Pancreatic imaging: current and emerging technologies

Advances in MRI of Chronic Pancreatitis

MRI and MRCP play an essential role in diagnosing CP by imaging pancreatic parenchyma and ducts. Quantitative and semi-quantitative MR imaging offers potential advantages over conventional MR imaging, including simplicity of analysis, quantitative and population-based comparisons, and more direct interpretation of disease progression or response to drug therapy. Using parenchymal imaging techniques may provide quantitative metrics for determining the presence and severity of acinar cell loss and aid in diagnosing CP. Given that the parenchymal changes of CP precede the ductal involvement, there would be a significant benefit from developing a new MRI/MRCP based, more robust diagnostic criteria combining ductal and parenchymal findings.

Acute Pancreatitis

Acute pancreatitis is one of the most common reasons for gastroenterology-related hospitalization in the United States. With significant morbidity and subsequent mortality related to both the acute presentation and subsequent sequelae, prompt diagnosis and appropriate management are critical, especially in the first 24 hours of illness. It is also important to accurately recognize complications, such as pancreatic fluid collections and vascular events, and identify a definitive cause so that a strategy to prevent future attacks can be implemented.

Differentiating benign and malignant pancreatic masses: Ga-68 PSMA PET/CT as a new diagnostic avenue

OBJECTIVE

Differentiation of malignant and benign pancreatic lesions on anatomical imaging is difficult in some cases with overlapping features. Prostate-specific membrane antigen (PSMA) is overexpressed during angioneogenesis in many tumors. We aimed to evaluate the PSMA expression in pancreatic lesions to differentiate these lesions and explore the performance of Ga-68 PSMA-PET/CT vis-a-vis F-18 FDG-PET/CT.

METHODS

Patients with pancreatic lesions on conventional imaging were prospectively recruited. All the patients underwent a whole-body F-18 FDG-PET/CT and a regional abdominal Ga-68 PSMA-PET/CT. Focal tracer uptake (FDG or PSMA) on PET images was considered positive. Histopathology and/or cytopathology were considered the reference standard.

RESULTS

A total of forty patients (27 males, mean age 55.3 ± 9.8, range 37-71 years) were enrolled. Of these, 19 were diagnosed as malignant on histopathology/cytology. Patients with benign lesions showed no worsening of symptoms for at least 6 months on follow-up. FDG-PET/CT revealed 17 true-positive (TP), 9 false-positive (FP), 12 true-negative (TN), and 2 false-negative (FN) findings, whereas PSMA-PET/CT had 18 TP, 2 FP, 19 TN, and 1 FN finding. The sensitivity, specificity, PPV, NPV, and accuracy for FDG-PET/CT were 89.5%, 57.1%, 65.4%, 85.7%, and 72.5%, respectively, while for PSMA-PET/CT were 94.7%, 90.5%, 90%, 95%, and 92.5%, respectively. ROC curve analysis showed that the SUVmax value of 4.8 on PSMA-PET/CT could predict the malignant potential of a lesion with a specificity of 90.5% and a sensitivity of 84.2%.

CONCLUSIONS

Ga-68 PSMA-PET/CT imaging helped in establishing a non-invasive pre-operative diagnosis of primary pancreatic malignancy with a higher degree of specificity and accuracy compared with FDG-PET/CT.

KEY POINTS

• Conventional imaging such as CT and MRI are unable to reliably differentiate localized malignant pancreatic lesion from benign lesions mimicking malignancy such as mass-forming pancreatitis. • FDG PET/CT helps in detecting malignant foci in view of their increased glucose metabolism. However, it may be falsely positive in inflammatory lesions which may occasionally hinder its ability to differentiate between benign and malignant lesions. • Apart from prostatic malignancy, PSMA is overexpressed in neovasculature of many non-prostatic malignancies. The present study highlights that Ga68 PSMA PET/CT performed better in diagnosing malignancy non-invasively than FDG-PET/CT with a higher PPV (90.5% vs. 65.4%) and accuracy (92.5% vs. 72.5%).

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.

Pancreatic stiffness response to an oral glucose load in obese adults measured by magnetic resonance elastography

BACKGROUND

To test the feasibility of magnetic resonance elastography (MRE) for assessing changes in pancreatic stiffness of obese adults administered an oral glucose load.

METHODS

MRE scans were performed on 21 asymptomatic obese volunteers (BMI ≥ 27 kg/m²) before and after receiving a 75-g oral glucose load, and repeated in 7 days without a glucose load. Shear waves at 40 and 60 Hz were introduced into the upper abdomen by a pneumatic drum driver (diameter of 12 cm). Two radiologists subjectively graded the overall quality of the wave images of the pancreas using a scale from 1 to 4, in which suboptimal image quality was considered to be scores of 1 and 2.

RESULTS

Good inter-observer agreement was found for image quality at both frequencies (kappa = 0.805 for 40 Hz and 0.762 for 60 Hz). The median overall image quality score was significantly higher in 40 Hz than that of 60 Hz (4 versus 2). At 40 Hz, pancreatic stiffness in response to oral glucose had a decrease of 6.7% (pre vs post: 1.17 ± 0.13 kPa vs 1.08 ± 0.12 kPa; P < 0.001), whereas the change in stiffness was not significant at 60 Hz (pre vs post: 2.01 ± 0.21 kPa vs 2.02 ± 0.24 kPa; P = 0.695). Excellent intersession agreement was found for MRE acquisitions at 40 Hz with an overall intraclass correlation coefficient = 0.947 (95% confidence interval: 0.913-0.967).

CONCLUSION

MRE at 40 Hz provides good-quality wave images and high sensitivity to changes in the mechanical properties of pancreatic tissue in obese volunteers after an oral glucose load.

Differentiation of benign and malignant solid pancreatic masses using magnetic resonance elastography with spin-echo echo planar imaging and three-dimensional inversion reconstruction: a prospective study

OBJECTIVES

To determine the diagnostic performance of MR elastography (MRE) and compare it with serum CA19-9 in differentiating malignant from benign pancreatic masses, with emphasis on differentiating between pancreatic ductal adenocarcinoma (PDAC) and mass-forming pancreatitis (MFP).

METHODS

We performed a prospective, consecutive, 24-month study in 85 patients with solid pancreatic masses confirmed by histopathologic examinations. The mass stiffness and stiffness ratio (calculated as the ratio of mass stiffness to the parenchymal stiffness) were assessed. The diagnostic accuracy was analysed by calculating the area under the ROC curve (AUROC).

RESULTS

The final diagnosis included 54 malignant tumours (43 patients with PDAC) and 31 benign masses (24 patients with MFP). The stiffness ratio showed better diagnostic performance than the mass stiffness and serum CA19-9 for the differentiation between malignant and benign masses (AUC: 0.912 vs. 0.845 vs. 0.702; P = 0.026, P < 0.001) and, specifically, between PDAC and MFP (AUC: 0.955 vs. 0.882 vs. 0.745; P = 0.026, P = 0.003). The sensitivity, specificity, and accuracy of stiffness ratio for the differentiation of PDAC and MFP were all higher than 0.9.

CONCLUSIONS

MRE presents an effective and quantitative strategy for non-invasive differentiation between PDAC and MFP based on their mechanical properties.

KEY POINTS

• 3D MRE is useful for calculating stiffness of solid pancreatic tumours. • Stiffness ratio outperformed stiffness and CA19-9 for differentiating PDAC from MFP. • Incorporation of 3D MRE into a standard MRI protocol is recommended.

Detection of exocrine dysfunction by MRI in patients with early chronic pancreatitis

PURPOSE

To determine if T1-weighted MR signal of the pancreas can be used to detect early CP.

METHODS

A retrospective analysis was performed on 51 suspected CP patients, who had both secretin-enhanced magnetic resonance cholangiopancreatography (S-MRCP) and an intraductal secretin stimulation test (IDST). There were 29 patients in normal and 22 patients in the low bicarbonate group. Bicarbonate level, total pancreatic juice volume, and excretory flow rate were recorded during IDST. Signal intensity ratio of pancreas (SIR), fat signal fraction, pancreatograms findings, and grade of duodenal filling were recorded on S-MRCP by two blinded radiologists.

RESULTS

There was a significant difference in the signal intensity ratio of the pancreas to spleen (SIR_p/s) between the normal and low bicarbonate groups (p < 0.0001). A significant positive correlation was found between pancreatic fluid bicarbonate level and SIR_p/s (p < 0.0001). SIR_p/s of 1.2 yielded sensitivity of 77% and specificity of 83% for detection of pancreatic exocrine dysfunction (AUC: 0.89).

CONCLUSION

T1-weighted MR signal of the pancreas has a high sensitivity and specificity for the detection of parenchymal abnormalities related to exocrine dysfunction and can therefore be helpful in evaluation of suspected early CP.

Use of acoustic radiation force impulse elastography to diagnose acute pancreatitis at hospital admission: comparison with sonography and computed tomography

OBJECTIVES

To compare the diagnostic success rate of acoustic radiation force impulse (ARFI) elastography with those of sonography and computed tomography (CT) for acute pancreatitis at hospital admission.

METHODS

B-mode sonography and ARFI elastography were performed on 88 patients with symptoms of acute pancreatitis and 50 healthy control participants who were admitted to our hospital between February 2013 and July 2013. Acute pancreatitis was verified in the 88 patients based on clinical and laboratory findings. Computed tomography was performed on 41 patients, and the CT results from these patients were compared with those of ARFI elastography. The appearances of the pancreases of the patients were classified into 6 groups using visual color encodings obtained with ARFI elastography. The elasticity values of pancreatic head, body, and tail regions were evaluated with Virtual Touch imaging and Virtual Touch tissue quantification (Siemens Medical Solutions, Mountain View, CA). The success rates of sonography, CT, and ARFI elastography for diagnosing acute pancreatitis at hospital admission were compared.

RESULTS

Forty-six of the 88 patients had a diagnosis of pancreatitis by B-mode sonography; pancreatitis was diagnosed in all patients by ARFI elastography; and 10 of 41 patients could not be diagnosed by CT. The sensitivity and specificity of Virtual Touch tissue quantification were 100% and 98%, respectively, when a cutoff value of 1.63 m/s was used. The control group had color scores of 1 or 2, whereas all patients with pancreatitis had color scores of 3 to 6 on color scale evaluation with Virtual Touch imaging.

CONCLUSIONS

Acoustic radiation force impulse elastography is a rapid, radiation-free, and noninvasive tool for diagnosis of acute pancreatitis at initial hospital admission, with a higher success rate for diagnosis of acute pancreatitis than the grayscale sonography and CT.

Endoscopic ultrasound and pancreatic applications: what the radiologist needs to know

As the technology has improved, endoscopic ultrasound (EUS) has taken on an important role in the diagnosis of a number of different neoplastic and non-neoplastic pancreatic diseases. EUS can provide high-resolution images with subtle anatomic detail, and has also taken on an important role in the targeted biopsy of the pancreas and adjacent structures. This review seeks to familiarize radiologists with the role of EUS in the diagnosis of chronic and autoimmune pancreatitis, solid pancreatic masses, and cystic pancreatic neoplasms.

Molecular imaging in pancreatic cancer--a roadmap for therapeutic decisions

Pancreatic ductaladeno carcinoma (PDAC) is a deadly cancer characterized by multiple molecular alterations, the presence of an intense stroma, poor perfusion, and resistance to therapy. In addition to standard imaging techniques, experimental imaging strategies, such as those utilizing molecular probes, nanoparticle-based agents, and tagged antibodies are actively being explored experimentally. It is hoped that advances in these technologies will allow for detecting PDAC at an early stage, and could serve to validate experimental therapies, rapidly identify non-responders, and assist in the design of novel therapeutic strategies tailored to the patient's molecular profile.

Role of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography in the characterization of pancreatic masses: experience from tropics

BACKGROUND AND AIM

Early detection and differentiation of malignant from benign pancreatic tumors is very essential as mass-forming pancreatitis is a frequently encountered problem. Positron emission tomography (PET) has a role in establishing the diagnosis of pancreatic carcinoma when the conventional imaging modalities or biopsies are nondiagnostic. In this prospective study, the utility of fluorodeoxyglucose (FDG)-PET/computed tomography (CT) in the characterization of mass-forming lesions of the pancreas was reported.

METHODS

(18)F-FDG-PET/CT was prospectively performed in 87 patients diagnosed to have periampullary or pancreatic mass. Lesions with focally increased FDG uptake in PET/CT were considered malignant, whereas those with diffuse or no FDG uptake were considered benign. Semiquantitative analysis with maximum standardized uptake value (SUVmax) was also calculated. The PET/CT results were compared with histopathological results in all patients.

RESULTS

Based on the FDG uptake pattern, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for FDG-PET/CT in characterizing the periampullary and pancreatic masses into benign and malignant lesions were 93%, 90%, 95%, 87%, and 92% respectively. Receiver operating characteristics curve analysis of the SUVmax of the lesions yielded a cut-off value of 2.8, with a sensitivity and specificity of 87.5% and 45% respectively.

CONCLUSION

The FDG uptake pattern in PET/CT can differentiate malignant from benign mass-forming lesions of the pancreas with high accuracy and a discrete cut-off value of SUVmax could not be defined for the same as even lesions with pancreatic tuberculosis showed very high FDG uptake. Hence, in patients with a suspicion of malignancy in the pancreas, a focally increase FDG uptake in PET/CT suggests the diagnosis of malignancy.

Imaging of β-cell mass and insulitis in insulin-dependent (Type 1) diabetes mellitus

Insulin-dependent (type 1) diabetes mellitus is a metabolic disease with a complex multifactorial etiology and a poorly understood pathogenesis. Genetic and environmental factors cause an autoimmune reaction against pancreatic β-cells, called insulitis, confirmed in pancreatic samples obtained at autopsy. The possibility to noninvasively quantify β-cell mass in vivo would provide important biological insights and facilitate aspects of diagnosis and therapy, including follow-up of islet cell transplantation. Moreover, the availability of a noninvasive tool to quantify the extent and severity of pancreatic insulitis could be useful for understanding the natural history of human insulin-dependent (type 1) diabetes mellitus, to early diagnose children at risk to develop overt diabetes, and to select patients to be treated with immunotherapies aimed at blocking the insulitis and monitoring the efficacy of these therapies. In this review, we outline the imaging techniques currently available for in vivo, noninvasive detection of β-cell mass and insulitis. These imaging techniques include magnetic resonance imaging, ultrasound, computed tomography, bioluminescence and fluorescence imaging, and the nuclear medicine techniques positron emission tomography and single-photon emission computed tomography. Several approaches and radiopharmaceuticals for imaging β-cells and lymphocytic insulitis are reviewed in detail.

Evaluation of a novel, ultrathin, tip-bending endoscope in a synthetic force-sensing pancreas with comparison to medical guide wires

Purpose

Direct visualization of pancreatic ductal tissue is critical for early diagnosis of pancreatic diseases and for guiding therapeutic interventions. A novel, ultrathin (5 Fr) scanning fiber endoscope (SFE) with tip-bending capability has been developed specifically to achieve high resolution imaging as a pancreatoscope during endoscopic retrograde cholangiopancreatography (ERCP). This device has potential to dramatically improve both diagnostic and therapeutic capabilities during ERCP by providing direct video feedback and tool guidance to clinicians.

Methods

Invasiveness of the new tip-bending SFE was evaluated by a performance comparison to ERCP guide wires, which are routinely inserted into the pancreatic duct during ERCP. An in vitro test model with four force sensors embedded in a synthetic pancreas was designed to detect and compare the insertion forces for 0.89 mm and 0.53 mm diameter guide wires as well as the 1.7 mm diameter SFE. Insertions were performed through the working channel of a therapeutic duodenoscope for the two types of guide wires and using a statistically similar direct insertion method for comparison to the SFE.

Results

Analysis of the forces detected by the sensors showed the smaller diameter 0.53 mm wire produced significantly less average and maximum forces during insertion than the larger diameter 0.89 mm wire. With the use of tip-bending and optical visualization, the 1.7 mm diameter SFE produced significantly less average force during insertion than the 0.89 mm wire at every sensor, despite its larger size. It was further shown that the use of tip-bending with the SFE significantly reduced the forces at all sensors, compared to insertions when tip-bending was not used.

Conclusion

Combining high quality video imaging with two-axis tip-bending allows a larger diameter guide wire-style device to be inserted into the pancreatic duct during ERCP with improved capacity to perform diagnostics and therapy.

Diagnostic and radiological management of cystic pancreatic lesions: important features for radiologists

Cystic pancreatic neoplasms are often an incidental finding, the frequency of which is increasing. The understanding of such lesions has increased in recent years, but the numerous types of lesions involved can hinder differential diagnosis. They include, in particular, intraductal papillary mucinous neoplasms (IPMN), serous cystic neoplasms (SCN), and mucinous cystic neoplasms (MCN). Knowledge of their histological and radiological structure, as well as distribution in terms of localization, age, and sex, helps to differentiate such tumours from common pancreatic pseudocysts. Several types of cystic pancreatic neoplasms can undergo malignant transformation and, therefore, require differentiated radiological management. This review aims to develop a broader understanding of the pathological and radiological characteristics of cystic pancreatic neoplasms, and provide a guideline for everyday practice based on current concepts in the radiological management of the given lesions.

Molecular imaging of Cathepsin E-positive tumors in mice using a novel protease-activatable fluorescent probe

The purpose of this study is to demonstrate the ability of imaging Cathepsin E (Cath E) positive tumors in living animals through selective targeting of Cath E proteolytic activity using a sensitive molecular imaging agent.

METHODS

A peptide-based Cath E imaging probe and a control probe were synthesized for this study. Human Cath E-positive cancer cells (MPanc96-E) were implanted subcutaneously in nude mice. Tumor-bearing mice were examined in vivo with near-infrared fluorescence (NIRF) imaging at various time points after intravenous injection of the Cath E sensing imaging probe. Excised organs and tissues of interest were further imaged ex vivo.

RESULTS

Upon specific Cath E proteolytic activation, the NIRF signal of the imaging probe a was converted from an optically quenched initial state to a highly fluorescent active state. Imaging probe a was able to highlight the Cath E-positive tumors as early as 24 h post injection. Fluorescent signal in tumor was 3-fold higher than background. The confined specificity of imaging probe a to tumor associated Cath E was verified by using control imaging probe b. Both in vivo and ex vivo imaging results confirmed the superior selectivity and sensitivity of imaging probe a in Cath E imaging.

CONCLUSIONS

The small animal studies demonstrated the capability of probe a for imaging Cath E-positive tumors. The developed optical probe could be applied in early diagnostic imaging and guiding subsequent surgical procedure.

Incidence of synchronous and metachronous pancreatic carcinoma in 168 patients with branch duct intraductal papillary mucinous neoplasm

BACKGROUND/AIMS

Although branch duct intraductal papillary mucinous neoplasms of the pancreas (BD-IPMN) are being diagnosed with increasing frequency, the incidence of concomitant pancreatic carcinoma (PC) is not well known. We investigated the incidence and clinical features of synchronous and metachronous PC in patients with BD-IPMN.

METHODS

We studied 168 BD-IPMN patients diagnosed by various imaging modalities, including endoscopic retrograde pancreatography, between 1990 and 2008. We reviewed the medical records and clinical features in both patients developing and not developing PC. The diagnosis of PC was histologically verified in all patients.

RESULTS

PC was observed in 9 (5.4%) of 168 patients. Five were synchronously detected at the time of BD-IPMN diagnosis, whereas four were metachronously identified during the follow-up period. All PCs occurred in regions separate from the BD-IPMN lesion. All PCs represented histologically invasive ductal adenocarcinomas, whereas the BD-IPMN lesion was diagnosed as adenoma. Patients developing PC were significantly older than patients not developing PC (p = 0.017). The diameters of the BD-IPMN lesions and main pancreatic ducts were significantly smaller in patients developing PC than patients not developing PC (p = 0.013 and p < 0.001, respectively).

CONCLUSIONS

It was not infrequent for PC to occur in the pancreas with BD-IPMN. Particular attention should therefore be paid to the development of PC, even in low-risk BD-IPMN, as well as to changes in BD-IPMN.

A proposal for a new clinical classification of chronic pancreatitis

BACKGROUND

The clinical course of chronic pancreatitis is still unpredictable, which relates to the lack of the availability of a clinical classification. Therefore, patient populations cannot be compared, the course and the outcome of the disease remain undetermined in the individual patient, and treatment is not standardized.

AIM

To establish a clinical classification for chronic pancreatitis which is user friendly, transparent, relevant, prognosis- as well as treatment-related and offers a frame for future disease evaluation.

METHODS

Diagnostic requirements will include one clinical criterion, in combination with well defined imaging or functional abnormalities.

RESULTS

A classification system consisting of three stages (A, B and C) is presented, which fulfils the above-mentioned criteria. Clinical criteria are: pain, recurrent attacks of pancreatitis, complications of chronic pancreatitis (e.g. bile duct stenosis), steatorrhea, and diabetes mellitus. Imaging criteria consist of ductal or parenchymal changes observed by ultrasonography, ERCP, CT, MRI, and/or endosonography.

CONCLUSION

A new classification of chronic pancreatitis, based on combination of clinical signs, morphology and function, is presented. It is easy to handle and an instrument to study and to compare the natural course, the prognosis and treatment of patients with chronic pancreatitis.

Quantitative perfusion analysis of transabdominal contrast-enhanced ultrasonography of pancreatic masses and carcinomas

BACKGROUND & AIMS

Preoperative differential diagnosis of pancreatic ductal adenocarcinoma (PDAC) and focal masses in patients with chronic pancreatitis (CP) can be challenging. There are fine differences in the vascularization of these lesions; ultrasound contrast agents can aid in their differentiation. We evaluated the value of software-aided quantitative analysis of transabdominal contrast-enhanced ultrasonography for differential diagnosis of PDAC vs focal masses.

METHODS

Sixty patients for whom it was not possible to differentiate between an inflammatory focal lesion of the pancreas and a pancreatic carcinoma underwent contrast-enhanced ultrasonography with a second-generation contrast agent. Time-intensity curves were obtained for all exams in 2 regions of interest within the lesion and within the normal pancreatic tissue. Images were processed using Axius ACQ software; the following parameters were obtained: maximum intensity, arrival time, time-to-peak, and area under the curve. Absolute values and differences between the lesion and the normal tissue were evaluated.

RESULTS

Histology analysis revealed 45 PDACs and 15 inflammatory masses in patients with CP. Time-dependent parameters (arrival time and time to peak) were significantly longer in PDACs compared to focal masses. Although markedly lower than in healthy pancreata, the maximum intensity and area under the curve parameters were not significantly different between PDACs and focal lesions in patients with CP.

CONCLUSIONS

In cases of CP, PDAC and focal masses exhibit different perfusion patterns at a capillary level that can be visualized using the small microbubbles of ultrasound contrast agents. Contrast quantification software supplements a subjective visual assessment with objective criteria to facilitate the differential diagnosis of focal lesions in pancreatic cancer and chronic pancreatitis.

Infectious complications in patients with severe acute pancreatitis

This study aims to investigate the clinical characteristics of infectious complications in severe acute pancreatitis (SAP). From September 2003 to March 2005, 140 patients with SAP were retrospectively identified. SAP was defined by the diagnostic criteria formulated for SAP at the 2002 Bangkok World Congress of Gastroenterology in Thailand. Clinical data of the infected and non-infected patients was compared and the characteristics of infection were also analyzed. There were 44 patients who developed infectious complications with a rate of 31.4% (44/140). The severity index, the incidence of complications and mortality, was significantly higher in the infected patients than in the non-infected patients (P<0.05). Of 65 episodes of infection, infected (peri) pancreatic necrosis accounted for 47.7% (31/65), pneumonia for 27.7% (18/65), bacteremia for 10.8% (7/65), urinary tract infection for 6.1% (4/65), and gastrointestinal tract infection for 7.7% (5/65). The earliest infection was observed in pneumonia (10.7±2.5 days), followed by bacteremia (13.7±1.5 days), gastrointestinal tract infection (16.8±3.9 days), infected (peri)pancreatic necrosis (17.6±2.9 days), and urinary tract infection (20.5±4.8 days). Gram-negative bacteria were preponderantly found, comprising 56.6% (64/113) of the isolated strains. Gram-positive bacteria and fungus accounted for 22.1% (25/113) and 21.2% (24/113) of the isolated strains, respectively. Infectious complications in patients with SAP occurred in those who had severe episodes, and consequently complicated the clinical courses. Infected (peri)pancreatic necrosis is the most susceptible and pneumonia is the earliest. Gram-negative bacteria were predominant in multi-microorganisms.

Preoperative evaluation of pancreatic cancer: comparison of gadolinium-enhanced dynamic MRI with MR cholangiopancreatography versus MDCT

PURPOSE

To determine the accuracy of magnetic resonance imaging (MRI) including dynamic imaging using three-dimensional gradient-echo (3D-GRE) sequences and MR cholangiopancreatograpy (MRCP) compared with that of multidetector row CT (MDCT) with regard to resectability in pancreas cancer.

MATERIALS AND METHODS

From February 2004 to July 2008, 54 patients (32 men, 22 women: age range, 28-83 years; mean age, 63.1 years old) with surgically proven pancreatic carcinoma, who had undergone preoperative gadolinium-enhanced 3D-GRE MRI with MRCP and triple-phase MDCT, were included in this retrospective study. Two, clinically experienced attending radiologists independently reviewed the two image sets. These readers evaluated the tumor conspicuity, presence of vascular invasion, choledochal and duodenal invasion, lymph node metastases, distant metastasis, and tumor resectability. The results were compared with the surgical and histopathologic findings using receiver operating characteristic analysis (Az) and kappa statistics.

RESULTS

Curative resections were performed on 42 patients. Regarding the tumor conspicuity, MRI had a significantly higher Az value compared with MDCT according to both reviewers (P < 0.05). The accuracy of resectability was Az = 0.753 and 0.768 on MRI and Az = 0.829 and 0.762 on MDCT for each reviewer, and the difference in the accuracy of resectability was not significant between MRI and MDCT for either reviewer (P > 0.05). Two imaging sets showed a similar diagnostic performance in the evaluation of vascular involvement, lymph node metastasis, and distant metastasis.

CONCLUSION

Dynamic 3D-GRE MRI with MRCP shows superior tumor conspicuity and similar diagnostic performance compared with MDCT in evaluating the resectability of pancreatic cancer.

Selective cytotoxicity of Ponciri Fructus against glucose-deprived PANC-1 human pancreatic cancer cells via blocking activation of GRP78

Pancreatic cancer cells are sometimes exposed to stressful microenvironments such as glucose deprivation, hypoxia, and starvation of other nutrients. These stresses, which are characteristic of poorly vascularized solid tumors, activate the unfolded protein response (UPR). The UPR is a stress-signaling pathway present in tumor cells that is associated with molecular chaperone GRP78. Induction of GRP78 has been found to increase cell survival and decrease apoptotic potential through genetic alterations. Thus GRP78 may represent a novel target in the development of anticancer drugs. Here we established a novel screening program to identify chaperone modulators that exhibit preferential cytotoxic activity in glucose-deprived pancreatic cancer cells. During the course of our screening, we isolated an active substance, Ponciri Fructus (PF), from an herbal medicine source and identified it as a down-regulator of GRP78. As expected, PF inhibited expression of the GRP78 protein under glucose-deprivation conditions in a dose-dependent manner. Furthermore, it induced selective cytotoxicity against glucose-deprived cancer cells; this effect was not observed under normal growth conditions. We also detected apoptotic bodies on Hoechst staining and attempted to determine whether PF-induced apoptosis involved caspase-3 activation. Our results suggest that the GRP78-inhibitory action of PF was dependent on strict hypoglycemic conditions and that it resulted in the selective death of glucose-deprived pancreatic cancer cells.

Sixty-one years of pancreatic cancer in Denmark from 1943 to 2003: a nationwide study

OBJECTIVES

We report the incidence rates of pancreatic cancer in Denmark during 61 years of data registration, from 1943 to 2003.

METHODS

On the basis of reports in the nationwide, population-based Danish Cancer Registry, we calculated age-standardized, period-specific incidence rates of pancreatic cancer.

RESULTS

A total of 32,654 incident cases of pancreatic cancer were evaluated (male-female ratio, 1.4). The age-standardized incidence rate of pancreatic cancer increased steadily in the beginning of the study period from 3.75/100,000 person-years in 1943 to 1947 to the maximum of 9.96/100,000 person-years in 1968 to 1972 among men and from 2.95 in 1943 to 1947 to the maximum of 7.04 in 1978 to 1982 among women. The incidence rates declined between 1968 to 1972 and 1988 to 1992 for men and between 1978 to 1982 and 2003 for women. Most tumors were located in the exocrine pancreas, and most were adenocarcinomas. More than 40% were located in the head of the pancreas; 14% were localized, 21% were regionally spread, and 36% were metastatic at the time of diagnosis. During the period 1978 to 2003, the percentages of histologically or cytologically verified adenocarcinomas remained relatively steady, approximately 30%.

CONCLUSIONS

The incidence rate of pancreatic cancer increased at the beginning of the 61 years of registration and declined slightly thereafter.

Role of endoscopic ultrasound in the diagnosis and staging of pancreatic cancer

Early diagnosis of pancreatic cancer remains a difficult task, and multiple imaging tests have been proposed over the years. The aim of this review is to describe the current role of endoscopic ultrasound (EUS) for the diagnosis and staging of patients with pancreatic cancer. A detailed search of MEDLINE between 1980 and 2007 was performed using the following keywords: pancreatic cancer, endoscopic ultrasound, diagnosis, and staging. References of the selected articles were also browsed and consulted. Despite progress made with other imaging methods, EUS is still considered to be superior for the detection of clinically suspected lesions, especially if the results of other cross-sectional imaging modalities are equivocal. The major advantage of EUS is the high negative predictive value that approaches 100%, indicating that the absence of a focal mass reliably excludes pancreatic cancer. The introduction of EUS-guided fine needle aspiration allows a preoperative diagnosis in patients with resectable cancer, as well as a confirmation of diagnosis before chemoradiotherapy for those that are not. This comprehensive review highlighted the diagnostic capabilities of EUS including the newest refinements such as contrast-enhanced EUS, EUS elastography, and 3-dimensional EUS. The place of EUS-guided biopsy is also emphasized, including the addition of molecular marker techniques.

Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) have long fascinated clinicians and investigators despite their relative rarity. Their clinical presentation varies depending on whether the tumor is functional or not, and also according to the specific hormonal syndrome produced. Tumors may be sporadic or inherited, but little is known about their molecular pathology, especially the sporadic forms. Chromogranin A appears to be the most useful serum marker for diagnosis, staging, and monitoring. Initially, therapy should be directed at the hormonal syndrome because this has the major initial impact on the patient's health. Most PETs are relatively indolent but ultimately malignant, except for insulinomas, which predominantly are benign. Surgery is the only modality that offers the possibility of cure, although it generally is noncurative in patients with Zollinger-Ellison syndrome or nonfunctional PETs with multiple endocrine neoplasia-type 1. Preoperative staging of disease extent is necessary to determine the likelihood of complete resection although debulking surgery often is believed to be useful in patients with unresectable tumors. Once metastatic, biotherapy is usually the first modality used because it generally is well tolerated. Systemic or regional therapies generally are reserved until symptoms occur or tumor growth is rapid. Recently, a number of newer agents, as well as receptor-directed radiotherapy, are being evaluated for patients with advanced disease. This review addresses a number of recent advances regarding the molecular pathology, diagnosis, localization, and management of PETs including discussion of peptide-receptor radionuclide therapy and other novel antitumor approaches. We conclude with a discussion of future directions and unsettled problems in the field.

Value of pancreatic antibiotic concentration in treatment of secondary infection of serve acute pancreatitis

Secondary pancreatic infection represents the most serious complication with fatal outcome in severe acute pancreatitis (SAP). Preventing and curing secondary infection of pancreas is the key obstacle to minimize the mortality of these patients. The studies on blood-pancreatic juice barrier as well as penetration and pancreatic tissue concentration of antibiotics have improved the antibiotic prophylaxis or treatment of pancreatic infection. In the future, potential therapeutics that can enhance the antibiotic concentration and efficacy may help to prevent and treat the secondary infection of SAP.

Highly sensitive detection of early-stage pancreatic cancer by multimodal near-infrared molecular imaging in living mice

Pancreatic cancer is a serious disease with poor patient outcome, often as a consequence of late diagnosis in advanced stages. This is in large part due to the lack of diagnostic tools for early detection. To address this deficiency, we have investigated novel molecular near-infrared fluorescent (NIRF) in vivo imaging techniques in clinically relevant mouse models of pancreatic cancer. Genome wide gene expression profiling was used to identify cathepsin cystein proteases and matrix metalloproteinases (MMP) as targets for NIRF imaging. Appropriate protease activatable probes were evaluated for detection of early-stage pancreatic cancer in mice with orthotopically implanted pancreatic cancer cell lines. Mice with pancreatitis served as controls. Whole body in vivo NIRF imaging using activatable cathepsin sensitive probes specifically detected pancreatic tumors as small as 1-2 mm diameter. Imaging of MMP activity demonstrated high specificity for MMP positive tumors. Intravital flexible confocal fluorescence lasermicroscopy of protease activity enabled specific detection of pancreatic tumors at the cellular level. Importantly, topical application of NIRF-probes markedly reduced background without altering signal intensity. Taken together, macroscopic and confocal lasermicroscopic molecular in vivo imaging of protease activity is highly sensitive, specific and allows discrimination between normal pancreatic tissue, inflammation and pancreatic cancer. Translation of this approach to the clinic could significantly improve endoscopic and laparoscopic detection of early-stage pancreatic cancer.

Preoperative evaluation of pancreatic adenocarcinoma

The preoperative evaluation of resectability for pancreatic cancer fails to identify up to 25% of patients who are unfortunately found to be unresectable at surgical exploration. Inoperative findings in this circumstance is usually due to either small volume metastatic disease or regional tumor invasion. While advances in computed tomography (CT) technology has increased accuracy of local tumor extent, occult metastatic disease remains a common problem. Although 2-[(18)F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been demonstrated to be useful in the staging of many malignancies (e.g. esophageal cancer, recurrent colorectal cancer, lung cancer), it has not been found to significantly increase the accuracy of determining resectability preoperatively in pancreatic cancer, especially with regard to detection of small volume metastatic disease. There are a variety of pancreatic cancer-specific antigens which are being developed as a method for targeted molecular imaging; we provide preliminary data targeting the integrin alpha(v)beta(6) to demonstrate the potential feasibility of this approach. Further developments may allow the accurate determination of patients with resectable pancreatic cancer, and more importantly, those with unresectable disease that may forego unnecessary surgery, the associated morbidity, and the subsequent delay of appropriate therapy.

Sociodemographic and tumor characteristics associated with pancreatic cancer surgery in the United States

BACKGROUND AND OBJECTIVES

Surgical resection is the only curative treatment for pancreatic cancer. The aim of this project was to compare risk and prognostic factors between pancreatic cancer patients treated with and without surgery.

METHODS

Data from 32,318 cases collected from 1988 to 2002 in the Surveillance Epidemiology and End Results program were used to evaluate the odds of having surgery for pancreatic adenocarcinoma. Multivariate logistic regression was used to estimate odds ratios and 95% confidence intervals for the associations of demographic and tumor characteristics with surgical treatment.

RESULTS

Overall, men were less likely to have surgery than women (OR = 0.90, 95% CI 0.83, 0.98). Compared to married patients, surgery was significantly less likely among those who were divorced/separated (OR = 0.78, 95% CI 0.68, 0.89) or widowed (OR = 0.76, 95% CI 0.67, 0.85). Black patients were less likely to receive surgery than white patients (OR = 0.79, 95% CI 0.70, 0.91). Patients diagnosed in 1997-2002 were more likely to have surgery then those diagnosed in 1988-1996. Geographic differences also exist in the frequency of surgical treatment reported by different registries.

CONCLUSIONS

There are differences in sociodemographic characteristics between surgically and non-surgically treated pancreatic cancers that are not entirely attributable to age, primary site, or stage at diagnosis.

Scanning single fiber endoscopy: a new platform technology for integrated laser imaging, diagnosis, and future therapies

Remote optical imaging of human tissue in vivo has been the foundation for the growth of minimally invasive medicine. This article describes a new type of endoscopic imaging that has been developed and applied to the human esophagus, pig bile duct, and mouse colon. The technology is based on a single optical fiber that is scanned at the distal tip of an ultrathin and flexible shaft that projects red, green, and blue laser light onto tissue in a spiral pattern. The resulting images are high-quality color video that is expected to produce future endoscopes that are thinner, longer, more flexible, and able to directly integrate the many recent advances of laser diagnostics and therapies.

Diagnostic impact of 18F-FDG PET-CT evaluating solid pancreatic lesions versus endosonography, endoscopic retrograde cholangio-pancreatography with intraductal ultrasonography and abdominal ultrasound

PURPOSE

This prospective single-centre phase II trial assessed the diagnostic impact of (18)F-FDG PET-CT in the evaluation of solid pancreatic lesions (phi >or= 10 mm) compared to endosonography (EUS), endoscopic retrograde cholangio-pancreatography (ERCP) with intraductal ultrasound (IDUS), abdominal ultrasound (US) and histopathological reference.

METHODS

Forty-six patients (32 men/14 women, phi 61.7 years) with suspected pancreatic neoplasms underwent PET-CT with contrast-enhanced biphasic multi-detector CT of the upper abdomen followed by a diagnostic work-up with EUS, ERCP with IDUS and US within 3 weeks. PET-CT data sets were analysed by two expert readers in a consensus reading. Histology from surgery, biopsy/fine-needle aspiration and/or clinical follow-up >or=12 months served as standard of reference.

RESULTS

Twenty-seven pancreatic malignancies were histopathologically proven; 19 patients had benign diseases: 36/46 lesions (78%) were detected in the head of the pancreas, 7/46 and 3/46 in the body and tail region, respectively. Sensitivity and specificity of PET-CT were 89% and 74%, respectively; positive predictive value (PPV) and negative predictive value (NPV) were 83% and 82%, respectively. Sensitivity (81-89%), specificity (74-88%), PPV (83-90%) and NPV (77-82%) achieved by EUS, ERCP and US were not significantly different. PET analysis revealed significantly higher maximum mean standardised uptake values (SUV(max) 6.5+/-4.6) in patients with pancreatic malignancy (benign lesions: SUV(max) 4.2+/-1.5; p<0.05). PET-CT revealed cervical lymphonodal metastasis from occult bronchogenic carcinoma and a tubular colon adenoma with intermediate dysplasia on polypectomy, respectively.

CONCLUSIONS

(18)F-FDG PET-CT achieves a comparably high diagnostic impact evaluating small solid pancreatic lesions versus conventional reference imaging modalities. Additional clinical diagnoses are derived from concomitant whole-body PET-CT imaging.

Diagnosis of solid pancreatic masses by endoscopic ultrasound-guided fine-needle aspiration

BACKGROUND

Endoscopic ultrasound (EUS) with fine-needle aspiration (FNA) is increasingly being used in the staging algorithm for pancreatic carcinoma. This allows for a tissue diagnosis, which was previously difficult to obtain. The aim of this study is to assess the utility of EUS-FNA in establishing the diagnosis of solid pancreatic mass lesions in an Australian population.

METHODS

A retrospective review of the EUS databases of St Vincent's Hospital Melbourne and Western Hospital, Melbourne from November 2002 to May 2006 was undertaken. The focus was on patients with a solid pancreatic mass who underwent EUS-FNA. Surgical pathology or long-term follow up was used to identify false-positive or false-negative results.

RESULTS

EUS was undertaken to investigate a solid pancreatic or distal common bile duct mass lesion in 155 patients. Seventy-two of these underwent EUS-guided FNA. Mean age was 68 years. A positive tissue diagnosis of malignancy could be made in 55 (76%). Nine (13%) had benign histology, with 8 (11%) having inadequate tissue obtained from FNA. A later tissue diagnosis of carcinoma was made in eight of those with either benign or inadequate histology, although in all cases there were EUS features diagnostic of malignancy, with FNA limited by technical difficulties. The overall utility of EUS-FNA showed a sensitivity of 87%, specificity 100%, positive predictive value 100%, negative predictive value 52% and overall accuracy 89%.

CONCLUSION

EUS-FNA gives a high return for histological diagnosis of solid pancreatic mass lesions and should be part of the standard management algorithm for pancreatic carcinoma.

[Pancreatic incidentalomas. Correct assessment and therapy]

Due to recent advances in CT/MRI technology, incidentalomas of the pancreas are detected with increasing frequency. Pancreatic incidentalomas should be differentiated into solid and cystic tumors. In both subgroups definitive classification of the tumor is often not possible. Operative therapy is recommended in premalignant or malignant pathologies. Thus solid incidentalomas should be resected independently of their size, if the patient is without serious comorbidities. In case of cystic incidentalomas, benign cystic lesions should be excluded as far as possible. Otherwise they should be resected if their size is >or=2 cm. In case of IPMN with specific risk factors, resection is recommended when the tumor size exceeds 1 cm.