Pancreatic duct stenosis: Differential diagnosis between malignant and benign conditions at secretin-enhanced MRCP

Pancreatic tail cancer in the setting of pancreatitis with a review of the literature: A case report

Environmental risk factors for pancreatic cancer include acute and chronic pancreatitis, obesity, and tobacco use. Differentiating a pancreatic neoplasm in a patient with pancreatitis can be challenging due to their similar presentations. A 57-year-old African American man with a history of congestive heart failure, pancreatitis, and incomplete pancreas divisum presented with an epigastric abdominal pain that radiated to his back. Imaging showed necrotizing pancreatitis, a developing splenic infarct, and a mass at the pancreas tail. The patient was discharged with pain medications and was recommended follow-up imaging after resolution of his pancreatitis. He was readmitted to the emergency department 2 weeks later with recurrent acute abdominal pain. Computed tomography scan of abdomen and pelvis followed by magnetic resonance imaging and endoscopic ultrasound revealed an infiltrative pancreatic tail mass. Biopsy of the mass confirmed a locally advanced pancreatic tail adenocarcinoma. Chronic pancreatitis is associated with pancreatic cancer. Practitioners should be aware of the co-existence of chronic pancreatitis and pancreatic cancer, and the initial steps to evaluate a malignancy in chronic pancreatitis.

Pancreatic Cancer in Chronic Pancreatitis: Pathogenesis and Diagnostic Approach

Chronic pancreatitis is one of the main risk factors for pancreatic cancer, but it is a rare event. Inflammation and oncogenes work hand in hand as key promoters of this disease. Tobacco is another co-factor. During alcoholic chronic pancreatitis, the cumulative risk of cancer is estimated at 4% after 15 to 20 years. This cumulative risk is higher in hereditary pancreatitis: 19 and 12% in the case of PRSS1 and SPINK1 mutations, respectively, at an age of 60 years. The diagnosis is difficult due to: (i) clinical symptoms of cancer shared with those of chronic pancreatitis; (ii) the parenchymal and ductal remodeling of chronic pancreatitis rendering imaging analysis difficult; and (iii) differential diagnoses, such as pseudo-tumorous chronic pancreatitis and paraduodenal pancreatitis. Nevertheless, the occurrence of cancer during chronic pancreatitis must be suspected in the case of back pain, weight loss, unbalanced diabetes, and jaundice, despite alcohol withdrawal. Imaging must be systematically reviewed. Endoscopic ultrasound-guided fine-needle biopsy can contribute by targeting suspicious tissue areas with the help of molecular biology (search for KRAS, TP53, CDKN2A, DPC4 mutations). Short-term follow-up of patients is necessary at the clinical and paraclinical levels to try to diagnose cancer at a surgically curable stage. Pancreatic surgery is sometimes necessary if there is any doubt.

Standardization of MRI Screening and Reporting in Individuals With Elevated Risk of Pancreatic Ductal Adenocarcinoma: Consensus Statement of the PRECEDE Consortium

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with a dismal survival rate. Screening the general population for early detection of PDAC is not recommended, but because early detection improves survival, high-risk individuals, defined as those meeting criteria based on a family history of PDAC and/or the presence of known pathogenic germline variant genes with PDAC risk, are recommended to undergo screening with MRI and/or endoscopic ultrasound at regular intervals. The Pancreatic Cancer Early Detection (PRECEDE) Consortium was formed in 2018 and is composed of gastroenterologists, geneticists, pancreatic surgeons, radiologists, statisticians, and researchers from 40 sites in North America, Europe, and Asia. The overarching goal of the PRECEDE Consortium is to facilitate earlier diagnosis of PDAC for high-risk individuals to increase survival of the disease. A standardized MRI protocol and reporting template are needed to enhance the quality of screening examinations, improve consistency of clinical management, and facilitate multiinstitutional research. We present a consensus statement to standardize MRI screening and reporting for individuals with elevated risk of pancreatic cancer.

Diagnostic Accuracy of Magnetic Resonance Cholangiopancreatography to Detect Benign and Malignant Biliary Strictures

Background:

Magnetic resonance cholangiopancreatography (MRCP) is a noninvasive method to detect pancreaticobiliary strictures. In this study, we aimed to evaluate the diagnostic performance of MRCP and detect sensitive and specific radiologic features in distinguishing malignant and benign pathologies.

Materials and Methods:

In this study, 50 patients with biliary obstruction and a confirmed diagnosis using histopathology were included. The pathologies were evaluated using MRCP which were categorized into malignant and benign strictures. The etiology of strictures was detected using histopathology and endoscopic retrograde cholangiopancreatography. The diagnostic performance of MRCP was calculated using SPSS software. P < 0.05 was considered statistically significant.

Results:

Of 50 patients, 23 patients (46%) had malignant strictures based on MRCP and histopathology. The sensitivity and specificity of MRCP to detect malignancy were 95.7% and 96.3%, respectively. The most sensitive MRCP features to detect malignancy were upstream biliary duct dilation, abrupt tapering, and the presence of a solid mass with sensitivity 100%, 95.7%, and 78.2%, respectively. The malignancy rate was significantly higher in the strictures with length >11.5 mm or wall thickness >2.75 mm (P < 0.05).

Conclusion:

MRCP is a sensitive method to differentiate malignant lesions from benign pathologies. A long and thick stricture with the presence of a solid mass, upstream biliary duct dilation, and abrupt tapering is highly suggestive of malignancy.

Multimodel magnetic resonance imaging of mass-forming autoimmune pancreatitis: differential diagnosis with pancreatic ductal adenocarcinoma

PURPOSE

To assess the value of the multimodel magnetic resonance imaging (MRI), including unenhanced images, dynamic contrast-enhanced MRI (DCE-MRI), MR-cholangiopancreatography (MRCP), and diffusion-weighted imaging (DWI), in differentiation of mass-forming autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).

METHODS

Twelve patients with mass-forming AIP and 30 with PDAC were included. All patients underwent unenhanced MRI, DCE-MRI, DWI, and MRCP. Relevant values including sensitivity and specificity of the imaging features and their diagnostic performance for predicting mass-forming AIP were analyzed.

RESULTS

Several statistically significant MR findings and quantitative indexes differentiating mass-forming AIP from PDAC, including multiplicity, irregularity or conformation, capsule-like rim enhancement, absence of internal cystic or necrotic portion, homogeneous enhancement during pancreatic, venous, and delayed phases, skipped stricture or stricture of MPD, absence of side branch dilation, maximum upstream MPD diameter < 2.4 mm, ContrastUP > 0.739, ContrastAP > 0.710, ContrastPP > 0.879, and ContrastVP or ContrastDP > 0.949, indicated mass-forming AIP (P < 0.05). The apparent diffusion coefficient (ADC) value was also significantly lower in mass-forming AIP compared to that in PDAC (P = 0.006). The cutoff value of ADC for distinguishing mass-forming AIP from PDAC was 1.099 × 10-3 mm2/s.

CONCLUSION

Multimodel MRI, including unenhanced MRI, DCE-MRI with DWI and MRCP can provide qualitative and quantitative information about mass-forming AIP characterization. Multimodel MRI are valuable for differentiating mass-forming AIP from PDAC.

Comprehensive review of diagnostic modalities for early chronic pancreatitis

Chronic pancreatitis (CP) is a progressive condition caused by several factors and characterised by pancreatic fibrosis and dysfunction. However, CP is difficult to diagnose at an early stage. Various advanced methods including endoscopic ultrasound based elastography and confocal laser endomicroscopy have been used to diagnose early CP, although no unified diagnostic standards have been established. In the past, the diagnosis was mainly based on imaging, and no comprehensive evaluations were performed. This review describes and compares the advantages and limitations of the traditional and latest diagnostic modalities and suggests guidelines for the standardisation of the methods used to diagnose early CP.

Mass-forming pancreatitis versus pancreatic ductal adenocarcinoma: CT and MR imaging for differentiation

Various inflammatory abnormalities of the pancreas can mimic pancreatic ductal adenocarcinoma (PDAC) at cross-sectional imaging. Misdiagnosis of PDAC at imaging may lead to unnecessary surgery. On the other hand, chronic pancreatitis (CP) bears a greater risk of developing PDAC during the course of the disease. Thus, differentiation between mass-forming chronic pancreatitis (MFCP) and PDAC is important to avoid unnecessary surgery and not to delay surgery of synchronous PDAC in CP.

Imaging features such as the morphology of the mass including displacement of calcifications, presence of duct penetrating, sign appearance of duct stricturing, presence or absence of vessel encasement, apparent diffusion coefficient (ADC) value and intravoxel incoherent motion (IVIM) at diffusion-weighted imaging (DWI), fluorodeoxyglucose (FDG) uptake in PET/CT, and mass perfusion parameters can help to differentiate between PDAC and MFCP. Correct interpretation of imaging features can appropriately guide biopsy and surgery, if necessary. This review summarizes the relevant computed tomography (CT) and magnetic resonance imaging (MRI) features that can help the radiologist to come to a confident diagnosis and to guide further management in equivocal cases.

International consensus guidelines on surveillance for pancreatic cancer in chronic pancreatitis. Recommendations from the working group for the international consensus guidelines for chronic pancreatitis in collaboration with the International Association of Pancreatology, the American Pancreatic Association, the Japan Pancreas Society, and European Pancreatic Club

BACKGROUND

Patients with chronic pancreatitis (CP) have an increased risk of pancreatic cancer. We present the international consensus guidelines for surveillance of pancreatic cancer in CP.

METHODS

The international group evaluated 10 statements generated from evidence on 5 questions relating to pancreatic cancer in CP. The GRADE approach was used to evaluate the level of evidence available per statement. The working group voted on each statement for strength of agreement, using a nine-point Likert scale in order to calculate Cronbach's alpha reliability coefficient.

RESULTS

In the following domains there was strong consensus: (1) the risk of pancreatic cancer in affected individuals with hereditary pancreatitis due to inherited PRSS1 mutations is high enough to justify surveillance; (2) the risk of pancreatic cancer in patients with CP associated with SPINK1 p. N34S is not high enough to justify surveillance; (3) surveillance should be undertaken in pancreatic specialist centers; (4) surveillance should only be introduced after the age of 40 years and stopped when the patient would no longer be suitable for surgical intervention. All patients with CP should be advised to lead a healthy lifestyle aimed at avoiding risk factors for progression of CP and pancreatic cancer. There was only moderate or weak agreement on the best methods of screening and surveillance in other types of environmental, familial and genetic forms of CP.

CONCLUSIONS

Patients with inherited PRSS1 mutations should undergo surveillance for pancreatic cancer, but the best methods for cancer detection need further investigation.

Chronic Pancreatitis or Pancreatic Tumor? A Problem-solving Approach

Certain inflammatory pancreatic abnormalities may mimic pancreatic ductal adenocarcinoma at imaging, which precludes accurate preoperative diagnosis and may lead to unnecessary surgery. Inflammatory conditions that may appear masslike include mass-forming chronic pancreatitis, focal autoimmune pancreatitis, and paraduodenal pancreatitis or "groove pancreatitis." In addition, obstructive chronic pancreatitis can mimic an obstructing ampullary mass or main duct intraductal papillary mucinous neoplasm. Secondary imaging features such as the duct-penetrating sign, biliary or main pancreatic duct skip strictures, a capsulelike rim, the pancreatic duct-to-parenchyma ratio, displaced calcifications in patients with chronic calcific pancreatitis, the "double duct" sign, and vessel encasement or displacement can help to suggest the possibility of an inflammatory mass or a neoplastic process. An awareness of the secondary signs that favor a diagnosis of malignant or inflammatory lesions in the pancreas can help the radiologist to perform the differential diagnosis and determine the degree of suspicion for malignancy. Repeat biopsy or surgical resection may be necessary to achieve an accurate diagnosis and prevent unnecessary surgery for inflammatory conditions. Online supplemental material and DICOM image stacks are available for this article. ^©RSNA, 2019.

Primary lymphomas of the intraabdominal solid organs and the gastrointestinal tract: spectrum of imaging findings with histopathological confirmation

Unlike nodal lymphoma, primary lymphomas of the intraabdominal organs are uncommon neoplasms whose diagnosis may be challenging in certain clinical circumstances. Despite this difficulty for imaging diagnosis, there are several imaging features on ultrasonography, computed tomography, magnetic resonance imaging, and positron emission tomography that may suggest the correct diagnosis. The scope of this review is to describe and illustrate the imaging features of primary lymphoma of intraabdominal organs providing clues to the diagnosis, together with their pathological correlations.

Type 1 and Type 2 Autoimmune Pancreatitis: Distinctive Clinical and Pathological Features, But Are There Any Differences at Magnetic Resonance? Experience From a Referral Center

OBJECTIVES

This study aimed to evaluate magnetic resonance imaging findings of autoimmune pancreatitis (AIP) and to find radiological patterns that could differentiate type 1 and type 2 AIP.

METHODS

Eighty-four patients with diagnosis of AIP were enrolled. Image analysis included pancreatic signal intensity abnormalities, enhancement pattern, extrapancreatic involvement, and main pancreatic duct alterations.

RESULTS

Pancreatic parenchyma resulted in hypointensity on T1-weighted images in 65 (98.5%) of 66 cases in type 1 and in 17 (94.5%) of 18 in type 2 (P > 0.05) and in hyperintensity on T2-weighted images in 41 (62%) of 66 and in 15 (83.4%) of 18, respectively (P > 0.05). Lesions were hypovascular in 64 (97%) of 66 cases in type 1 and in 16 (88.9%) of 18 in type 2 with delayed contrast retention in 56 (84.8%) of 66 and in 17 (94.5%) of 18, respectively (P > 0.05). Autoimmune cholangitis was found in 29 (43.9%) of 66 patients with type 1 and in 3 (16.7%) of 18 with type 2 (P = 0.02); renal involvement was observed in 20 (30.3%) of 66 and 1 (5.5%) of 18, respectively (P = 0.02). Both subtypes presented with multiple stenoses (P > 0.05). Dilation of upstream duct was more frequent in type 1 (P = 0.02).

CONCLUSIONS

Magnetic resonance imaging is useful in detecting extrapancreatic involvement, typically seen in type 1. Dilation of the upstream duct suggests type 1 AIP.

Guidelines for the Diagnostic Cross Sectional Imaging and Severity Scoring of Chronic Pancreatitis

The paper presents the international guidelines for imaging evaluation of chronic pancreatitis. The following consensus was obtained: Computed tomography (CT) is often the most appropriate initial imaging modality for evaluation of patients with suspected chronic pancreatitis (CP) depicting most changes in pancreatic morphology. CT is also indicated to exclude other potential intraabdominal pathologies presenting with symptoms similar to CP. However, CT cannot exclude a diagnosis of CP nor can it be used to exclusively diagnose early or mild disease. Here magnetic resonance imaging (MRI) and MR cholangiopancreatography (MRCP) is superior and is indicated especially in patients where no specific pathological changes are seen on CT. Secretin-stimulated MRCP is more accurate than standard MRCP in the depiction of subtle ductal changes. It should be performed after a negative MRCP, when there is still clinical suspicion of CP. Endoscopic ultrasound (EUS) can also be used to diagnose parenchymal and ductal changes mainly during the early stage of the disease. No validated radiological severity scoring systems for CP are available, although a modified Cambridge Classification has been used for MRCP. There is an unmet need for development of a new and validated radiological CP severity scoring system based on imaging criteria including glandular volume loss, ductal changes, parenchymal calcifications and parenchymal fibrosis based on CT and/or MRI. Secretin-stimulated MRCP in addition, can provide assessment of exocrine function and ductal compliance. An algorithm is presented, where these imaging parameters can be incorporated together with clinical findings in the classification and severity grading of CP.

Management of delayed stenosis of pancreatico-enteric anastomosis following pancreatoduodenectomy

Stenosis of the pancreatico-enteric anastomosis following pancreatoduodenectomy (PD), a late post-operative complication that is seen mainly after PD for diseases with good prognosis, has been reported in less than 3% of cases in the literature. Most often asymptomatic, pancreatic-enteric anastomotic stenosis can lead to pancreatitis, pain or pancreatic insufficiency. Symptomatic stenosis is difficult to treat and its management is not standardized. Magnetic resonance cholangiopancreatography is the best investigation to confirm the diagnosis of stenosis. The Endoscopic UltraSonography (EUS) « rendezvous » technique, associating an endoscopic approach and EUS-guided puncture of the main pancreatic duct, has been available since 2010. Of note, however, the failure rate of the EUS series is as high as 25%, leading to repeat procedures. Surgical reconstruction of the anastomosis has been reported with good results in terms of morbidity. Surgical re-do of the pancreatico-enteric anastomosis for stenosis following PD carries a low risk of pancreatic fistula (around 5%) and an overall morbidity rate of around 20%.

CT imaging of primary pancreatic lymphoma: experience from three referral centres for pancreatic diseases

Purpose

To describe CT characteristics of primary pancreatic lymphoma (PPL), a rare disease with features in common with adenocarcinoma.

Materials and methods

Fourteen patients were enrolled. CT: unenhanced scan, contrast-enhanced pancreatic and venous phases. Image analysis: tumour location; peri-pancreatic vessel encasement; necrosis; enlarged lymph nodes; fat stranding; enlarged bile duct and pancreatic duct; neoplasm longest dimension, volume and density.

Results

Histopathological diagnoses: follicular non-Hodgkin lymphoma (5/14), diffuse large B-cell lymphoma (6/14) and high-grade B-cell lymphoma not otherwise specified (3/14). Six of 14 PPLs were located in the pancreatic head and 7/14 in the body-tail; 1/14 involved the whole gland. In 5/14 cases the superior mesenteric artery and vein were encased; splenic vein and artery encasement was depicted in 2 PPLs. Necrosis was present in 2/14. Enlarged retroperitoneal lymph nodes were found in 11 cases and fat stranding in all patients. The bile duct was dilated in six cases and the pancreatic duct in five. Mean neoplasm longest diameter and volume were 8.05 cm and 210.8 cm³. Mean tumour attenuation values were 39.1 HU at baseline, 60.6 HU in the pancreatic phase and 71.4 HU in the venous phase.

Conclusions

PPL presents as a large mass lesion with delayed homogeneous enhancement; peri-pancreatic fat stranding and vessel encasement are present, without vascular infiltration. Pancreatic duct dilatation is rare.

Key points

• Primary pancreatic lymphoma (PPL) is a rare haematological disease

• PPL presents imaging features in common with pancreatic carcinoma but also some distinctive findings

• The majority of PPLs are large lesions with delayed homogeneous enhancement

• Peri-pancreatic fat stranding and vessel encasement are common in PPL

• Vascular infiltration and pancreatic duct dilatation are rare in PPL

Dynamic non-invasive ASL perfusion imaging of a normal pancreas with secretin augmented MR imaging

OBJECTIVES

To investigate prospectively the repeatability of pancreatic perfusion measurements using arterial spin labelling (ASL) and to determine the increase in perfusion due to secretin stimulation.

MATERIAL AND METHODS

An (FAIR)-TrueFISP ASL sequence was applied to determine the perfusion of the pancreatic head in a 3T MRI scanner. Ten healthy volunteers (four men, six women: mean age 28.5 ± 4.6 years; age range 25-40 years) were investigated twice within 1 week. The inter-individual variability was calculated using the standard deviation. Intra-individual agreement between the first and second scan was estimated using the Pearson correlation coefficient. A paired Wilcoxon rank-sum test was used to compare perfusion at baseline (BL) and during secretin stimulation.

RESULTS

The mean BL perfusion of the pancreatic head was 285 ± 96 mL/100 g/min with an intra-individual correlation coefficient of 0.67 (strong) for repeated measurements. Secretin stimulation led to a significant increase (by 81%) in perfusion of the pancreatic head to 486 ±156 mL/100 g/min (p=0.002) with an intra-individual correlation of 0.29 (weak). A return to BL values was observed after 239 ± 92 s with a moderate intra-individual correlation coefficient of 0.42 for repeat measurements.

CONCLUSION

Dynamic non-invasive ASL imaging of the pancreas permitted quantification of pancreatic perfusion in a clinically applicable setting.

KEY POINTS

• ASL imaging of the pancreas permitted quantification of pancreatic perfusion • Secretin stimulation led to a significant increase in pancreatic perfusion • The intra-individual correlation coefficient for baseline perfusion was strong for repeated measurements.

Paraduodenal pancreatitis as a mimicker of pancreatic adenocarcinoma: MRI evaluation

PURPOSE

To evaluate the MRI features of paraduodenal pancreatitis (PDP) and to define useful signs to differentiate PDP from pancreatic ductal adenocarcinoma (PDAC).

MATERIAL AND METHODS

We reviewed the MRI scans of 56 patients, 28 affected by PDP and 28 by PDAC, all pathologically proven. The following parameters were evaluated: signal intensity of the lesion on T1-, T2-WI, DWI (b800) and after contrast medium administration; presence of cysts; dilation of common hepatic duct and main pancreatic duct; focal thickening of the second portion of the duodenum; maximum diameter and volume of the lesion.

RESULTS

Both PDPs and PDACs were more frequently hypointense on T1-WI, iso-hyperintense on T2-WI, hypointense in the pancreatic phase and iso-hypointense in the venous phase (p>0.05); in the delayed phase most PDP were hyperintense (p=0.0031); on DWI 71.4% PDPs were isointense and all PDACs were hyperintense (p=0.0041). Cystic components were present in 85.7% PDPs (p=0.0011); double duct sign was present in 50% PDACs (p=0.0048); focal thickening of the duodenum was depicted in 89.3 PDPs (p=0.0012). PDPs were larger than PDACs (p=0.0003).

CONCLUSION

The most suggestive signs of PDP are: signal hyperintensity in the delayed phase, isointensity on DWI, presence of cysts, focal thickening of the duodenum and large size of the lesion.