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

Contrast-enhanced guided endoscopic ultrasound procedures

Contrast-enhanced endoscopic ultrasound (CH-EUS) can overcome the limitations of endoscopic ultrasound-guided acquisition by identifying microvessels inside inhomogeneous tumours and improving the characterization of these tumours. Despite the initial enthusiasm that oriented needle sampling under CH-EUS guidance could provide better diagnostic yield in pancreatic solid lesions, further studies did not confirm the supplementary values in cases of tissue acquisition guided by CH-EUS. This review details the knowledge based on the available data on contrast-guided procedures. The indications for CH-EUS tissue acquisition include isoechoic EUS lesions with poor visible delineation where CH-EUS can differentiate the lesion vascularisation from the surrounding parenchyma and also the mural nodules within biliopancreatic cystic lesions, which occur in select cases. Additionally, the roles of CH-EUS-guided therapy in patients whose pancreatic fluid collections or bile ducts that have an echogenic content have indications for drainage, and patients who have nonvisualized vessels that need to be highlighted via Doppler EUS are presented. Another indication is represented if there is a need for an immediate assessment of the post-radiofrequency ablation of pancreatic neuroendocrine tumours, in which case CH-EUS can be used to reveal the incomplete tumour destruction.

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.

Pancreatic Ductal Adenocarcinoma: The Characteristics of Contrast-Enhanced Ultrasound Are Correlated with the Hypoxic Microenvironment

A hypoxic microenvironment is associated with an increased risk of metastasis, treatment resistance and poor prognosis of pancreatic ductal adenocarcinoma (PDAC). This study aimed to identify contrast-enhanced ultrasound (CEUS) characteristics that could predict the hypoxic microenvironment of PDAC. A total of 102 patients with surgically resected PDAC who underwent CEUS were included. CEUS qualitative and quantitative characteristics were analyzed. The expression of hypoxia-inducible factor-1α (HIF-1) and glucose transporter-1 (GLUT1) were demonstrated by immunohistochemistry. The associations between CEUS characteristics and the HIF-1α and GLUT1 expression of PDACs were evaluated. We found that HIF-1α-high PDACs and GLUT1-high PDACs had a larger tumor size and were more prone to lymph node metastasis. There was a significant positive linear correlation between the expression of HIF-1α and GLUT1. CEUS qualitative characteristics including completeness of enhancement and peak enhancement degree (PED) were related to the expression of HIF-1α and GLUT1. A logistic regression analysis showed that tumor size, lymph node metastasis, incomplete enhancement and iso-enhancement of PED were independent predictors for HIF-1α-high PDACs and GLUT1-high PDACs. As for quantitative characteristics, HIF-1α-high PDACs and GLUT1-high PDACs showed higher peak enhancement (PE) and wash-in rate (WIR). CEUS can effectively reflect the hypoxia microenvironment of PDAC, which may become a noninvasive imaging biomarker for prognosis prediction and individualized treatment.

A review of contrast-enhanced harmonic endoscopic ultrasonography for pancreatic solid tumors

Endoscopic ultrasonography (EUS) is superior to other imaging modalities in the detection of pancreatic masses, although differentiating the types of pancreatic masses detected on EUS remains challenging. However, the value of contrast-enhanced harmonic EUS (CH-EUS) using ultrasound contrast agents for this differentiation has been reported. CH-EUS plays a pivotal role in analysis of small lesions that can only be detected with EUS. Recently, CH-EUS was used for staging and/or determining the resectability of pancreatic cancer in several clinical trials. In addition, it is used to estimate the response of pancreatic cancer to chemotherapy and to determine the prognosis in cases of pancreatic cancer and pancreatic neuroendocrine neoplasms. It is also postulated that CH-EUS improves the diagnostic performance of endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) through complementary diagnoses using CH-EUS and EUS-FNAB, or CH-EUS-guided EUS-FNAB. Thus, CH-EUS has been employed for various qualitative diagnoses, including differentiation of pancreatic masses. Second-generation contrast agents such as Sonazoid are used clinically for ultrasound diagnostic imaging of liver and breast disease. The positioning of CH-EUS with Sonazoid as a test for the diagnosis of solid pancreatic tumors is an issue for further studies.

Endoscopic ultrasound-guided tissue acquisition for pancreatic ductal adenocarcinoma in the era of precision medicine

Endoscopic ultrasound-guided tissue acquisition (EUS-TA) currently plays a central role in the diagnosis of pancreatic ductal adenocarcinoma (PDAC). Although fine-needle aspiration has been the gold standard, novel biopsy needles for fine-needle biopsy (FNB) were developed to overcome its limitations, which include low tumor cellularity and the inability to retain cellular architecture. Following recent improvements in FNB needles, the pathological diagnosis has shifted from cytology to histology and now to genetic diagnosis. Genetic analysis using EUS-TA samples began with a search for the presence of K-ras mutations. However, the introduction of next-generation sequencers has dramatically changed genetic analysis and led to the gradual elucidation of the mechanism of PDAC, enabling personalized medicine by performing multiple gene analyses simultaneously. Comprehensive genomic profiling is currently applied in the clinical setting and there is an increasing need for gene analysis using EUS-TA samples. Although target genome sequencing is feasible even with cytological specimens, it can be difficult to proceed with full genetic analysis including whole-exome sequence or whole-genome sequence if the samples are too small. Genetic analysis will become highly important in determining indications for personalized medicine such as poly (ADP-ribose) polymerase inhibitors or immune checkpoint inhibitors. Therefore, the endosonographer must always take gene analysis into consideration when collecting samples for diagnosis and further improvement of the puncture technique and needle development are anticipated in the future.

Contrast-enhanced ultrasound of pancreatic melanoma: A case report and literature review

Melanoma is a malignant tumor that originates from melanocytes, most of which are of cutaneous origin. Most melanomas identified in the pancreas are metastatic, and primary pancreatic melanoma is extremely rare and has rarely been discussed. The correct preoperative diagnosis of pancreatic metastatic melanoma, especially primary melanoma, is challenging. Herein, we report a 43-year-old man who presented to our hospital due to unexplained left abdominal distension and pain. Abdominal ultrasound examination demonstrated multiple space-occupying lesions of the pancreas, and hypoechoic masses partially filled the splenic vein behind the pancreatic body. In the contrast-enhanced ultrasound (CEUS), all of these lesions showed iso-enhancement to slight hypo-enhancement in the arterial phase and hypo-enhancement in the venous phase. Masses in the splenic vein also showed hypo-enhancement. Imaging features suggested that the pancreatic lesions were malignant tumors. The tumor markers carcinoembryonic antigen, carbohydrate antigen 125 and carbohydrate antigen 19-9 were within normal limits. Based on clinical symptoms, imaging findings and incidence of pancreatic tumors, the patient’s clinical diagnosis was pancreatic carcinoma. Surgery was performed for the patient, while postoperative pathology confirmed malignant melanoma of the pancreas. Therefore, it is significant to identify the clinical and imaging manifestations of pancreatic melanoma in order to better manage the disease. Herein, we reported this case and reviewed the literature from 2000 to 2021 on the clinical and imaging features of 26 patients with pancreatic melanoma. It may improve clinicians’ awareness of the clinical and imaging performance of pancreatic melanoma, resulting in improved diagnosis, differential diagnosis, treatment, and outcomes.

Contrast-Enhanced Ultrasonography Findings Correlate with Pathologic Grades of Pancreatic Neuroendocrine Tumors

The correlation of sonographic findings with pathologic grades of pancreatic neuroendocrine tumors (PNETs) remains unclear. This study aimed to evaluate the usefulness of sonographic features in diagnosing the pathologic grade of PNETs. Conventional and contrast-enhanced ultrasonography findings of PNETs diagnosed by surgical pathology from July 2010 to June 2020 were retrospectively reviewed. Sonographic features were compared among three pathologic grades of PNETs according to the World Health Organization 2010 classification. Ordinal regression models were constructed to evaluate the usefulness of the sonographic features in diagnosing the pathologic grade of PNETs. This study enrolled 93 participants with PNETs: 50 grade 1, 31 grade 2 and 12 grade 3. Multivariate ordinal regression analysis suggested that tumor size ≥2 cm (odds ratio [OR], 0.110; 95% confidence interval [CI], 0.020-0.606; p = 0.011), dilation of the main pancreatic duct (OR, 0.103; 95% CI, 0.025-0.430; p = 0.002), hepatic metastases (OR, 0.250; 95% CI, 0.072-0.869; p = 0.029) and hyper-enhancement in arterial phase (OR, 4.676; 95% CI, 1.656-13.206; p = 0.004) were significantly associated with the pathologic grades of PNETs. The accuracy of the ordinal logistic regression model in identifying grade 1, 2 and 3 PNETs was 77.4%, 67.7% and 90.3%, respectively. The findings suggest that sonographic features, including tumor size, pancreatic duct dilation and hepatic metastasis, as well as the enhancement level in arterial phase, may help identify different pathologic grades of PNETs.

The usefulness of EUS-FNA with contrast-enhanced harmonic imaging of solid pancreatic lesions: A prospective study

BACKGROUND AND AIM

Few studies have investigated endoscopic ultrasound-guided fine-needle aspiration with contrast-enhanced harmonic imaging (EUS-FNA-CHI) for diagnosing and adequately sampling pancreatic lesions. This study aimed to investigate the efficacy of EUS-FNA-CHI compared with that of endoscopic ultrasound-guided fine-needle aspiration with fundamental B mode imaging (EUS-FNA-FBI) for diagnosing solid pancreatic lesions.

METHODS

Consecutive patients with solid pancreatic lesions were enrolled prospectively (UMIN 000024467). Only samples obtained during the first needle pass (EUS-FNA-FBI) and second needle pass (EUS-FNA-CHI) were used to compare the accuracy rate for diagnosing pancreatic lesions and rate of adequate sampling for histological evaluation. In patients with hypo-enhancing lesions on contrast-enhanced harmonic EUS (CH-EUS), subgroup analyses were performed. Patients were classified into those with a heterogeneous area in the whole lesion (whole group), those with a heterogeneous area with a non-enhancing area (non-enhancing group), and those with a heterogeneous area with a homogeneous area (homogeneous group).

RESULTS

Ninety-three patients were enrolled. Overall, the rates of adequate sampling and sensitivity were significantly higher with EUS-FNA-CHI than with EUS-FNA-FBI (84.9% vs 68.8%, P = 0.003 and 76.5% vs 58.8%, P = 0.011, respectively). The adequate sampling rate and sensitivity were significantly higher with EUS-FNA-CHI than with EUS-FNA-FBI when the mass was > 15 mm. In the non-enhancing and homogeneous groups, the adequate sampling rate and sensitivity were significantly higher with EUS-FNA-CHI than with EUS-FNA-FBI.

CONCLUSIONS

CH-EUS enables improved observation of pancreatic lesions and helps identify the target of EUS-FNA among different pathological areas of the lesions particularly of > 15 mm.

Endoscopic Ultrasound-Guided Fine-Needle Aspiration (EUS-FNA) with Image Enhancement

Although endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is useful in the differential diagnosis of solid pancreatic lesions, lymph nodes, and liver lesions, inadequate sampling may result in an incorrect pathological diagnosis. The accuracy of EUS for the evaluation of pancreatobiliary lesions may be increased by image enhancement technologies, including contrast-enhanced harmonic (CH)-EUS and EUS-elastography. These methods can provide information that complement EUS-FNA for the diagnosis and staging of pancreatobiliary cancer, and can help to identify the EUS-FNA target, reducing the requirement for repeat FNA.

Enhancement parameters of contrast-enhanced computed tomography for pancreatic ductal adenocarcinoma: Correlation with pathologic grading

BACKGROUND

Pancreatic ductal adenocarcinoma (PDA) is a malignancy with a high mortality rate and short survival time. The conventional computed tomography (CT) has been worldwide used as a modality for diagnosis of PDA, as CT enhancement pattern has been thought to be related to tumor angiogenesis and pathologic grade of PDA.

AIM

To evaluate the relationship between the pathologic grade of pancreatic ductal adenocarcinoma and the enhancement parameters of contrast-enhanced CT.

METHODS

In this retrospective study, 42 patients (Age, mean ± SD: 62.43 ± 11.42 years) with PDA who underwent surgery after preoperative CT were selected. Two radiologists evaluated the CT images and calculated the value of attenuation at the aorta in the arterial phase and the pancreatic phase (VA_arterial and VA_pancreatic) and of the tumor (VT_arterial and VT_pancreatic) by finding out four regions of interest. Ratio between the tumor and the aorta enhancement on the arterial phase and the pancreatic phase (TAR_arterial and TAR_pancreatic) was figured out through dividing VT_arterial by VA_arterial and VT_pancreatic by VA_pancreatic. Tumor-to-aortic enhancement fraction (TAF) was expressed as the ratio of the difference between attenuation of the tumor on arterial and parenchymal images to that between attenuation of the aorta on arterial and pancreatic images. The Kruskal-Wallis analysis of variance and Mann-Whitney U test for statistical analysis were used.

RESULTS

Forty-two PDAs (23 men and 19 women) were divided into three groups: Well-differentiated (n = 13), moderately differentiated (n = 21), and poorly differentiated (n = 8). TAF differed significantly between the three groups (P = 0.034) but TAR_arterial (P = 0.164) and TAR_pancreatic (P = 0.339) did not. The median value of TAF for poorly differentiated PDAs (0.1011; 95%CI: 0.01100-0.1796) was significantly higher than that for well-differentiated PDAs (0.1941; 95%CI: 0.1463-0.3194).

CONCLUSION

Calculation of TAF might be useful in predicting the pathologic grade of PDA.

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.

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.

Contrast-enhanced harmonic endoscopic ultrasonography for evaluating the response to chemotherapy in pancreatic cancer

BACKGROUND AND AIMS

Contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) is used for the diagnosis of pancreatic cancer (PC). Here, we examined the usefulness of CH-EUS for evaluating therapeutic responses in PC.

METHODS

The study included 23 patients with PC who received chemotherapy. Patients underwent contrast-enhanced computed tomography (CE-CT) and CH-EUS before chemotherapy and at the time of evaluation of the therapeutic response. Patients with a ≧50% reduction in serum carbohydrate antigen 19-9 levels after chemotherapy were defined as "super responders". The incidence of an avascular area in the tumor on CH-EUS after chemotherapy was compared between "super responders" and non-super responders.

RESULTS

Nine patients were included in the "super responders" group.Tumor reduction rates did not differ significantly between CE-CT and CH-EUS in the "super responders". The appearance of an avascular area was detected in 7 of 9 super responders (77.8%) and in 4 of 14 non-super responders (28.6%), and the difference was significant (P = 0.036). The mean survival time of patients with an avascular area after chemotherapy was longer than that of without an avascular area.

CONCLUSIONS

Detection of avascular areas by CH-EUS after chemotherapy may predict long-term survival of patients with PC.

Multiphase evaluation of contrast-enhanced endoscopic ultrasonography in the diagnosis of pancreatic solid lesions

BACKGROUND/OBJECTIVES

Time-intensity curve (TIC) under contrast-enhanced EUS (CE-EUS) allows continuous and quantitative evaluation of targeted area in the pancreas. However, TIC is not always available and the procedure is complicated. We aimed to propose a simplified method by evaluating multiple phases of CE-EUS in the diagnosis of pancreatic solid lesions.

METHODS

We retrospectively reviewed 210 patients with pancreatic solid lesions including 142 with pancreatic ductal cancer (PDAC), 31 with pancreatic neuroendocrine neoplasm, 13 with solid pseudopapillary neoplasm and 24 with mass-forming pancreatitis who underwent CE-EUS and achieved final diagnoses. The CE-EUS images were continuously recorded for 60 s, and each image at 20, 40 and 60 s was used for the evaluation. The images were classified into three patterns as hypoechoic, hyperechoic and isoechoic vascular patterns compared with the surrounding pancreas, and the relevance between the multiphase evaluation of CE-EUS and each disease group was investigated.

RESULTS

In PDAC group, majority of the lesions showed hypovascular pattern at 20 or 40 s after injection of contrast medium following early enhancement. The sensitivity, specificity and accuracy of PDAC pattern in the differentiation of PDAC from other lesions was 83.1%, 86.8% and 84.3%, respectively. On histopathological analysis, significant differences were seen in histologic types, infiltration (INF), and neural invasion (ne) between those who showed PDAC pattern and those who didn't.

CONCLUSIONS

Multiphase evaluation of CE-EUS is convenient and useful method for the differentiation of pancreatic solid lesions which can be alternatively used for TIC.

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.

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.

Impact of avascular areas, as measured by contrast-enhanced harmonic EUS, on the accuracy of FNA for pancreatic adenocarcinoma

BACKGROUND AND AIMS

EUS-guided FNA (EUS-FNA) is used for the diagnosis of pancreatic adenocarcinoma, but sometimes the method results in a false negative. Occasionally, an avascular area may be observed within the pancreatic adenocarcinoma tumor during contrast-enhanced harmonic EUS (CH-EUS). The aim of this study was to evaluate whether the diagnostic sensitivity of EUS-FNA for pancreatic adenocarcinoma was affected by the presence of avascularity on CH-EUS.

METHODS

Two hundred ninety-two patients with pancreatic adenocarcinoma who presented at Kindai University Hospital for EUS-FNA and CH-EUS between June 2009 and August 2013 were retrospectively evaluated. This was a single-center retrospective analysis of prospectively collected data held in a registry. The overall sensitivity of EUS-FNA for the diagnosis of pancreatic adenocarcinoma was calculated. The sensitivities of cytology, histology, and the combination of cytology and histology were also evaluated. These variables were individually evaluated according to the presence or absence of an avascular area on CH-EUS to assess whether the diagnostic sensitivity of EUS-FNA for pancreatic adenocarcinoma was related to the presence of an avascular area within the tumors.

RESULTS

The overall sensitivity of EUS-FNA was 90.8% (265/292). The sensitivities of EUS-FNA for lesions with and without an avascular area were 72.9% (35/48) and 94.3% (230/244), respectively, with the difference being statistically significant (P < .001).

CONCLUSIONS

EUS-FNA has lower sensitivity for pancreatic adenocarcinoma with avascular areas on CH-EUS.

How to treat pancreatic adenocarcinoma in elderly: How far can we go in 2017?

Pancreatic adenocarcinoma is one of the most fatal cancers that frequently affects older patients. Limited data suggest that older patients are as likely to benefit from surgery, radiation, and chemotherapy as younger patients. The only potentially curative approach for pancreatic cancer is surgery but this is only performed in less than 20% of patients considered resectable. With improvements in surgical techniques, older patients without major comorbidities show a course of disease after resection similar to that of younger patients. The use of adjuvant chemotherapy in an attempt to prolong survival is therefore reasonable for this population of patients. Historically, patients with locally-advanced disease will be offered gemcitabine as standard chemotherapy, with radiotherapy considered at a later time. In the majority, metastatic patients will preferably be offered gemcitabine chemotherapy, which can be used at a lower dose in frail or very old patients. In some cases in patients in a very good health condition, two recent intensive chemotherapies can be proposed with modified doses and a close follow-up: the 5-fluoroucil, leucovorin, irinotecan, oxaliplatin (FOLFIRINOX) regimen and the combination of gemcitabine plus nab-paclitaxel. For older patients with terminal disease and palliative needs, which is the majority of cases, better use of pain control and palliative measures can be beneficial. Each of these issues will be examined in detail in this review.

The Expanding Role of Contrast-Enhanced Endoscopic Ultrasound in Pancreatobiliary Disease

Since its introduction into clinical practice in the 1980s, endoscopic ultrasound (EUS) has been described as a good imaging modality for the diagnosis of pancreatobiliary diseases. However, differential diagnosis of certain lesions based only on B-mode ultrasound images can be challenging. Clinical use of ultrasound contrast agents has expanded the utility of EUS from that of detection to characterization of pancreatobiliary lesions based on the enhancement features of contrast-enhanced EUS (CE-EUS). Current low mechanical index techniques for CE-EUS using second-generation contrast agents have a number of distinct advantages over conventional diagnostic modalities in evaluating pancreatobiliary lesions, including real-time assessment of perfusion pattern, availability, and the absence of exposure to radiation. This article describes the technical aspects of CE-EUS and reviews the expanding indications in pancreatobiliary diseases and further development of this technique.

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.

Ultrasonographic features and differential diagnosis of solid pseudopapillary tumors of the pancreas

AIM: To explore the ultrasonographic features of solid pseudopapillary tumors of the pancreas (SPTP) and their differential diagnosis from pancreatic neuroendocrine tumors (PNET) and pancreatic cancer (PC).

METHODS: Clinical data including conventional ultrasonographic characteristics for 52 patients with pathologically confirmed SPTP, 63 patients with PNET, and 68 patients with PC and the patterns of contrast enhanced ultrasonography (CEUS) in 6 cases of SPTP, 10 cases of PNET and 21 cases of PC were retrospectively analyzed.

RESULTS: There were significant differences between the SPTP group and the PNET group in age, sex, jaundice, tumor size, shape, calcification, liquefaction, separation, blood flow, arterial phase and late phase enhancement mode and non-enhancement area in the lesions (P < 0.05), while presence of abdominal pain, elevated CA-199, number of tumors, location, expansion of the main pancreatic duct and recurrence or metastasis had no statistical significance (P > 0.05). There were significant differences between the SPTP group and the PC group in age, sex, abdominal pain, jaundice, elevated CA-199, tumor size, location, shape, calcification, liquefaction, expansion of the main pancreatic duct, recurrence or metastasis, arterial phase enhancement mode and non-enhancement area in the lesions (P < 0.05), while number of tumors, separation, blood flow and late phase enhancement mode had no statistical significance (P > 0.05).

CONCLUSION: A solid or cystic-solid pancreatic tumor which shows peripheral ring enhancement in the arterial phase, hypo-enhancement in the late phase and central non-enhancement area could be considered as an SPTP in young female patients without jaundice, elevated CA-199 or main pancreatic duct dilation. It should be differentiated from PNET and PC.

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.

Utility of Contrast-Enhanced Transabdominal Ultrasonography to Diagnose Early Chronic Pancreatitis

Purpose. The purpose of this study was to establish the relationship between the grade of chronic pancreatitis (CP) and pancreatic blood flow as measured by contrast-enhanced transabdominal ultrasonography (CEUS) and to diagnose early CP easily. Methods. This pilot study was conducted in 8 patients with CP, 7 patients with early CP, and 6 control participants. After injecting 0.015 mL/kg of perflubutane by manual bolus, values in one region of interest (ROI) in pancreatic parenchyma and one ROI including the superior mesenteric artery (SMA) were measured. Results. The ratio of blood flow in the SMA and pancreatic parenchyma increased with grade of CP and was significantly higher in patients with CP (5.41; 2.10–11.02) than in patients with early CP (2.46; 1.41–5.05) and control participants (2.32; 1.25–3.04) (P = 0.0279, P = 0.0142, resp.). The ratio of blood flow in the SMA and pancreatic parenchyma correlated with grade of CP (rs = 0.5904, P = 0.0048). Conclusion. The ratio of blood flow correlates with grade of CP on CEUS. This safe and convenient method may be useful to diagnose early CP.

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.

Clinical controversies in endoscopic ultrasound

The field of diagnostic and therapeutic endoscopic ultrasound (EUS) is growing rapidly. Although EUS has enhanced our ability to diagnose and treat a wide variety of GI conditions, there are many controversial issues regarding the appropriate application of EUS techniques. In this review we discuss five controversial topics in EUS: the utility of EUS in staging of esophageal and gastric cancer; selection of appropriate needle gauge for fine needle aspiration (FNA); use of the stylet in FNA; and the emerging role of contrast agents in endoscopic ultrasound.

Application of contrast-enhanced ultrasound in the diagnosis of solid pancreatic lesions--a comparison of conventional ultrasound and contrast-enhanced CT

OBJECTIVE

To explore the diagnostic value of contrast-enhanced ultrasound (CEUS) by comparison with conventional ultrasound (US) and contrast-enhanced CT (CECT) in solid pancreatic lesions.

METHOD

Ninety patients with solid pancreatic focal lesions were enrolled, including 36 cases of pancreatic carcinoma, 28 cases of pancreatitis, 6 cases of pancreatic neuroendocrine tumor, 12 cases of solid pseudopapillary tumor of the pancreas, 6 cases of pancreatic metastases, 1 case of cavernous hemolymphangioma and 1 case of lymphoma. US and CEUS were applied respectively for the diagnosis of a total of 90 cases of solid pancreatic lesions. The diagnostic results were scored on a 5-point scale. Results of CEUS were compared with CECT.

RESULTS

(1) 3-score cases (undetermined) diagnosed by CEUS were obviously fewer than that of US, while the number of 1-score (definitely benign) and 5-score (definitely malignant) cases diagnosed by CEUS was significantly more than that of US. There was a significant difference in the distribution of final scores using the two methods (p<0.001). The overall diagnostic accuracies of the 90 cases for CEUS and US were 83.33% and 44.44%, respectively, which indicated an obvious advantage for CEUS (p<0.001). (2) The diagnostic consistency among three ultrasound doctors: the kappa values calculated for US were 0.537, 0.444 and 0.525, compared with 0.748, 0.645 and 0.795 for CEUS. The interobserver agreement for CEUS was higher than that for US. (3) The sensitivity, specificity and accuracy of the diagnosis of pancreatic carcinoma with CEUS and CECT were 91.7% and 97.2%, 87.0% and 88.9%, and 88.9% and 92.2%, respectively, while for the diagnosis of pancreatitis, the corresponding indices were 82.1% and 67.9%, 91.9% and 100%, and 88.9% and 90%, respectively, showing no significant differences (p>0.05).

CONCLUSION

CEUS has obvious superiority over conventional US in the general diagnostic accuracy of solid pancreatic lesions and in the diagnostic consistency among doctors. The performances of CEUS are similar to that of CECT in the diagnosis of pancreatic carcinoma and focal pancreatitis.

Contrast-enhanced endoscopic ultrasound

The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) introduced guidelines on the use of contrast-enhanced ultrasound (CEUS) in 2004. This EFSUMB-document focused mainly on liver applications. However, new applications extending beyond the liver were developed thereafter. Increased interest in recent years in CEUS technique and in the application of CEUS in novel fields like endoscopic ultrasound (EUS) has revolutionized indications and applications. As a result, the EFSUMB initiated a new update of the guidelines in 2011 to include this additional knowledge. Some of the contrast-enhanced EUS (CE-EUS) indications are established, whereas others are preliminary; these latter indications are categorized as emergent CEUS applications since the available evidence is insufficient for general recommendation. This article focuses on the use of CE-EUS in various clinical settings. The reader will get an overview of current indications and possible applications of CE-EUS. This involves the introduction of different contrast studies including color Doppler techniques (known as contrast-enhanced high mechanical index endosonography or CEHMI-EUS) as well as more modern high-resolution contrast-enhanced techniques (known as contrast-enhanced low mechanical index endosonography or CELMI EUS).

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.

Dynamic quantitative evaluation of contrast-enhanced endoscopic ultrasonography in the diagnosis of pancreatic diseases

OBJECTIVES

This study aimed to investigate the usefulness of contrast-enhanced endoscopic ultrasonography (EUS) with time-intensity curve (TIC) in differentiating pancreatic diseases.

METHODS

Patients who underwent contrast-enhanced EUS between January 2007 and June 2009 were analyzed retrospectively, including 48 with pancreatic ductal cancer (PC), 14 with autoimmune pancreatitis (AIP), 13 with mass-forming pancreatitis (MFP), and 16 with pancreatic endocrine tumor (PET). After intravenous injection of contrast agent, contrast imaging pattern, TIC-based quantitative evaluation, and diagnostic ability of EUS in combination with TIC to diagnose benignancy or malignancy were assessed.

RESULTS

Hypovascular and heterogeneous pattern (42/48) in PC, isovascular and homogenous (21/27) in AIP and MFP, and hypervascular and rapid stained (16/16) in PET were observed. The echo intensity reduction rate from the peak at 1 minute was the greatest in PC followed by MFP, AIP, and PET (P < 0.05). The diagnostic accuracies based on contrast imaging pattern (84.0%) and TIC (88.0%) were higher than those based on B-mode imaging (82.6%) and dynamic computed tomography (81.3%). In EUS in combination with TIC, sensitivity, specificity, and accuracy rose up to 95.8%, 92.6%, and 94.7%, respectively.

CONCLUSIONS

Contrast-enhanced EUS with the dynamic quantitative analysis preparing TIC increased the diagnostic accuracy for pancreatic diseases.

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.

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.

Assessment of contrast-enhanced ultrasonography in diagnosis and preoperative localization of insulinoma

OBJECTIVE

This study was to evaluate the value of contrast-enhanced ultrasonography (CEUS) in the diagnosis and preoperative localization of insulinoma and explore the enhancement patterns of the tumors.

METHODS

Unenhanced and contrast-enhanced ultrasonographic examinations of 31 patients who underwent resection of insulinomas were retrospectively reviewed. The diagnosis sensitivity and localization specificity of CEUS for insulinomas were determined. Results of unenhanced ultrasonography and CEUS were compared by Chi-square test.

RESULTS

Unenhanced ultrasonography could display 9 of 37 (24.3%) surgically verified insulinomas in 31 patients, while the diagnosis sensitivity and localization specificity of preoperative CEUS was 33 (89.2%) and 32 (86.5%) of the 37 tumors, respectively. In contrast to the unenhanced ultrasonography, the improvement of CEUS in the diagnosis and preoperative localization of insulinomas was significant (p<0.0001). The enhancement pattern of insulinoma on CEUS was fast wash-in and slow wash-out. All the tumors were homogeneous hypervascularity in the earlier arterial phase, while the tumors still displayed hyperenhancing pattern in the late phase.

CONCLUSION

Our study demonstrates the great potential of CEUS in the diagnosis and preoperative localization of insulinomas. Since CEUS is a convenient, inexpensive, effective and non-invasive modality, the study supports the use of CEUS as a primary tool in the evaluation of patients with insulinomas.

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.

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.

Contrast-enhanced ultrasound of the pancreas

The introduction of contrast-enhanced ultrasonography (CEUS) has led to major improvements in the diagnostic capabilities of ultrasound (US). The innovative use of CEUS for study of the pancreas has created the need for a definition of the most frequent dynamic features of solid and cystic masses. CEUS is less expensive compared to computed tomography and magnetic resonance imaging and is able to significantly improve the accuracy of US, allowing better characterization and staging of pancreatic pathologies.

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.

Contribution of contrast-enhanced ultrasonography to nonoperative management of segmental ischemia of the head of a pancreas graft

A 32-year-old recipient of a pancreas transplant (PTx) alone was diagnosed with segmental graft ischemia, involving the head of the pancreas graft (HPG), based on color Doppler ultrasonography (CDU) and computed tomography (CT) angiography. For investigational purposes, graft supply was further checked by contrast-enhanced ultrasonography (CEU). Surprisingly, CEU showed collateral blood supply to the HPG starting from 40 s after contrast injection and resulting in homogenous parenchymography at 90 s. Full-dose heparin infusion, followed by long-term oral anticoagulation, allowed graft salvage without reoperation. At the longest follow-up of 18 months, the patient is insulin independent. This case report shows that CEU may be employed in PTx recipients suspected to harbor vascular complications. To the best of our knowledge, this is the first description of the use of CEU in PTx and the first description of graft salvage, without partial pancreatectomy after CDU and CT diagnosis of segmental graft ischemia.

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.

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.