Ultrasonography of the pancreas. 1. Conventional imaging

Differential Diagnosis of Solid Pancreatic Lesions Using Detective Flow Imaging Endoscopic Ultrasonography

The differential diagnosis of solid pancreatic lesions (SPLs) using B-mode endoscopic ultrasonography (EUS) is challenging. Detective flow imaging (DFI) offers the potential for detecting low-flow vessels in the pancreas, thus enhancing diagnostic accuracy. This retrospective study aimed to investigate DFI-EUS findings of SPLs and analyze their differential diagnostic accuracy for pancreatic cancer. We included 104 patients with pathologically confirmed SPLs who underwent EUS between April 2021 and June 2023. Expert endosonographers, blinded to the patients' clinical data, evaluated images obtained through B-mode, eFLOW, and DFI-EUS. The frame rate and vessel detection sensitivity were compared between eFLOW and DFI, and the diagnostic criteria for pancreatic cancer were established. The visualization rate for vessels in SPLs was significantly higher with DFI-EUS (96%) compared to eFLOW (27%). Additionally, DFI showed a superior frame rate, sensitivity (99%), and accuracy (88%) for detecting pancreatic cancer, although with a modest specificity (43%). On DFI-EUS, characteristics such as hypovascularity, peritumoral vessel distribution, or spotty vessel form were suggestive of pancreatic cancer. DFI-EUS significantly improved the visualization of vascular structures within the SPLs, highlighting its efficacy as a diagnostic modality for pancreatic cancer.

Repetitive Cerulein-Induced Chronic Pancreatitis in Growing Pigs-A Pilot Study

Chronic pancreatitis (CP) is an irreversible and progressive inflammatory disease. Knowledge on the development and progression of CP is limited. The goal of the study was to define the serum profile of pro-inflammatory cytokines and the cell antioxidant defense system (superoxidase dismutase-SOD, and reduced glutathione-GSH) over time in a cerulein-induced CP model and explore the impact of these changes on selected cytokines in the intestinal mucosa and pancreatic tissue, as well as on selected serum biochemical parameters. The mRNA expression of CLDN1 and CDH1 genes, and levels of Claudin-1 and E-cadherin, proteins of gut barrier, in the intestinal mucosa were determined via western blot analysis. The study showed moderate pathomorphological changes in the pigs' pancreas 43 days after the last cerulein injection. Blood serum levels of interleukin (IL)-1-beta, IL-6, tumor necrosis factor alpha (TNF-alpha), C-reactive protein (CRP), lactate dehydrogenase (LDH), gamma-glutamyl transpeptidase (GGTP), SOD and GSH were increased following cerulein injections. IL-1-beta, IL-6, TNF-alpha and GSH were also increased in jejunal mucosa and pancreatic tissue. In duodenum, decreased mRNA expression of CDH1 and level of E-cadherin and increased D-lactate, an indicator of leaky gut, indicating an inflammatory state, were observed. Based on the current results, we can conclude that repetitive cerulein injections in growing pigs not only led to CP over time, but also induced inflammation in the intestine. As a result of the inflammation, the intestinal barrier was impaired.

Integrated US-OCT-NIRF Tri-Modality Endoscopic Imaging System for Pancreaticobiliary Duct Imaging

Pancreaticobiliary carcinomas is a highly malignant gastrointestinal tumor. Most pancreaticobiliary cancers arise from epithelial proliferation within the pancreaticobiliary ducts, referred to as pancreatic intraepithelial neoplasias (PanINs). Some PanINs are benign metaplasia, while others progress to invasive duct adenocarcinoma (IDAC). However, there is no standard program to diagnose the progression from PanINs to IDAC. In this study, we present a tri-modality imaging system, which integrates ultrasound (US), optical coherence tomography (OCT), and near-infrared fluorescence (NIRF) for pancreaticobiliary duct imaging. This system can obtain OCT, US, and NIRF images in real-time with a frame rate of 30 frames per second. For the endoscopy probe with an outer diameter of 0.9 mm, the US transducer and fiber ball lens were placed back to back. In vivo experiments were performed on the rectums of Sprague-Dawley rats to demonstrate the imaging performance of US, OCT, and fluorescence angiography. An ex vivo experiment on a human pancreatic duct was performed for a more accurate assessment of the pancreaticobiliary duct. The tomography images of rat rectums and human pancreatic ducts were correlated with hematoxylin and eosin (H&E) histology to check the measurement accuracy. The integrated tri-modality system has great clinical potential in mechanism studies, early diagnosis, and prognosis evaluation of malignant pancreaticobiliary carcinomas.

Value of Low-Mechanical-Index Contrast-Enhanced Transabdominal Ultrasound for Diagnosis of Pancreatic Cancer: A Meta-analysis

The incidence and mortality rates of pancreatic cancer (PC) are increasing. It is important to discriminate PC from the other pancreatic lesions; however, differential diagnosis based on conventional transabdominal ultrasound (US) remains challenging even though US is often the first examination performed. Transabdominal contrast-enhanced ultrasound (CEUS) has high diagnostic accuracy for PC. This meta-analysis aimed to examine the utility of low-mechanical-index CEUS with enhancement for PC diagnosis. A systematic meta-analysis of all potentially relevant articles was performed. Fixed-effects or random-effects models were used to investigate pooled sensitivity, specificity, positive likelihood ratio (LR) and negative LR. The study enrolled 983 patients from nine eligible studies. The pooled estimates of sensitivity and specificity were 92% (95% confidence interval [CI]: 0.89-0.94) and 76% (95% CI: 0.71-0.81), respectively. The diagnostic odds ratio (DOR) for CEUS was high (53.62). The area under the summary receiver operating characteristic curve was 0.95. Funnel plots revealed no publication bias, and there was no significant relationship between the DORs and study characteristics, including continent, type of contrast agent, contrast agent dosage and scan phase. Only number of patients affected diagnostic ability. This meta-analysis indicates that CEUS with enhancement pattern is useful for diagnosis of PC.

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.

SIUMB recommendations for focal pancreatic lesions

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

Optimum imaging of chronic pancreatitis

Chronic pancreatitis is an inflammatory process of the pancreas characterized by progressive parenchyma destruction, resulting in pain and exocrine and endocrine insufficiency. In the advanced stages the diagnosis by imaging is usually straightforward, while in the early phases of the disease there can be a paucity of findings at imaging, thus making an early diagnosis challenging. Different imaging modalities can have a role in the initial diagnosis and in the longitudinal follow-up of patients affected by chronic pancreatitis, also enabling to assess the complications of the disease. Radiography, Ultrasonography, CT and MRI can all provide morphological information, and MRI with the administration of secretin can also provide functional information. The use of an appropriate technique is fundamental for optimizing the examination to the clinical question.

Negative effect of fatty liver on visualization of pancreatic cystic lesions at screening transabdominal ultrasonography

RATIONALE, AIMS, AND OBJECTIVES

The aim of this observational study is to identify factors by which some pancreatic cystic lesions (PCLs) were undetectable at transabdominal ultrasonography (TAUS), using magnetic resonance imaging (MRI) as reference standard.

METHODS

The database for 781 consecutive subjects who underwent a health checkup including fat computed tomography and upper abdominal MRI as option was searched. The presence of fatty liver and fatty pancreas was diagnosed by TAUS, and atrophic pancreas was determined by reevaluating the image of the pancreas in the chest computed tomography for screening. Subjects with PCL detected and those undetected at TAUS were statistically compared in clinical characteristics.

RESULTS

The prevalence of PCL detected at MRI was 17.8% in the general population. Multivariate logistic regression analysis showed that fatty liver, body mass index, and the size of PCL were significantly associated with the factors influencing the visualization of PCL at TAUS (odds ratio [OR]: 0.337, 95% confidence interval [CI]: 0.154-0.734, P = 0.006; OR: 0.852, 95% CI: 0.737-0.985, P = 0.030; OR:1.120, 95% CI: 1.045-1.200, P = .001). Thirty-six PCLs (64.3%) in a total of 56 PCLs were undermeasured by TAUS. Additionally, nine (56%) out of 16 PCLs (≥ 15 mm) were undermeasured by 5 mm or more by TAUS, although a significantly higher detection rate was observed for PCLs (≥ 15 mm) in comparison with that for PCLs (< 15 mm) (80% vs 33.6%, P = .000).

CONCLUSIONS

It should be noted that coexisting fatty liver may lower the detection of PCL, and its size may be underestimated by TAUS.

Ecografía en cirugía general

La ecografía es un estudio de imágenes diagnósticas con una amplia historia de uso en todas las especialidades de la Medicina; su advenimiento ha ayudado al enfoque diagnóstico e, incluso, al abordaje terapéutico de los pacientes. Desde su origen en el siglo XIX con mediciones de la velocidad del sonido en el agua, hasta el desarrollo de las máquinas de ultrasonografía sustentadas en los avances de la tecnología, la física y la ingeniería, se ha utilizado de manera notable en la Medicina. No hay duda de que, en el campo de la Cirugía General, ha sido útil para el manejo de los pacientes con enfermedad abdominal. La tecnología ecográfica permite identificar las características de un órgano normal y, cuando este patrón se afecta, orienta sobre la causa o determina la enfermedad que puede estar produciendo la alteración. En la presente revisión, se hace un recuento histórico del nacimiento de la ecografía, su aplicación en el campo de la medicina y su utilidad para el cirujano general en diversas circunstancias de la práctica quirúrgica.

The quality of abdominal ultrasound: a much-needed consensus

The abdominal ultrasound (AU) is a diagnostic imaging modality that is yet to be established in most Gastrointestinal (GI) Units in Spain. This is largely due to the difficulties that GI specialists face with regard to the appropriate training received when starting the specialty. Insufficient resources have been allocated to develop AU units in many GI units where AUs are performed. The equipment is obsolete and there are no adaptations to the needs of the GI specialist to provide good medical care. Thus, due to all the above, the AU does not hold the position it deserves in our specialty. This probably stems from a lack of impulse and/or support to the technique, which has underestimated its usefulness and has limited the implementation of resources in the GI units. For the AU to overcome these obstacles, it needs to be considered as a process or a series of activities based on scientific evidence and the experience of professionals that achieves a result that covers the patients' needs with minimal risk. In this article, we defend the need to boost AU as a key discipline for the diagnosis of digestive diseases. Quality is considered as the key aspect on which this transformation and improvement is founded.

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.

What should be known prior to performing EUS?

Direct referral of patients for EUS - instead of preprocedural consultation with the endosonographer - has become standard practice (like for other endoscopic procedures) as it is time- and cost-effective. To ensure appropriate indications and safe examinations, the endosonographer should carefully consider what information is needed before accepting the referral. This includes important clinical data regarding relevant comorbidities, the fitness of the patient to consent and undergo the procedure, and the anticoagulation status. In addition, relevant findings from other imaging methods to clarify the clinical question may be necessary. Appropriate knowledge and management of the patients' anticoagulation and antiplatelet therapy, antibiotic prophylaxis, and sedation issues can avoid unnecessary delays and unsafe procedures. Insisting on optimal preparation, appropriate indications, and clear clinical referral questions will increase the quality of the outcomes of EUS. In this paper, important practical issues regarding EUS preparations are raised and discussed from different points of view.

Transabdominal Ultrasound Detection of Pancreatic Cysts Incidentally Detected at CT, MRI, or Endoscopic Ultrasound

OBJECTIVE

The objective of our study was to evaluate the detection rate of incidental pancreatic cysts on transabdominal ultrasound (TAUS) as well as factors influencing detection rates.

MATERIALS AND METHODS

Nine hundred thirty-eight patients with 1064 pancreatic cysts who underwent both TAUS and other imaging examinations including CT, MRI, or endoscopic ultrasound (EUS) were enrolled. We reviewed formal reports and assessed the effect of cyst size and location and the effect of the correlative images for cyst detection on TAUS. Statistical analyses were performed using the chi-square test, t test, and Cramér value (V).

RESULTS

The overall detection rate of TAUS was 88.3% (940/1064). Cysts detected on TAUS were more often in younger patients and male patients. The detected cysts (median, 13 mm; interquartile range [IQR], 8-18 mm) were significantly larger than the undetected cysts (median, 10 mm; IQR, 6-14 mm) (p < 0.0001). However, waist circumference did not affect the detection rate. The detection rate was significantly improved from 49.2% (289/587) to 86.7% (830/957) when TAUS was performed after correlative imaging (p < 0.001). Although the detection rate for cysts in the entire pancreas was significantly increased with correlative images (p < 0.001), the detection rate for cysts in the uncinate process showed a much greater increase using correlative images (p < 0.001). However, detection of cysts in the tail of the pancreas showed the least improvement using correlative images. The detection rate was significantly improved with correlative images for cysts 25 mm or smaller.

CONCLUSION

Because the detection rate of TAUS for pancreatic cysts was significantly improved after CT, MRI, or EUS, TAUS could be a useful surveillance imaging tool for pancreatic cysts incidentally detected on CT, MRI, or EUS.

Importance of Distending Stomach With Fluid for Ultrasound Detection of Focal Lesion in the Elongated Left Lobe of the Liver

OBJECTIVES

The purpose of this study was to evaluate distending the stomach with water for ultrasound detection of focal lesions in the elongated left lobe of the liver.

METHODS

A total of 13,277 patients undergoing liver ultrasound were evaluated for the presence of an elongated left lobe of the liver and a focal lesion. Patients with an elongated left lobe of the liver had their stomach distended with oral water for further evaluation of a focal lesion. A portion of the patients had computed tomography (CT) examinations, which were compared with the ultrasound studies.

RESULTS

A total of 643 patients were found with elongated left lobe of the liver by ultrasound; of them, 451 underwent CT, 259 out of the 451 patients meeting the inclusion criteria underwent second ultrasound and final analysis, and 16 of these 259 patients had focal lesion in the elongated left lobe of the liver on CT study. The sonographic visualization of the liver and spleen at the same scan view before and after distending the stomach were 7% (7 of 100) and 100% (100 of 100), respectively (P < .001). The sonographic detection of the lesions before and after distending the stomach were zero and 87.5%, respectively (P < .001).

CONCLUSIONS

Distending the stomach with water can greatly increase ultrasound detection of focal lesions in the elongated left lobe of the liver.

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.

Diagnostic Accuracy of Transabdominal Ultrasound in Chronic Pancreatitis

The performance of transabdominal ultrasound (US) in chronic pancreatitis (CP) following the advances in US technology made during recent decades has not been explored. Our aim in this prospective study was to evaluate the diagnostic accuracy of modern abdominal US compared with the Mayo score in CP. One hundred thirty-four patients referred for suspected CP were included in the study. Fifty-four patients were assigned the diagnosis CP. After inclusion, transabdominal US was performed. Ductal features (calculi, dilations and caliber variations, side-branch dilations and hyper-echoic duct wall margins) and parenchymal features (calcifications, cysts, hyper-echoic foci, stranding, lobulation and honeycombing) were recorded. Features were counted and scored according to a weighting system defined at the international consensus meeting in Rosemont, Illinois (Rosemont score). Diagnostic performance indices (95% confidence interval) of US were calculated: The unweighted count of features had a sensitivity of 0.69 (0.54-0.80) and specificity of 0.97 (0.90-1). The Rosemont score had a sensitivity of 0.81 (0.69-0.91) and specificity of 0.97 (0.90-1). Exocrine pancreatic failure was most pronounced in Rosemont groups I and II (p < 0.001). We conclude that using both unweighted and weighted scores, the diagnostic accuracy of modern transabdominal US is good. The extent of pancreatic changes detected by the method is correlated with exocrine pancreatic function.

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.

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.

Distinguishing benign from malignant main duct intraductal papillary mucinous neoplasms of the pancreas by multislice helical computed tomography

Main duct intraductal papillary mucinous neoplasms (MD-IPMNs) of the pancreas are located in the dilated main pancreatic duct and associated with mucin overproduction. They may have a high degree of malignancy and lack specific clinical manifestations. With advantages of thin slice thickness, high resolution, multi-phase dynamic scan and multiple post-processing techniques, multislice helical computed tomography (MSCT) can accurately diagnose and differentiate malignant from benign MD-IPMNs. This paper will review the current advances in differentiating malignant from benign MD-IPMNs by MSCT.

Acoustic radiation force impulse with shear wave speed quantification of pancreatic masses: A prospective study

BACKGROUND

Acoustic Radiation Force Impulse (ARFI) is a new ultrasound technique that evaluates mechanical properties of tissues. To evaluate the use of ARFI with shear waves speed quantification for pancreatic masses characterization during the ultrasound examination.

METHODS

123 pancreatic lesions were prospectively evaluated. Median shear waves speeds were compared with Mann-Whitney U test. Two reading methods were applied for the characterization of adenocarcinoma: more than one measurement above the top shear waves speed (SWS) value. Two reading methods were applied to diagnose mucinous lesion: at least 2 (method 1) or 3 (method 2) numerical measurements. Sensitivity, specificity, positive and negative predictive values and accuracy of each reading method were calculated. Forty volunteers were included for normal ARFI values.

RESULTS

In the adenocarcinoma group median SWS value was 2.74 m/s. In the volunteers group the median SWS value was 1.17 m/s. Significant difference between SWS median values of adenocarcinoma and normal pancreas was found (P < 0.05). For the diagnosis of pancreatic solid masses if more than one measurement is above the top SWS value of 4.00 m/s results in the study, the diagnosis of ductal adenocarcinoma is highly specific with specificity and PPV of 100%. Good sensitivity (73.3%) and specificity (83.3%) were obtained for the characterization of mucinous cystic lesions.

CONCLUSIONS

Acoustic Radiation Force Impulse imaging could help in the non-invasive characterization of solid and cystic lesions of the pancreas during a conventional US examination.

Pancreatic atrophy in patients with chronic graft-versus-host disease

PURPOSE

To determine if patients with chronic graft-versus-host disease (cGVHD) following allogeneic hematopoietic stem cell transplantation (HSCT) develop greater loss of pancreatic tissue than patients without cGVHD.

MATERIALS AND METHODS

This is an IRB-approved, HIPAA-compliant retrospective study of patients receiving allogeneic HSCT at our institution from 01/2006 to 01/2010 with abdominal CT performed within 3 months prior to HSCT and CT performed at least 3 months after HSCT. Measurement of glandular tissue thickness of the head, body, and tail of the pancreas was performed independently by two radiologists blinded to clinical data. Statistical analysis was performed using the Student t-test, and interobserver agreement was evaluated with linear-weighted kappa.

RESULTS

117 patients underwent HSCT during study period, with 36 patients meeting inclusion criteria. 22 subjects (61%) had clinical features of cGVHD, and 14 patients (39%) did not have evidence of cGVHD. Following HSCT, there was a significant decrease in mean total thickness (10.9%, p = 0.002) of the pancreas in the group of patients with cGVHD. The change from pretreatment to the nadir in pancreatic thickness was significantly greater in patient with cGVHD (13.9 ± 12.1 mm), but not in non-cGVHD patients (5.4 ± 4.7 mm) (p = 0.02), with head of the pancreas atrophy accounting for the difference (decrease of 4.8 ± 4.6 mm in cGVHD patients vs. 1.6 ± 2.1 mm in non-cGVHD patients (p = 0.02)).

CONCLUSION

Patients with cGVHD develop significantly greater loss of pancreatic glandular tissue than patients without cGVHD following HSCT, with atrophy of pancreatic head being a major contributor.

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

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

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.

Is routine imaging necessary after pancreatic resection? An appraisal of postoperative ultrasonography for the detection of pancreatic fistula

OBJECTIVES

This study aimed to assess whether routine transabdominal ultrasonography (US) is clinically helpful for the early detection of postoperative pancreatic fistula (PF).

METHODS

In a prospective cohort of patients undergoing partial pancreatectomy, US was performed on postoperative day (POD) 3. Potential predictors of PF, including amylase value in drains (AVD) on POD 1, were investigated. A tree-based classification model of the independent predictors of PF was also performed.

RESULTS

One hundred seventy-three patients were analyzed. A peripancreatic collection on US and an AVD 5000 U/L or greater on POD 1 were predictors of PF. In the tree-based classification model, patients were stratified by AVD on POD 1. For values less than 5000 U/L (incidence of PF, 11.3%), US had a sensitivity of 23.1% and a specificity of 97.5%. For AVD 5000 U/L or greater (incidence of PF, 70.7%), sensitivity was 46.3% and specificity was 100%.

CONCLUSIONS

Despite the presence of a peripancreatic collection as a predictor of PF, US-as a diagnostic test-resulted to be highly specific but poorly sensitive even in the tree-based classification model. Therefore, its role does not seem to be clinically relevant and does not add value to AVD on POD 1, which remains the most powerful and relevant early predictor of PF.

Current options for the diagnosis of chronic pancreatitis

The diagnostic options for chronic pancreatitis have evolved over recent years. The previous gold standard references for structural imaging and exocrine pancreatic function testing have both been supplanted and redesigned. Endoscopic retrograde pancreatography has now been overtaken by endoscopic ultrasound and magnetic resonance cholangiopancreatography, whilst the old technique for Dreiling tube pancreatic function testing has now been replaced by the endoscopic pancreatic function test. New advances in endoscopic ultrasound elastography have also extended the options for evaluating pancreatic masses to differentiate mass-forming chronic pancreatitis from malignancy. Genetic contribution to chronic pancreatitis is also now more widely recognized than ever before.

Three-dimensional contrast-enhanced ultrasonography of intraductal papillary mucinous neoplasms of the pancreas: a comparison with magnetic resonance imaging

OBJECTIVES

The objective of this study was to prospectively compare the diagnostic accuracy of 3-dimensional contrast-enhanced ultrasonography (3D-CEUS) with that of magnetic resonance imaging (MRI) in the study of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas.

METHODS

Thirty consecutive patients with IPMN were studied.

RESULTS

Three patients (10.0%) did not undergo diagnostic 3D-CEUS because of technical problems. Three dimensional CEUS identified 12 (44.4%) main-duct IPMNs versus no cases by MRI (P < 0.001). Intraductal papillary mucinous neoplasm localization showed poor agreement between 3D-CEUS and MRI (κ = 0.058), whereas good agreement was found in detecting the pancreatic calcifications (κ = 1.000). Significant differences between 3D-CEUS and MRI were found regarding the number of lesions detected (1.4 ± 0.8 vs 3.8 ± 3.6; P < 0.001), the detection of mucinous plugs (3.7% vs 50.0%; P < 0.001), chronic pancreatitis (7.4% vs 26.7%; P = 0.031), pancreatic atrophy (0% vs 50.0%; P < 0.001), thick septa (22.2% vs 53.3%; P = 0.004), and mural nodules (25.9% vs 3.3%; P = 0.016). Three dimensional CEUS showed similar results as compared with MRI in evaluating IPMNs smaller than 1 cm of diameter or greater than 2 cm.

CONCLUSIONS

Even if MRI remains the criterion standard technique for the diagnosis of IPMNs, 3D-CEUS can be safely used to follow patients with IPMNs of less than 1 cm.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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.