Evaluation of contrast enhancement patterns in pancreatic tumors by coded harmonic sonographic imaging with a microbubble contrast agent

The Impact of Combined Chemotherapy and Intra-Tumoural Injection of Phosphorus-32 Microparticles on Vascularity in Locally Advanced Pancreatic Carcinoma

BACKGROUND

Poor intra-tumoural vascularity contributes to a lack of response to chemotherapy in pancreatic cancers. Preliminary data suggest that the addition of endoscopic ultrasound (EUS)-guided intra-tumoural injection of phosphorus-32 (32P) microparticles to standard chemotherapy is potentially beneficial in locally advanced pancreatic cancer (LAPC). We aimed to assess changes in pancreatic tumour vascularity following 32P implantation, using contrast-enhanced EUS (CE-EUS).

METHODS

This was a prospective single-centre trial from January 2022 to 2024 of patients with unresectable, non-metastatic LAPC undergoing standard FOLFIRINOX chemotherapy and 32P implantation. We performed CE-EUS pre-implantation after two chemotherapy cycles and 4 and 12 weeks after implantation. Time-intensity curves were analysed for 90 s after IV contrast bolus to ascertain peak intensity and intensity gain.

RESULTS

A total of 20 patients underwent 32P implantation, with 15 completing 12-week follow-up. The technical success of 32P implantation was 100%. The median primary tumour size reduced from 32 mm (IQR 27.5-38.75) pre-implantation to 24 mm (IQR 16-26) 12 weeks post-implantation (p < 0.001). Five patients (25%) had tumour downstaging, and four underwent resections. The baseline (pre-implantation, post-chemotherapy) median intensity gain of contrast enhancement within the tumour was 32.15 (IQR 18.08-54.35). This increased to 46.85 (IQR 35.05-76.6; p = 0.007) and 66.3 (IQR 54.7-76.3; p = 0.001) at 4 weeks and 12 weeks post-implantation, respectively. Over a median follow-up of 11.2 months (IQR 7.8-12.8), 15/20 (75%) of patients remained alive, with 3/20 (15%) demonstrating local disease progression. Overall survival was not significantly different between patients with or without an increased intensity of 10 a.u. or more at 12 weeks post-implantation.

CONCLUSION

This is the first clinical study to demonstrate treatment-induced increased vascularity within pancreatic primary tumours, which followed 32P implantation and FOLFIRINOX chemotherapy. Larger comparative trials are warranted.

Pancreatic ductal adenocarcinoma: CEUS characteristics are correlated with pathological findings and help predict early recurrence after resection

OBJECTIVES

To identify characteristics of preoperative contrast-enhanced ultrasound (CEUS) that could predict early recurrence after curative resection of pancreatic ductal adenocarcinoma (PDAC).

METHODS

From January 2017 to September 2022, a total of 110 patients with PDAC (all confirmed by samples obtained via operation) who underwent CEUS within 1 month before surgery were enrolled. We proposed five CEUS enhancement patterns (Pattern I, homogeneous enhancement; Pattern II, heterogeneous enhancement without cystic components; pattern III, ring enhancement; Pattern IV, starry enhancement; Pattern V, heterogeneous enhancement with cystic components) of PDAC. Clinical-pathologic and CEUS characteristics for predicting early recurrence (recurrence within 1 year after curative resection) were analyzed. Important CEUS characteristics were compared with the pathological findings.

RESULTS

Tumor size and TNM stage were closely associated with early recurrence. Incomplete-enhancement and enhancement pattern III, IV and V at CEUS imaging were more prone to early recurrence. Incomplete-enhancement lesions had higher histological tumor grades, less frequent remaining acini, and more frequent necrosis within the tumor. PDACs with pattern I and II had lower histological tumor grades, and pattern III, IV and V had higher histological tumor grades. PDACs with pattern I, II and IV had less frequent intratumoral necrosis than PDACs with pattern III and V, and PDACs with pattern IV had lower MVD values.

CONCLUSIONS

PDACs with incomplete enhancement and enhancement pattern III, IV and V were more prone to early recurrence after attempted curative resection, and these important CEUS characteristics were closely related to the pathological findings of PDAC.

Development and validation of an ultrasound-based prediction model for differentiating between malignant and benign solid pancreatic lesions

OBJECTIVE

To identify the diagnostic ability of precontrast and contrast-enhanced ultrasound (CEUS) in differentiating between malignant and benign solid pancreatic lesions (MSPLs and BSPLs) and to develop an easy-to-use diagnostic nomogram.

MATERIALS AND METHODS

This study was approved by the institutional review board. Patients with pathologically confirmed solid pancreatic lesions were enrolled from one tertiary medical centre from March 2011 to June 2021 and in two tertiary institutions between January 2015 and June 2021. A prediction nomogram model was established in the training set by using precontrast US and CEUS imaging features that were independently associated with MSPLs. The performance of the prediction model was further externally validated.

RESULTS

A total of 155 patients (mean age, 55 ± 14.6 years, M/F = 84/71) and 78 patients (mean age, 59 ± 13.4 years, M/F = 36/42) were included in the training and validation cohorts, respectively. In the training set, an ill-defined border and dilated main pancreatic duct on precontrast ultrasound, CEUS patterns of hypoenhancement in both the arterial and venous phases of CEUS, and hyperenhancement/isoenhancement followed by washout were independently associated with MSPLs. The prediction nomogram model developed with the aforementioned variables showed good performance in differentiating MSPLs from BSPLs with an area under the curve (AUC) of 0.938 in the training set and 0.906 in the validation set.

CONCLUSION

Hypoenhancement in all phases, hyperenhancement/isoenhancement followed by washout on CEUS, an ill-defined border, and a dilated main pancreatic duct were independent risk factors for MSPLs. The nomogram constructed based on these predictors can be used to diagnose MSPLs.

KEY POINTS

• An ill-defined border and dilated main pancreatic duct on precontrast ultrasound, hypoenhancement in all phases of CEUS, and hyperenhancement/isoenhancement followed by washout were independently associated with MSPLs. • The ultrasound-based prediction model showed good performance in differentiating MSPLs from BSPLs with an AUC of 0.938 in the training set and 0.906 in the external validation set. • An ultrasound-based nomogram is an easy-to-use tool to differentiate between MSPLs and BSPLs with high efficacy.

Evaluation of the diagnostic performance of the EFSUMB CEUS Pancreatic Applications guidelines (2017 version): a retrospective single-center analysis of 455 solid pancreatic masses

OBJECTIVES

To explore the diagnostic performance of EFSUMB CEUS Pancreatic Applications guidelines (version 2017) before and after the addition of iso-enhancement and very fast/fast washout as supplementary diagnostic criteria for PDAC.

METHODS

In this retrospective study, patients diagnosed with solid pancreatic lesions from January 2017 to December 2020 were evaluated. Pancreatic ductal adenocarcinoma (PDAC) is reported to show hypo-enhancement in all phases according to the EFSUMB guidelines. First, based on this definition, all lesions were categorized as PDAC and non-PDAC. Then, iso-enhancement and very fast/fast washout were added as supplementary diagnostic criteria, and all lesions were recategorized. The diagnostic performance was assessed in terms of the accuracy (ACC), sensitivity (SEN), specificity (SPE), positive predictive value (PPV), and negative predictive value (NPV). The reference standard consisted of histologic evaluation or composite imaging and clinical follow-up findings.

RESULTS

A total of 455 nodules in 450 patients (median age, 58.37 years; 250 men) were included. The diagnostic performance using the EFSUMB CEUS guidelines for PDAC had an ACC of 69.5%, SEN of 65.4%, SPE of 84%, PPV of 93.5%, NPV of 40.6%, and ROC of 0.747. After recategorization according to the supplementary diagnostic criteria, the diagnostic performance for PDAC had an ACC of 95.8%, SEN of 99.2%, SPE of 84%, PPV of 95.7%, NPV of 96.6%, and ROC of 0.916.

CONCLUSION

The EFSUMB guidelines and recommendations for pancreatic lesions can effectively identify PDAC via hypo-enhancement on CEUS. However, the diagnostic performance may be further improved by the reclassification of PDAC lesions after adding iso-enhancement and very fast/fast washout mode.

KEY POINTS

• In the EFSUMB guidelines, the only diagnostic criterion for PDAC is hypo-enhancement, to which iso-enhancement and very fast/fast washout mode were added in our research. • Using hypo-enhancement/iso-enhancement with very fast/fast washout patterns as the diagnostic criteria for PDAC for solid pancreatic masses on CEUS has high diagnostic accuracy. • The blood supply pattern of PDAC can provide important information, and CEUS has unique advantages in this respect due to its real-time dynamic attenuation ability.

SIUMB recommendations for focal pancreatic lesions

Contrast-enhanced ultrasonography (CEUS) is increasingly being performed in Italy and Europe, particularly in the field of hepato-gastroenterology. Initially, it was mainly carried out to characterize focal hepatic lesions, but, since then, numerous studies have demonstrated its efficacy in the differential diagnosis of focal pancreatic pathologies (D'Onofrio et al. in Expert Rev Med Devices 7(2):257-273, 2010; Vidili et al. in J Ultrasound 22(1):41-51, 2019). The purpose of this paper is to provide Italian Medical Doctors with recommendations and thereby practical guidelines on the management of these patients. The present paper reports the final conclusions reached by the SIUMB guideline commission. This paper addresses particularly percutaneous ultrasound (US) examination (transabdominal US) and is drawn up specifically for publication.

Application of Contrast-Enhanced Ultrasound in the Diagnosis of Solid Pseudopapillary Tumors of the Pancreas: Imaging Findings Compared With Contrast-Enhanced Computed Tomography

OBJECTIVES

The purpose of this study was to assess the characterization and usefulness of contrast-enhanced ultrasound (CEUS) for diagnosing solid pseudopapillary tumors of the pancreas (SPTP) and compare the enhancement patterns with contrast-enhanced computed tomography (CECT).

METHODS

Forty-three SPTP lesions proved by pathologic findings in 42 patients examined with CEUS and CECT were included in this study. The enhancement characteristics and typical CEUS features of the tumors were investigated. These characteristics were compared according to lesion sizes. The enhancement patterns of CEUS were compared with CECT.

RESULTS

The most common enhancement levels of SPTP in the early phase and late phase for CEUS were isoenhancement (19 of 43 [44.2%]) and hypoenhancement (32 of 43 [74.4%]), respectively. The 4 most common enhancement patterns were hypo-hypo (16 of 43 [37.2%]), iso-iso (11 of 43 [25.6%]), hyper-hypo (8 of 43 [18.6%]), and iso-hypo (8 of 43 [18.6%]) enhancement. For the 43 SPTP lesions, typical CEUS features such as lesion membrane, intralesional vessel, and intralesional compartmentalization enhancements were detected in 30 (69.8%), 27 (62.8%), and 10 (23.2%) cases. Compared with CECT, isoenhancement during the early phase and hypoenhancement during the late phase were the most common imaging characteristics of CEUS.

CONCLUSIONS

Lesion membrane, intralesional vessel, and intralesional compartmentalization enhancements are typical CEUS features of SPTP, especially for large lesions (lesion size ≥3.0 cm). Isoenhancement during the early phase and hypoenhancement during the late phase are the most common imaging characteristics of CEUS and CECT, making CEUS a viable alternative diagnostic method that is noninvasive.

Clinical use of contrast-enhanced ultrasound beyond the liver: a focus on renal, splenic, and pancreatic applications

Contrast-enhanced ultrasound (CEUS) is a relatively novel, but increasingly used, diagnostic imaging modality. In recent years, due to its safety, quickness, and repeatability, several studies have demonstrated the accuracy, specificity, and sensitivity of CEUS. The European Federation of Societies for Ultrasound in Medicine and Biology has recently updated the previous guidelines from 2012 for the use of CEUS in non-hepatic applications. This review deals with the clinical use and applications of CEUS for the evaluation of non-hepatic abdominal organs, focusing on renal, splenic, and pancreatic applications.

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.

A case of stage IA pancreatic ductal adenocarcinoma accompanied with focal pancreatitis demonstrated by contrast-enhanced ultrasonography

A patient with slight dilatation of the main pancreatic duct was followed-up with ultrasonography every 6 months as a high-risk case of pancreatic cancer. Twelve years later, a faint hypoechoic area 13 mm in diameter was first detected on the body of the pancreas. Contrast-enhanced ultrasonography revealed a well-demarcated hypoenhanced area 8 mm in diameter and a hyperenhanced area with an unclear margin. The former was suspected to be a small pancreatic cancer lesion, and the latter to be focal pancreatitis accompanying cancer. However, contrast-enhanced dynamic CT did not suggest any tumor, diagnosis of adenocarcinoma was confirmed with pancreatic juice cytology through endoscopic retrograde pancreatography. Surgical resection was performed, and the lesion was pathologically diagnosed as invasive ductal carcinoma as follows: pTS1 (1.0 cm), infiltrative type (pT1), stage IA. When comparing the images from contrast-enhanced ultrasonography with the pathological findings, the hypoenhanced area corresponded to ductal adenocarcinoma, and the hyperenhanced area to focal pancreatitis. Contrast-enhanced ultrasonography was able to reveal detailed information on the focal lesion in the pancreas, and it was effective for the early diagnosis of pancreatic cancer.

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.

Amendment of the Japanese Consensus Guidelines for Autoimmune Pancreatitis, 2013 I. Concept and diagnosis of autoimmune pancreatitis

BACKGROUND

In response to the proposal of the international consensus diagnostic criteria (ICDC) for autoimmune pancreatitis (AIP) and the Japanese diagnostic criteria in 2011, the 2009 Japanese consensus guidelines for managing AIP required revision.

METHODS

Three committees [the professional committee for making clinical questions (CQs) and statements by Japanese specialists, the expert panelist committee for rating statements by the modified Delphi method, and the evaluating committee by moderators] were organized. Fifteen specialists for AIP extracted the specific clinical statements from 1,843 articles published between 1963 and 2012 (obtained from Pub Med and a secondary database, and developed the CQs and statements. The expert panel individually rated the clinical statements using a modified Delphi approach, in which a clinical statement receiving a median score greater than seven on a nine-point scale from the panel was regarded as valid.

RESULTS

The professional committee created 13 CQs and statements for the current concept and diagnosis of AIP, 6 for extra-pancreatic lesions, 6 for differential diagnosis, and 11 for treatment.

CONCLUSION

After evaluation by the moderators, amendments to the Japanese consensus guidelines for AIP have been proposed for 2013.

Clinicopathological analysis of contrast-enhanced ultrasonography using perflubutane in pancreatic adenocarcinoma

The contrast harmonic imaging technique allows visualization of micro bubbles and has facilitated the detection of blood flow on contrast-enhanced ultrasonography (CE-US). In hypovascular tumors such as pancreatic cancer a hypoxic nutrition-deficient environment increases tumor malignancy. In this study, we investigated the relation between CE-US findings, intratumoral microvessel density (MVD), and pathological analysis in pancreatic cancer, and we also investigated the clinicopathological significance of CE-US.The subjects were 16 pancreatic cancer patients who underwent CE-US before surgery. A time-signal intensity curve (TIC) was prepared based on the region of interest (ROI) in the tumor on CE-US, and the signal intensity (SI) was defined as an increase from the value before contrast imaging to the maximum value. Regarding MVD, histological sections were stained with anti-CD34 and α-smooth muscle actin (α-SMA) antibodies, and double stained micro-blood vessels were counted. The correlation between SI and MVD was investigated. In addition, disease-free survival (DFS) was compared between the hypo (≤mean SI) and hyper (>mean SI) SI groups.SI in cancerous lesions was 54.6±42.9 dB (mean±SD), and MVD in cancerous lesions was 12.5±5.02 (mean±SD). A positive correlation was noted between the SI and MVD (r(2)=0.408, p=0.008). The median DFS were 212 and 606 days in the hypo and hyper SI groups, respectively, showing a significantly shorter DFS in the hypo SI group (P=0.003). No patient died of the primary disease during the follow-up period in the hyper SI group, and a maximum 47-month follow-up was possible. A positive correlation was noted between SI and MVD, indicating that MVD of pancreatic cancer could be evaluated using CE-US. We suggested that CE-US is a useful predictor of patient prognosis after pancreatic cancer surgery.

Contrast-enhanced ultrasound in the differential diagnosis of exocrine versus neuroendocrine pancreatic tumors

OBJECTIVES

Contrast-enhanced ultrasound (CEUS) has been developed to better characterize the microvasculature of solid masses in several organs, including the pancreas. In this study, we assessed CEUS accuracy in differentiating exocrine from endocrine pancreatic tumors.

METHODS

A total of 127 patients with single, undetermined pancreatic masses were prospectively examined with transabdominal ultrasound and CEUS, before surgical resection or percutaneous biopsy.

RESULTS

Exocrine and endocrine pancreatic tumors showed different intralesional vascularization patterns: 98.9% (90/91) of exocrine tumors were hypoenhancing, whereas 95.8 % (23/24) of endocrine tumors had a hypervascular supply. A hypoenhancing pattern, indicative of ductal adenocarcinoma, had a significant (P < 0.001) diagnostic accuracy of 91.3% with a sensitivity of 96.8%, a specificity of 85.3%, a positive predictive value and a negative predictive value of 94.7% and 90.6%, respectively. The hyperenhancing pattern, indicative of endocrine tumors, had a significant (P = 0.031) diagnostic accuracy of 73.8% with a sensitivity of 83.3%, a specificity of 60.0%, a positive predictive value and negative predictive value of 83.3% and 60.0%, respectively.

CONCLUSIONS

Contrast-enhanced ultrasound has a valuable diagnostic accuracy in differentiating exocrine from endocrine pancreatic tumors, which is a fundamental step to address appropriate histological evaluation, therapeutic approach, and follow-up.

Intra-/Interobserver Agreement of Enhancement Pattern for Pancreatic Head Lesions Using Contrast-Enhanced Ultrasound: According to EFSUMB Guidelines

Objective: To evaluate the intra-/interobserver agreement of the visual interpretation of contrast-enhanced ultrasound (CEUS) of pancreatic head lesions and its concordance with the histological test results. Material and Methods: Two observers (A + B) evaluated by simple visual interpretation 40 consecutive CEUS examinations of pancreatic head lesions and one of the observers evaluated the examinations twice (A1 + A2). The examinations were evaluated according to the criteria outlined in EFSUMB guidelines. The two experienced observers were blinded to histological evidence and clinical information of tumor type and to each other’s results. Results: The kappa value for the intraobserver evaluation between observer A1 and A2 was 0.89, equating to almost perfect agreement. The kappa value for the interobserver evaluation between observer A1 and B was 0.76 and between observer A2 and B it was 0.75, both equating to substantial agreement. Evaluation of the visual interpretation compared to the histological test result showed a positive predictive value for A1, A2 and B versus biopsy of 97%, 94% and 90% respectively and an accuracy of 83%, 88% and 73% respectively. Conclusions: Visual interpretation for assessment of contrast enhancement of pancreatic head lesions seemed to be an accurate method with reproducible results and good concordance with the histological test results.

Pancreatic multicenter ultrasound study (PAMUS)

AIM

To describe the typical CEUS pattern of pancreatic lesions and to evaluate the diagnostic accuracy of Contrast-enhanced ultrasound (CEUS) in their characterization.

MATERIALS AND METHODS

All US and CEUS examinations of focal pancreatic masses performed in six centers during a period of five years were reviewed. Inclusion criteria were: focal pancreatic mass pathologically proved, visible at ultrasound (US) and studied with CEUS. All lesions were then evaluated for size, aspect and enhancement pattern. Sensitivity, specificity, positive and negative predictive values with 95% CIs were calculated to define diagnostic accuracy of CEUS in respect to pathology. Diagnostic confidence of US and CEUS, discerning between benign and malignant lesions, were represented by using ROC (receiver operating characteristics) curves. Agreement was evaluated by means of k statistics.

RESULTS

1439 pancreatic lesions were included. At CEUS the lesions were divided into solid (89%) and cystic (12%) masses and classified into six and eight categories, respectively. Among the solid lesions, adenocarcinomas were characterized with an accuracy of 87.8%. Among the cystic lesions, cystic tumors were diagnosed with an accuracy of 97.1%. ROC curve area increased from 0.637 for US to 0.877 for CEUS (p<0.0001). Inter-observer agreement was slightly higher for solid (k=0.78) than cystic (k=0.62) lesions. In none of the centers side effects were reported.

CONCLUSION

CEUS is accurate in the characterization of pancreatic lesions. CEUS should be considered as a complementary imaging method for pancreatic lesions characterization.

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.

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.

Multimodal imaging in functional endocrine pancreatic tumors

Endocrine pancreatic tumors, also known as pancreatic islet tumors, are rare entities of neuroendocrine origin that are located within the pancreas or in its close proximity. Approximately 50% of these tumors secrete biologically active substances that lead to the development of specific clinical syndromes. Once diagnosis has been established on the basis of clinical and laboratory findings, localization of the source of pathologic hormone secretion is warranted. Endocrine pancreatic tumor imaging comprises anatomical imaging modalities, such as ultrasound, computed tomography (CT) and MRI, as well as functional radiological studies, including arterial calcium stimulation with hepatic venous sampling, and functional nuclear medicine imaging modalities, such as scintigraphy and PET. The recent combination of high-resolution anatomic studies and functional imaging, such as PET/CT and single-photon emission CT/CT, allows excellent diagnostic evaluation of pancreatic islet cell tumors and has, therefore, especially high value. Given that none of these imaging methods are exclusively superior to the others, visualization of pancreatic islet cell tumors often requires the combination of different imaging modalities.

Usefulness of contrast-enhanced transabdominal ultrasound for tumor classification and tumor staging in the pancreatic head

OBJECTIVE

To evaluate contrast-enhanced ultrasound (CEUS) and compare it to ultrasound (US) and 64-slice-CT (64-CT) for diagnosing, staging and evaluation of resectability of pancreatic cancer.

MATERIAL AND METHODS

US, CEUS and 64-CT were performed in 49 consecutive patients with pancreatic head tumors and with suspected cancer. After evaluation 44 patients had pancreatic head adenocarcinoma and 5 had chronic pancreatitis, all confirmed by histology.

RESULTS

The sensitivity of US, CEUS and 64-CT for diagnosing malignant pancreatic head tumors was 89%, 86% and 93%, respectively, and the overall accuracy was 82%, 86% and 88% respectively. There was no significant difference in the malignant tumor size measurement between US and CEUS (p = 0.3619) or between US and 64-CT (p = 0.2129), but a significant difference was seen in the size measured by CEUS and 64-CT (p = 0.0197). The CEUS measurements on the tumor size were smaller. The overall accuracy for M staging of the patients who had surgery for adenocarcinoma was 86% and 90% for US + CEUS and 64-CT, respectively. By performing the CEUS and 64-CT we additionally found, respectively, 35% and 45% non-resectable patients of a group of patients, who were considered resectable on the primary radiological image material.

CONCLUSIONS

CEUS may be a useful diagnostic tool in the diagnosis and staging of pancreatic head tumors. For the assessment of resectability CEUS did not prove useful. However, CEUS seemed very useful as an additional instrument in the detection of non-resectable patients already considered resectable on primary radiological image material.

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.

Imaging techniques in pancreatic tumors

Conventional ultrasonography represents the first diagnostic imaging modality for the study of pancreatic tumors. Contrast-enhanced ultrasound has significantly improved the accuracy of first-line examination and may influence the choice of second-line investigations: multidetector computed tomography is considered the gold standard for studying pancreatic solid lesions and tumor staging, while MRI with magnetic resonance cholangiopancreatography allows better study of pancreatic cystic lesions and the ductal system. To definitely diagnose a pancreatic lesion, image-guided fine-needle-aspiration or biopsy are very often required. PET with 18-fluorodeoxyglucose, endoscopic ultrasound and intraoperative ultrasonography remain techniques often employed in the third line. This article reviews the imaging techniques generally used for diagnosing the main pancreatic tumors, and a work-up algorithm is finally proposed.

Japanese consensus guidelines for management of autoimmune pancreatitis: I. Concept and diagnosis of autoimmune pancreatitis

As the number of patients with autoimmune pancreatitis (AIP) is increasing in Japan, practical guidelines for managing AIP need to be established. Three committees [the professional committee for developing clinical questions (CQs) and statements by Japanese specialists, the expert panelist committee for rating statements by the modified Delphi method, and the evaluating committee of moderators] were organized. Fifteen AIP specialists extracted specific clinical statements from a total of 871 articles in the literature using a PubMed search (1963-2008) and a secondary database, and developed the CQs and statements. The expert panelists individually rated these clinical statements using a modified Delphi approach in which a clinical statement receiving a median score greater than 7 on a 9-point scale from the panel was regarded as valid. The professional committee developed 13, 6, 6, and 11 CQs and statements for the concept and diagnosis, extra-pancreatic lesions, differential diagnosis and treatment, respectively. The expert panelists regarded them as valid after two-round modified Delphi approaches.After evaluation by the moderators, the Japanese clinical guidelines for AIP were established. The digest versions of the present guidelines have been published in the official journal of the Japan Pancreas Society, "Pancreas." Full versions divided into three series are scheduled to be published in the present and followings two issues in the Journal of Gastroenterology with approval of Professor Go VLW, the Editor-in-Chief of "Pancreas."

Resectable pancreatic adenocarcinoma: is the enhancement pattern at contrast-enhanced ultrasonography a pre-operative prognostic factor?

The aim of our study was to determine whether the enhancement pattern of pancreatic adenocarcinoma at contrast-enhanced ultrasonography (CEUS) is related to patient prognosis after resection. CEUS of 42 resected adenocarcinomas were retrospectively reviewed. Tumors were divided into two groups: group A=poorly vascularized (presence of avascular areas) or group B=well vascularized (absence of avascular areas). All lesions were resected and underwent pathological examination assessing tumor differentiation as: undifferentiated (poorly differentiated) or differentiated (moderately and well differentiated). Mean vascular density (MVD) was also evaluated. CEUS enhancement and pathology were correlated (Spearman's test). Survival was analyzed with the Kaplan-Meier method. Multivariate analysis was performed with the Cox regression model. There were 30 differentiated and 12 undifferentiated adenocarcinomas at pathology. At CEUS, 10 lesions were poorly vascularized, whereas 32 lesions were well vascularized. Positive correlation was observed between CEUS groups and tumoral differentiation (rs=0.51; p=0.001) and between CEUS and MVD (rs=0.74; p<0.0001). Median survival in patients with group A vascularization at CEUS was significantly lower than in group B (p=0.015). Cox proportional hazard model revealed the presence of poorly vascularized tumor at CEUS (p=0.0001) as a predictor of higher mortality. In conclusion, CEUS enables accurate depiction of the vascularization of adenocarcinoma, with positive correlation to histology grade and MVD.

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.

Japanese clinical guidelines for autoimmune pancreatitis

OBJECTIVES

As the patients with autoimmune pancreatitis (AIP) are increasing in Japan, the practical guideline for managing AIP is required to be established.

METHODS

Three committees (the professional committee for making clinical questions [CQs] and statements by Japanese specialists, the expert panelist committee for rating statements by the modified Delphi method, and the evaluating committee by moderators) were organized. Fifteen specialists for AIP extracted the specific clinical statements from a total of 871 literatures by PubMed search (approximately 1963-2008) and from a secondary database and made the CQs and statements. The expert panelists individually rated these clinical statements using a modified Delphi approach, in which a clinical statement receiving a median score greater than 7 on a 9-point scale from the panel was regarded as valid.

RESULTS

The professional committee made 13, 6, 6, and 11 CQs and statements for the concept and diagnosis, extrapancreatic lesions, differential diagnosis, and treatment, respectively. The expert panelists regarded them as valid after a 2-round modified Delphi approach.

CONCLUSIONS

After evaluation by the moderators, the Japanese clinical guideline for AIP has been established. Further studies for the international guideline are needed after international consensus for diagnosis and treatment.

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.

Autoimmune pancreatitis without a response to steroid therapy: a case which met criteria after withdrawal of steroid

Autoimmune pancreatitis (AIP) sometimes forms a pancreatic mass lesion, which is often difficult to distinguish from pancreatobiliary malignancy, however it generally responds to steroid therapy. A 70-year-old man was referred to our institute with the suspected diagnosis of pancreatic cancer due to a mass lesion detected at the pancreatic head. Various images demonstrated an ill-defined mass at the enlarged pancreatic head with focal narrowing of the main pancreatic duct. Serum antinuclear antibody (ANA) was negative (x40 dilution) on the onset. Forceps biopsy from the narrowed pancreaticobiliary duct and fine-needle aspiration biopsy under endoscopic ultrasonography (EUS-FNAB) ruled out pancreatobiliary malignancy. Steroid therapy was started at 40 mg per day but was not effective according to subsequent image analyses. Repeated EUS-FNA from the pancreatic mass was performed but was again negative for carcinoma. Seven months later, under steroid-off condition, still no response was recognized in the clinical image but the titer of serum ANA was increased to be positive (x80), satisfying the criteria of AIP in Japan (2006). Although very rare, this is a case meeting Japanese criteria of AIP after withdrawal of steroid without response to steroid in the clinical images, suggesting the necessity of careful follow-up.

Changes in tumor vascularity depicted by contrast-enhanced ultrasonography as a predictor of chemotherapeutic effect in patients with unresectable pancreatic cancer

OBJECTIVES

This study was conducted to assess changes in tumor vascularity using contrast-enhanced ultrasonography in patients with pancreatic carcinoma under systemic chemotherapy and to examine the correlation among vascular change, clinicopathologic factors, and outcome.

METHODS

Forty-one consecutive patients with histopathologically confirmed pancreatic carcinoma who had distant metastases and were under systemic chemotherapy were recruited. Contrast-enhanced ultrasonography was performed before and after 1 and 2 cycles of treatment.The vascular signals from the tumor were continuously recorded,and the highest signal intensity was selected and classified into 5 categories by their intensity.

RESULTS

As for the tumor response determined by dynamic computed tomography after 2 cycles, 6 patients showed a partial response, 25 remained stable, and in 10 patients, the disease progressed. A significant relationship was observed between vascular change after 1 cycle and tumor response (P G 0.001). Progression-free survival and overall survival were significantly short in the case of patients showing increased vascularity after 1 and 2 cycles of chemotherapy, compared with those who did not (P G 0.001).

CONCLUSIONS

Contrast-enhanced ultrasonography was useful to evaluate tumor vascular changes and thereby the effect of systemic chemotherapy, as well as the prognosis of patients with advanced pancreatic carcinoma.

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.

Resectable pancreatic adenocarcinoma: depiction of tumoral margins at contrast-enhanced ultrasonography

To evaluate if contrast-enhanced ultrasonography (CEUS) improves the depiction of tumoral margins of pancreatic adenocarcinoma in relation to tumor enhancement, using pathology as criterion standard.

METHODS

Two hundred forty-one patients affected by pancreatic ductal adenocarcinoma were investigated at CEUS with a second-generation contrast medium of sulfur-hexafluoride microbubbles. Sixty-seven (27.8%) of 241 tumors were resected. By consensus, 2 radiologists reviewed the CEUS examination results of the 67 tumors judging the enhancement as low (hypovascular lesions, hypoechoic tothe adjacent parenchyma) or high (iso- or hypervascular lesions, iso- or hyperechoic to the adjacent parenchyma). The resected tumors were evaluated at pathology for the presence of positive neoplastic (R+) or negative neoplastic (R-) resected margins.

RESULTS

Of the 67 resected tumors, 35 (52.3%) were R-, whereas 32 (47.7%) were R+. Moreover, at CEUS, of the 67 resected tumors, 43 (64.1%) were hypovascular with low enhancement and 24 (35.8%) were iso-hypervascular with high enhancement. In the R- group, 27 (77.1%) of 35 tumors were hypovascular. In the R+ group, 16 (50%) of 32 lesions were hypovascular.

CONCLUSIONS

At CEUS the depiction of tumoral margins of pancreatic adenocarcinoma is more accurate in low enhancement than in high enhancement. The pattern of enhancement of pancreatic adenocarcinoma influences the depiction of tumoral margins at CEUS.

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 recurrent pancreatitis: An autoimmune disease?

In this review article, we will briefly describe the main characteristics of autoimmune pancreatitis and then we will concentrate on our aim, namely, evaluating the clinical characteristics of patients having recurrence of pain from the disease. In fact, the open question is to evaluate the possible presence of autoimmune pancreatitis in patients with an undefined etiology of acute pancreatitis and for this reason we carried out a search in the literature in order to explore this issue. In cases of recurrent attacks of pain in patients with “diopathic”pancreatitis, we need to keep in mind the possibility that our patients may have autoimmune pancreatitis. Even though the frequency of this disease seems to be quite low, we believe that in the future, by increasing our knowledge on the subject, we will be able to diagnose an ever-increasing number of patients having acute recurrence of pain from autoimmune pancreatitis.

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.

Differential diagnosis of non-functional islet cell tumor and pancreatic carcinoma with sonography

OBJECTIVE

To investigate the differential diagnosis of non-functional islet cell tumor (NFICT) and pancreatic ductal adenocarcinoma (pancreatic carcinoma) with clinical presentation and sonographic features.

MATERIALS AND METHODS

Twenty cases of NFICT were investigated in the study, and 41 cases of pancreatic carcinoma were included as the control group. Among them, 5 NFICT and 32 pancreatic carcinomas underwent CEUS with SonoVue. Clinical presentation and sonographic characteristics were evaluated with Logistic regression analysis. Furthermore, the preliminary result of contrast enhanced ultrasound (CEUS) was analyzed.

RESULTS

Statistic analysis showed four significant factors in differential diagnosis for NFICT and pancreatic carcinoma, including age (P<0.001), tumor size (P=0.006), tumor margin (P<0.001) and vascularity of tumor (P=0.004). Combined these four factors, the sensitivity, specificity and accuracy are 95.0%, 95.1% and 95.1%, respectively. When the patient is younger than 60 years, and tumor is smaller than 5 cm with well-defined margin and hypervascular, it would be most likely a NFICT other than pancreatic carcinoma. NFICT often shows early enhancement and more homogeneous infusion than pancreatic carcinoma on CEUS (P=0.005 and 0.008).

CONCLUSIONS

Sonography is able to provide useful differential information for NFICT, which is often misdiagnosed as pancreatic carcinoma.

Contrast-enhanced sonography of pancreatic carcinoma: correlations with pathological findings

BACKGROUND

We examined contrast-enhanced harmonic gray-scale sonographic findings of pancreatic carcinoma in relation to the pathological findings in resected specimens to evaluate correlations between observations made by this modality and the pathological findings.

METHODS

The pathological findings of surgical specimens obtained from 16 patients were examined in relation to the contrast-enhanced harmonic gray-scale sonography findings. Lesion vascularity was examined by contrast-enhanced harmonic gray-scale sonography from 20 to 50 s after the injection of Levovist (Schering, Berlin, Germany) (early phase), and lesion enhancement was also monitored at approximately 90 s after injection (delayed phase).

RESULTS

Contrast-enhanced harmonic gray-scale sonography showed positive enhancement in 12 of the 16 lesions (peripheral tumor region alone, n = 9; entire tumor, n = 3), while the other 4 lesions showed no contrast enhancement in any region. Twelve enhanced regions (9 peripheral tumor region and 3 entire tumor regions) detected by contrast-enhanced harmonic gray-scale sonography showed: (1) mild fibrosis with inflammation, in 10 regions (83%); (2) the presence of both carcinoma cells and residual acinar cells in 8 (67%); and (3) presence of relatively large arteries in 2 (17%). In contrast, 13 non-enhanced regions (4 entire tumor regions and 9 central regions) showed: (1) severe fibrosis in 10 regions (77%); (2) necrosis in 7 (54%); and (3) mucin in 4 (31%).

CONCLUSIONS

Contrast-enhanced harmonic gray-scale sonographic findings of pancreatic carcinoma are influenced by interstitial histological features associated with tumor growth.

Contrast-enhanced ultrasonography of small solid pseudopapillary tumors of the pancreas: enhancement pattern and pathologic correlation of 2 cases

OBJECTIVE

The purpose of this series is to describe the value of contrast-enhanced ultrasonography (CEUS) in the characterization of small pseudopapillary tumors (SPTs) of the pancreas.

METHODS

Two cases of SPTs found on conventional ultrasonography, both located at the pancreatic body, were studied with spiral computed tomography, magnetic resonance imaging, and CEUS. A final diagnosis was obtained with histologic analysis after distal pancreatectomy. Immunohistochemical analysis of the tumors with the CD34 antigen was performed.

RESULTS

At CEUS, the 2 SPTs had a slight peripheral rim enhancement in the early dynamic phases. The presence of this enhancement pattern at CEUS, not clear at spiral computed tomography or at magnetic resonance imaging, suggested the diagnosis of SPTs with a peripheral pseudocapsule deriving from the compression of the pancreatic parenchyma. The presence of a perilesional pseudocapsule was proved at immunohistochemical analysis of the tumors with the CD34 antigen.

CONCLUSIONS

Contrast-enhanced ultrasonography can improve the characterization of SPTs by showing the typical rim enhancement of these pancreatic tumors.

Noninvasive assessment of tumor vascularity by contrast-enhanced ultrasonography and the prognosis of patients with nonresectable pancreatic carcinoma

BACKGROUND

Studies have shown that angiogenesis is one of the factors that influences the prognosis of patients with solid tumors, including pancreatic carcinomas. However, none have assessed noninvasively the relation between angiogenesis and prognosis in patients with pancreatic carcinoma. Contrast-enhanced ultrasonography (US) not only is a convenient, harmless, and noninvasive imaging modality, but it also provides detailed information on tumor vascularity. The objectives of this study were to assess the vascularity of pancreatic carcinoma noninvasively by contrast-enhanced US and to clarify the prognostic value of tumor vascularity in patients with nonresectable pancreatic carcinoma.

METHODS

Thirty-five consecutive patients with pathologically confirmed, nonresectable pancreatic carcinoma were examined with contrast-enhanced US before systemic chemotherapy. The correlations among tumor vascularity, clinicopathologic factors, and clinical outcomes then were analyzed statistically to investigate prognostic indicators.

RESULTS

The median time to progression (TTP) was longer in patients who had avascular tumors compared with patients who had vascular tumors (110 days vs. 28 days, respectively; P=0.0072; log-rank test). The median survival also was longer in patients who had avascular tumors (267 days vs. 115 days, respectively; P=0.0034; log-rank test). A multivariate analysis using a Cox proportional hazards model revealed that tumor vascularity was a significant, independent factor that influenced TTP (P <0.001) and survival (P=0.022) along with primary tumor size and serum lactate dehydrogenase (LDH) level, which are well known as prognostic factors in patients with pancreatic carcinoma.

CONCLUSIONS

The current results indicated that contrast-enhanced US may be useful in assessing the prognosis of patients with nonresectable pancreatic carcinoma who receive systemic chemotherapy.