time duration between the two ultrasound investigations was at least 3 months. Consequently, a total of 78 ultrasound investigations were done in 58 patients. With respect to their clinical symptoms, all patients were further investigated within 2 weeks after ultrasound with magnetic resonance imaging, and/or computed tomography, and/or enteroclysis, and/or endoscopy with biopsy. Together with clinical data (Crohn's disease activity index) and surgical findings these investigations were used as reference procedure.

RESULTS

The sensitivity, specificity, positive predictive and negative predictive values of ultrasound were as follows: 0.86, 0.90, 0.83 and 0.92 for stenoses; 0.78, 0.95, 0.86, and 0.91 for fistulas; 0.90, 0.99, 0.90 and 0.99 for abscesses, respectively.

CONCLUSIONS

High-resolution transabdominal ultrasound done by experienced examiners has an excellent diagnostic accuracy in the diagnosis of complications in patients with Crohn's disease. Thus, it can be recommended as one of the primary investigative procedures for evaluation of Crohn's disease.

Contrast-enhanced endoscopic ultrasound and elastosonoendoscopy

Until recently, there was no contrast harmonic imaging technique available for EUS examination. Second-generation US contrast agents produce harmonic signals at lower acoustic powers and, therefore, are suitable for EUS imaging at low acoustic powers. CE-EUS could provide a contribution to the differential diagnosis between a primary pancreatic carcinoma, chronic pancreatitis and a pancreatic metastasis, and therefore can have a decisive influence on the selection of appropriate therapeutic strategies (follow-up, chemotherapy or surgery, for example). However, histology remains the standard in the differential diagnosis of pancreatic tumours. Regarding lymph nodes, CE-EUS cannot replace EUS-guided fine-needle aspiration. Elastography examines the elastic properties of tissues by applying a slight compression to the tissue and comparing an image obtained before and after this compression. EUS elastography is a new application in the field of endosonography and seems to be able to differentiate fibrous and benign tissue from malignant lesions. While our results are very encouraging, further research will be needed to further define the place of this new technique and should be aimed at further defining criteria for accurate elastography as well as subsequently assessing the technique using multiple operators in a blinded setting. EUS-guided sonoelastography has the potential for further guiding the diagnosis and therapy of gastrointestinal-related tumours.

Molecular imaging in neuroendocrine tumors: molecular uptake mechanisms and clinical results

Neuroendocrine tumors can originate almost everywhere in the body and consist of a great variety of subtypes. This paper focuses on molecular imaging methods using nuclear medicine techniques in neuroendocrine tumors, coupling molecular uptake mechanisms of radiotracers with clinical results. A non-systematic review is presented on receptor based and metabolic imaging methods. Receptor-based imaging covers the molecular backgrounds of somatostatin, vaso-intestinal peptide (VIP), bombesin and cholecystokinin (CCK) receptors and their link with nuclear imaging. Imaging methods based on specific metabolic properties include meta-iodo-benzylguanide (MIBG) and dimercapto-sulphuric acid (DMSA-V) scintigraphy as well as more modern positron emission tomography (PET)-based methods using radio-labeled analogues of amino acids, glucose, dihydroxyphenylalanine (DOPA), dopamine and tryptophan. Diagnostic sensitivities are presented for each imaging method and for each neuroendocrine tumor subtype. Finally, a Forest plot analysis of diagnostic performance is presented for each tumor type in order to provide a comprehensive overview for clinical use.

Duodeno-pancreatic neuroendocrine tumours

Duodeno-pancreatic neuroendocrine tumours (DP-ETs) are increasingly diagnosed today due to the widespread use of modern imaging methods. Duodeno-pancreatic endocrine tumours should be treated by radical surgical resection, which offers a high chance for cure when the disease is localized. A high index of suspicion is required in these patients for the presence of a multiple endocrine neoplasia type syndrome. We present four patients with DP-ET surgically treated at our department between 2000 and 2004. Histological/immunohistochemical diagnosis was somatostatin-producing tumour in the first patient, oncocytic endocrine tumour positive for neurone-specific enolase and focally for chromogranin in the second patient, glucagonoma and pancreatic polypeptide-producing endocrine pancreatic tumour in the third patient, and gastrin, somatostatin, calcitonin, insulin and adrenocorticotropic hormone (ACTH)-producing tumour in the fourth. The second patient died 6.5 years following surgery due to disseminated disease.

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.

Improved differentiation of pancreatic tumors using contrast-enhanced endoscopic ultrasound

BACKGROUND & AIMS

Endoscopic ultrasound is a widely accepted imaging method for staging of ductal adenocarcinoma and the localization of neuroendocrine tumors of the pancreas. We prospectively evaluated conventional color Doppler imaging and contrast-enhanced endoscopic Doppler ultrasound (CE-EDUS) as a new imaging technique for further characterization and differentiation of solid pancreatic tumors.

METHODS

From 300 patients with pancreatic lesions investigated using contrast-enhanced endoscopic ultrasound we could finally include 93 patients with an undetermined, solitary, predominantly solid, lesion 40 mm or less, and a definite histologically proven diagnosis. After bolus injection of the contrast agent SHU 508A 4 g (400 mg/dL) the vascular pattern of the lesion during the arterial phase was compared with the vascularity of the residual pancreatic parenchyma.

RESULTS

Color Doppler imaging did not reveal vascularity of the pancreatic parenchyma in any of the patients, and therefore tumor hypovascularity could not be determined in contrast to all CE-EDUS-examined patients revealing at least some degree of parenchymal vascularity. Fifty-seven of 62 patients with ductal adenocarcinoma of the pancreas showed a hypovascularity of the tumor using CE-EDUS. All other pancreatic lesions revealed an isovascular or hypervascular pattern using contrast-enhanced endoscopic ultrasound (20 neuroendocrine tumors, 10 serous microcystic adenomas, and 1 teratoma). Hypovascularity as a sign of malignancy in contrast-enhanced endoscopic ultrasound obtained 92% (82%-97%) sensitivity and 100% specificity (89%-100%).

CONCLUSIONS

Contrast-enhanced endoscopic ultrasound is effective in differentiating small solid pancreatic tumors of different origin in most cases. Hypovascularity indicates malignancy of pancreatic tumors.

Improved characterisation of solitary solid pancreatic tumours using contrast enhanced transabdominal ultrasound

BACKGROUND

Contrast enhanced ultrasound (CEUS) is a new imaging method for detection and characterisation of liver tumours. The role of CEUS in pancreatic disease is less obvious. We prospectively evaluated CEUS for characterization of undetermined solid pancreatic lesions (gold standard histology).

PATIENTS AND METHODS

A total of 112 solitary undetermined pancreatic masses (70 ductal adenocarcinoma and 42 neoplastic nodules of other origin) were prospectively examined in patients without metastatic disease using transabdominal ultrasound. Tumour enhancing features were analyzed in comparison to the surrounding pancreatic parenchyma in patients with adequate visualisation.

RESULTS

The sign of iso-hypervascularity as a sign of non-ductal adenocarcinoma showed a sensitivity of 100%, specifity of 90% and accuracy of 93.8%. The sign of hypovascularity as a sign of ductal adenocarcinoma showed a sensitivity of 90%, specifity of 100% and an accuracy of 93.8%.

CONCLUSION

CEUS allows differential diagnosis of ductal adenocarcinoma and non-ductal adenocarcinoma (mainly neuroendocrine tumours and (microcystic) serous pancreatic adenoma) in the most of cases.

Acute severe pancreatitis: contrast-enhanced sonography

Early assessment and differentiation of oedematous acute pancreatitis and necrotizing or severe acute pancreatitis allow distinct therapeutic algorithms. Spiral computed tomography is currently considered the gold standard for staging of acute severe pancreatitis. Conventional transabdominal ultrasound plays only a limited role in the staging of acute pancreatitis. The problem is that with this procedure a detection of pancreatic necrosis is difficult because it cannot assess organ perfusion. Through the use of contrast-enhancers, however, even ultrasound can nowadays examine the vascularization behaviour of the pancreas and liver parenchyma in sufficient detail. The aim of the present update article is to explain the usefulness of contrast-enhanced ultrasound in the detection of parenchymal necrosis in patients with acute severe pancreatitis.

Contrast-enhanced sonography in pancreatic diseases

Contrast-enhanced sonography is a widely available imaging modality for the diagnosis of pancreatic diseases. With this procedure, pancreatic tumours can be differentiated better. Furthermore, contrast-enhanced sonography produces good results in the staging of acute pancreatitis severity, especially in the detection of pancreatic necrosis. In this review article the value of contrast-enhanced sonography in the diagnosis of pancreatic diseases will be described and discussed.

Sonographic diagnosis and endoscopic therapy of a biliopancreatic fistula complicating a pancreatic pseudocyst

This is the first report of a case of biliopancreatic fistula complicating a pancreatic pseudocyst diagnosed correctly by transabdominal ultrasound. The diagnosis was confirmed by magnetic resonance and endoscopic retrograde cholangiopancreatography. The fistula was treated successfully with biliary stenting. The clinical and imaging features of this exceptional complication are presented along with a brief review of the topic.

Echo-enhanced ultrasound with pulse inversion imaging: A new imaging modality for the differentiation of cystic pancreatic tumours

AIM: To describe and discuss echo-enhanced sonography in the differential diagnosis of cystic pancreatic lesions.

METHODS: The pulse inversion technique (with intravenous injection of 2.4 mL SonoVue^®) or the power-Doppler mode under the conditions of the 2^nd harmonic imaging (with intravenous injection of 4 g Levovist^®) was used for echo-enhanced sonography.

RESULTS: Cystadenomas frequently showed many vessels along fibrotic strands. On the other hand, cystadenocarcinomas were poorly and chaotically vascularized. ”Young pseudocysts” were frequently found to have a highly vascularised wall. However, the wall of the ”old pseudocysts” was poorly vascularized. Data from prospective studies demonstrated that based on these imaging criteria the sensitivities and specificities of echo-enhanced sonography in the differentiation of cystic pancreatic masses were > 90%.

CONCLUSION: Cystic pancreatic masses have a different vascularization pattern at echo-enhanced sonography. These characteristics are useful for their differential diagnosis, but histology is still the gold standard.

Echo-enhanced ultrasound--a new imaging modality for the differentiation of pancreatic lesions

INTRODUCTION

Echo-enhanced ultrasound is a newly available mode of imaging for differential diagnosis of pancreatic tumours. Ductal carcinomas are often hypovascularised compared with the surrounding tissue. Neuroendocrine tumours, on the other hand, are hypervascularised lesions. Tumours associated with pancreatitis have a different vascularisation pattern depending on inflammation and necrosis. Cystadenomas frequently have many vessels along the fibrotic strands.

RESULTS

Data from prospective studies have demonstrated, on the basis of these imaging criteria, that the sensitivity and specificity of echo-enhanced sonography for differentiation of pancreatic masses are >or=85 and >or=90%, respectively.

CONCLUSIONS

Pancreatic tumours have a different vascularisation pattern in echo-enhanced ultrasound. These characteristics can be used with high diagnostic accuracy for differential diagnosis.

Endocrine tumours of the gastrointestinal tract. Management of metastatic endocrine tumours

Gastroenteropancreatic tumours are rare. They compromise a heterogenous class of neoplasm. If there is no hypersecretion syndrome, symptoms may be uncharacteristic and thus diagnosis occurs rather late after the first manifestations of the disease. The most important prognostic parameters are histological classification, the localisation of the primary, the tumour size and stage at diagnosis, and the presence or absence of metachronous or synchronous neoplasia. The article will focus on the importance of each of these parameters for the various treatment options in patients with metastatic disease.

Differentiation of cystic pancreatic neoplasms and pseudocysts by conventional and echo-enhanced ultrasound

BACKGROUND AND AIMS

Echo-enhanced sonography is a non-invasive and increasingly used procedure for the differentiation of pancreatic tumors. However, the diagnostic accuracy of this procedure compared to conventional ultrasound for the differential diagnosis of cystic pancreatic neoplasms from pseudocysts has never been investigated in a prospective study.

METHODS

Thirty-one patients with a cystic pancreatic lesion at the conventional ultrasound (mean age 57 years, range 36-82 years) were included in the study. Sonography was performed by an experienced examiner who was unaware of the patients' clinical diagnosis. The exact diagnosis was based on histological evidence from biopsy examination (surgical or transabdominal fine needle biopsy for all cystic neoplasms and five pseudocysts), or a follow-up of at least 18 months (four pseudocysts).

RESULTS

Of the 31 patients, 19 had cystadenomas, three had cystadenocarcinomas, and nine had pseudocysts. Only 27% of the cystadenomas and 67% of the pseudocysts could be correctly classified by conventional ultrasound. Conversely, 95% of the cystadenomas (P = 0.0001) and all pseudocysts were diagnosed correctly by echo-enhanced sonography. The sensitivity of echo-enhanced sonography with respect to diagnosing cystadenoma was 95% and its specificity was 92%. The corresponding values for pseudocysts were both 100%.

CONCLUSION

Echo-enhanced sonography has a high sensitivity and specificity in the differential diagnosis of cystic pancreatic tumors. With this procedure the differentiation of cystadenomas and pseudocysts can be improved. However, histology is the standard of reference.

Evaluation of diagnostic criteria for liver metastases of adenocarcinomas and neuroendocrine tumours at conventional ultrasound, unenhanced power Doppler sonography and echo-enhanced ultrasound

PURPOSE

In order to improve the differential diagnosis between liver metastases of neuroendocrine tumours and adenocarcinomas, criteria for the masses at conventional ultrasound, unenhanced power Doppler sonography and echo-enhanced ultrasound were evaluated.

METHODS

Seventy-three patients with histologically proven liver metastases of a neuroendocrine tumour (n = 26) or an adenocarcinoma (n = 47) were investigated by conventional ultrasound as well as unenhanced power Doppler sonography and echo-enhanced ultrasound focusing on specific properties of the lesions.

RESULTS

Liver metastases of neuroendocrine tumours and adenocarcinomas showed a different contrast behaviour with echo-enhanced sonography. A hypervascularisation at the arterial and capillary phase were found in 85% of the neuroendocrine metastases, and in 17% of the masses of adenocarcinomas, respectively (p < 0.05).

CONCLUSIONS

The successful treatment of liver metastases requires a highly sensitive and specific diagnostic procedure for their differentiation. A hypervascularisation of the lesions during the arterial and capillary phase at echo-enhanced ultrasound may point to a neuroendocrine primary tumour. However, histology is the only standard of reference for the differentiation of liver metastases, and is necessary for optimal therapy.

Diagnosis of non-functioning neuro-endocrine gastro-enteropancreatic tumours

Non-functioning neuro-endocrine gastro-enteropancreatic tumours are neoplasms of neuro-endocrine differentiation without symptoms of hormonal hypersecretion. In pancreatic tumours, symptoms are related to an expanding tumour mass, while most midgut tumours are small and symptoms of intermittent intestinal entrapment are due to mesenteric fibrosis. Positive somatostatin receptor imaging indicates the neuro-endocrine differentiation of the tumour. The high spatial resolution of MRI/CT improves preoperative planning. In localized pancreatic tumours, curative resection of the primary improves survival. In midgut tumours, resection of the primary should be performed, irrespective of the presence of liver metastases. Palliative surgery and cytoreductive therapy of liver metastases may prolong survival in both, pancreatic and midgut tumours. Combination chemotherapy is effective in pancreatic disease, while in midgut tumours the response rate is only 22%. As the antiproliferative effect of biotherapy is still uncertain, it cannot yet be recommended as a routine treatment in non-functioning neuro-endocrine gastro-enteropancreatic tumours.

Echo-enhanced sonography--an increasingly used procedure for the differentiation of pancreatic tumors

Echo-enhanced sonography is increasingly being used for differential diagnosis of pancreatic tumors. Ductal carcinomas are often hypovascularized compared with the surrounding tissue. On the other hand, neuroendocrine tumors are hypervascularized lesions. Tumors associated with pancreatitis have a different vascularization pattern depending on inflammation and necrosis. Cystadenomas frequently show many vessels along the fibrotic strands. Pancreatic tumors have a different vascularization pattern in echo-enhanced sonography. These characteristics can be used for differential diagnosis. However, histology is the standard of reference.