Pancreatic carcinoma versus chronic pancreatitis: dynamic MR imaging

Pancreatic Cancer and Detection Methods

The pancreas is a vital organ with exocrine and endocrine functions. Pancreatitis is an inflammation of the pancreas caused by alcohol consumption and gallstones. This condition can heighten the risk of pancreatic cancer (PC), a challenging disease with a high mortality rate. Genetic and epigenetic factors contribute significantly to PC development, along with other risk factors. Early detection is crucial for improving PC outcomes. Diagnostic methods, including imagining modalities and tissue biopsy, aid in the detection and analysis of PC. In contrast, liquid biopsy (LB) shows promise in early tumor detection by assessing biomarkers in bodily fluids. Understanding the function of the pancreas, associated diseases, risk factors, and available diagnostic methods is essential for effective management and early PC detection. The current clinical examination of PC is challenging due to its asymptomatic early stages and limitations of highly precise diagnostics. Screening is recommended for high-risk populations and individuals with potential benign tumors. Among various PC screening methods, the N-NOSE plus pancreas test stands out with its high AUC of 0.865. Compared to other commercial products, the N-NOSE plus pancreas test offers a cost-effective solution for early detection. However, additional diagnostic tests are required for confirmation. Further research, validation, and the development of non-invasive screening methods and standardized scoring systems are crucial to enhance PC detection and improve patient outcomes. This review outlines the context of pancreatic cancer and the challenges for early detection.

Multitasking dynamic contrast enhanced magnetic resonance imaging can accurately differentiate chronic pancreatitis from pancreatic ductal adenocarcinoma

Background and aims

Accurate differentiation of chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) is an area of unmet clinical need. In this study, a novel Multitasking dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI) technique was used to quantitatively evaluate the microcirculation properties of pancreas in CP and PDAC and differentiate between them.

Methods

The Multitasking DCE technique was able to acquire one 3D image per second during the passage of MRI contrast agent, allowing the quantitative estimation of microcirculation properties of tissue, including blood flow F_p, plasma volume fraction v_p, transfer constant K^trans, and extravascular extracellular volume fraction v_e. Receiver operating characteristic (ROC) analysis was performed to differentiate the CP pancreas, PDAC pancreas, normal control pancreas, PDAC tumor, PDAC upstream, and PDAC downstream. ROCs from quantitative analysis and conventional analysis were compared.

Results

Fourteen PDAC patients, 8 CP patients and 20 healthy subjects were prospectively recruited. The combination of F_p, v_p, K^trans, and v_e can differentiate CP versus PDAC pancreas with good AUC (AUC [95% CI] = 0.821 [0.654 - 0.988]), CP versus normal pancreas with excellent AUC (1.000 [1.000 - 1.000]), PDAC pancreas versus normal pancreas with excellent AUC (1.000 [1.000 - 1.000]), CP versus PDAC tumor with excellent AUC (1.000 [1.000 - 1.000]), CP versus PDAC downstream with excellent AUC (0.917 [0.795 - 1.000]), and CP versus PDAC upstream with fair AUC (0.722 [0.465 - 0.980]). This quantitative analysis outperformed conventional analysis in differentiation of each pair.

Conclusion

Multitasking DCE MRI is a promising clinical tool that is capable of unbiased quantitative differentiation between CP from PDAC.

Comparison of contrast-enhanced versus conventional EUS-guided FNA/fine-needle biopsy in diagnosis of solid pancreatic lesions: a randomized controlled trial

BACKGROUND AND AIMS

Contrast-enhanced harmonic EUS (CEH-EUS) is useful in the differential diagnosis of solid pancreatic lesions (SPLs). However, there is lack of verification about the usefulness of CEH-EUS-guided FNA/fine-needle biopsy (FNB) sampling. This study aimed to investigate the usefulness of CEH-EUS-guided FNA/FNB sampling without on-site cytopathology.

METHODS

Patients with SPLs were prospectively enrolled and randomly assigned (1:1) to 2 parallel groups, the interventional group (CEH-EUS) or the control group (conventional EUS). The diagnostic sensitivity and optimal number of needle passes for pathologic diagnosis were investigated and compared between groups.

RESULTS

Two hundred forty patients were enrolled from March 2016 to September 2019, with 120 patients assigned to each group. Pancreatic malignancies and neuroendocrine tumors were found in 202 (90.83%) and 9 (3.75%) patients, respectively. There was no statistically significant difference between the groups in terms of age, sex, lesion size (30.96 ± 12.09 mm in the CEH-EUS group vs 33.09 ± 16.39 mm in the conventional EUS group; P = .252), lesion location, adverse event rate, and disease distribution. The diagnostic sensitivity values in the CEH-EUS and conventional EUS groups were 85.8% and 88.3%, respectively (P = .564). All patients in the conventional EUS group and most in the CEH-EUS group received a pathologic diagnosis within 3 needle passes.

CONCLUSIONS

Diagnostic sensitivity for SPLs was not different between the CEH-EUS and conventional EUS groups, and no independent factors were found that could improve diagnostic sensitivity. CEH-EUS-guided FNA/FNB sampling does not need to be used routinely and may be selectively considered for small, indeterminate lesions. (Clinical trial registration number: KCT 0001840.).

Pancreatitis and PDAC: association and differentiation

The discrimination of mass-forming chronic pancreatitis (MFCP) from pancreatic ductal adenocarcinoma (PDAC) is a central diagnostic dilemma. It is important to differentiate these entities since they have markedly different prognoses and management. Importantly, the appearance of these two entities significantly overlaps on a variety of imaging modalities. However, there are imaging features that may be suggestive of one entity more than the other. MFCP and PDAC may show different enhancement patterns on perfusion computed tomography (CT) and/or dynamic contrast-enhanced MRI (DCE-MRI). The duct-penetrating sign on magnetic resonance cholangiopancreatography (MRCP) is more often associated with MFCP, whereas abrupt cutoff with upstream dilatation of the main pancreatic duct and the double-duct sign (obstruction/cutoff of both the common bile duct and pancreatic duct) are more often associated with PDAC. Nevertheless, tissue sampling is the most reliable method to differentiate between these entities and is currently generally necessary for management.

Inflammatory mimickers of pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma can be a difficult imaging diagnosis early in its course given its subtle imaging findings such as focal pancreatic duct dilatation, abrupt duct cut-off, and encasement of vasculature. A variety of pancreatitidies have imaging findings that mimic pancreatic ductal adenocarcinoma and lead to mass formation making diagnosis even more difficult on imaging alone. These conditions include acute focal pancreatitis, chronic pancreatitis, autoimmune pancreatitis, and paraduodenal ("groove") pancreatitis. This review will focus on imaging findings that can help differentiate these inflammatory processes from pancreatic ductal adenocarcinoma.

Non-neoplastic hepatopancreatobiliary lesions simulating malignancy: can we differentiate?

Despite the success of cross-sectional imaging in evaluating hepatopancreatobiliary system malignancies, several non-malignant disease processes may closely mimic malignancy. Differentiating these benign diseases from malignancy may be difficult, or even impossible, even in the hands of experienced imagers. In this manuscript, we present benign mimics involving the hepatopancreatobiliary system and try to increase awareness of these potential pitfalls.

Six-dimensional quantitative DCE MR Multitasking of the entire abdomen: Method and application to pancreatic ductal adenocarcinoma

PURPOSE

To develop a quantitative DCE MRI technique enabling entire-abdomen coverage, free-breathing acquisition, 1-second temporal resolution, and T₁ -based quantification of contrast agent concentration and kinetic modeling for the characterization of pancreatic ductal adenocarcinoma (PDAC).

METHODS

Segmented FLASH readouts following saturation-recovery preparation with randomized 3D Cartesian undersampling was used for incoherent data acquisition. MR Multitasking was used to reconstruct 6-dimensional images with 3 spatial dimensions, 1 T₁ recovery dimension for dynamic T₁ quantification, 1 respiratory dimension to resolve respiratory motion, and 1 DCE time dimension to capture the contrast kinetics. Sixteen healthy subjects and 14 patients with pathologically confirmed PDAC were recruited for the in vivo studies, and kinetic parameters v_p , K^trans , v_e , and K_ep were evaluated for each subject. Intersession repeatability of Multitasking DCE was assessed in 8 repeat healthy subjects. One-way unbalanced analysis of variance was performed between control and patient groups.

RESULTS

In vivo studies demonstrated that v_p , K^trans , and K_ep of PDAC were significantly lower compared with nontumoral regions in the patient group (P = .002, .003, .004, respectively) and normal pancreas in the control group (P = .011, <.001, <.001, respectively), while v_e was significantly higher than nontumoral regions (P < .001) and healthy pancreas (P < .001). The kinetic parameters showed good in vivo repeatability (interclass correlation coefficient: v_p , 0.95; K^trans , 0.98; v_e , 0.96; K_ep , 0.99).

CONCLUSION

The proposed Multitasking DCE is promising for the quantification of vascular properties of PDAC. Quantitative DCE parameters were repeatable in vivo and showed significant differences between normal pancreas and both tumor and nontumoral regions in patients with PDAC.

CT and MR features that can help to differentiate between focal chronic pancreatitis and pancreatic cancer

Diagnosis of a focal pancreatic mass in routine clinical practice can be a challenge because patients with chronic pancreatitis may present with symptoms and imaging findings that can be difficult to distinguish from pancreatic cancer. Markers, such as cancer antigen 19-9 and carcinoembryonic antigen, are helpful if abnormal, but normal values do not rule out pancreatic cancer. One of the strongest complicating factors is that chronic pancreatitis is a risk factor for pancreatic cancer. Transition of chronic pancreatitis to pancreatic cancer is relatively rare, but it normally has a poor prognosis because diagnosis is often delayed. From a radiologic diagnosis perspective, the classic so-called double-duct sign is helpful. This sign is considered a hallmark sign of pancreatic cancer on magnetic resonance cholangiopancreatography, but it can also be identified in patients with chronic pancreatitis or with other conditions. A number of additional imaging findings or signs are, therefore, necessary. The aim of this article was to describe the strong CT and MR imaging features or integrated imaging features that can help to differentiate between pancreatic cancer and focal chronic pancreatitis.

Imaging of Tropical Chronic Pancreatitis—A Unique Clinico-Radiological Entity

Tropical chronic pancreatitis (TCP) is a unique juvenile nonalcoholic form of chronic pancreatitis prevalent in tropical developing countries. TCP is characterized by the younger age of onset, rapid progression, higher prevalence of diabetes and pancreatic calculi, and greater propensity to develop pancreatic malignancy. Identifying the distinct imaging features is critical for the diagnosis of TCP. Awareness of this condition will not only enable the radiologist to recognize it early but also help in better management. In this article, we review the etiopathogenesis, distinct imaging features, and complications of TCP.

Measurement of T1 and T2 relaxation times of the pancreas at 7 T using a multi-transmit system

Objective

To determine T₁ and T₂ relaxation times of healthy pancreas parenchyma at 7 T using a multi-transmit system.

Materials and methods

Twenty-six healthy subjects were scanned with a 7 T MR system using eight parallel transceiver antennas, each with two additional receive loops. A Look-Locker sequence was used to obtain images for T₁ determination, while T₂ was obtained from spin-echo images and magnetic resonance spectroscopy measurements with different echo times. T₁ and T₂ times were calculated using a mono-exponential fit of the average magnitude signal from a region of interest in the pancreas and were tested for correlation with age.

Results

The age range of the included subjects was 21–72 years. Average T₁ and T₂ relaxation times in healthy pancreas were 896 ± 149 ms, and 26.7 ± 5.3 ms, respectively. No correlation with age was found.

Conclusion

T₁ and T₂ relaxation times of the healthy pancreas were reported for 7 T, which can be used for image acquisition optimization. No significant correlations were found between age and T₁ or T₂ relaxation times of the pancreas. Considering their low standard deviation and no observable age dependence, these values may be used as a baseline to study potentially pancreatic tissue affected by disease.

Mass forming chronic pancreatitis mimicking pancreatic cystic neoplasm: A case report

Mass forming chronic pancreatitis is very rare. Diagnosis could be done by the pathologic findings of focal inflammatory fibrosis without evidence of tumor in pancreas. A 34-year-old man presented with right upper abdominal pain for a few weeks and slightly elevated bilirubin level on clinical findings. Radiological findings of multidetector-row computed tomography, magnetic resonance (MR) imaging with MR cholangiopancreatography and endoscopic ultrasonography revealed focal branch pancreatic duct dilatation with surrounding delayed enhancing solid component at uncinate process and head of pancreas, suggesting branch duct type intraductal papillary mucinous neoplasm. Surgery was done and pathology revealed the focal chronic inflammation, fibrosis, and branch duct dilatation. Herein, I would like to report the first case report of mass forming chronic pancreatitis mimicking pancreatic cystic neoplasm.

Imitators of chronic pancreatitis: diffuse neuroendocrine tumour of the pancreas

We report a rare case of diffuse replacement of the pancreas with neuroendocrine tumour mimicking chronic pancreatitis. A 55-year-old female with no significant past medical history initially presented with abdominal pain in 2006. A CT of the abdomen and pelvis was performed, revealing diffuse pancreatic parenchymal calcifications with mild pancreatic ductal dilatation and no discrete mass. She was diagnosed with chronic pancreatitis and followed clinically until 2015, where she presented with recurrent abdominal pain. A repeat CT and MRI of the abdomen were performed which revealed new hypoenhancing masses within the pancreas, particularly in the pancreatic tail. There was a persistent background of pancreatic parenchymal calcifications. The possibility of pancreatic neuroendocrine tumour was raised, and an indium-111 Octreotide scan was recommended. Diffuse intense uptake was identified throughout the pancreas on the indium-111 imaging. Given the concern for neuroendocrine tumour, a total pancreatectomy was performed, with histopathology revealing replacement of the pancreas with coalescing well-circumscribed nodules. Many of the nodules had numerous calcifications and localized amyloid deposition. Immunohistochemical stains of the neoplastic cells were strong for neuroendocrine markers chromogranin A and synaptophysin. Overall the findings were consistent with numerous neuroendocrine tumours of the pancreas, Grade II, as per the 2010 WHO criteria for neuroendocrine tumours of the pancreas. Neuroendocrine tumours of the pancreas are lesions that arise from the islet cells, with an approximate incidence of five cases per million people per year. Only one other case report has been documented in the literature by Singh et al demonstrating diffuse pancreatic neuroendocrine tumour replacing the entire pancreas. As diffuse pancreatic neuroendocrine tumour can look similar on imaging to chronic pancreatitis or other infiltrative processes, we wanted to present this case and some of the more specific imaging findings in distinguishing these entities.

Imaging modalities for characterising focal pancreatic lesions

BACKGROUND

Increasing numbers of incidental pancreatic lesions are being detected each year. Accurate characterisation of pancreatic lesions into benign, precancerous, and cancer masses is crucial in deciding whether to use treatment or surveillance. Distinguishing benign lesions from precancerous and cancerous lesions can prevent patients from undergoing unnecessary major surgery. Despite the importance of accurately classifying pancreatic lesions, there is no clear algorithm for management of focal pancreatic lesions.

OBJECTIVES

To determine and compare the diagnostic accuracy of various imaging modalities in detecting cancerous and precancerous lesions in people with focal pancreatic lesions.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, and Science Citation Index until 19 July 2016. We searched the references of included studies to identify further studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We planned to include studies reporting cross-sectional information on the index test (CT (computed tomography), MRI (magnetic resonance imaging), PET (positron emission tomography), EUS (endoscopic ultrasound), EUS elastography, and EUS-guided biopsy or FNA (fine-needle aspiration)) and reference standard (confirmation of the nature of the lesion was obtained by histopathological examination of the entire lesion by surgical excision, or histopathological examination for confirmation of precancer or cancer by biopsy and clinical follow-up of at least six months in people with negative index tests) in people with pancreatic lesions irrespective of language or publication status or whether the data were collected prospectively or retrospectively.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched the references to identify relevant studies and extracted the data. We planned to use the bivariate analysis to calculate the summary sensitivity and specificity with their 95% confidence intervals and the hierarchical summary receiver operating characteristic (HSROC) to compare the tests and assess heterogeneity, but used simpler models (such as univariate random-effects model and univariate fixed-effect model) for combining studies when appropriate because of the sparse data. We were unable to compare the diagnostic performance of the tests using formal statistical methods because of sparse data.

MAIN RESULTS

We included 54 studies involving a total of 3,196 participants evaluating the diagnostic accuracy of various index tests. In these 54 studies, eight different target conditions were identified with different final diagnoses constituting benign, precancerous, and cancerous lesions. None of the studies was of high methodological quality. None of the comparisons in which single studies were included was of sufficiently high methodological quality to warrant highlighting of the results. For differentiation of cancerous lesions from benign or precancerous lesions, we identified only one study per index test. The second analysis, of studies differentiating cancerous versus benign lesions, provided three tests in which meta-analysis could be performed. The sensitivities and specificities for diagnosing cancer were: EUS-FNA: sensitivity 0.79 (95% confidence interval (CI) 0.07 to 1.00), specificity 1.00 (95% CI 0.91 to 1.00); EUS: sensitivity 0.95 (95% CI 0.84 to 0.99), specificity 0.53 (95% CI 0.31 to 0.74); PET: sensitivity 0.92 (95% CI 0.80 to 0.97), specificity 0.65 (95% CI 0.39 to 0.84). The third analysis, of studies differentiating precancerous or cancerous lesions from benign lesions, only provided one test (EUS-FNA) in which meta-analysis was performed. EUS-FNA had moderate sensitivity for diagnosing precancerous or cancerous lesions (sensitivity 0.73 (95% CI 0.01 to 1.00) and high specificity 0.94 (95% CI 0.15 to 1.00), the extremely wide confidence intervals reflecting the heterogeneity between the studies). The fourth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (dysplasia) provided three tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing invasive carcinoma were: CT: sensitivity 0.72 (95% CI 0.50 to 0.87), specificity 0.92 (95% CI 0.81 to 0.97); EUS: sensitivity 0.78 (95% CI 0.44 to 0.94), specificity 0.91 (95% CI 0.61 to 0.98); EUS-FNA: sensitivity 0.66 (95% CI 0.03 to 0.99), specificity 0.92 (95% CI 0.73 to 0.98). The fifth analysis, of studies differentiating cancerous (high-grade dysplasia or invasive carcinoma) versus precancerous (low- or intermediate-grade dysplasia) provided six tests in which meta-analysis was performed. The sensitivities and specificities for diagnosing cancer (high-grade dysplasia or invasive carcinoma) were: CT: sensitivity 0.87 (95% CI 0.00 to 1.00), specificity 0.96 (95% CI 0.00 to 1.00); EUS: sensitivity 0.86 (95% CI 0.74 to 0.92), specificity 0.91 (95% CI 0.83 to 0.96); EUS-FNA: sensitivity 0.47 (95% CI 0.24 to 0.70), specificity 0.91 (95% CI 0.32 to 1.00); EUS-FNA carcinoembryonic antigen 200 ng/mL: sensitivity 0.58 (95% CI 0.28 to 0.83), specificity 0.51 (95% CI 0.19 to 0.81); MRI: sensitivity 0.69 (95% CI 0.44 to 0.86), specificity 0.93 (95% CI 0.43 to 1.00); PET: sensitivity 0.90 (95% CI 0.79 to 0.96), specificity 0.94 (95% CI 0.81 to 0.99). The sixth analysis, of studies differentiating cancerous (invasive carcinoma) from precancerous (low-grade dysplasia) provided no tests in which meta-analysis was performed. The seventh analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) provided two tests in which meta-analysis was performed. The sensitivity and specificity for diagnosing cancer were: CT: sensitivity 0.83 (95% CI 0.68 to 0.92), specificity 0.83 (95% CI 0.64 to 0.93) and MRI: sensitivity 0.80 (95% CI 0.58 to 0.92), specificity 0.81 (95% CI 0.53 to 0.95), respectively. The eighth analysis, of studies differentiating precancerous or cancerous (intermediate- or high-grade dysplasia or invasive carcinoma) from precancerous (low-grade dysplasia) or benign lesions provided no test in which meta-analysis was performed.There were no major alterations in the subgroup analysis of cystic pancreatic focal lesions (42 studies; 2086 participants). None of the included studies evaluated EUS elastography or sequential testing.

AUTHORS' CONCLUSIONS

We were unable to arrive at any firm conclusions because of the differences in the way that study authors classified focal pancreatic lesions into cancerous, precancerous, and benign lesions; the inclusion of few studies with wide confidence intervals for each comparison; poor methodological quality in the studies; and heterogeneity in the estimates within comparisons.

The endoscopist's role in the diagnosis and management of pancreatic cancer

Pancreatic cancer remains one of the most lethal malignancies with little improvement in survival over the past several decades in spite of advances in imaging, risk factor identification, surgical technique and chemotherapy. This disappointing outcome is mainly due to failures to make an early diagnosis. In fact, the majority of the patients present with inoperable advanced stages of the disease. Though some of the new tumor markers are promising, we are still in search of the one that has a high sensitivity and accuracy, yet is inexpensive and easy to obtain. The paradigm of management has shifted from up-front surgery followed by adjuvant chemotherapy to neoadjuvant chemoradiation followed by surgery, especially for borderline resectable cancers and even for some resectable cancers. In this article, we will critically assess the limitations of tumor markers and review the advancements in endoscopic techniques in the management of pancreatic cancer.

Diffusion-weighted magnetic resonance imaging for non-neoplastic conditions in the hepatobiliary and pancreatic regions: pearls and potential pitfalls in imaging interpretation

Potentially, diffusion-weighted magnetic resonance imaging (DWI) can assess the functional information on concerning the status of tissue cellularity, because increased cellularity is associated with impeded diffusion. DWI in the hepatobiliary and pancreatic regions has demonstrated the usefulness to detect malignant lesions and differentiate them from benign lesions. However, it has been shown more recently that there is some overlap in ADC values for benign and malignant neoplasms. Moreover, some non-neoplastic lesions in the hepatobiliary and pancreatic regions exhibit restricted diffusion on DWI, because of pus, inflammation, or high cellularity. Focal eosinophilic liver disease, hepatic inflammatory myofibroblastic tumor, granulomatous liver disease, acute cholecystitis, xanthogranulomatous cholecystitis, focal pancreatitis, or autoimmune pancreatitis frequently exhibit restricted diffusion on DWI, which may be confused with malignancy in the hepatobiliary and pancreatic regions. Thus, DWI should not be interpreted in isolation, but in conjunction with other conventional images, to avoid the diagnostic pitfalls of DWI. Nevertheless, the presence of diffusion restriction in the non-neoplastic lesions sometimes provides additional information regarding the diagnosis, in problematic patients where conventional images have yielded equivocal findings. DWI may help differentiate hepatic abscess from malignant necrotic tumors, gallbladder empyema from dense bile or sludge in the gallbladder, and pylephlebitis from bland thrombosis in the portal vein. Therefore, knowledge of DWI findings to conventional imaging findings of diffusion-restricted non-neoplastic conditions in the hepatobiliary and pancreatic regions helps establishing a correct diagnosis.

Pancreatic adenocarcinoma: MRI conspicuity and pathologic correlations

PURPOSE

To identify the MRI sequences producing the greatest pancreatic adenocarcinoma conspicuity and to assess correlations linking MRI signal intensity and apparent diffusion coefficient to histopathological findings.

METHODS

We retrospectively included 22 patients with pancreatic adenocarcinoma who underwent MRI (1.5 or 3 T) before surgical resection. Fat-suppressed (FS) T1- and T2-weighted sequences; 3D FS dynamic T1-weighted gadolinium-enhanced gradient-echo (GRE) imaging at the arterial, portal, and delayed phases; and diffusion-weighted imaging (DWI) with b values of 600-800 s/mm(2) were reviewed. On each sequence, we assessed tumor conspicuity both qualitatively (3-point scale) and quantitatively (tumor-to-proximal and -distal pancreas contrast ratios), and we performed paired Wilcoxon tests to compare these data across sequences. We evaluated correlations between histopathological characteristics and MRI features.

RESULTS

21/22 (95%) tumors were hypointense by 3D FS T1 GRE arterial phase imaging, which produced the greatest tumor conspicuity (p ≤ 0.02). By DWI, 5/20 (25%) of tumors were isointense. The correlation between size by histology and MRI was strongest with DWI. A progressive enhancement pattern was associated with extensive and dense fibrous stroma (p ≤ 0.03).

CONCLUSIONS

3D FS T1 GRE arterial phase imaging produces greater pancreatic adenocarcinoma conspicuity compared to DWI but underestimates tumor size. DWI provides the best size evaluation but fails to delineate the tumor in one-fourth of cases.

Pancreatic ductal adenocarcinoma and chronic mass-forming pancreatitis: Differentiation with dual-energy MDCT in spectral imaging mode

OBJECTIVE

To investigate the value of dual-energy MDCT in spectral imaging in the differential diagnosis of chronic mass-forming chronic pancreatitis (CMFP) and pancreatic ductal adenocarcinoma (PDAC) during the arterial phase (AP) and the pancreatic parenchymal phase (PP).

MATERIALS AND METHODS

Thirty five consecutive patients with CMFP (n=15) or PDAC (n=20) underwent dual-energy MDCT in spectral imaging during AP and PP. Iodine concentrations were derived from iodine-based material-decomposition CT images and normalized to the iodine concentration in the aorta. The difference in iodine concentration between the AP and PP, contrast-to-noise ratio (CNR) and the slope K of the spectrum curve were calculated.

RESULTS

Normalized iodine concentrations (NICs) in patients with CMFP differed significantly from those in patients with PDAC during two double phases (mean NIC, 0.26±0.04 mg/mL vs. 0.53±0.02 mg/mL, p=0.0001; 0.07±0.02 mg/mL vs. 0.28±0.04 mg/mL, p=0.0002, respectively). There were significant differences in the value of the slope K of the spectrum curve in two groups during AP and PP (K(CMFP)=3.27±0.70 vs. K(PDAC)=1.35±0.41, P=0.001, and K(CMFP)=3.70±0.17 vs. K(PDAC)=2.16±0.70, p=0.003, respectively). CNRs at low energy levels (40-70 keV) were higher than those at high energy levels (80-40 keV).

CONCLUSION

Individual patient CNR-optimized energy level images and the NIC can be used to improve the sensitivity and the specificity for differentiating CMFP from PDAC by use of dual-energy MDCT in spectral imaging with fast tube voltage switching.

Differentiation of pancreatobiliary-type from intestinal-type periampullary carcinomas using 3.0T MRI

PURPOSE

To differentiate pancreatobiliary-type from intestinal-type periampullary carcinomas using combined magnetic resonance cholangiopancreatography (MRCP), contrast-enhanced MRI, and diffusion-weighted imaging (DWI).

MATERIALS AND METHODS

MRI (3.0T) results of 41 patients with pathologically confirmed periampullary carcinoma were retrospectively assessed. Two radiologists, blinded to histologic type of each tumor, evaluated image findings independently. MRCP image features, enhancement pattern, and apparent diffusion coefficient (ADC) values were analyzed. Independent-sample t-test, chi-square, or Fisher's exact test were used to determine differential image findings between the pancreatobiliary-type and the intestinal-type group. Cohen's κ statistic or interclass correlation coefficient (ICC) were used to evaluate interobserver agreement between two observers. Univariate and multiple logistic regression analysis were performed to identify MRI features with predictive values.

RESULTS

On the basis of hematoxylin-eosin staining, 27 patients were classified as having pancreatobiliary-type carcinomas, and 14 patients the intestinal type. The pancreatobiliary-type carcinomas more commonly showed progressive enhancement than the intestinal type (P = 0.003). The minimum ADC (ADCmin ) value of the pancreatobiliary-type group ([0.95 ± 0.21] × 10(-3) mm(2) /s) was significantly lower than the intestinal-type group ([1.10 ± 0.25] × 10(-3) mm(2) /s) (P = 0.047). For interobserver agreement, the κ values and ICCs for all parameters exceeded 0.8, indicating almost perfect agreement. At multiple logistic regression analysis, the enhancement pattern was the only significant independent predictor (P = 0.011, odds ratio [OR] = 0.105). When the enhancement pattern and ADCmin were used in combination, we could identify 70.4% of pancreatobiliary-type and 78.6% of intestinal-type carcinomas.

CONCLUSION

Progressive enhancement and low ADCmin values suggest a pancreatobiliary-type periampullary carcinoma.

Establishment of optimal scan delay for multi-phase computed tomography using bolus-tracking technique in canine pancreas

To establish a protocol for a multi-phase computed tomography (CT) of the canine pancreas using the bolus-tracking technique, dynamic scan and multi-phase CT were performed in six normal beagle dogs. The dynamic scan was performed for 60 sec at 1-sec intervals after the injection (4 ml/sec) of a contrast medium, and intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were measured. The multi-phase CT with 3 phases was performed three times using a bolus-tracking technique. Scan delays were 0, 15 and 30 in first multi-phase scan; 5, 20 and 35 in second multi-phase scan; and 10, 25 and 40 sec in third multi-phase scan, respectively. Attenuation values and contrast enhancement pattern were analyzed from the aorta, pancreas and portal vein. The intervals from aortic enhancement appearance to aortic, pancreatic parenchymal and portal vein peaks were 3.8 ± 0.7, 8.7 ± 0.9 and 13.3 ± 1.5 sec, respectively. The maximum attenuation values of the aorta, pancreatic parenchyma and portal vein were present at scan sections with no scan delay, a 5-sec delay and a 10-sec delay, respectively. When a multi-phase CT of the canine pancreas is triggered at aortic enhancement appearance using a bolus-tracking technique, the recommended optimal delay times of the arterial and pancreatic parenchymal phases are no scan delay and 5 sec, respectively.

Differentiation of pancreatic ductal adenocarcinoma from other neoplastic solid pancreatic lesions: a tertiary oncology center experience

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC), pancreatic neuroendocrine tumors (pNET), and metastatic lesions (pMET) are the most common neoplastic solid pancreatic lesions (SPLs). Early diagnosis enables prompt treatment.

OBJECTIVE

To identify factors differentiating PDAC from non-PDAC lesions and assess the accuracy of EUS-guided FNA.

DESIGN AND SETTING

Retrospective tertiary center.

PATIENTS AND INTERVENTION

Consecutive patients referred for EUS evaluation of SPLs from 2004 to 2011.

MAIN OUTCOME MEASUREMENTS

Pretest (preceding EUS-guided FNA [EUS-FNA]) predictors of PDAC among neoplastic SPLs and accuracy of EUS-FNA.

RESULTS

A total of 1333 EUS scans with 1108 EUS-FNAs were performed for pancreatic lesions. Of the 672 patients with neoplastic SPLs, 528 had PDAC and 144 non-PDAC. The sensitivity, specificity, positive predictive value, and accuracy of EUS-FNA for the diagnosis of PDAC were 97.3%, 99.3%, 99.8%, and 97.8%, respectively. Years of EUS experience significantly correlated with fewer needle passes (Rs = -0.18, P < .001). Controlling for all potential confounders, multivariable regression analysis demonstrated that patients with PDAC compared with pNETs and pMETs were older (odds ratio [OR] 4.42; 95% confidence interval [CI], 2.1-9.5; P < .001), had weight loss (OR 3.0; 95% CI, 1.6-5.4; P < .001), hyperbilirubinemia (OR 3.7; 95% CI, 1.8-7.5; P < .001), elevated CA19-9 (OR 6.9; 95% CI, 2.4-20.3; P < .01), evidence of arterial invasion (OR 6.5; 95% CI, 2.7-15.4; P < .001), and PD dilation (OR 3.3; 95% CI, 1.8-5.9; P < .001).

LIMITATIONS

Retrospective design, single center.

CONCLUSIONS

When evaluating neoplastic SPLs, demographic, clinical, laboratory, and imaging characteristics can reliably discern and suggest PDAC. In addition, EUS-FNA is exceedingly sensitive and specific for PDAC.

Use of diffusion-weighted MRI to differentiate chronic pancreatitis from pancreatic cancer

OBJECTIVE

The purpose of this study was to compare diffusion-weighted MRI (DWI) and conventional (non-DWI) MRI sequences in differentiating mass-forming chronic pancreatitis from pancreatic cancer.

MATERIALS AND METHODS

A retrospective cohort study included 36 patients who underwent pancreatic resection for pancreatic cancer (n = 13) and chronic pancreatitis (n = 23) after preoperative MRI with DWI. Two independent reviewers assessed the DW images for signal intensity and apparent diffusion coefficient (ADC) values. Four weeks later, they reviewed the other MR images for size of mass, double-duct sign, pancreatic duct cutoff, and perivascular soft-tissue cuffing. A score for conventional MRI was given with 1 meaning definitely benign and 5 meaning definitely malignant. Univariate and multivariate analyses and receiver operating characteristic (ROC) curve analysis were performed with surgical pathologic examination as the reference standard.

RESULTS

The only finding that differentiated the two groups was the presence of a well-defined mass, favoring the diagnosis of cancer (p = 0.02, p < 0.01). There was no significant difference between the two groups in signal intensity on DW images (p = 0.82, p = 0.85) or ADC (p = 0.51, p = 0.76). Double-duct sign, pancreatic duct cutoff, and perivascular soft-tissue cuffing were not useful in differentiating the two groups. The areas under the ROC curve were 0.873 and 0.878 for the conventional MRI scores, compared with 0.602 and 0.552 for ADC measurements (p = 0.02, p = 0.008).

CONCLUSION

The addition of DWI to conventional MRI does not facilitate differentiation of pancreatic cancer from chronic pancreatitis.

The heparin-binding protein interactome in pancreatic diseases

BACKGROUND

The cellular microenvironment plays an important role in the regulation of homoeostasis and is a source of potential biomarkers and drug targets. In a genome-wide analysis the extracellular proteins that bind to heparin (HBPs) have been shown to form highly modular and interconnected extracellular protein regulatory networks. Using a systems biology approach, we have investigated the role of HBP networks in the normal pancreas and pancreatic digestive diseases.

METHODS

Lists of mRNAs encoding for HBPs associated with the normal pancreas (NP), acute pancreatitis (AP), chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) were obtained using public databases and publications. Networks of the putative protein interactomes derived from mRNA expression data of HBPs were built and analysed using cluster analysis, gene ontology term enrichment and canonical pathways analysis.

RESULTS

The extracellular heparin-binding putative protein interactomes in the pancreas were better connected than their non heparin-binding counterparts, having higher clustering coefficients in the normal pancreas (0.273), acute pancreatitis (0.457), chronic pancreatitis (0.329) and pancreatic ductal adenocarcinoma (0.269). 'Hepatic Fibrosis/Hepatic Stellate Cell Activation' appears to be a significant canonical pathway in pancreatic homoeostasis in health and disease with a large number of important HBPs.

CONCLUSIONS

Our analyses clearly demonstrate that HBPs form disease-specific and highly connected networks that can be explored for potential biomarkers and as collective drug targets via the modification of heparin binding properties.

Correlation of apparent diffusion coefficient measured by diffusion-weighted MRI and clinicopathologic features in pancreatic cancer patients

BACKGROUND/PURPOSE

The aim of this study was to evaluate the clinical usefulness of diffusion-weighted magnetic resonance imaging (DWI) in patients with pancreatic cancer by comparing the apparent diffusion coefficient (ADC) value with clinicopathologic features.

METHODS

Twenty-two consecutive patients (12 men, 10 women; mean age 64.4 years) with pancreatic cancer underwent DWI before surgery. We retrospectively investigated the correlations between tumor ADC value and clinicopathologic features.

RESULTS

Apparent diffusion coefficient value was significantly lower for pancreatic cancer than for noncancerous tissue (P < 0.001). Receiver operating characteristic analysis yielded an optimal ADC cutoff value of 1.21 × 10(-3) mm(2)/s to distinguish pancreatic cancer from noncancerous tissue. There was a significant negative correlation between ADC value and tumor size (r = -0.59, P = 0.004) and between ADC value and number of metastatic lymph nodes (r = -0.56, P = 0.007). Tumors with low ADC value had a significant tendency to show high portal venous system invasion (P = 0.02) and extrapancreatic nerve plexus invasion (P = 0.01).

CONCLUSIONS

Apparent diffusion coefficient value appears to be a promising parameter for detecting pancreatic cancer and evaluating the degree of malignancy of pancreatic cancer.

Paraduodenal pancreatitis: clinical performance of MR imaging in distinguishing from carcinoma

PURPOSE

To evaluate the diagnostic performance of contrast material-enhanced magnetic resonance (MR) imaging for distinguishing paraduodenal pancreatitis (PDP) from pancreatic head duct adenocarcinoma (CA) in patients with diagnoses confirmed by histopathologic analysis.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and is HIPAA compliant. Between July 2007 and July 2010, 47 patients who underwent Whipple procedure and MR imaging less than 60 days before surgery were identified retrospectively. Two relatively inexperienced fellowship trainees with 9 months of body fellowship training were asked to record the presence or absence of three MR imaging features: focal thickening of the second portion of the duodenum; abnormal enhancement of the second portion of the duodenum; and cystic focus in the expected region of the accessory pancreatic duct. Strict criteria for diagnosis of PDP included presence of all three imaging features. Any case that did not fulfill the criteria was classified as CA. Sensitivity, specificity, positive predictive value, and negative predictive value for characterization of PDP was calculated for each reader with 95% confidence intervals. A κ test assessed level of agreement between readers.

RESULTS

Each reader correctly categorized 15 of 17 (88.2%) PDP cases when all three imaging criteria were met. Alternatively, 26 of 30 (86.7%) pancreatic duct CA were correctly categorized as inconsistent with PDP. Four patients with histopathologic diagnosis of CA were incorrectly classified as PDP by each reader. Agreement between the two readers showed substantial κ agreement for the diagnosis of PDP and differentiation from pancreatic duct CA.

CONCLUSION

Contrast-enhanced MR imaging may help accurately identify PDP and distinguish it from CA when strict diagnostic criteria are followed.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13112056/-/DC1.

A solid pancreatic mass: tumour or inflammation?

The prognosis for pancreatic cancer is poor, and early diagnosis is essential for surgical management. By comparison with its classic form, the presence of acute or chronic inflammatory signs will hinder its detection and delay its diagnosis. The atypical forms of acute pancreatitis need to be known in order to detect patients who require additional morphological investigations to search for an underlying tumour. In contrast, pseudotumoral forms of inflammation (chronic pancreatitis, cystic dystrophy in heterotopic pancreas, autoimmune pancreatitis) may simulate a cancer, and make up 5-10% of the surgical procedures for suspected cancer. Faced with these pseudotumoral masses, interpretation relies on various differentiating signs and advances in imaging.

MRI of the pancreas: problem solving tool

Advances in MR hardware and pulse sequence design over the years have improved the quality and robustness of MR imaging of the pancreas. Today, MRI is an indispensible tool for studying the pancreas and can provide useful information not attainable with other noninvasive or minimally invasive imaging techniques. In the present review, specific cases are reviewed where the strengths of MRI demonstrate the utility of this imaging modality as a problem solving tool.

Randomized phase III multi-institutional study of TNFerade biologic with fluorouracil and radiotherapy for locally advanced pancreatic cancer: final results

PURPOSE

TNFerade biologic is a novel means of delivering tumor necrosis factor alpha to tumor cells by gene transfer. We herein report final results of the largest randomized phase III trial performed to date among patients with locally advanced pancreatic cancer (LAPC) and the first to test gene transfer against this malignancy.

PATIENTS AND METHODS

In all, 304 patients were randomly assigned 2:1 to standard of care plus TNFerade (SOC + TNFerade) versus standard of care alone (SOC). SOC consisted of 50.4 Gy in 28 fractions with concurrent fluorouracil (200 mg/m(2) per day continuous infusion). TNFerade was injected intratumorally before the first fraction of radiotherapy each week at a dose of 4 × 10(11) particle units by using either a percutaneous transabdominal or an endoscopic ultrasound approach. Four weeks after chemoradiotherapy, patients began gemcitabine (1,000 mg/m(2) intravenously) with or without erlotinib (100 to 150 mg per day orally) until progression or toxicity.

RESULTS

The analysis included 187 patients randomly assigned to SOC + TNFerade and 90 to SOC by using a modified intention-to-treat approach. Median follow-up was 9.1 months (range, 0.1 to 50.5 months). Median survival was 10.0 months for patients in both the SOC + TNFerade and SOC arms (hazard ratio [HR], 0.90; 95% CI, 0.66 to 1.22; P = .26). Median progression-free survival (PFS) was 6.8 months for SOC + TNFerade versus 7.0 months for SOC (HR, 0.96; 95% CI, 0.69 to 1.32; P = .51). Among patients treated on the SOC + TNFerade arm, multivariate analysis showed that TNFerade injection by an endoscopic ultrasound-guided transgastric/transduodenal approach rather than a percutaneous transabdominal approach was a risk factor for inferior PFS (HR, 2.08; 95% CI, 1.06 to 4.06; P = .032). The patients in the SOC + TNFerade arm experienced more grade 1 to 2 fever and chills than those in the SOC arm (P < .001) but both arms had similar rates of grade 3 to 4 toxicities (all P > .05).

CONCLUSION

SOC + TNFerade is safe but not effective for prolonging survival in patients with LAPC.

Imaging of pancreatic cancer: An overview

Pancreatic cancer (PaCa) is the fourth leading cause of cancer-related death in the United States. The median size of pancreatic adenocarcinoma at the time of diagnosis is about 31 mm and has not changed significantly in last three decades despite major advances in imaging technology that can help diagnose increasingly smaller tumors. This is largely because patients are asymptomatic till late in course of pancreatic cancer or have nonspecific symptoms. Increased awareness of pancreatic cancer amongst the clinicians and knowledge of the available imaging modalities and their optimal use in evaluation of patients suspected to have pancreatic cancer can potentially help in diagnosing more early stage tumors. Another major challenge in the management of patients with pancreatic cancer involves reliable determination of resectability. Only about 10% of pancreatic adenocarcinomas are resectable at the time of diagnosis and would potentially benefit from a R0 surgical resection. The final determination of resectability cannot be made until late during surgical resection. Failure to identify unresectable tumor pre-operatively can result in considerable morbidity and mortality due to an unnecessary surgery. In this review, we review the relative advantages and shortcomings of imaging modalities available for evaluation of patients with suspected pancreatic cancer and for preoperative determination of resectability.

Diffusion-weighted imaging of biliopancreatic disorders: Correlation with conventional magnetic resonance imaging

Diffusion-weighted magnetic resonance imaging (DWI) is a well established method for the evaluation of intracranial diseases, such as acute stroke. DWI for extracranial application is more difficult due to physiological motion artifacts and the heterogeneous composition of the organs. However, thanks to the newer technical development of DWI, DWI has become increasingly used over the past few years in extracranial organs including the abdomen and pelvis. Most previous studies of DWI have been limited to the evaluation of diffuse parenchymal abnormalities and focal lesions in abdominal organs, whereas there are few studies about DWI for the evaluation of the biliopancreatic tract. Although further studies are needed to determine its performance in evaluating bile duct, gallbladder and pancreas diseases, DWI has potential in the assessment of the functional information on the biliopancreatic tract concerning the status of tissue cellularity, because increased cellularity is associated with impeded diffusion, as indicated by a reduction in the apparent diffusion coefficient. The detection of malignant lesions and their differentiation from benign tumor-like lesions in the biliopancreatic tract could be improved using DWI in conjunction with findings obtained with conventional magnetic resonance cholagiopancreatography. Additionally, DWI can be useful for the assessment of the biliopancreatic tract in patients with renal impairment because contrast-enhanced computed tomography or magnetic resonance scans should be avoided in these patients.

Distinguishing pancreatic cancer from chronic pancreatitis and healthy individuals by (1)H nuclear magnetic resonance-based metabonomic profiles

OBJECTIVES

To develop a noninvasive and accessible diagnostic method for pancreatic cancer (PC).

DESIGN AND METHODS

We presented a metabolomic method, pattern recognition techniques applied to (1)H nuclear magnetic resonance ((1)H NMR) spectra, to investigate the plasma metabolites obtained from 19 patients with PC, 20 patients with chronic pancreatitis (CP) and 20 healthy individuals.

RESULTS

Metabolic changes associated with PC included abnormal amino acid and lipid metabolism, and possible multiple metabolic syndrome. PC elevated plasma levels of N-acetyl glycoprotein (NAG), dimethylamine (DMA), very low density lipoprotein (VLDL), and acetone, and reduced levels of 3-hydroxybutyrate, lactate, high density lipoprotein (HDL), low density lipoprotein (LDL), citrate, alanine, glutamate, glutamine, histidine, isoleucine, lysine, and valine. These metabolites could be a biomarker group for PC that distinguishes between PC and CP patients and healthy individuals.

CONCLUSIONS

NMR-based metabonomic strategy appears as a promising approach for distinguishing pancreatic cancer and identifying new strategies for prevention or therapy in the clinical practice.

Multimodality imaging of neoplastic and nonneoplastic solid lesions of the pancreas

Solid lesions of the pancreas represent a heterogeneous group of entities that can be broadly classified as either neoplastic or nonneoplastic. Neoplastic lesions include pancreatic adenocarcinoma, pancreatic neuroendocrine tumor, solid pseudopapillary tumor, pancreatoblastoma, pancreatic lymphoma, metastases to the pancreas, and rare miscellaneous neoplasms. Nonneoplastic lesions include focal pancreatitis, fatty infiltration-replacement, intrapancreatic accessory spleen, congenital anomalies such as prominent pancreatic lobulation and bifid pancreatic tail (pancreatic bifidum), and rare miscellaneous lesions (eg, pancreatic sarcoidosis, Castleman disease of the pancreas). A variety of imaging modalities are available for assessing these solid lesions, including ultrasonography (US), computed tomography (CT), magnetic resonance imaging, endoscopic US, and hybrid nuclear imaging techniques such as single photon emission computed tomography-CT and positron emission tomography-CT, each of which has its own strengths and limitations. Accurate diagnosis can be challenging, and use of a multimodality imaging approach is often helpful in equivocal or complex cases. Knowledge of relevant clinical information and key radiologic features is essential for confident lesion characterization and differentiation.

Advances in diagnosis, treatment and palliation of pancreatic carcinoma: 1990-2010

Several advances in genetics, diagnosis and palliation of pancreatic cancer (PC) have occurred in the last decades. A multidisciplinary approach to this disease is therefore recommended. PC is relatively common as it is the fourth leading cause of cancer related mortality. Most patients present with obstructive jaundice, epigastric or back pain, weight loss and anorexia. Despite improvements in diagnostic modalities, the majority of cases are still detected in advanced stages. The only curative treatment for PC remains surgical resection. No more than 20% of patients are candidates for surgery at the time of diagnosis and survival remains quite poor as adjuvant therapies are not very effective. A small percentage of patients with borderline non-resectable PC might benefit from neo-adjuvant chemoradiation therapy enabling them to undergo resection; however, randomized controlled studies are needed to prove the benefits of this strategy. Patients with unresectable PC benefit from palliative interventions such as biliary decompression and celiac plexus block. Further clinical trials to evaluate new chemo and radiation protocols as well as identification of genetic markers for PC are needed to improve the overall survival of patients affected by PC, as the current overall 5-year survival rate of patients affected by PC is still less than 5%. The aim of this article is to review the most recent high quality literature on this topic.

Staging cancer of the pancreas

Pancreatic carcinoma is the fourth cause of death from cancer in the United States, with a survival rate at 5 years of less than 5%. About 60% of tumors originate at the head of the pancreas, 15% in the body, 5% in the tail; 20% are diffuse within the pancreas. This article discusses the imaging and staging of pancreatic cancer.

Contrast enhanced endoscopic ultrasound: More than just a fancy Doppler

Contrast enhanced endoscopic ultrasound (CEUS) is a new modality that takes advantage of vascular structure and blood flow to distinguish different clinical entities. Contrast agents are microbubbles that oscillate when exposed to ultrasonographic waves resulting in characteristic acoustic signals that are then converted to colour images. This permits exquisite imaging of macro- and microvasculature, providing information to help delineate malignant from non-malignant processes. The use of CEUS may significantly increase the sensitivity and specificity over conventional endoscopic ultrasound. Currently available contrast agents are safe, with infrequent adverse effects. This review summarizes the theory and technique behind CEUS and the current and future clinical applications.

PET and PET/CT for pancreatic malignancies

FDG PET imaging is useful for preoperative diagnosis of pancreatic carcinoma in patients with suspected pancreatic cancer in whom CT fails to identify a discrete tumor mass or in whom FNAs are nondiagnostic. FDG PET imaging is useful for M staging and restaging by detecting CT occult metastatic disease, allowing noncurative resection to be avoided in this group of patients. FDG PET can differentiate post-therapy changes from recurrence and holds promise for monitoring neoadjuvant chemoradiation therapy. The technique is less useful in periampullary carcinoma and marginally helpful in staging except for M staging. As with other malignancies, FDG PET is complementary to morphologic imaging with CT, therefore, integrated PET/CT imaging provides optimal images for interpretation and thus more optimal patient care.

Evidence-based imaging of pancreatic malignancies

A high-quality pancreatic protocol computed tomography (CT) is the primary imaging modality for diagnosing and staging pancreatic malignancy. The main limitation of CT is the lack of sensitivity for early pancreatic lesions. Endoscopic ultrasound (EUS) provides an excellent complement to CT for both diagnosis and staging of pancreatic cancer, and allows easy access for needle aspiration and tissue diagnosis. Magnetic resonance (MR) can be helpful for evaluating small hepatic nodules or cystic lesions of the pancreas, but in general, the role of MR and positron emission tomography remains limited to special situations when the results of CT and EUS are equivocal.

Pancreatic adenocarcinoma tumor grade determination using contrast-enhanced magnetic resonance imaging

OBJECTIVES

To determine whether the degree of enhancement of pancreatic adenocarcinoma visualized on arterial phase gadolinium-enhanced magnetic resonance imaging (MRI) correlates with the histopathological tumor grade.

METHODS

Thirty-nine patients with pancreatic adenocarcinoma had MRI within 14 days before tumor resection. Gadolinium-chelate-enhanced (Gd) 3-dimensional gradient echo images were acquired including the arterial phase. Tumor imaging patterns on the arterial phase images were classified for low, moderate, or high degree of enhancement and compared against conventional histological grading.

RESULTS

Based on histological grading, there were 12 poorly differentiated, 2 poorly to moderately differentiated, 22 moderately differentiated, and 3 well-differentiated adenocarcinomas. There was agreement between the MRI arterial enhancement pattern and histological grading in 30 of 39 cases. The mean size of tumors grouped by enhancement pattern or grade was not significantly different between groups. Although minor discordance was found in 9 of the 39 cases, statistical analysis showed agreement between the degree of arterial enhancement on MRI and histological tumor differentiation; the Cohen's kappa value was 0.64 with a 95% confidence interval of 0.46-0.83.

CONCLUSIONS

Pancreatic adenocarcinoma arterial phase enhancement correlates with the histological grade of differentiation.

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.

Autoimmune pancreatitis: imaging findings on contrast-enhanced MR, MRCP and dynamic secretin-enhanced MRCP

PURPOSE

This study retrospectively determined magnetic resonance (MR), MR cholangiopancreatography (MRCP) and secretin-MRCP findings in patients with autoimmune pancreatitis (AIP).

MATERIALS AND METHODS

The MR examinations of 28 patients with histopathologically proven AIP were reviewed. In 14 cases, secretin-enhanced MRCP was performed. The observers evaluated pancreatic parenchymal enlargement, signal intensity abnormalities, enhancement, vascular involvement, bile-duct diameter and main pancreatic duct (MPD) narrowing (diffuse/focal/segmental). After secretin administration, the presence of the "duct-penetrating" sign was evaluated.

RESULTS

MR imaging showed diffuse pancreatic enlargement in 8/28(29%) cases, focal pancreatic enlargement in 16/28 (57%) cases and no enlargement in 4/28 (14%) cases. The alteration of pancreatic signal intensity was diffuse in 8/28 (29%) cases (eight diffuse AIP) and focal in 20/28 (71%) cases (20 focal AIP). Delayed pancreatic enhancement was present in all AIP, with peripheral rim of enhancement in 8/28 (29%) AIP (1/8 diffuse, 7/20 focal); vascular encasement was present in 7/28 (25%) AIP (1/8 diffuse, 6/20 focal); distal common bile duct narrowing was present in 12/28(43%) AIP (5/8 diffuse, 7/20 focal). MRCP showed MPD narrowing in 17/28 (61%) AIP (4/8 diffuse, 15/20 focal), MPD dilation in 8/28(29%) AIP (3/8 diffuse, 5/20 focal) and normal MPD in 1/8 diffuse AIP. Secretin-MRCP showed the duct-penetrating sign in 6/14(43%) AIP (one diffuse AIP with MPD segmental narrowing, five focal AIP with MPD focal narrowing), demonstrating integrity of the MPD.

CONCLUSIONS

Delayed enhancement and MPD stenosis are suggestive for AIP on MR and MRCP imaging. Secretin-enhanced MRCP is a problem-solving tool in the differential diagnosis between focal AIP and ductal adenocarcinoma.

EUS/EUS-FNA for suspected pancreatic cancer: influence of chronic pancreatitis and clinical presentation with or without obstructive jaundice on performance characteristics

BACKGROUND

The clinical utility of EUS-FNA is debated in patients with obstructive jaundice (ObJ) because of a very high pretest probability of pancreatobiliary malignancy (PBM) and biliary stent-induced inflammation that can potentially confound EUS-FNA diagnosis. EUS-FNA also has lower accuracy in patients with underlying chronic pancreatitis (CP).

OBJECTIVE

Our purpose was to determine the clinical value of EUS-FNA for PBM diagnosis based on clinical presentation and presence of CP.

DESIGN

Retrospective analysis of prospective database.

SETTING

University hospital.

PATIENTS

Patients who underwent EUS-FNA from 2002 to 2006 for suspected PBM based on (1) ObJ with biliary stricture or a mass lesion or (2) abnormal pancreatic imaging by CT/MRI: a focal pancreatic "mass" lesion; dilated pancreatic duct +/- common bile duct; or an enlarged head of pancreas.

INTERVENTIONS

EUS was performed with a radial echoendoscope followed by a linear echoendoscope if a focal pancreatic lesion was identified. Fine-needle aspirates were assessed immediately by an attending cytopathologist.

MAIN OUTCOME MEASUREMENTS

(1) Prevalence of cancer and (2) performance characteristics of EUS-FNA.

RESULTS

PBM was diagnosed in 73.9% of patients with ObJ and biliary stricture or pancreatic mass, in 49.6% of patients with pancreatic mass, and in 7.0% of patients with an enlarged head of pancreas or dilated pancreatic duct +/- common bile duct. The prevalence of PBM was lower in all 3 presentations with associated CP. Both CP and presentation with ObJ lowered performance characteristics of EUS-FNA, but CP did so only in the subset of patients with ObJ. All except 1 false-negative diagnoses were due to cytologic misinterpretation.

LIMITATION

Retrospective design.

CONCLUSION

Among patients with suspected PBM, the accuracy of EUS-FNA is significantly lower only in a subset of patients with ObJ with underlying CP, largely as a result of difficulty in cytologic interpretation.

Differential diagnosis of groove pancreatic carcinomas vs. groove pancreatitis: usefulness of the portal venous phase

PURPOSE

To clarify if the portal venous phase is helpful for the differential diagnosis of groove pancreatic carcinomas and groove pancreatitis.

MATERIALS AND METHODS

MDCT and MRI of groove pancreatic carcinomas (n=7) and groove pancreatitis (n=15) were retrospectively reviewed by two radiologists independently. The signal intensity on T2-weighted images was subjectively assessed. The presence or absence of common bile duct (CBD) and main pancreatic duct (MPD) strictures, calcifications, and cystic lesions was evaluated. Additionally, the appearance of groove pancreatic carcinoma and that of groove pancreatitis in the portal venous phase on dynamic MDCT and MRI were compared.

RESULTS

There were no significant differences in the signal intensity on T2-weighted images and in the presence or absence of CBD and MPD strictures, calcifications, and cystic lesions between groove pancreatic carcinomas and groove pancreatitis. However, patchy focal enhancement in the portal venous phase was more commonly observed in groove pancreatitis than groove pancreatic carcinoma (Reviewers 1 and 2: 14/15 [93.3%] vs. 1/7 [14.3%], P<0.0001). In addition, peripheral enhancement was only seen in groove pancreatic carcinomas (Reviewer 1: 4/7 [57.1%] vs. 0/15 [0%], P<0.005, and Reviewer 2: 3/7 [42.9%] vs. 0/15 [0%], P<0.05).

CONCLUSION

The portal venous phase may be helpful for the differential diagnosis of groove pancreatic carcinomas and groove pancreatitis.