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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Development and validation of a nomogram model based on pretreatment ultrasound and contrast-enhanced ultrasound to predict the efficacy of neoadjuvant chemotherapy in patients with borderline resectable or locally advanced pancreatic cancer

OBJECTIVES

To develop a nomogram using pretreatment ultrasound (US) and contrast-enhanced ultrasound (CEUS) to predict the clinical response of neoadjuvant chemotherapy (NAC) in patients with borderline resectable pancreatic cancer (BRPC) or locally advanced pancreatic cancer (LAPC).

METHODS

A total of 111 patients with pancreatic ductal adenocarcinoma (PDAC) treated with NAC between October 2017 and February 2022 were retrospectively enrolled. The patients were randomly divided (7:3) into training and validation cohorts. The pretreatment US and CEUS features were reviewed. Univariate and multivariate logistic regression analyses were used to determine the independent predictors of clinical response in the training cohort. Then a prediction nomogram model based on the independent predictors was constructed. The area under the curve (AUC), calibration plot, C-index and decision curve analysis (DCA) were used to assess the nomogram's performance, calibration, discrimination and clinical benefit.

RESULTS

The multivariate logistic regression analysis showed that the taller-than-wide shape in the longitudinal plane (odds ratio [OR]:0.20, p = 0.01), time from injection of contrast agent to peak enhancement (OR:3.64; p = 0.05) and Peaktumor/ Peaknormal (OR:1.51; p = 0.03) were independent predictors of clinical response to NAC. The predictive nomogram developed based on the above imaging features showed AUCs were 0.852 and 0.854 in the primary and validation cohorts, respectively. Good calibration was achieved in the training datasets, with C-index of 0.852. DCA verified the clinical usefulness of the nomogram.

CONCLUSIONS

The nomogram based on pretreatment US and CEUS can effectively predict the clinical response of NAC in patients with BRPC and LAPC; it may help guide personalized treatment.

Early detection of pancreatic tumors by advanced EUS imaging

The early detection of pancreatic ductal adenocarcinoma (PDAC) dramatically improves outcome. All available state-of-the-art imaging methods allow early detection with EUS being the best technique for exclusion of PDAC and detection of very early PDAC. Etiological differentiation of small SPL is important to guide individually tailored patients' management including radical surgery in resectable PDAC, medical (neoadjuvant or palliative intended) treatment in patients with non-resectable malignancy, pancreatic parenchyma saving strategies in some non-PDAC, and follow-up in particular in low-grade PanNEN or other small benign lesions. Multimodality EUS imaging including B-Mode assessment, elastography, contrast-enhancement and EUS-guided sampling is the most appropriate technique for diagnosis and risk assessment of small SPL. We present a review discussing modern (endoscopic) ultrasound imaging techniques including contrast enhanced ultrasound and elastography for the early detection and characterization of solid pancreatic lesions.

Nonhypovascular pancreatic ductal adenocarcinomas: CEUS imaging findings and differentiation from other types of solid pancreatic lesions

OBJECTIVES

To observe and assess the diagnostic value of contrast-enhanced ultrasound (CEUS) in patients with iso-/hypervascular solid pancreatic lesions.

METHODS

70 pancreatic lesions (all confirmed by surgery or biopsy pathology) that manifested iso-/hyperenhancement on CEUS were retrospectively studied from January 2018 to January 2022, including 24 pancreatic ductal adenocarcinomas (PDAC), 15 mass-forming pancreatitis (MFP), 24 pancreatic neuroendocrine tumors (PNET) (14 hyper-PNETs, 10 iso-PNETs), and 7 solid pseudopapillary tumors of pancreas (SPTP). 65 pancreatic ductal adenocarcinomas (PDAC) that manifested hypoenhancement on CEUS were retrospectively studied from January 2020 to January 2022. CEUS patterns and the clinical and pathologic features were analyzed, and the diagnostic ability of CEUS for iso/hyperenhanced solid pancreatic lesions was assessed.

RESULTS

Centripetal enhancement, heterogeneous enhancement, early washout, and hypoenhancement in the late phase mostly appeared in iso-/hyper-PDACs (p < 0.05). Heterogeneous enhancement in small lesions (< 3 cm) as the diagnostic criterion for iso-/hyper-PDACs had an accuracy of 74.3% and a specificity of 91.3%. Iso-PNETs more commonly had larger tumor sizes and more often showed heterogeneous enhancement than hyper-PNETs (p = 0.007, p = 0.035, respectively). The characteristics of the combination of isoenhancement, homogeneous enhancement, and synchronous wash-in/out for MFP had a high accuracy of 90%. Capsular enhancement with heterogeneous enhancement inside for SPTP had an accuracy of 97.1%.

CONCLUSION

CEUS enhancement patterns have potentially great value in the differentiation of iso-/hyperenhanced pancreatic lesions.

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.

Correlation Between Enhancement Patterns on Transabdominal Ultrasound and Survival for Pancreatic Ductal Adenocarcinoma

Objective

Investigate the CEUS enhancement patterns of PDAC and analyse correlations between the CEUS enhancement pattern and both the degree of tumour tissue differentiation and overall survival (OS).

Methods

The study included 56 patients with locally advanced PDAC, performed conventional ultrasound and CEUS, and analysed characteristics of the CEUS enhancement patterns. In addition, clinical data, such as serum level of CA19-9, TNM stage were collected, and patients’ survival times were followed up. TICs of dynamic CEUS images were acquired using image processing software to obtain the peak, TP, sharpness, and AUC. Correlations of the CEUS enhancement patterns of PDAC with the degree of differentiation of tumour tissue and OS were quantitatively analysed, as were the correlations of the TIC parameters and CEUS enhancement patterns with OS.

Results

Enhancement in the arterial phase included iso-enhancement (30.3%) and hypo-enhancement (69.6%), and was not significantly correlated with sex, age at disease onset, or lesion size. Also was not significantly correlated with tumour tissue differentiation. Clear survival times were obtained for 50 patients during follow-up, and the median survival time was significantly longer for the patients with iso-enhancement than hypo-enhancement. Among the TIC parameters, peak_tumour, sharpness_tumour, AEsharpness, and REsharpness differed significantly between the group with iso-enhancement and hypo-enhancement (p < 0.05).

Conclusion

The CEUS enhancement patterns of PDAC in the arterial phase include iso-enhancement and hypo-enhancement. Enhancement pattern was not significantly correlated with the degree of differentiation of tumour tissue, but patient survival time differed significantly between the two enhancement patterns, with longer survival for patients with iso-enhancement.

Comparison of sulfur hexafluoride microbubbles and perfluorobutane for performance of contrast-enhanced ultrasonography of the pancreas in dogs

OBJECTIVE

To compare qualitative features and quantitative parameters of 2 contrast agents (sulfur hexafluoride microbubbles [SHM; SonoVue] and perfluorobutane [PFB; Sonazoid]) for performance of contrast-enhanced ultrasonography (CEUS) of the pancreas in dogs.

ANIMALS

8 healthy Beagles.

PROCEDURES

In a crossover study design, CEUS of the pancreas was performed twice in each dog, once with SHM and once with PFB, in random order with at least 3 days between examinations. The recorded cine images were qualitatively assessed for homogeneity of pancreatic enhancement and conspicuity of the pancreatic signal relative to the background. For the quantitative assessment, circular regions of interest were placed over the pancreatic body, and a time-intensity curve was obtained. For each region of interest, CEUS parameters including peak intensity (PI), time to peak pancreatic enhancement, area under the curve (AUC), and wash-in rate were obtained.

RESULTS

The homogeneity of the pancreatic parenchyma was not significantly different between contrast agents. The signal conspicuity relative to background noise was significantly higher with PFB than with SHM. Mean values of PI, wash-in rate, and AUC were significantly higher with PFB than with SHM. Time to peak enhancement was not significantly different between contrast agents.

CONCLUSIONS AND CLINICAL RELEVANCE

Pancreatic CEUS with SHM and PFB produced similar homogeneity scores, but only PFB provided excellent signal conspicuity. Perfluorobutane produced higher values of PI, wash-in rate, and AUC. Findings indicated that PFB can provide homogeneous and strong enhancement of the pancreas during CEUS in healthy dogs and that pancreatic CEUS parameter values differ with the contrast agent used.

Modern ultrasound imaging of pancreatic tumors

In patients with solid pancreatic lesions (SPLs), the differential diagnosis must be evaluated to determine whether radical surgery, pancreatic parenchyma-saving strategies, or follow-up is indicated. Contrast-enhanced (endoscopic) ultrasonography and elastography facilitate the further characterization of SPLs. The majority of cases of pancreatic ductal adenocarcinoma exhibit hypoenhancement with contrast-enhanced ultrasonography. Elastographically soft SPLs are benign with very few exceptions, whereas stiffer SPLs can be malignant or benign. This article reviews the current use of modern ultrasound imaging techniques, including contrast-enhanced ultrasonography and elastography, for the detection and characterization of SPLs. In particular, the unexcelled diagnostic potential of multiparametric endoscopic ultrasonography to detect and characterize small SPLs is highlighted.

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.

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.

Diagnostic performance of contrast-enhanced ultrasound for pancreatic neoplasms: A systematic review and meta-analysis

BACKGROUND

Early diagnosis of pancreatic cancer is essential to optimize treatment strategies.

OBJECTIVES

To evaluate the diagnostic performance of contrast-enhanced ultrasound for benign and malignant pancreatic neoplasms.

DATA SOURCES

Pubmed, Embase, Web of Science, and Cochrane Library databases.

STUDY ELIGIBILITY CRITERIA

Retrospective or prospective studies.

PARTICIPANTS

Patients with a confirmed diagnosis of benign and malignant pancreatic neoplasms.

INTERVENTION

Contrast-enhanced ultrasound.

STUDY APPRAISAL AND SYNTHESIS

Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic risk ratio, and corresponding 95% confidence intervals; summary receiver operating characteristic (SROC) curve; a Fagan nomogram.

RESULTS

Ten studies involving 641 patients were included. Pooled sensitivity, specificity, and positive and negative predictive values were 91% (95% CI: 87%, 93%), 87% (95% CI: 78%, 93%), 7.2 (95% CI: 4.3, 12.3), and 0.11 (95% CI: 0.08, 0.15), respectively; and the odds ratio for diagnosis was 67 (95% CI: 34, 113). Contrast-enhanced ultrasound had good diagnostic ability and accuracy. Pre- and post-test probability of disease was 50% and 88%, respectively, when the positive likelihood ratio was 7.

CONCLUSION

Contrast-enhanced ultrasound can be used for qualitative diagnosis of benign and malignant pancreatic neoplasms.

IMPLICATIONS OF KEY FINDINGS

CEUS should be considered as an important imaging tool for the characterization of pancreatic tumors.

SYSTEMATIC REVIEW REGISTRATION NUMBER

CRD42017070434 (PROSPERO).

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.

Percutaneous Radiofrequency Ablation of Unresectable Locally Advanced Pancreatic Cancer: Preliminary Results

AIM

The objective of this study was to evaluate the efficacy of percutaneous radiofrequency ablation of locally advanced pancreatic cancer located in the pancreatic body.

MATERIALS AND METHODS

Patients with biopsy-proven locally advanced pancreatic adenocarcinoma were considered for percutaneous radiofrequency ablation. Postprocedural computed tomography studies and Ca19.9 tumor marker evaluation were performed at 24 hours and 1 month. At computed tomography, treatment effect was evaluated by excluding the presence of complications. The technical success of the procedure is defined at computed tomography as the achievement of tumoral ablated area.

RESULTS

Twenty-three patients have been included in the study. Five of the 23 patients were excluded. At computed tomography, the mean size of the intralesional postablation necrotic area was 32 mm (range: 15-65 mm). Technical success of the procedure has been obtained in 16 (93%) of the 18 cases. None of the patients developed postprocedural complications. Mean Ca19.9 serum levels 1 day before, 1 day after, and 1 month after the procedure were 285.8 U/mL (range: 16.6-942.0 U/mL), 635.2 U/mL (range: 17.9-3368.0 U/mL), and 336.0 U/mL (range: 7.0-1400.0 U/mL), respectively. Follow-up duration was less than 6 months for 11 patients and more than 6 months for 7 patients. At the time of the draft of this article, the mean survival of the patients included in the study was 185 days (range: 62-398 days).

CONCLUSION

Percutaneous radiofrequency ablation of locally advanced adenocarcinoma has a high technical success rate and is effective in cytoreduction both at imaging and laboratory controls.

Differential diagnosis between intraductal papillary mucinous neoplasm with an associated invasive carcinoma and pancreatic ductal adenocarcinoma on ultrasonography: the utility of echo intensity and contrast enhancement

Purpose

The aim of this study was to investigate the utility of echo intensity and contrast enhancement in the differential diagnosis between intraductal papillary mucinous neoplasm with an associated invasive carcinoma (IPMN-IC) and pancreatic ductal adenocarcinoma (PDAC) on ultrasonography.

Methods

This study included eight and 37 patients who had pathologically confirmed IPMN-IC and PDAC, respectively, and were enrolled for a comparative analysis of the sonographic features of the tumors. In the quantitative echo intensity evaluation, the two groups were compared with respect to the difference between the tumor intensity and the pancreatic intensity (TI-PI) and between the tumor intensity and the vascular intensity (TI-VI). In the quantitative contrast enhancement evaluation, the increase in echo intensity (ΔTI) and increase in echo intensity per unit of time (slope) were compared between the groups. The echo intensity and contrast enhancement were also compared between the two groups in patients with T3-T4 disease. In addition, the correlations of the histological type, tumor size, stromal type, and T factor with echogenicity and contrast enhancement were analyzed.

Results

IPMN-IC had significantly greater echo intensity and contrast enhancement than PDAC (TI-PI, P=0.004; TI-VI, P=0.001; ΔTI, P=0.012; slope, P=0.002). In T3-T4 disease, IPMN-IC also showed greater echo intensity and faster enhancement than PDAC. Echo intensity and contrast enhancement were correlated with histological type (TI-PI, P=0.003; TI-VI, P<0.001; ΔTI, P=0.007; slope, P<0.001).

Conclusion

IPMN-IC and PDAC can be differentiated by the quantitative evaluation of echo intensity and contrast enhancement.

Thermal Ablation of the Pancreas With Intraoperative High-Intensity Focused Ultrasound: Safety and Efficacy in a Porcine Model

OBJECTIVE

New focal destruction technologies such as high-intensity focused ultrasound (HIFU) may improve the prognosis of pancreatic ductal adenocarcinoma. Our objectives were to demonstrate the safety and efficacy of intraoperative pancreatic HIFU ablation in a porcine model.

METHODS

In a porcine model (N = 12), a single HIFU ablation was performed in either the body or tail of the pancreas, distant to superior mesenteric vessels. All animals were sacrificed on the eighth day. The primary objective was to obtain an HIFU ablation measuring at least 1 cm without premature death.

RESULTS

In total, 12 HIFU ablations were carried out. These ablations were performed within 160 seconds and on average measured 20 (15-27) × 16 (8-26) mm. The primary objective was fulfilled in all but 1 pig. There were no premature deaths or severe complications. High-intensity focused ultrasound treatment was associated with a transitory increase in amylase and lipase levels, and pseudocysts were observed in half of the pigs without being clinically apparent. All ablations were well delimited at both gross and histological examinations.

CONCLUSIONS

Intraoperative thermal destruction of porcine pancreas with HIFU is feasible. Reproducibility and safety have to be confirmed when applied close to mesenteric vessels and in long-term preclinical studies.

Ultrasound imaging features of isolated pancreatic tuberculosis

Background and Objectives:

Isolated pancreatic tuberculosis (PTB) is extremely rare worldwide. The purpose of this multicenter retrospective study is to analyze imaging features of histologically confirmed isolated PTB in order to determine the diagnostic features of the new methods contrast enhanced ultrasound (CEUS), ultrasound elastography and contrast enhanced endoscopic ultrasound (CE-EUS).

Patients and Methods:

We report on a retrospective data collection of 12 cases of PTB confirmed by histology or cytology. All examinations were interpreted by two independent readers in consensus. CEUS, CE-EUS and ultrasound elastography were performed according to the European Federation of Societies for Ultrasound in Medicine and Biology guidelines.

Results:

In PTB patients the common bile duct was never dilated. Multiple retroperitoneal lymph nodes are the second important B-mode ultrasound feature detected in 75% of PTB patients. CE-EUS was performed in three PTB patients demonstrating hyperenhancement. On elastography, all PTB lesions were markedly stiffer than surrounding pancreatic parenchyma.

Conclusions:

Here we report the first time on CEUS and elastography features of PTB. PTB had some typical imaging features with iso- or hyperenhancement on CE(E) US. PTB is markedly stiffer on elastography. If clinicians are aware of clinical features of PTB and conduct appropriate investigations with multiple modalities including B-mode ultrasound, CEUS, and EUS guided fine needle aspiration, diagnosis of PTB without laparotomy is possible and the disease can be effectively treated with anti-tuberculous drugs.

Differential diagnosis of small solid pancreatic lesions

BACKGROUND AND AIMS

Pancreatic ductal adenocarcinoma (PDAC) is typically diagnosed at a late stage. Little is known about the incidental finding of early-stage PDAC. The aim of the current study was to determine the etiology of small solid pancreatic lesions (≤15 mm) to optimize clinical management.

METHODS

Inclusion criterion for the retrospective study analysis was the incidental finding of primarily undetermined small solid pancreatic lesions ≤15 mm in 394 asymptomatic patients. Final diagnoses were based on histology or cytology obtained by imaging-guided biopsy (and at least 12-month follow-up) and/or surgery. Contrast-enhanced US or contrast-enhanced EUS was performed in 219 patients.

RESULTS

The final diagnoses of 394 patients were as follows: 146 PDACs, 156 neuroendocrine tumors, 28 metastases into the pancreas from other primary sites, and 64 various other etiologies. Contrast-enhanced US allowed differential diagnosis of PDAC and non-PDAC in 189 of 219 patients (86%).

CONCLUSIONS

Approximately 40% of patients with small solid pancreatic lesions had very early stage PDAC. Approximately 60% of small solid pancreatic lesions ≤15 mm are not PDAC and, therefore, do not require radical surgery. Without preoperative diagnosis, an unacceptably large proportion of patients would be exposed to radical surgery with significant morbidity and mortality.

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.

CT Imaging Biomarkers Predict Clinical Outcomes After Pancreatic Cancer Surgery

This study aimed to determine whether changes in contrast-enhanced computed tomography (CT) parameters could predict postsurgery overall and progression-free survival (PFS) in pancreatic cancer patients. Seventy-nine patients with a final pathological diagnosis of pancreatic adenocarcinoma were included in this study from June 2008 to August 2012. Dynamic contrast-enhanced (DCE) CT of tumors was obtained before curative-intent surgery. Absolute enhancement change (AEC) and relative enhancement change (REC) were evaluated on DCE-CT. PFS and overall survival (OS) were compared based on CT enhancement patterns. The markers of fibrogenic alpha-smooth muscle antigen (α-SMA) and periostin in tumor specimens were evaluated by immunohistochemical staining. The χ test was performed to determine whether CT enhancement patterns were associated with α-SMA-periostin expression levels (recorded as positive or negative). Lower REC (<0.9) was associated with shorter PFS (HR 0.51, 95% CI: 0.31-0.89) and OS (HR 0.44, 95% CI: 0.25-0.78). The α-SMA and periostin expression level were negatively correlated with REC (both P = 0). Among several CT enhancement parameters, REC was the best predictor of patient postsurgery survival. Low REC was associated with a short progression-free time and poor survival. The pathological studies suggested that REC might be a reflection of cancer fibrogenic potential.

Pancreatic Cancer: a Challenge to Cure

Pancreatic ductal adenocarcinoma (PDA) is a challenging disease, as overall survival has not improved over the last several decades. The disease is characterized by late diagnosis, difficult major surgery in resectable patients, and a biologically chemoresistant tumor. Intense research in the field is ongoing to develop biomarkers for early detection and prognostication. Surgery is presently the crux of the management of PDA and has been standardized over the years with high-volume centers reporting <5 % operative mortality. The biggest problem is to overcome the inherent chemoresistance of the tumor that is densely fibrotic and hypoxic and has a tendency to invade surrounding neuronal plexuses. This review attempts to summarize in brief the reasons why PDA is difficult to treat, and provides a glimpse of the ongoing research in the field.

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 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.

Pancreatic cancer: why is it so hard to treat?

No common malignancy is as rapidly and inevitably fatal as pancreatic ductal adenocarcinoma (PDA). This grim fact has driven substantial research efforts into this disease in recent decades. Unfortunately, the investment has yet to result in a meaningful increase in 5-year survival. This has prompted many pancreatic cancer researchers and advocates to redouble their efforts, but also requires one to step back and ask why the previous efforts were lacking and to consider why pancreatic cancer is so difficult to treat. The difficulties are legion. PDA is characterized by an insidious clinical syndrome, but is rarely diagnosed at a time when surgical resection is feasible. We lack markers of early detection and screening programs remain unproven even in high risk populations. The location of the tumor in the retroperitoneum, the advanced age of patients, and the systemic effects of disease limit the options for local therapy. Chemotherapy may provide a small benefit, but most efforts to improve on the current regimens consistently and stubbornly fail in advanced clinical trials. The molecular and cellular features of ductal pancreatic tumors are aggressive and underlay multiple levels of therapeutic resistance. Non-cell-autonomous features including stromal proliferation, reduced vascular density and immune suppression also contribute to therapeutic resistance. Growing awareness of these the fundamental features of PDA has begun to guide ongoing research efforts. Clinical trials are now specifically targeting these tumor properties and actively focusing on the therapeutic implications of tumor stroma. As reviewed here, reflecting on the fundamental question of why pancreatic cancer is so difficult to treat is a necessary and informative exercise that will aid our efforts to improve patient outcomes. These efforts will lead to improvements in clinical trial design, expand our focus to include the molecular and histologic implications of novel treatment paradigms, and ultimately change the lives of our patients.

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.

Xenon-inhalation computed tomography for noninvasive quantitative measurement of tissue blood flow in pancreatic tumor

BACKGROUND AND AIMS

The purpose of this prospective study was to demonstrate the ability to measure pancreatic tumor tissue blood flow (TBF) with a noninvasive method using xenon inhalation computed tomography (xenon-CT) and to correlate TBF with histological features, particularly microvascular density (MVD).

METHODS

TBFs of pancreatic tumors in 14 consecutive patients were measured by means of xenon-CT at diagnosis and following therapy. Serial abdominal CT scans were obtained before and after inhalation of nonradioactive xenon gas. TBF was calculated using the Fick principle. Furthermore, intratumoral microvessels were stained with anti-CD34 monoclonal antibodies before being quantified by light microscopy (×200). We evaluated MVD based on CD34 expression and correlated it with TBF.

RESULTS

The quantitative TBF of pancreatic tumors measured by xenon CT ranged from 22.3 to 111.4 ml/min/100 g (mean ± SD, 59.6 ± 43.9 ml/min/100 g). High correlation (r = 0.885, P < 0.001) was observed between TBF and intratumoral MVD.

CONCLUSION

Xenon-CT is feasible in patients with pancreatic tumors and is able to accurately estimate MVD noninvasively.

Radiofrequency ablation of locally advanced pancreatic adenocarcinoma: an overview

Radiofrequency ablation (RFA) of pancreatic neoplasms is restricted to locally advanced, non-resectable but non-metastatic tumors. RFA of pancreatic tumors is nowadays an ultrasound-guided procedure performed during laparotomy in open surgery. Intraoperative ultrasound covers the mandatory role of staging, evaluation of feasibility, guidance and monitoring of the procedure. Different types of needle can be used. The first aim in the evaluation of RFA as a treatment for locally advanced pancreatic ductal adenocarcinoma, in order of evaluation but not of importance, is to determine the feasibility of the procedure. The second aim is to establish the effect of RFA on tumoral mass in terms of necrosis and cytoreduction. The most important aim, third in order of evaluation, is the potential improvement of quality of life and survival rate. Nowadays, only a few studies assess the feasibility of the procedure. The present paper is an overview of RFA for pancreatic adenocarcinoma.

Contrast harmonic echo-endoscopic ultrasound improves accuracy in diagnosis of solid pancreatic masses

BACKGROUND & AIMS

Contrast harmonic echo (CHE) has been developed for endoscopic ultrasound (EUS). This new technique detects echo signals from microbubbles in vessels with very slow flow, without artifacts. We assessed whether CHE-EUS increases the accuracy of diagnosis of pancreatic solid lesions.

METHODS

At a tertiary-care EUS center, we examined 90 patients who were suspected of having pancreatic solid neoplasm. Radial and linear echoendoscopes were used with dedicated software for CHE. Sonovue (Bracco International BV, Amsterdam, The Netherlands) uptake, pattern, and washout were studied; data were compared for pancreatic lesions and adjacent parenchyma. The final diagnosis was obtained based on results of surgical pathology and/or EUS-fine needle aspiration (FNA) analyses.

RESULTS

The finding of a hypoenhancing mass with an inhomogeneous pattern was a sensitive and accurate identifier of patients with adenocarcinoma (96% and 82%, respectively) (49 of 51 patients with primary pancreatic adenocarcinoma had a hypoenhancing mass that was inhomogeneous and had fast washout). This finding was more accurate in diagnosis than the finding of a hypoechoic lesion using standard EUS (P < .000). Hyperenhancement specifically excluded adenocarcinoma (98%), although sensitivity was low (39%). Of neuroendocrine tumors, 11 of 13 were non-hypo-enhancing (9 hyperenhancing, 2 isoenhancing). Interestingly, CHE-EUS allowed detection of small lesions in 7 patients who had uncertain standard EUS findings because of biliary stents (n = 5) or chronic pancreatitis (n = 2). Targeted EUS-FNA was performed on these lesions.

CONCLUSIONS

Detection of a hypoenhancing and inhomogeneous mass accurately identified patients with pancreatic adenocarcinoma. CHE-EUS increased the detection of malignant lesions in difficult cases (patients with chronic pancreatitis or biliary stents) and helped guide EUS-FNA. A hyperenhancing pattern could be used to rule out adenocarcinoma.

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.