[Evaluation of doppler ultrasonography criteria for the differential diagnosis of pancreatic tumors]

Ultrasound diagnosis of pancreatic solid tumors

INTRODUCTION

Advances and widespread use of various diagnostic imaging modalities have dramatically improved our ability to visualize and diagnose pancreatic diseases. In particular, ultrasonography in pancreatic diseases plays an important role from screening to diagnosis as a simple and safe examination method.

METHODS

The basic scanning method of transabdominal pancreatic ultrasonography, characterization, and differential diagnosis by ultrasonography including contrast-enhanced ultrasonography (CEUS) for solid pancreatic tumors are reviewed with reference to various papers.

RESULTS

In recent years, the ability to visualize and diagnose pancreatic mass lesions has been dramatically improved with advances in ultrasound equipment. In particular, CEUS using an ultrasound contrast agent has made it possible to evaluate hemodynamics in organs or lesions as well as in the flow signal of arterial blood vessels, and it has played an important role not only in diagnosis of the presence of a lesion but also in the qualitative diagnosis. The enhancement behavior and pattern with CEUS of pancreatic solid tumors is shown in text and Fig. 9. Moreover, the flow chart for diagnosing pancreatic solid tumors with CEUS classifying the enhancement behavior and pattern for pancreatic solid tumors on CEUS is shown (Fig. 10). In meta-analyses, the pooled sensitivity in the differential diagnosis of pancreatic adenocarcinomas and other pancreatic focal masses with CEUS was 86-90%, and the pooled specificity was 75-88%.

CONCLUSION

CEUS is a minimally invasive and useful diagnostic method that can be used to make a simple and quick qualitative diagnosis of pancreatic diseases. CEUS provides a lot of information important for diagnosis, and has led to changes in the conventional diagnostic systems in pancreatic diseases.

Quantitative low mechanical index contrast-enhanced endoscopic ultrasound for the differential diagnosis of chronic pseudotumoral pancreatitis and pancreatic cancer

BACKGROUND

Second-generation intravenous blood-pool ultrasound contrast agents are increasingly used in endoscopic ultrasound (EUS) for characterization of microvascularization, differential diagnosis of benign and malignant focal lesions, as well as improved staging and guidance of therapeutic procedures.

METHODS

The aim of our study was to prospectively compare the vascularisation patterns in chronic pseudotumoral pancreatitis and pancreatic cancer using quantitative low mechanical index (MI) contrast-enhanced EUS. We included 51 patients with chronic pseudotumoral pancreatitis (n = 19) and pancreatic cancer (n = 32). Perfusion imaging started with a bolus injection of Sonovue (2.4 ml), followed by analysis in the early arterial (wash-in) and late venous (wash-out) phase. Perfusion analysis was performed by post-processing of the raw data (time intensity curve [TIC] analysis). TIC analysis was performed inside the tumor and the pancreatic parenchyma, with depiction of the dynamic vascular pattern generated by specific software. Statistical analysis was performed on raw data extracted from the TIC analysis. Final diagnosis was based on a combination of EUS-FNA, surgery and follow-up of minimum 6 months in negative cases.

RESULTS

The sensitivity and specificity of low MI contrast enhanced EUS using TIC were sensitivity and specificity of low MI contrast enhanced EUS using TIC analysis were 93.75% (95% CI = 77.77-98.91%) and 89.47% (95% CI = 65.46-98.15%), respectively. Pseudotumoral chronic pancreatitis showed in the majority of cases a hypervascular appearance in the early arterial phase of contrast-enhancement, with a dynamic enhancement pattern similar with the rest of the parenchyma. Statistical analysis of the resulting series of individual intensities revealed no statistically relevant differences (p = .78). Pancreatic adenocarcinoma was usually a hypovascular lesion, showing low contrast-enhancement during the early arterial and also during the late venous phase of contrast-enhancement, also lower than the normal surrounding parenchyma. We found statistically significant differences in values during TIC analysis (p < .001).

CONCLUSIONS

Low MI contrast enhanced EUS technique is expected to improve the differential diagnosis of focal pancreatic lesions. However, further multicentric randomized studies will confirm the exact role of the technique and its place in imaging assessment of focal pancreatic lesions.

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.

Quantitative perfusion analysis of transabdominal contrast-enhanced ultrasonography of pancreatic masses and carcinomas

BACKGROUND & AIMS

Preoperative differential diagnosis of pancreatic ductal adenocarcinoma (PDAC) and focal masses in patients with chronic pancreatitis (CP) can be challenging. There are fine differences in the vascularization of these lesions; ultrasound contrast agents can aid in their differentiation. We evaluated the value of software-aided quantitative analysis of transabdominal contrast-enhanced ultrasonography for differential diagnosis of PDAC vs focal masses.

METHODS

Sixty patients for whom it was not possible to differentiate between an inflammatory focal lesion of the pancreas and a pancreatic carcinoma underwent contrast-enhanced ultrasonography with a second-generation contrast agent. Time-intensity curves were obtained for all exams in 2 regions of interest within the lesion and within the normal pancreatic tissue. Images were processed using Axius ACQ software; the following parameters were obtained: maximum intensity, arrival time, time-to-peak, and area under the curve. Absolute values and differences between the lesion and the normal tissue were evaluated.

RESULTS

Histology analysis revealed 45 PDACs and 15 inflammatory masses in patients with CP. Time-dependent parameters (arrival time and time to peak) were significantly longer in PDACs compared to focal masses. Although markedly lower than in healthy pancreata, the maximum intensity and area under the curve parameters were not significantly different between PDACs and focal lesions in patients with CP.

CONCLUSIONS

In cases of CP, PDAC and focal masses exhibit different perfusion patterns at a capillary level that can be visualized using the small microbubbles of ultrasound contrast agents. Contrast quantification software supplements a subjective visual assessment with objective criteria to facilitate the differential diagnosis of focal lesions in pancreatic cancer and chronic pancreatitis.

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.

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 blood flow in pancreatic ductal carcinoma using contrast-enhanced, wide-band Doppler ultrasonography: correlation with tumor characteristics and vascular endothelial growth factor

BACKGROUND AND AIMS

Tumor vascularization has been attracting attention. However, there have been only a few reports on tumor vascularization in pancreatic ductal carcinoma, especially on vascularization depicted by imaging modalities. We investigated the relationship among wide-band Doppler signals, clinicopathological factors, and vascular endothelial growth factor (VEGF) expression.

METHODS

Sixty-nine patients with pancreatic ductal carcinoma were investigated. The vascular signals from carcinoma lesions were assessed by contrast-enhanced, wide-band Doppler ultrasonography (dynamic flow). VEGF expression was quantitated by enzyme immunoassay for 28 patients. Depending on the intensity of the signals, the patients were classified into type A (definite vascular signal) or type B (almost no vascular signal).

RESULTS

Type A patients and type B patients accounted for 65% and 35% of patients, respectively. According to multivariate analysis of vascular signal type and clinicopathological factors, liver metastasis occurred significantly more frequently in the type A group. VEGF expression was also significantly higher in the type A group than in the type B group.

CONCLUSIONS

Dynamic flow has very high sensitivity for detecting the vascular signals from pancreatic ductal carcinoma. The quantity of vascular signals correlated with tumor characteristics and VEGF.

Differentiation of a pancreatic metastasis of a renal cell carcinoma from a primary pancreatic carcinoma by echo-enhanced power Doppler sonography

In a 70-year-old patient who had been treated for a renal cell carcinoma, a pancreatic mass was detected on CT scan. To differentiate a pancreatic metastasis of the renal cell carcinoma from a pancreatic carcinoma, an echo-enhanced power Doppler sonography was performed. The pancreatic mass demonstrated a strong echo enhancement, proving its hypervascularization. This behaviour favoured the diagnosis of a pancreatic metastasis of the renal cell carcinoma which was confirmed by histology. The principles and the role of echo-enhanced power Doppler sonography in the differential diagnosis between a primary pancreatic carcinoma and a metastasis of a renal carcinoma in the pancreas are discussed. We conclude that this technique can provide an important contribution to the diagnosis in this special instance. However, histology is the standard in the differential diagnosis of pancreatic tumours.

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.

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.

Evaluation of criteria for the activity of Crohn's disease by power Doppler sonography

BACKGROUND/AIM

In recent years, power Doppler sonography has been proposed as a method to assess disease activity in patients with Crohn's disease. The aim of this prospective study was to evaluate diagnostic criteria for power Doppler sonography by blinded comparison with ileocolonoscopy.

METHODS

Twenty-two patients with confirmed Crohn's disease were prospectively investigated with B-mode and power Doppler sonography (HDI 5000, Philips Ultrasound) as well as ileocolonoscopy. Sonography was performed within 3 days before endoscopy. All procedures were performed by experienced examiners who were blinded to the clinical data and other results. Defined ultrasound parameters (bowel wall thickness, vascularization pattern) were used to determine a sonographic score of the activity. The degree of activity was scored from 1 (none) to 4 (high) by both ultrasound and ileocolonoscopy (pattern, extent of typical lesions). For each patient all segments of the colon and the terminal ileum were evaluated by both ultrasound and endoscopy. The weighted kappa test was used (StatXact software) for statistical analysis.

RESULTS

In total, 126 bowel segments were evaluated by both ultrasound and endoscopy. The study showed a high concordance of power Doppler sonography and ileocolonoscopy (weighted kappa by region: sigmoid colon: 0.81; transverse colon: 0.78; ascending colon: 0.75; cecum: 0.84; terminal ileum: 0.82). Highest concordance was found in the descending colon (weighted kappa: 0.91; 95% CI: 0.83-0.98).

CONCLUSIONS

Combination of B-mode and power Doppler sonography has a high accuracy in the determination of disease activity in Crohn's disease when compared to ileocolonoscopy. The diagnostic criteria established in this study can be useful for the evaluation of inflammatory bowel diseases by ultrasound.

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

BACKGROUND AND AIMS

Echo-enhanced power Doppler sonography is a noninvasive procedure that has been increasingly used for the differential diagnosis of pancreatic tumors. However, to our knowledge, the diagnostic accuracy of this procedure in comparison with somatostatin receptor scintigraphy for the differentiation of neuroendocrine lesions from other pancreatic tumors has never been investigated in a prospective, controlled study.

SUBJECTS AND METHODS

One hundred thirty-seven patients were included in the study; the patients were selected from 190 consecutive patients (mean age, 59.8 years; range, 16-85 years) who presented to our department from January 1998 through June 2001 with suspicion of a pancreatic tumor. An experienced examiner who was unaware of the patients' clinical diagnoses performed sonography. Twenty-nine patients with sonographically and/or clinically suspected neuroendocrine tumors were investigated additionally by somatostatin receptor scintigraphy. The exact diagnosis was based upon histologic evidence from biopsy examination (surgical and transabdominal fine-needle biopsy) or a follow-up of at least 18 months.

RESULTS

The sensitivity of echo-enhanced power Doppler sonography for diagnosing a neuroendocrine pancreatic tumor was 94%, and its specificity was 96%. The corresponding values for somatostatin receptor scintigraphy were 54% and 81%, respectively.

CONCLUSIONS

Echo-enhanced power Doppler sonography has high sensitivity and high specificity for the differentiation of neuroendocrine lesions from other pancreatic tumors. However, histologic evidence is the standard of reference for the differential diagnosis of pancreatic tumors.