Ultrasonography of the pancreas. 4. Contrast-enhanced imaging

Ultrasound Contrast Agents: Current Role in Adults and Children for Various Indications

Intravenous contrast-enhanced ultrasound (CEUS) is a rapidly evolving imaging technique that uses a microbubble contrast agent to enhance ultrasonographic images by augmenting characterization of blood vessels and organ perfusion. CEUS is considered as a useful problem-solving tool and as an indicated first-line imaging modality in select settings. CEUS technique has an inherent advantage over its predecessor B-mode and Doppler imaging. This article reviews different approved and off-label use of CEUS in the pediatric and adult population and also discusses Food and Drug Administration-approved contrast agents in the United States, their reported side effects, and ongoing efforts in the field.

Applications and Prospects of Artificial Intelligence-Assisted Endoscopic Ultrasound in Digestive System Diseases

Endoscopic ultrasound (EUS) has emerged as a widely utilized tool in the diagnosis of digestive diseases. In recent years, the potential of artificial intelligence (AI) in healthcare has been gradually recognized, and its superiority in the field of EUS is becoming apparent. Machine learning (ML) and deep learning (DL) are the two main AI algorithms. This paper aims to outline the applications and prospects of artificial intelligence-assisted endoscopic ultrasound (EUS-AI) in digestive diseases over the past decade. The results demonstrated that EUS-AI has shown superiority or at least equivalence to traditional methods in the diagnosis, prognosis, and quality control of subepithelial lesions, early esophageal cancer, early gastric cancer, and pancreatic diseases including pancreatic cystic lesions, autoimmune pancreatitis, and pancreatic cancer. The implementation of EUS-AI has opened up new avenues for individualized precision medicine and has introduced novel diagnostic and treatment approaches for digestive diseases.

Innovative Imaging Techniques Used to Evaluate Borderline-Resectable Pancreatic Adenocarcinoma

A diagnosis of pancreatic cancer carries a 5-y survival rate of less than 10%. Furthermore, the detection of pancreatic cancer occurs most often in later stages of the disease due to its location in the retroperitoneum and lack of symptoms (in most cases) until tumors become more advanced. Once diagnosed, cross-sectional imaging techniques are heavily utilized to determine the tumor stage and the potential for surgical resection. However, a major determinant of resectability is the extent of local vascular involvement of the mesenteric vessels and critical tributaries; current imaging techniques have limited capacity to accurately determine vascular involvement. Surrounding inflammation and fibrosis can be difficult to discriminate from viable tumor, making determination of the degree of vascular involvement unreliable. New innovations in fluorescence and optoacoustic imaging techniques may overcome these limitations and make determination of resectability more accurate. These imaging modalities are able to more clearly discern between viable tumor tissue and non-neoplastic inflammation or desmoplasia, allowing clinicians to more reliably characterize vascular involvement and develop individualized treatment plans for patients. This review will discuss the current imaging techniques used to diagnose pancreatic cancer, the barriers that current techniques raise to accurate staging, and novel fluorescence and optoacoustic imaging techniques that may provide more accurate clinical staging of pancreatic cancer.

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.

Assessment of Carotid Body Tumors by Superb Microvascular Imaging of Feeding Arteries During Preoperative Evaluation

Purpose:

Superb microvascular imaging (SMI) has led to new advances in vascular imaging applications. This study aimed to explore the blood supply and feeding arteries of carotid body tumors (CBTs) on SMI to improve the accuracy of information available to surgeons.

Methods

Twenty-six CBT lesions were subjected to color Doppler flow imaging (CDFI) and SMI and were later confirmed by pathology. The blood flow patterns and feeding arteries of the CBTs on CDFI and SMI were graded and compared.

Results

The feeding arteries of two CBT lesions, which were not visible on CDFI, were identified as the internal carotid artery (ICA) on SMI. The feeding arteries of three CBTs were judged to stem from both the ICA and the external carotid artery (ECA) (MIX) based on SMI compared to the ICA or ECA on CDFI. We classified the feeding arteries of CBTs as originating from the ICA or others (including the ECA and MIX). One hundred percent (3/3) of the CBT lesions stemming from the ICA had Adler I or Adler II blood flow patterns, and 100% (23/23) of the CBT lesions stemming from other arteries had Adler II or Adler III blood flow patterns. Higher Adler categories were assigned based on SMI than CDFI (P < 0.001).

Conclusion

SMI may be superior to CDFI in detecting the vascularity of CBTs, and SMI revealed more potential feeding arteries of CBTs than CDFI. CBTs originating from the ICA are less vascular than those originating from the ECA.

Diagnosing Pancreatic Adenocarcinoma With Contrast-Enhanced Ultrasonography: A Literature Review of Research in Europe and Asia

The National Cancer Institute names pancreatic cancer the 11^th most common type of cancer in the United States. However, even with a somewhat low prevalence, in 2017, the American Cancer Society reported pancreatic cancer as the fourth leading cause of cancer-related death. With a lack of symptomology and a broad range of risk factors, pancreatic cancer is frequently diagnosed in a later phase than many other types of cancers, thus resulting in higher metastasis along with a poorer prognosis. This highlights the need for early detection and diagnosis. Currently, abdominal ultrasound or contrast-enhanced CT imaging of the abdomen are standard of care. A new technology: contrast-enhanced ultrasound (CEUS), which employs contrast agents to act as acoustic enhancers for ultrasound, has FDA approval for use in hepatic and renal lesions, but not pancreatic. By examining seven individual studies from Europe and Asia, this review aims to examine the diagnostic value of CEUS to initially diagnose pancreatic adenocarcinomas, potentially followed by a biopsy to confirm, when compared against modalities currently used such as conventional ultrasound and CT imaging. CEUS would potentially be more accurate when compared to conventional ultrasound due to the addition of contrast, and when compared against CT and MRI, CEUS would be advantageous in its low cost, similar sensitivities, and specificities, limited renal toxicity, lack of ionizing radiation, short half-life, and its safe use in both adult and pediatric patients. Due to this, additional research is warranted for further FDA approval and future clinical implementation.

Advances in the diagnosis of acute pancreatitis in dogs

In the last 20 years, the diagnosis of pancreatitis has become more frequent as a result of improved diagnostic modalities such as abdominal ultrasound examination, advanced imaging, and immunoassays for the measurement of pancreatic lipase. Our aim is to provide a state‐of‐the‐art overview of the clinical diagnosis of acute pancreatitis (AP) in dogs with a particular focus on pancreatic lipase assay validation and clinical performance, in addition to advanced imaging modalities. We also discuss the potential indications for cytology and histopathology in dogs with suspected AP.

Clinical value of contrast-enhanced ultrasound enhancement patterns for differentiating solid pancreatic lesions

OBJECTIVES

To explore the diagnostic value of contrast-enhanced ultrasound (CEUS) enhancement patterns for differentiating solid pancreatic lesions and compare them with conventional ultrasound (US) and enhanced computed tomography (CT).

METHODS

A total of 210 patients with solid pancreatic lesions who had definite pathological or clinical diagnoses were enrolled. Six CEUS enhancement patterns were proposed for solid pancreatic lesions. Two US doctors blindly observed the CEUS patterns of solid pancreatic lesions and the interrater agreement was analyzed. The diagnostic value of CEUS enhancement patterns for differentiating solid pancreatic lesions was evaluated, and the diagnostic accuracy was compared with that of US and enhanced CT.

RESULTS

There was good concordance for six CEUS enhancement patterns of solid pancreatic lesions between the two doctors, with a kappa value of 0.767. Hypo-enhancement (Hypo-E) or centripetal enhancement (Centri-E) as the diagnostic criteria for pancreatic carcinoma had an accuracy of 87.62%; hyper-enhancement (Hyper-E) for neuroendocrine tumors had an accuracy of 92.89%; capsular enhancement with low or uneven enhancement inside the tumor (Capsular-E) for solid pseudopapillary tumors had an accuracy of 97.63%; and iso-enhancement (Iso-E) or iso-enhancement with focal hypo-enhancement (Iso-fhypo-E) for focal pancreatitis had an accuracy of 89.10%. The diagnostic accuracy of CEUS was significantly different from that of US for 210 cases of solid pancreatic lesions (p < 0.05) and was not significantly different from that of enhanced CT for 146 cases of solid pancreatic lesions (p > 0.05).

CONCLUSIONS

The different enhancement patterns of solid pancreatic lesions on CEUS were clinically valuable for differentiation.

KEY POINTS

• Six CEUS enhancement (E) patterns, including Hyper-E, Iso-E, Iso-fhypo-E, Hypo-E, Centri-E, and Capsular-E, are proposed for the characterization of solid pancreatic lesions. • Using Hypo-E or Centri-E as the diagnostic criteria for pancreatic carcinoma, Hyper-E for neuroendocrine tumors, Capsular-E for solid pseudopapillary tumors, and Iso-E or Iso-fhypo-E for focal pancreatitis on CEUS had relatively high diagnostic accuracy. • The diagnostic accuracy of CEUS was greatly increased over that of US and was not different from that of enhanced CT.

Role of radio-ablative technique for optimizing the survival of patients with locally advanced pancreatic adenocarcinoma (Review)

Pancreatic ductal adenocarcinoma (PDAC) is one of the most common and frequently diagnosed malignant tumor of the pancreas with few treatment options and poor life expectancy. Despite the advances in the surgical field, 40% of the patients are diagnosed with locally advanced disease which is not suitable for surgery. Radio-frequency ablation (RFA) has been described as a new ‘weapon’ in the multimodal treatment of PDAC, representing a cytoreductive procedure which must be completed with radiotherapy or chemo-radiotherapy. A systematic research was carried out utilizing the PubMed database in regards to this subject, to evaluate the role of RFA in PDAC management. Abstracts, letters-to-the-editor and non-English language manuscripts were excluded. The literature showed that RFA can be used in open and laparoscopic surgery but it is also feasible for endoscopic ultrasound (EUS-guided RFA) or percutaneous approach. Even though we found optimistic and encouraging reports on overall survival (OS), randomized studies are still required to corroborate these findings. Our review research underline that surgical resection remains the only radical treatment option, RFA being a safe and feasible technique reserved for unresectable, non-metastatic pancreatic tumors. Its combination with oncological treatment can improve the OS of these patients.

Focal Pancreatic Lesions: Role of Contrast-Enhanced Ultrasonography

The introduction of contrast-enhanced ultrasonography (CEUS) has led to a significant improvement in the diagnostic accuracy of ultrasound in the characterization of a pancreatic mass. CEUS, by using a blood pool contrast agent, can provide dynamic information concerning macro- and micro-circulation of focal lesions and of normal parenchyma, without the use of ionizing radiation. On the basis of personal experience and literature data, the purpose of this article is to describe and discuss CEUS imaging findings of the main solid and cystic pancreatic lesions with varying prevalence.

Role of Radiofrequency Ablation in the Management of Unresectable Pancreatic Cancer

Pancreatic cancer is one of the most aggressive malignancies of the digestive tract and carries a poor prognosis. The majority of patients have advanced disease at the time of diagnosis. Surgical resection offers the only curative treatment, but only a small proportion of patients can undergo surgical resection. Radiofrequency ablation (RFA) is a well-known modality in the management of solid organ tumors, however, its utility in the management of pancreatic cancer is under investigation. Since the past decade, there is increasing use of RFA as it provides a feasible palliation treatment in the management of unresectable pancreatic cancer. RFA causes tumor cytoreduction through multiple mechanisms such as coagulative necrosis, protein denaturation, and activation of anticancer immunity. The safety profile of RFA is controversial because of the high risk for complications, however, small prospective and retrospective studies have shown promising results in its applicability for palliative management of unresectable pancreatic malignancies. In this review, we discuss different approaches of RFA, their indications, technical accessibility, safety, and major complications in the management of unresectable pancreatic cancer.

Enhanced EUS imaging (with videos)

BACKGROUND AND AIMS

EUS remains a primary diagnostic tool for the evaluation of pancreaticobiliary disease. Although EUS combined with FNA or biopsy sampling is highly sensitive for the diagnosis of neoplasia within the pancreaticobiliary tract, limitations exist in specific clinical settings such as chronic pancreatitis. Enhanced EUS imaging technologies aim to aid in the detection and diagnosis of lesions that are commonly evaluated with EUS.

METHODS

We reviewed technologies and methods for enhanced imaging during EUS and applications of these methods. Available data regarding efficacy, safety, and financial considerations are summarized.

RESULTS

Enhanced EUS imaging methods include elastography and contrast-enhanced EUS (CE-EUS). Both technologies have been best studied in the setting of pancreatic mass lesions. Robust data indicate that neither technology has adequate specificity to serve as a stand-alone test for pancreatic malignancy. However, there may be a role for improving the targeting of sampling and in the evaluation of peritumoral lymph nodes, inflammatory pancreatic masses, and masses with nondiagnostic FNA or fine-needle biopsy sampling. Further, novel applications of these technologies have been reported in the evaluation of liver fibrosis, pancreatic cysts, and angiogenesis within neoplastic lesions.

CONCLUSIONS

Elastography and CE-EUS may improve the real-time evaluation of intra- and extraluminal lesions as an adjunct to standard B-mode and Doppler imaging. They are not a replacement for EUS-guided tissue sampling but provide adjunctive diagnostic information in specific clinical situations. The optimal clinical use of these technologies continues to be a focus of ongoing research.

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.

Comparison of combination therapies in the management of locally advanced pancreatic cancer: Induction chemotherapy followed by irreversible electroporation vs radiofrequency ablation

Background

Locally advanced pancreatic cancer (LAPC) remains a challenge for current treatments. Local destructive therapies, such as irreversible electroporation (IRE) and radiofrequency ablation (RFA), were used more and more frequently in the treatment of LAPC.

Objective

This study aimed to compare the efficacy of IRE with RFA in patients with LAPC.

Methods

From August 2015 to August 2017, 58 LAPC patients after IRE or RFA therapy, which was performed through open approach, were retrospectively reviewed. The survival outcomes after IRE (36 patients) and RFA (18 patients) were compared after propensity score matching (PSM) analysis.

Results

Before PSM analysis, IRE after the induction chemotherapy resulted in significant higher overall survival (OS) rates and progression‐free survival (PFS) rates to RFA (2‐year OS, 53.5% vs 30.8%, P = .013; 2‐year PFS, 28.4% vs 12.1%, P = .043). After PSM analysis, compared with RFA, the survival benefit of IRE was even more obvious, (2‐year OS, 53.5% vs 27.0%, P = .010; 2‐year PFS, 28.4% vs 6.4%, P = .018). For patients with tumor larger than 4 cm, IRE resulted in comparable OS and PFS between RFA and IRE while IRE also achieved better long‐term OS to RFA for those with tumor smaller than 4 cm. Multivariate analysis illustrated that IRE was a favorable prognostic factor in terms of OS and PFS in patients with LAPC.

Conclusions

IRE after induction chemotherapy is superior to RFA after induction chemotherapy for treating LAPC patients while these two therapies have comparable efficacy for tumors which were larger than 4 cm.

Combination of CEUS and MRI for the diagnosis of periampullary space-occupying lesions: a retrospective analysis

Background

The value of magnetic resonance imaging (MRI), contrast-enhanced ultrasound (CEUS), and the combination of CEUS and MRI (CCWM) for the diagnosis of periampullary space-occupying lesions (PSOL) was investigated.

Methods

A total of 102 patients diagnosed with PSOLs by surgery or biopsy were recruited retrospectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MRI, CEUS, and CCWM were analyzed.

Results

MRI, CEUS, and CCWM allowed for the accurate detection of 91.17, 92.15, and 99.01% of PSOLs, respectively. The specificity, PPV, and accuracy of CCWM were significantly different from MRI and CEUS (p < 0.05). However, there the sensitivity and NPV were not significantly different among the three diagnostic technologies. In addition, the specificity, PPV, and accuracy were not significantly different between MRI and CEUS (all p > 0.05).

Conclusions

CCWM is valuable for differentiating benign and malignant PSOL, which provides important guiding significances for the clinic.

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.

Pancreatic Ultrasound: State of the Art

An ultrasound (US) study is often the first imaging approach in patients with abdominal symptoms or signs related to abdominal diseases, and it is often part of the routine workup. The pancreatic gland, despite its retroperitoneal site, can be efficiently examined with US thanks to advances in US technologies. Nowadays, a pancreatic US study could be considered complete if multiparametric, including the use of Doppler imaging, US elastography, and contrast-enhanced imaging for the study of a pancreatic mass. A complete US examination could contribute to a faster diagnosis, especially if the pancreatic lesion is incidentally detected, addressing second-step imaging modalities correctly.

Double contrast-enhanced ultrasound improves the detection and localization of occult lesions in the pancreatic tail: a initial experience report

PURPOSE

The aim of this study is to review our initial experience of Double contrast-enhanced ultrasonography (DCEUS) in the preoperative detection of pancreatic tail occult tumors.

METHODS

Thirty-five patients were recruited to undergo DCEUS of the pancreas suspected by occult lesions of pancreatic with MRI or clinical evidence. The radiologists assessed the images (conventional US, DCEUS, and MRI) for enhancement phases, tumor presence, location, enhancement characteristics, and tumor conspicuity. The differences in the onset times of the phases between DCEUS and MRI were noted. Tumor conspicuity was graded on a four-point scale for conspicuity comparison among three imaging modalities.

RESULTS

Pancreatic tail tumors were missed on conventional transabdominal US in 11 of 35 patients. DCEUS revealed 12 lesions of 35 patients. Pancreatic tail tumors were identified on MRI in 10 of 35 patients. The sensitivity and specificity of DCEUS for depicting occult lesions of ≤ 2.2 cm were 92% and 95%, respectively. In contrast, the sensitivity and specificity of conventional US were 67% and 66%, respectively. The sensitivity and specificity of MRI were 91% and 88%, respectively. The conspicuity ratings of the three phases did not significantly differ between the DCEUS and MRI groups (P > 0.05). The DCEUS phases started much earlier than the corresponding MRI phases.

CONCLUSION

DCEUS is a promising technique in the detection of occult pancreatic tail tumors and is possibly superior to dynamic enhanced MRI in the case of some peripheral lesions.

Ultrasound-guided percutaneous procedures in pancreatic diseases: new techniques and applications

Ultrasound (US) is not only an important diagnostic tool for the evaluation of the pancreas, but is also a fundamental imaging technique to guide percutaneous interventions for several pancreatic diseases (fluid aspiration and drainage; invasive diagnosis by means fine-needle aspiration and core-needle biopsy; tumour ablation by radiofrequency, microwaves, irreversible electroporation, cryoablation, and high-intensity focused US). Technical improvements, such as contrast media and fusion imaging, have recently increased precision and safety and reduced procedure-related complications. New treatment US techniques for the ablation of pancreatic tumours, such as contrast-enhanced US and multimodality fusion imaging, have been recently developed and have elicited a growing interest worldwide. The purpose of this article was to review the most up-to-date role of US in percutaneous procedures for pancreatic diseases.

Contrast-Enhanced Ultrasound

Contrast-enhanced ultrasound imaging is a recently approved technique in the United States that uses a specific contrast agent, namely, microbubbles, consisting mainly of a gas core and a stabilized biological shell. These compounds allow for the visualization of small vascular beds and improve characterization of anatomic structures and lesions. They have a relatively safe profile and are primarily excreted through the lungs.

Contrast-enhanced ultrasonography of the pancreas shows impaired perfusion in pancreas insufficient cystic fibrosis patients

Background

Perfusion assessment of the pancreas is challenging and poorly evaluated. Pancreatic affection is a prevalent feature of cystic fibrosis (CF). Little is known about pancreatic perfusion in CF. We aimed to assess pancreatic perfusion by contrast-enhanced ultrasound (CEUS) analysed in the bolus-and-burst model and software.

Methods

We performed contrast enhanced ultrasound of the pancreas in 25 CF patients and 20 healthy controls. Perfusion data was analysed using a dedicated perfusion model providing the mean capillary transit-time (MTT), blood flow (BF) and blood-volume (BV). CF patients were divided according to exocrine function.

Results

The pancreas insufficient CF patients had longer MTT (p ≤ 0.002), lower BF (p < 0.001) and lower BV (p < 0.05) compared to the healthy controls and sufficient CF patients. Interrater analysis showed substantial agreement for the analysis of mean transit time.

Conclusion

The bolus-and-burst method used on pancreatic CEUS-examinations demonstrates reduced perfusion in CF patients with pancreas affection. The perfusion model and software requires further optimization and standardization to be clinical applicable for the assessment of pancreatic perfusion.

Electronic supplementary material

The online version of this article (10.1186/s12880-018-0259-3) contains supplementary material, which is available to authorized users.

Clinical Value of Contrast-Enhanced Ultrasound Enhancement Patterns for Differentiating Focal Pancreatitis From Pancreatic Carcinoma: A Comparison Study With Conventional Ultrasound

OBJECTIVES

We explored the clinical value of using contrast-enhanced ultrasound (US) enhancement patterns for the differential diagnosis of focal pancreatitis from pancreatic carcinoma.

METHODS

A total of 136 solid pancreatic lesions with final diagnoses from January 2010 to February 2016 were enrolled in this study. Twenty-five cases were focal pancreatitis; 86 cases were pancreatic carcinoma; and 25 cases were other types. All of the patients received conventional and contrast-enhanced US examinations. Two experienced US physicians analyzed the contrast-enhanced US enhancement patterns and made diagnoses according to the conventional and contrast-enhanced US manifestations. The inter-rater agreement for the contrast enhancement patterns between the readers was analyzed. The diagnostic efficiency of contrast enhancement patterns for differentiating focal pancreatitis from pancreatic carcinoma was analyzed and compared with that of conventional US.

RESULTS

The κ test showed good concordance for contrast enhancement patterns between the readers (P < .05). The diagnostic sensitivity, specificity, and accuracy of isoenhancement or isoenhancement with focal hypoenhancement in both the early and late phases for diagnosing focal pancreatitis were 72.0%, 95.5%, and 91.2%, respectively. The diagnostic sensitivity of isoenhancement or isoenhancement with focal hypoenhancement in both the early and late phases greatly increased for diagnosing focal pancreatitis in comparison with isoenhancement (72.0% versus 32.0%; P < .05). The diagnostic accuracy of contrast-enhanced US was greatly increased over that of conventional US (85.6% versus 49.5%; P < .001).

CONCLUSIONS

Contrast-enhanced US is a valuable tool for differentiating focal pancreatitis from pancreatic carcinoma and can greatly increase the diagnostic accuracy over conventional US.

Serous pancreatic neoplasia, data and review

AIM

To describe the imaging features of serous neoplasms of the pancreas using ultrasound, endoscopic ultrasound, computed tomography and magnetic resonance imaging.

METHODS

This multicenter international collaboration enhances a literature review to date, reporting features of 287 histologically confirmed cases of serous pancreatic cystic neoplasms (SPNs).

RESULTS

Female predominance is seen with most SPNs presenting asymptomatically in the 5^th through 7^th decade. Mean lesion size was 38.7 mm, 98% were single, 44.2% cystic, 46% mixed cystic and solid, and 94% hypoechoic on B-mode ultrasound. Vascular patterns and contrast-enhancement profiles are described as hypervascular and hyperenhancing.

CONCLUSION

The described ultrasound features can aid differentiation of SPN from other neoplastic lesions under most circumstances.

Discrimination of serous cystadenoma from mucinous cystadenoma in the pancreas with contrast-enhanced ultrasonography: a prospective study in 61 patients

Objectives

The preoperative diagnosis between serous cystadenomas (SCAs) and mucinous cystadenomas (MCAs) in pancreas is significant due to their completely different biological behaviors. The purpose of our study was to examine and compare detailed contrast-enhanced ultrasonography (CEUS) images of SCAs and MCAs and to determine whether there are significant findings that can contribute to the discrimination between these two diseases.

Methods

From April 2015 to June 2016, 61 patients (35 patients with SCAs and 26 patients with MCAs) were enrolled in this study. Forty-three cases were confirmed by surgical pathology and 18 by comprehensive clinical diagnoses. All of the CEUS characteristics of these lesions were recorded: size, location, echogenicity, shape, wall characteristics, septa characteristics, and the presence of a honeycomb pattern or nodules. CEUS examinations were performed by two ultrasound physicians.

Results

Location (P=0.003), shape (P=0.000), thickness of the wall (P=0.005), the number of septa (P=0.001), and the honeycomb pattern (P=0.001) were statistically significantly different. A head–neck location, a lobulated shape, an inner regular honeycomb pattern, and a thin wall (<3 mm thick) were significant in diagnosing patients with SCAs. When two of these four findings were combined, we could achieve a sensitivity of 71.4% and a specificity of 80.8% to diagnose SCA; when three of these four findings were combined, the specificity was 100%. A body–tail location, a round/oval shape, 0–2 septa, and a thick wall (≥3 mm thick) were most often detected in patients with MCAs. When two of these four findings were combined, we could achieve a sensitivity of 88.5% and a specificity of 65.7% to diagnose MCA; when three of these four findings were combined, the area under the curve (Az) was highest at 0.832, with a sensitivity of 80.8% and a specificity of 85.7%.

Conclusions

The characteristics of tumor location, shape, thickness of the wall, the number of septa, and the honeycomb pattern by CEUS play an important role in the diagnosis of SCAs and MCAs. A combination of these findings can provide better diagnostic performance in the discrimination of SCAs from MCAs.

Imaging in pancreatic disease

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

Uncommon presentations of common pancreatic neoplasms: a pictorial essay

Pancreatic neoplasms are a wide group of solid and cystic lesions with different and often characteristic imaging features, clinical presentations, and management. Among solid tumors, ductal adenocarcinoma is the most common: it arises from exocrine pancreas, comprises about 90% of all pancreatic neoplasms, and generally has a bad prognosis; its therapeutic management must be multidisciplinary, involving surgeons, oncologists, gastroenterologists, radiologists, and radiotherapists. The second most common solid pancreatic neoplasms are neuroendocrine tumors: they can be divided into functioning or non-functioning and present different degrees of malignancy. Cystic pancreatic neoplasms comprise serous neoplasms, which are almost always benign, mucinous cystic neoplasms and intraductal papillary mucinous neoplasms, which can vary from benign to frankly malignant lesions, and solid pseudopapillary tumors. Other pancreatic neoplasms, such as lymphoma, metastases, or pancreatoblastoma, are rarely seen in clinical practice and have different and sometimes controversial managements. Rare clinical presentations and imaging appearance of the most common pancreatic neoplasms, both solid and cystic, are more frequently seen and clinically relevant than rare pancreatic tumors; their pathologic and radiologic appearances must be known to improve their management. The purpose of this paper is to present some rare or uncommon clinical and radiological presentations of common pancreatic neoplasms providing examples of multi-modality imaging approach with pathologic correlations, thus describing the histopathological bases that can explain the peculiar imaging features, in order to avoid relevant misdiagnosis and to improve lesion management.

Contrast-Enhanced Ultrasonography of Pancreatic Carcinoma: Correlation with Pathologic Findings

We concluded that contrast-enhanced ultrasound (CEUS) has clinical value in identifying the pathologic changes of pancreatic carcinomas. Forty-three patients diagnosed with pancreatic carcinoma through surgery were retrospectively investigated. CEUS examinations were performed on all patients before surgery. Enhancement patterns on CEUS were observed. Time-intensity curves of CEUS were generated for the regions of interest in the pancreas, and quantitative parameters were obtained. Resected cancer specimens were stained with hematoxylin and eosin for histologic analysis, and the microvascular density (MVD) of the specimens was determined by CD34 immunohistochemical staining. Enhancement patterns of CEUS were compared with histopathologic findings in pancreatic carcinomas. Correlations between time-intensity curve parameters and microvascular density were analyzed. Twenty cases manifested centripetal enhancement, and 23 cases, global enhancement. The amount of tumor necrosis or mucus in the centripetally enhanced pancreatic carcinomas was greater than that in the globally enhanced pancreatic carcinomas (p = 0.027). Thirty-eight of 43 (88.4%) pancreatic carcinomas manifested hypo-enhancement with a maximum intensity (IMAX) <90%. Contrast arrival time in pancreatic carcinoma was longer than that in adjacent pancreatic tissue (p < 0.05). IMAX was positively correlated with microvascular density (r = 0.577, p < 0.05). We concluded that CEUS manifestations could reflect the histologic changes of pancreatic carcinomas and CEUS can be used to evaluate blood perfusion of tumors, as IMAX is positively correlated with microvascular density.

Local Ablative Strategies for Ductal Pancreatic Cancer (Radiofrequency Ablation, Irreversible Electroporation): A Review

Pancreatic ductal adenocarcinoma (PDAC) has still a dismal prognosis. Locally advanced pancreatic cancer (LAPC) accounts for the 40% of the new diagnoses. Current treatment options are based on chemo- and radiotherapy regimens. Local ablative techniques seem to be the future therapeutic option for stage-III patients with PDAC. Radiofrequency Ablation (RFA) and Irreversible Electroporation (IRE) are actually the most emerging local ablative techniques used on LAPC. Initial clinical studies on the use of these techniques have already demonstrated encouraging results in terms of safety and feasibility. Unfortunately, few studies on their efficacy are currently available. Even though some reports on the overall survival are encouraging, randomized studies are still required to corroborate these findings. This study provides an up-to-date overview and a thematic summary of the current available evidence on the application of RFA and IRE on PDAC, together with a comparison of the two procedures.

Contrast-enhanced ultrasound of pancreatic tumours

Indication/purpose: To review contrast‐enhanced ultrasound features of the most common pancreatic tumours.

Methods: Contrast‐enhanced ultrasound (CEUS) can provide distinctive features of pancreatic tumours that are reported in the present paper, providing radiologic‐pathological correlations and clarifying the main differential diagnosis.

Conclusion: Contrast‐enhanced ultrasound plays a well‐established role in the evaluation of pancreatic tumours. When possible, CEUS should be always performed after the initial US diagnosis, in order to improve the accuracy of the first line examination.

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.

CONTRAST-ENHANCED ULTRASONOGRAPHY OF THE PANCREAS IN HEALTHY DOGS AND IN DOGS WITH ACUTE PANCREATITIS

Pancreatitis is the most frequent disease affecting the exocrine pancreas in dogs and reliable diagnostic techniques for predicting fatal complications are lacking. Contrast-enhanced ultrasound (CEUS) improves detection of tissue perfusion as well as organ lesion vascular pattern. Objectives of this prospective case control study were to compare perfusion characteristics and enhancement patterns of the pancreas in healthy dogs and dogs with pancreatitis using CEUS. Ten healthy dogs and eight dogs with pancreatitis were selected based on physical examination, abdominal ultrasound, and blood analysis findings. A CEUS study of the pancreas was performed for each dog and two observers who were aware of clinical status used advanced ultrasound quantification software to analyze time-intensity curves. Perfusion patterns were compared between healthy and affected dogs. In dogs with acute pancreatitis, mean pixel and peak intensity of the pancreatic parenchyma was significantly higher than that of normal dogs (P = 0.05) in between 6 and 60 s (P = <0.0001-0.046). This corresponds to a 311% increase in mean pixel intensity in dogs with acute pancreatitis compared to healthy dogs. Wash-in rates were greater and had a consistently steeper slope to peak in dogs with pancreatitis as opposed to healthy dogs. All dogs with pancreatitis showed a decrease in pixel intensity 10-15 days after the initial examination (P = 0.011) and their times to peak values were prolonged compared to the initial exam. Findings from the current study supported the use of CEUS for diagnosing pancreatitis, pancreatic necrosis, and disease monitoring following therapy in dogs.

Quantitative contrast-enhanced harmonic EUS in differential diagnosis of focal pancreatic masses (with videos)

BACKGROUND

The role of EUS with contrast agents can be expanded through the use of time-intensity curve (TIC) analysis and computer-aided interpretation.

OBJECTIVE

To validate the use of parameters derived from TIC analysis in an artificial neural network (ANN) classification model designed to diagnose pancreatic carcinoma (PC) and chronic pancreatitis (CP).

SETTING

Prospective, multicenter, observational trial-endoscopy units from Romania, Denmark, Germany, and Spain.

PATIENTS

A total of 167 consecutive patients with PC or CP.

INTERVENTIONS

Contrast-enhanced harmonic EUS (CEH-EUS) and EUS-guided FNA (EUS-FNA), TIC analysis, and ANN processing.

MAIN OUTCOME MEASUREMENTS

Sensitivity, specificity, positive and negative predictive values (PPV, NPV) for EUS-FNA, CEH-EUS, and the ANN.

RESULTS

After excluding all of the recordings that did not meet the technical and procedural criteria, 112 cases of PC and 55 cases of CP were included. EUS-FNA was performed in 129 patients, and the diagnosis was confirmed by surgery (n = 15) or follow-up (n = 23) in the remaining cases. Its sensitivity and specificity were 84.82% and 100%, respectively, whereas the PPV and NPV were 100% and 76.63%, respectively. The sensitivity of real-time quantitative assessment of CEH-EUS was 87.5%, specificity 92.72%, PPV 96.07%, and NPV 78.46%. Peak enhancement, wash-in area under the curve, wash-in rate, and the wash-in perfusion index were significantly different between the groups. No significant differences were found between rise time, mean transit time, and time to peak. For the ANN, sensitivity was 94.64%, specificity 94.44%, PPV 97.24%, and NPV 89.47%.

LIMITATIONS

Only PC and CP lesions were included.

CONCLUSION

Parameters obtained through TIC analysis can differentiate between PC and CP cases and can be used in an automated computer-aided diagnostic system with good diagnostic results. (

CLINICAL TRIAL REGISTRATION NUMBER

NCT01315548.).

Pancreatic congestion in liver cirrhosis correlates with impaired insulin secretion

BACKGROUND

Although impaired glucose tolerance is common in cirrhosis, this condition's pathogenesis remains undefined. This study aimed to clarify pathogenesis related to the pancreas in cirrhotic patients, and to evaluate associations between insulin secretion and pancreatic congestion due to portal hypertension.

METHODS

Pancreatic perfusion parameters were analyzed by dynamic contrast-enhanced ultrasound (CE-US) in 41 patients (20 cirrhotic, 21 non-cirrhotic; age, 67.9 ± 13.3; female, 19), and prospectively compared to delta C-peptide immunoreactivity (ΔCPR). In a separate study, a retrospective chart review with human autopsy specimens was conducted, and vessels and islets of the pancreas were analyzed in 43 patients (20 cirrhotic, 23 controls; age, 71.5 ± 11.6; female, 15).

RESULTS

In the CE-US study, the clinical characteristics indicative of portal hypertension (e.g., ascites and varices) had significantly higher incidences in the cirrhotic group than in the control group. Pancreatic drainage times were greater in the cirrhotic group (p < 0.0001), and had a significant negative correlation with ΔCPR (R = 0.42, p = 0.0069). In the histopathological study, the islets were enlarged in the cirrhotic group (p < 0.0001). However, the percentage of insulin-positive area per islet was decreased in the cirrhotic group (p < 0.0001), and had a significant negative correlation with the wall thickness of the pancreatic vein (R = 0.63, p < 0.0001).

CONCLUSIONS

Pancreatic congestion was present in cirrhotic patients. Moreover, pancreatic congestion and insulin secretion were significantly correlated. This pathogenesis could be a key factor underlying the development of hepatogenous diabetes in cirrhotic patients.

Contrast-enhanced ultrasonography of the pancreas in healthy cats

BACKGROUND

This study describes the pattern of ultrasonographic contrast enhancement of the pancreatic body and left lobe using a second-generation commercial contrast medium (Sonovue) in 10 clinically healthy cats.

RESULTS

Following contrast medium administration, microbubbles were observed within the splenic artery. This was followed by an inflow of contrast medium into the pancreatic capillary beds, providing a uniformly contrast-enhanced pancreas at peak intensity (PI). At the time of PI, a replenishment of the splenic and portal veins started and increased progressively during the wash-out phase. During the wash-out phase, the echogenicity of the pancreatic parenchyma decreased progressively. Perfusion parameters included arrival time (4.69 ± 1.26 s), time to peak from injection (7.52 ± 1.88 s), time to peak from initial rise (2.84 ± 0.88 s), peak intensity (6.58 ± 2.66 a.u.), and wash-in rate (2.11 ± 1.79 a.u./s).

CONCLUSIONS

This perfusion pattern of normal pancreatic parenchyma may be useful for characterising cats with exocrine pancreatic disorders.

Quantitative contrast-enhanced ultrasonographic assessment of naturally occurring pancreatitis in dogs

BACKGROUND

Quantitative contrast-enhanced ultrasonography (CEUS) can detect pancreatic perfusion changes in experimentally induced canine pancreatitis. However, its usefulness in detecting perfusion changes in naturally occurring pancreatitis is unclear.

HYPOTHESIS/OBJECTIVES

To determine the feasibility of using CEUS to detect pancreatic and duodenal perfusion changes in naturally occurring canine pancreatitis.

ANIMALS

Twenty-three client-owned dogs with pancreatitis, 12 healthy control dogs.

METHODS

Dogs diagnosed with pancreatitis were prospectively included. CEUS of the pancreas and duodenum were performed. Time-intensity curves were created from regions of interest in the pancreas and duodenum. Five perfusion parameters were obtained for statistical analyses: time to initial up-slope, peak time (Tp), time to wash-out (TTW), peak intensity (PI), and area under the curve (AUC).

RESULTS

For the pancreas, Tp of the pancreatitis group was prolonged when compared to controls (62 ± 11 seconds versus 39 ± 13 seconds; P < .001). TTW also was prolonged but not significantly (268 ± 69 seconds versus 228 ± 47 seconds; P = .47). PI and AUC were increased when compared to controls (95 ± 15 versus 78 ± 13 MPV; P = .009 and 14,900 ± 3,400 versus 11,000 ± 2,800 MPV*s; P = .013, respectively). For the duodenum, PI and AUC were significantly increased in the pancreatitis group when compared to controls.

CONCLUSIONS AND CLINICAL IMPORTANCE

Contrast-enhanced ultrasonography can detect pancreatic perfusion changes in naturally occurring canine pancreatitis characterized by delayed peak with prolonged hyperechoic enhancement of the pancreas on CEUS. Additionally, duodenal perfusion changes secondary to pancreatitis were observed.

Contrast-enhanced harmonic endoscopic ultrasound imaging: Basic principles, present situation and future perspectives

Over the last decade, the development of stabilised microbubble contrast agents and improvements in available ultrasonic equipment, such as harmonic imaging, have enabled us to display microbubble enhancements on a greyscale with optimal contrast and spatial resolution. Recent technological advances made contrast harmonic technology available for endoscopic ultrasound (EUS) for the first time in 2008. Thus, the evaluation of microcirculation is now feasible with EUS, prompting the evolution of contrast-enhanced EUS from vascular imaging to images of the perfused tissue. Although the relevant experience is still preliminary, several reports have highlighted contrast-enhanced harmonic EUS (CH-EUS) as a promising noninvasive method to visualise and characterise lesions and to differentiate benign from malignant focal lesions. Even if histology remains the gold standard, the combination of CH-EUS and EUS fine needle aspiration (EUS-FNA) can not only render EUS more accurate but may also assist physicians in making decisions when EUS-FNA is inconclusive, increasing the yield of EUS-FNA by guiding the puncture with simultaneous imaging of the vascularity. The development of CH-EUS has also opened up exciting possibilities in other research areas, including monitoring responses to anticancer chemotherapy or to ethanol-induced pancreatic tissue ablation, anticancer therapies based on ultrasound-triggered drug and gene delivery, and therapeutic adjuvants by contrast ultrasound-induced apoptosis. Contrast harmonic imaging is gaining popularity because of its efficacy, simplicity and non-invasive nature, and many expectations are currently resting on this technique. If its potential is confirmed in the near future, contrast harmonic imaging will become a standard practice in EUS.

Role of endoscopic ultrasound in the diagnosis of pancreatic cancer

Endoscopic ultrasonography (EUS) with or without fine needle aspiration has become the main technique for evaluating pancreatobiliary disorders and has proved to have a higher diagnostic yield than positron emission tomography, computed tomography (CT) and transabdominal ultrasound for recognising early pancreatic tumors. As a diagnostic modality for pancreatic cancer, EUS has proved rates higher than 90%, especially for lesions less than 2-3 cm in size in which it reaches a sensitivity rate of 99% vs 55% for CT. Besides, EUS has a very high negative predictive value and thus EUS can reliably exclude pancreatic cancer. The complication rate of EUS is as low as 1.1%-3.0%. New technical developments such as elastography and the use of contrast agents have recently been applied to EUS, improving its diagnostic capability. EUS has been found to be superior to the recent multidetector CT for T staging with less risk of overstaying in comparison to both CT and magnetic resonance imaging, so that patients are not being ruled out of a potentially beneficial resection. The accuracy for N staging with EUS is 64%-82%. In unresectable cancers, EUS also plays a therapeutic role by means of treating oncological pain through celiac plexus block, biliary drainage in obstructive jaundice in patients where endoscopic retrograde cholangiopancreatography is not affordable and aiding radiotherapy and chemotherapy.

Contrast-enhanced ultrasonography: advance and current status in abdominal imaging

In the field of contrast-enhanced ultrasonography (US), contrast agents are classified as either first- or second-generation agents depending on the gas within the microbubbles. In the case of first-generation contrast agents, a high-mechanical-index technique is used and only intermittent scanning is possible due to the early destruction of the microbubbles during the scanning. The use of second-generation contrast agents in a low-mechanical-index technique enables continuous scanning. Besides the detection and characterization of focal liver lesions, contrastenhanced US is helpful in the monitoring of radiofrequency ablation therapy and in the targeting step of an US-guided biopsy. Recently, there has been a demand for new criteria to evaluate the treatment response obtained using anti-angiogenic agents because morphologic criteria alone may not reflect the treatment response of the tumor and contrast-enhanced US can provide quantitative markers of tissue perfusion. In spite of the concerns related to its cost-effectiveness, contrast-enhanced US has the potential to be more widely used as a complimentary tool or to substitute the current imaging modalities in some occasions.

Current and future intraoperative imaging strategies to increase radical resection rates in pancreatic cancer surgery

Prognosis of patients with pancreatic cancer is poor. Even the small minority that undergoes resection with curative intent has low 5-year survival rates. This may partly be explained by the high number of irradical resections, which results in local recurrence and impaired overall survival. Currently, ultrasonography is used during surgery for resectability assessment and frozen-section analysis is used for assessment of resection margins in order to decrease the number of irradical resections. The introduction of minimal invasive techniques in pancreatic surgery has deprived surgeons from direct tactile information. To improve intraoperative assessment of pancreatic tumor extension, enhanced or novel intraoperative imaging technologies accurately visualizing and delineating cancer cells are necessary. Emerging modalities are intraoperative near-infrared fluorescence imaging and freehand nuclear imaging using tumor-specific targeted contrast agents. In this review, we performed a meta-analysis of the literature on laparoscopic ultrasonography and we summarized and discussed current and future intraoperative imaging modalities and their potential for improved tumor demarcation during pancreatic surgery.

Imaging diagnosis of pancreatic cancer: A state-of-the-art review

Pancreatic cancer (PC) remains one of the deadliest cancers worldwide, and has a poor, five-year survival rate of 5%. Although complete surgical resection is the only curative therapy for pancreatic cancer, less than 20% of newly-diagnosed patients undergo surgical resection with a curative intent. Due to the lack of early symptoms and the tendency of pancreatic adenocarcinoma to invade adjacent structures or to metastasize at an early stage, many patients with pancreatic cancer already have advanced disease at the time of their diagnosis and, therefore, there is a high mortality rate. To improve the patient survival rate, early detection of PC is critical. The diagnosis of PC relies on computed tomography (CT) and/or magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP), or biopsy or fine-needle aspiration using endoscopic ultrasound (EUS). Although multi-detector row computed tomography currently has a major role in the evaluation of PC, MRI with MRCP facilitates better detection of tumors at an early stage by allowing a comprehensive analysis of the morphological changes of the pancreas parenchyma and pancreatic duct. The diagnosis could be improved using positron emission tomography techniques in special conditions in which CT and EUS are not completely diagnostic. It is essential for clinicians to understand the advantages and disadvantages of the various pancreatic imaging modalities in order to be able to make optimal treatment and management decisions. Our study investigates the current role and innovative techniques of pancreatic imaging focused on the detection of pancreatic cancer.

[Pancreatic ultrasonography]

Despite the recent technological advances in imaging, abdominal ultrasonography continues to be the first diagnostic test indicated in patients with a suspicion of pancreatic disease, due to its safety, accessibility and low cost. It is an essential technique in the study of inflammatory processes, since it not only assesses changes in pancreatic parenchyma, but also gives an indication of the origin (bile or alcoholic). It is also essential in the detection and tracing of possible complications as well as being used as a guide in diagnostic and therapeutic punctures. It is also the first technique used in the study of pancreatic tumors, detecting them with a sensitivity of around 70% and a specificity of 90%.

Contrast enhanced ultrasound with quantitative perfusion analysis for objective characterization of pancreatic ductal adenocarcinoma: A feasibility study

The aim of this study was to determine whether contrast enhanced ultrasound (CEUS) quantitative perfusion analysis allows an objective characterization of ductal adenocarcinoma (ADK) of the pancreas. Patients with pancreatic ADK underwent CEUS. All examinations were performed on an Acuson S2000 system (Siemens, Erlangen, Germany) after the iv administration of 2.4 mL contrast agent (SonoVue^®, Bracco, Milan, Italy). All lesions were pathologically proved. An operator manually drew different regions of interest within the tumor and the adjacent parenchyma to allow the quantitative perfusion analysis. The mean values of peak of enhancement, time to peak and ascending curve were calculated and compared using the Student’s t test. The quantitative perfusion analysis was possible in all lesions. The mean values of the peak of enhancement, time to peak and ascending curve were 17.19%, 7.97 s and 159.52% s within the tumor and 33.57%, 8.89 s and 355.29% s within the adjacent parenchyma. The peak of enhancement and the ascending curve values were significantly different within the tumor and the adjacent parenchyma. Thus, CEUS allows the quantitative perfusion analysis of pancreatic ductal adenocarcinoma.

Qualitative and quantitative contrast-enhanced ultrasonographic assessment of cerulein-induced acute pancreatitis in dogs

Background

Acute pancreatitis (AP) is the most common disease of the canine exocrine pancreas, and accurate noninvasive diagnosis is challenging.

Hypothesis/Objectives

To determine the feasibility of using quantitative contrast‐enhanced ultrasonography (CEUS) to detect pancreatic perfusional changes in cerulein‐induced AP in dogs.

Animals

Six adult female Beagles.

Methods

Each dog received 2 hours of IV infusion with 7.5 μg/kg/h of cerulein diluted in saline. As control, all dogs received 2 hours of IV infusion of saline 2 weeks before cerulein infusion. CEUS of the pancreas and duodenum were performed before (0 hour), and at 2, 4, 6, and 12 hours after saline and cerulein infusion. Time‐intensity curves were created from regions of interest in the pancreas and duodenum. Five perfusional parameters were measured for statistical analysis: time to initial up‐slope, peak time, time to wash‐out, peak intensity (PI), and area under the curve (AUC).

Results

In cerulein‐induced AP, pancreatic PI increased at 2 and 4 hours when compared to 0 hour, and at 2, 4, and 6 hours when compared to control. AUC increased at 4 hours when compared to 0 hour, and at 2 and 4 hours when compared to control. Time to wash‐out was prolonged at 4 hours when compared to control. For saline control, peak time was faster at 2 hours when compared to 0 hour.

Conclusions and Clinical Importance

CEUS parameters PI and AUC can provide useful information in differentiating acute pancreatitis from normal pancreas. Cerulein‐induced AP was characterized by prolonged hyperechoic enhancement on CEUS.

Effectiveness of contrast-enhanced harmonic endoscopic ultrasound for the evaluation of solid pancreatic masses

AIM

To evaluate the usefulness of contrast-enhanced harmonic endoscopic ultrasound (CH-EUS) in differentiating between pancreatic adenocarcinomas and other pancreatic disease.

METHODS

This retrospective cohort study evaluated 90 patients who were seen between November 2010 and May 2013. All these patients had solid pancreatic masses that had a hypoechoic appearance on EUS. All patients underwent CH-EUS to evaluate this diagnostic method's usefulness. The mass lesions observed on CH-EUS were classified into three categories based on their echo intensity: hypoenhanced, isoenhanced, and hyperenhanced lesions. We adjusted the sensitivity and the specificity of each category for detecting malignancies. We also estimated the accuracy of CH-EUS by comparing it to a pathological diagnosis.

RESULTS

Of the 90 patients, 62 had a pancreatic adenocarcinoma. Fifty-seven out of 62 pancreatic adenocarcinomas showed a hypoenhanced pattern on CH-EUS. The sensitivity was 92%, the specificity 68% and the accuracy approximately 82%. The area under the curve of the receiver operating characteristic analysis for CH-EUS was 0.799. There is a significant association between the hypoenhanced pattern on CH-EUS and pancreatic duct adenocarcinoma (χ(2) = 35.264, P < 0.001). In pathological examinations, the number of specimens for EUS-fine needle aspiration (EUS-FNA) was considered insufficient for diagnosis in three patients, and in two patients, the results were reported to be negative for malignancy. Pancreatic masses in all five patients revealed a hypoenhanced pattern with CH-EUS. Three patients were diagnosed with pancreatic adenocarcinoma based on the pathology results of a biopsy, and the remaining two patients were clinically diagnosed with malignancy.

CONCLUSION

CH-EUS is useful for distinguishing between pancreatic adenocarcinoma and other pancreatic disease. When a pancreatic mass shows a hypoenhanced pattern on CH-EUS but involves either insufficient samples or negative results with EUS-FNA, clinicians might consider performing another pathologic diagnosis on the basis of an EUS-FNA sample or a biopsy.