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.

CT Enhancement and 3D Texture Analysis of Pancreatic Neuroendocrine Neoplasms.

To evaluate pancreatic neuroendocrine neoplasms (panNENs) grade prediction by means of qualitative and quantitative CT evaluation, and 3D CT-texture analysis. Patients with histopathologically-proven panNEN, availability of Ki67% values and pre-treatment CT were included. CT images were retrospectively reviewed, and qualitative and quantitative images analysis were done; for quantitative analysis four enhancement-ratios and three permeability-ratios were created. 3D CT-texture imaging analysis was done (Mean Value; Variance; Skewness; Kurtosis; Entropy). Subsequently, these features were compared among the three grading (G) groups. 304 patients affected by panNENs were considered, and 100 patients were included. At qualitative evaluation, frequency of irregular margins was significantly different between tumor G groups. At quantitative evaluation, for all ratios, comparisons resulted statistical significant different between G1 and G3 groups and between G2 and G3 groups. At 3D CT-texture analysis, Kurtosis resulted statistical significant different among three G groups and Entropy resulted statistical significant different between G1 and G3 and between G2 and G3 groups. Quantitative CT evaluation of panNENs can predict tumor grade, discerning G1 from G3 and G2 from G3 tumors. CT-texture analysis can predict panNENs tumor grade, distinguishing G1 from G3 and G2 from G3, and G1 from G2 tumors.

Imaging presentation of pancreatic neuroendocrine neoplasms.

Pancreatic neuroendocrine neoplasms (P-NENs) are the second most common solid pancreatic neoplasms. P-NENs have a wide range of imaging features presentations and they can be detected with typical and atypical imaging presentations. Typical and atypical appearances can be explained by pathologic correlations. P-NENs are generally hypervascular lesions, showing a typical enhancement behavior after contrast media injection during imaging methods, but they could also have different imaging features, creating some difficulty in differential diagnosis. For this reason, radiologists should be aware of different imaging presentations of these neoplasms. Radiological evaluation has a critical role in P-NENs identification, characterization, and staging of these neoplasms, especially in those cases in which surgery is the treatment of choice. The present paper shows, indicating the underlying pathologic correlations, typical and atypical presentations of NENs. KEY POINTS: • P-NENs have a wide range of imaging features presentations, typical and atypical. • Pathology could help in better understanding the typical P-NENs appearance at imaging. • P-NENs are generally hypervascular lesions. • Radiological evaluation has a critical role in P-NENs identification and management. • Radiologists should know every type of different imaging presentation of P-NENs to better diagnose these kinds of lesions.

CT Texture Analysis of Ductal Adenocarcinoma Downstaged After Chemotherapy.

BACKGROUND/AIM: Re-staging of ductal adenocarcinoma using computed tomography (CT) scan can be problematic so new imaging techniques and evaluation parameters are required. The aim of the study was to evaluate the added value of CT texture analysis in estimation of tissue changes in ductal adenocarcinoma downsized and resected after chemotherapy. MATERIALS AND METHODS: Patients with ductal adenocarcinoma downstaged after neoadjuvant treatment, and resected, were included. A pre- and post-treatment CT was obtained. In comparison, patients with disease progression were included for texture analysis evaluation at CT pre- and post-treatment. CT texture analysis results were compared. RESULTS: A total of 17 patients affected by un-resectable or borderline ductal adenocarcinoma reached the resectable stage after treatment. The comparison between Kurtosis pre- and Kurtosis post-treatment showed a statistically significant difference. On the contrary, in the comparison group composed of 14 patients with disease progression there was no statistical difference regarding this parameter. CONCLUSION: This evaluation may represent an added value in tumor tissue changes judgment and can be extremely useful to diagnose downstaging in those cases with no evident downsizing after chemotherapy.

Prevent Pancreatic Fistula after Pancreatoduodenectomy: Possible Role of Ultrasound Elastography.

BACKGROUND: The purpose of the study is to evaluate the utility of acoustic radiation force impulse (ARFI) on pancreatic tissue as a preoperative predictor of postoperative pancreatic fistula (POPF). Studied patients underwent exclusively to pancreaticoduodenectomy (PD) surgery. METHODS: Shear wave velocity of pancreas was measured using ARFI in 71 patients scheduled for PD. An intraoperative pancreas palpation was made by surgeons. A postoperative clinical evaluation to detect occurrence of POPF was performed. Sensitivity, specificity, positive and negative predictive values together with the accuracy of the method were investigated. RESULTS: Incidence of fistula observed in 17 patients with soft pancreas was approximately 53% vs. 47% without fistula. Percentage of patients without fistula was higher (66%) among 24 patients with medium parenchymal texture values, and was even higher (69%) in 26 patients with hard pancreas. Comparing ARFI and intraoperative pancreatic palpation, low wave velocity values (≤1.40 m/s) match 60% with soft parenchyma assessed by palpation and high values (>2 m/s) match 59% with hard pancreas on palpation. CONCLUSIONS: This study shows that ARFI elastography may be clinically useful as a preoperative predictor of pancreatic fistula following PD.

Unenhanced magnetic resonance imaging immediately after radiofrequency ablation of liver malignancy: preliminary results.

PURPOSE: To assess the accuracy of unenhanced magnetic resonance imaging (MRI) immediately after the percutaneous ultrasound-guided radiofrequency ablation (RFA) of liver malignancy in predicting treatment efficacy at CT follow-up. MATERIALS AND METHODS: Percutaneous ablation was prospectively performed in 23 liver malignancies (20 hepatocarcinomas and 3 metastases). After the procedure in the same day all patients were studied with unenhanced MRI. The best sequence to detect the coagulative necrosis was visually established. Pre-RFA CT and post-RFA MRI were registered with non-rigid transformation algorithm. Manual segmentation of lesions and ablated areas in pre-RFA CT, post-RFA MRI, and follow-up CT were obtained. Sensitivity, specificity, positive predictive value (PPV), negative predicitve value (NPV), and accuracy of MRI in predicting the correct centering and the complete treatment of the lesion were calculated in respect to the 1-month follow-up CT. RESULTS: Fat-saturated T1-weighted (fs T1-w) was the sequence in which the best conspicuity of the ablated area was depicted. Coagulative necrosis was hyperintense in fs T1-w sequence in 17/23 (74%). In respect to follow-up CT, MRI predicted the correct centering of the lesions in 19/20 lesions with sensitivity, specificity, PPV, NPV, and accuracy of 100%, 75%, 95%, 100%, and 100%, respectively. MRI predicted the complete treatment of the lesions in 17/17 lesions with sensitivity, specificity, PPV, NPV, and accuracy of 100%. CONCLUSION: MRI with the single fs T1-w sequence was highly accurate in predicting the treatment efficacy of percutaneous ablation of liver malignancies in comparison to follow-up CT control. Unnecessary CT in case of incomplete treatment can be therefore easily avoided.

Serous pancreatic neoplasia, data and review.

AIM: To describe the imaging features of serous neoplasms of the pancreas using ultrasound, endoscopic ultrasound, computed tomography and magnetic resonance imaging. METHODS: This multicenter international collaboration enhances a literature review to date, reporting features of 287 histologically confirmed cases of serous pancreatic cystic neoplasms (SPNs). RESULTS: Female predominance is seen with most SPNs presenting asymptomatically in the 5th through 7th decade. Mean lesion size was 38.7 mm, 98% were single, 44.2% cystic, 46% mixed cystic and solid, and 94% hypoechoic on B-mode ultrasound. Vascular patterns and contrast-enhancement profiles are described as hypervascular and hyperenhancing. CONCLUSION: The described ultrasound features can aid differentiation of SPN from other neoplastic lesions under most circumstances.

Perfusion CT Changes in Liver Metastases from Pancreatic Neuroendocrine Tumors During Everolimus Treatment.

AIM: To evaluate modifications of perfusional parameters assessed by perfusion computed tomography (P-CT) of liver metastases (LM) from pancreatic neuroendocrine tumors (PanNETs) during everolimus treatment. PATIENTS AND METHODS: All patients with LMs from G1-2 PanNETs undergoing everolimus treatment between January 2013 and January 2015 were prospectively evaluated with P-CT at baseline, and after 2 and 4 months of therapy. Size, perfusion, blood volume (BV), peak enhancement intensity (PEI) and time to peak for each lesion were calculated. RESULTS: A total of 33 LMs in nine patients with G1-2 PanNETs were prospectively evaluated: 23/33 (69.7%) were responders, 10/33 (30.3%) were non-responders. Among perfusional parameters, only numerical peak enhancement intensity values significantly differed between the two groups at baseline (p=0.043). BV increase was the most significant perfusional modification identifying responding lesions, even at an early stage of treatment, with a high positive predictive value (89.47%). CONCLUSION: P-CT seems to be useful for prediction of response to everolimus of LMs from PanNETs.

Percutaneous ablation of pancreatic cancer.

Pancreatic ductal adenocarcinoma is a highly aggressive tumor with an overall 5-year survival rate of less than 5%. Prognosis and treatment depend on whether the tumor is resectable or not, which mostly depends on how quickly the diagnosis is made. Chemotherapy and radiotherapy can be both used in cases of non-resectable pancreatic cancer. In cases of pancreatic neoplasm that is locally advanced, non-resectable, but non-metastatic, it is possible to apply percutaneous treatments that are able to induce tumor cytoreduction. The aim of this article will be to describe the multiple currently available treatment techniques (radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation), their results, and their possible complications, with the aid of a literature review.

Contrast enhancement ultrasound application in focal liver lesions characterization: a retrospective study about guidelines application (SOCEUS-CEUS survey).

INTRODUCTION: The SOCEUS survey aims to evaluate how contrast-enhanced ultrasound (CEUS) is effectively used in the focal liver lesions characterization. MATERIALS AND METHODS: In the survey were involved Verona, Brescia and Trieste Radiological Centers and Arezzo and Bologna Non-radiological Centers. Inclusion criteria were liver focal lesion detection at conventional ultrasound and studied by means of CEUS, with or without CT or MRI examinations, done previous or subsequent to CEUS. RESULTS: 1069 forms were collected. Patients with benign lesions, who did not undergo any other studies, were 255/561 (45.5 %). Among patients with diagnosis of hemangioma at CEUS, those who had no other investigations were 129/267 (48.3 %). Patients with malignant lesions who had studies pre-CEUS (CT and/or MRI) were 328/508 (65 %), whereas those who had examinations post-CEUS (CT and/or MRI) were 218/508 (42.9 %). Concordance rate between CEUS and CT investigations pre- and post-CEUS was, respectively, 66 and 89 %. Concordance rate between CEUS and MRI studies pre- and post-CEUS was, respectively, 87.5 and 81.5 %. CONCLUSION: This study proves contrast-enhanced ultrasound correct application in the involved centers.

Variation of tumoral marker after radiofrequency ablation of pancreatic adenocarcinoma.

BACKGROUND: To evaluate the correlation between variations of CA 19.9 blood levels and the entity of necrosis at CT after radiofrequency ablation (RFA) of unresectable pancreatic adenocarcinoma. METHODS: In this study, from June 2010 to February 2014, patients with diagnosis of unresectable and not metastatic pancreatic ductal adenocarcinoma, expressing tumor marker CA 19.9, treated with RFA procedure were included. All these patients underwent RFA. CT study was performed 1 week after RFA. The dosage of CA 19.9 levels was performed 1 month after RFA. Features of necrosis at CT, as mean entity, density and necrosis percentages compared to the original lesion, were evaluated and compared by using t-test with CA 19.9 blood levels variations after RFA procedure. RESULTS: In this study were included 51 patients with diagnosis of unresectable and not metastatic pancreatic ductal adenocarcinoma, expressing tumor marker CA 19.9, treated with RFA procedure and with CT study and CA 19.9 available for analysis. After the procedure, CA 19.9 blood levels reduced in 24/51 (47%), remained stable in 10/51 (20%) and increased in 17/51 (33%). In patients with CA 19.9 levels reduced, the tumor marker were reduced less than 20% in 4/24 (17%) and more than 20% in 20/24 (83%); instead the tumor marker were reduced less than 30% in 8/24 (33%) and more than 30% in 16/24 (67%). At CT scan necrotic area density difference was not statistically significant. Also there was no statistically significant difference among the mean area, the mean volume and the mean ablation volume in percentage related to the treated tumor among the three different groups of patients divided depending on the CA 19.9 blood levels. But a tendency to a statistically significant difference was found in comparing the mean percentage of ablation volume between two subgroups of patients with a decrease of CA 19.9 levels with less or more than 20% reduction of tumor markers and between two subgroups with less or more than 30% reduction of CA 19.9 levels. CONCLUSIONS: RFA of unresectable pancreatic adenocarcinoma induces reduction of CA 19.9 blood levels in about half of the cases.

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.