Chronic pancreatitis:Pain and computed tomography/magnetic resonance imaging findings

Chronic pancreatitis(CP)is a fibroinflammatory disease characterized by irreversible destruction of pancreatic tissue.With the development of the disease,it may lead to exocrine and/or endocrine insufficiency.CP is one of the common diseases that cause abdominal pain,which will not get permanent spontaneous relief as the disease evolves.The American College of Gastroenterology clinical guidelines recommend computed tomography or magnetic resonance imaging as the first-line examination for the diagnosis of CP.CP common imaging findings include pancreatic atrophy,irregular dilatation of the pancreatic duct,calcification of pancreatic parenchyma,pancreatic duct stones,etc.In clinical practice,whether any correlations between CP-induced abdominal pain patterns(no pain/constant/intermittent pain)and corresponding imaging findings present are not well known.Therefore,this review aims to comprehensively sort out and analyze the relevant information by collecting lots of literature on this field,so as to construct a cross-bridge between the clinical manifestations and imaging manifestations of CP patients.Also,it provides an imaging basis and foundation for the classification and diagnosis of abdominal pain types in clinical CP patients.

Prediction of the lymphatic,microvascular,and perineural invasion of pancreatic neuroendocrine tumors using preoperative magnetic resonance imaging

BACKGROUND Significant correlation between lymphatic,microvascular,and perineural invasion(LMPI)and the prognosis of pancreatic neuroendocrine tumors(PENTs)was confirmed by previous studies.There was no previous study reported the relationship between magnetic resonance imaging(MRI)parameters and LMPI.AIM To determine the feasibility of using preoperative MRI of the pancreas to predict LMPI in patients with non-functioning PENTs(NFPNETs).METHODS A total of 61 patients with NFPNETs who underwent MRI scans and lymphadenectomy from May 2011 to June 2018 were included in this retrospective study.The patients were divided into group 1(n=34,LMPI negative)and group 2(n=27,LMPI positive).The clinical characteristics and qualitative MRI features were collected.In order to predict LMPI status in NF-PNETs,a multivariate logistic regression model was constructed.Diagnostic performance was evaluated by calculating the receiver operator characteristic(ROC)curve with area under ROC,sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV)and accuracy.RESULTS There were significant differences in the lymph node metastasis stage,tumor grade,neuron-specific enolase levels,tumor margin,main pancreatic ductal dilatation,common bile duct dilatation,enhancement pattern,vascular and adjacent tissue involvement,synchronous liver metastases,the long axis of the largest lymph node,the short axis of the largest lymph node,number of the lymph nodes with short axis>5 or 10 mm,and tumor volume between two groups(P<0.05).Multivariate analysis showed that tumor margin(odds ratio=11.523,P<0.001)was a predictive factor for LMPI of NF-PNETs.The area under the receiver value for the predictive performance of combined predictive factors was 0.855.The sensitivity,specificity,PPV,NPV and accuracy of the model were 48.1%(14/27),97.1%(33/34),97.1%(13/14),70.2%(33/47)and 0.754,respectively.CONCLUSION Using preoperative MRI,ill-defined tumor margins can effectively predict LMPI in patients with NF-PNETs.

Gd-EOB-DTPA-enhanced magnetic resonance imaging for bile duct intraductal papillary mucinous neoplasms

AIM: To investigate gadolinium-ethoxybenzyldiethylenetriamine-pentaacetic acid(Gd-EOB-DTPA)-enhanced magnetic resonance imaging(MRI) of intraductal papillary mucinous neoplasms of the bile duct(IPMN-B). METHODS: The imaging findings of five cases of IPMN-B which were pathologically confirmed at our hospital between March 2012 and May 2013 were retrospectively analyzed. Three of these cases were diagnosed by duodenal endoscopy and biopsy pathology, and two cases were diagnosed by surgical pathology. All five patients underwent enhanced and non-enhanced computed tomography(CT), magnetic resonance cholangiopancreatography, and Gd-EOB-DTPA-enhanced MRI; one case underwent both Gd-EOB-DTPA-enhanced MRI and positron emission tomography-CT. The clinical data and imaging results for these cases were compared and are presented.RESULTS: Conventional imaging showed diffusedilatation of bile ducts and multiple intraductal polypoid and papillary neoplasms or serrated changes along the bile ducts. In two cases, Gd-EOB-DTPA-enhanced MRI revealed dilated biliary ducts and intraductal tumors, as well as filling defects caused by mucin in the dilated bile ducts in the hepatobiliary phase. GdEOB-DTPA-enhanced MRI in one case clearly showed a low-signal tumor in the hepatobiliary phase, similar to what was seen by positron emission tomographyCT. In two patients, routine inspection was unable to discern whether the lesions were inflammation or tumors. However, Gd-EOB-DTPA-enhanced MRI revealed a pattern of gradual enhancement during the hepatobiliary phase, and the signal intensity of the lesions was lower than the surrounding liver parenchyma, suggesting tissue inflammation in both cases, which were confirmed by surgical pathology. CONCLUSION: Gd-EOB-DTPA-enhanced MRI reveals the intraductal mucin component of IPMN-B in some cases and the extent of tumor infiltration beyond the bile ducts in invasive cases.

Common bile duct diameter in an asymptomatic population:A magnetic resonance imaging study

AIM: To measure the common bile duct(CBD) diameter by magnetic resonance cholangiopancreatography(MRCP) in a large asymptomatic population and analyze its some affecting factors.METHODS: This study included 862 asymptomatic subjects who underwent MRCP. The CBD diameter was measured at its widest visible portion on regular endexpiration MRCP for all subjects. Among these 862 subjects, 221 volunteers also underwent end-inspiration MRCP to study the effect of respiration on the CBD diameter. The age, sex, respiration, body length, body weight, body mass index(BMI), portal vein diameter(PVD), length of the extrahepatic duct and CBD, cystic junction radial orientation and location were recorded. The subjects were divided into 7 groups according to age. All of the above factors were compared with the CBD diameter on end-expiration MRCP.RESULTS: Among the 862 subjects, the CBD diameter was 4.13 ± 1.11 mm(range, 1.76-9.45 mm) and was correlated with age(r = 0.484; P < 0.05), with a dilation of 0.033 mm per year. The upper limit of the 95% reference range was 5.95 mm, resulting in a reasonable upper limit of 6 mm for the asymptomatic population. Respiration and other factors, including sex, body length, body weight, BMI, PVD, length of the extrahepatic duct and CBD, cystic junction radia orientation and location, were not related to the CBD diameter.CONCLUSION: We established a reference range for the CBD diameter on MRCP for an asymptomatic population. The CBD diameter is correlated with age. Respiration did not affect the non-dilated CBD diameter.

Multiparameter magnetic resonance imaging of liver fibrosis in a bile duct ligation mouse model

BACKGROUND Bile duct ligation(BDL)in animals is a classical method for mimicking cholestatic fibrosis.Although different surgical techniques have been described in rats and rabbits,mouse models can be more cost-effective and reproducible for investigating cholestatic fibrosis.Magnetic resonance imaging(MRI)has made great advances for noninvasive assessment of liver fibrosis.More comprehensive liver fibrotic features of BDL on MRI are important.However,the utility of multiparameter MRI to detect liver fibrosis in a BDL mouse model has not been assessed.AIM To evaluate the correlation between the pathological changes and multiparameter MRI characteristics of liver fibrosis in a BDL mouse model.METHODS Twenty-eight healthy adult male balb/c mice were randomly divided into four groups:sham,week 2 BDL,week 4 BDL,and week 6 BDL.Multiparameter MRI sequences,included magnetic resonance cholangiopancreatography,T1-weighted,T2-weighted,T2 mapping,and pre-and post-enhanced T1 mapping,were performed after sham and BDL surgery.Peripheral blood and liver tissue were collected after MRI.For statistical analysis,Student’s t-test and Pearson’s correlation coefficient were used.RESULTS Four mice died after BDL surgery;seven,six,five and six mice were included separately from the four groups.Signal intensities of liver parenchyma showed no difference on TI-and T2-weighted images.Bile duct volume,ΔT1 value,T2 value,and the rate of liver fibrosis increased steadily in week 2 BDL,week 4 BDL and week 6 BDL groups compared with those in the sham group(P<0.01).Alanine aminotransferase and aspartate transaminase levels initially surged after surgery,followed by a gradual decline over time.Strong correlations were found between bile duct volume(r=0.84),T2 value(r=0.78),ΔT1 value(r=0.62),and hepatic fibrosis rate(all P<0.01)in the BDL groups.CONCLUSION The BDL mouse model induces changes that can be observed on MRI.The MRI parameters correlate with the hepatic fibrosis rate and allow for detection of cholestatic fibrosis.

Magnetic resonance imaging biomarkers for pulsed focused ultrasound treatment of pancreatic ductal adenocarcinoma

BACKGROUND The robust fibroinflammatory stroma characteristic of pancreatic ductal adenocarcinoma(PDA)impedes effective drug delivery.Pulsed focused ultrasound(pFUS)can disrupt this stroma and has improved survival in an early clinical trial.Non-invasive methods to characterize pFUS treatment effects are desirable for advancement of this promising treatment modality in larger clinical trials.AIM To identify promising,non-invasive pre-clinical imaging methods to characterize acute pFUS treatment effects for in vivo models of PDA.METHODS We utilized quantitative magnetic resonance imaging methods at 14 tesla in three mouse models of PDA(subcutaneous,orthotopic and transgenic-KrasLSLG12D/+,Trp53LSL-R172H/+,Cre or“KPC”)to assess immediate tumor response to pFUS treatment(VIFU 2000 Alpinion Medical Systems;475 W peak electric power,1 ms pulse duration,1 Hz,duty cycle 0.1%)vs sham therapy,and correlated our results with histochemical data.These pFUS treatment parameters were previously shown to enhance tumor permeability to chemotherapeutics.T1 and T2 relaxation maps,high(126,180,234,340,549)vs low(7,47,81)b-value apparent diffusion coefficient(ADC)maps,magnetization transfer ratio(MTR)maps,and chemical exchange saturation transfer(CEST)maps for the amide proton spectrum(3.5 parts per million or“ppm”)and the glycosaminoglycan spectrum(0.5-1.5 ppm)were generated and analyzed pre-treatment,and immediately post-treatment,using ImageJ.Animals were sacrificed immediately following post-treatment imaging.The whole-tumor was selected as the region of interest for data analysis and subsequent statistical analysis.T-tests and Pearson correlation were used for statistical inference.RESULTS Mean high-b value ADC measurements increased significantly with pFUS treatment for all models.Mean glycosaminoglycan CEST and T2 measurements decreased significantly post-treatment for the KPC group.Mean MTR and amide CEST values increased significantly for the KPC group.Hyaluronic acid focal intensities in the treated regions were significantly lower following pFUS treatment for all animal models.The magnetic resonance imaging changes observed acutely following pFUS therapy likely reflect:(1)Sequelae of variable degrees of microcapillary hemorrhage(T1,MTR and amide CEST);(2)Lower PDA glycosaminoglycan content and associated water content(glycosaminoglycan CEST,T2 and hyaluronic acid focal intensity);and(3)Improved tumor diffusivity(ADC)post pFUS treatment.CONCLUSION T2,glycosaminoglycan CEST,and ADC maps may provide reliable quantitation of acute pFUS treatment effects for patients with PDA.

Effect of the extrahepatic bile duct anatomy on choledocholithiasis and its clinical significance

BACKGROUND A comprehensive understanding of the extrahepatic bile duct anatomy is vital to guide surgical procedures and perform endoscopic retrograde cholangiography.Anatomical irregularities within the extrahepatic bile duct may increase susceptibility to bile duct stones.AIM To investigate the anatomical risk factors associated with extrahepatic bile ducts in patients diagnosed with choledocholithiasis,with a specific focus on preventing stone recurrence after surgical intervention and endoscopic lithotomy.METHODS We retrospectively analyzed the medical records of 124 patients without choledocholithiasis and 108 with confirmed choledocholithiasis who underwent magnetic resonance cholangiopancreatography examinations at our center between January 2022 and October 2022.Logistic regression analyses were conducted to identify the anatomical risk factors influencing the incidence of common bile duct stones.RESULTS Multivariate logistic regression analysis revealed that several factors independently contributed to choledocholithiasis risk.Significant independent risk factors for choledocholithiasis were diameter of the common hepatic[adjusted odds ratio(aOR)=1.43,95%confidence interval(CI):1.07-1.92,adjusted P value=0.016]and common bile(aOR=1.68,95%CI:1.27-2.23,adjusted P value<0.001)ducts,length of the common hepatic duct(aOR=0.92,95%CI:0.84-0.99,adjusted P value=0.034),and angle of the common bile duct(aOR=0.92,95%CI:0.89–0.95,adjusted P value<0.001).The anatomical features of the extrahepatic bile duct were directly associated with choledocholithiasis risk.Key risk factors include an enlarged diameter of the common hepatic and bile ducts,a shorter length of the common hepatic duct,and a reduced angle of the common bile duct.

Acute pancreatitis:Structured report template of magnetic resonance imaging

Acute pancreatitis(AP)is a common acute abdomen disease of the digestive system.It has a potentially fatal risk because of its variable severity and various complications.With the widespread application of the Revised Atlanta Classification,new requirements for AP imaging reports are introduced.Experts in abdominal radiology and pancreatology in the United States published the first structured computed tomography reporting template for AP in 2020.However,there is no corresponding structured magnetic resonance imaging(MRI)reporting template globally.Therefore,this article focuses on the structured MRI report of AP images from our pancreatitis imaging center,which is intended to improve the systematic understanding of this disease and standardize the writing of MRI structured reports.In the meantime,we aim to promote the clinical diagnosis and assessment of MRI efficacy for AP and its multiple complications.It is further intended to facilitate academic exchanges and scientific research between different medical centers.

Magnetic resonance imaging for acute pancreatitis in type 2 diabetes patients

Type 2 diabetes mellitus(T2DM)and its complications have significantly increased the burden of mortality and disability globally,making diabetes one of the most dangerous and prevalent chronic diseases.Acute pancreatitis(AP)is one of the most frequent gastrointestinal causes for hospital admission,which is a common exocrine pancreatic inflammatory disease that can cause severe abdominal pain and multiple organ dysfunction.There is an inseparable relationship between AP and diabetes.Diabetes is a high risk factor of AP,and patients with AP can develop pancreatogenic diabetes.In T2DM patients,the incidence rate of AP is significantly higher than that of the general population,and the clinical symptoms are more severe,with the majority of cases being moderate to severe AP.This review briefly introduces the pathogenesis and clinical features of AP in T2DM patients,focusing on the magnetic resonance imaging(MRI)manifestations of AP in T2DM patients.Our aim is to evaluate the severity of AP in patients with T2DM by MRI,so as to help clinicians assess the patient's condition and prognosis.

Various diffusion magnetic resonance imaging techniques for pancreatic cancer

Pancreatic cancer is one of the most common malignanttumors and remains a treatment-refractory cancer with a poor prognosis. Currently, the diagnosis of pancreatic neoplasm depends mainly on imaging and which methods are conducive to detecting small lesions. Compared to the other techniques, magnetic resonance imaging(MRI) has irreplaceable advantages and can provide valuable information unattainable with other noninvasive or minimally invasive imaging techniques. Advances in MR hardware and pulse sequence design have particularly improved the quality and robustness of MRI of the pancreas. Diffusion MR imaging serves as one of the common functional MRI techniques and is the only technique that can be used to reflect the diffusion movement of water molecules in vivo. It is generally known that diffusion properties depend on the characterization of intrinsic features of tissue microdynamics and microstructure. With the improvement of the diffusion models, diffusion MR imaging techniques are increasingly varied, from the simplest and most commonly used technique to the more complex. In this review, the various diffusion MRI techniques for pancreatic cancer are discussed, including conventional diffusion weighted imaging(DWI), multi-b DWI based on intra-voxel incoherent motion theory, diffusion tensor imaging and diffusion kurtosis imaging. The principles, main parameters, advantages and limitations of these techniques, as well as future directions for pancreatic diffusion imaging are also discussed.

Pancreatic neuroendocrine neoplasms: Magnetic resonance imaging features according to grade and stage

AIMTo describe magnetic resonance (MR) imaging features of pancreatic neuroendocrine neoplasms (PanNENs) according to their grade and tumor-nodes-metastases stage by comparing them to histopathology and to determine the accuracy of MR imaging features in predicting their biological behavior.METHODSThis study was approved by our institutional review board; requirement for informed patient consent was waived due to the retrospective nature of the study. Preoperative MR examinations of 55 PanNEN patients (29 men, 26 women; mean age of 57.6 years, range 21-83 years) performed between June 2013 and December 2015 were reviewed. Qualitative and quantitative features were compared between tumor grades and stages determined by histopathological analysis.RESULTSIll defined margins were more common in G2-3 and stage III-IV PanNENs than in G1 and low-stage tumors (P < 0.001); this feature had high specificity in the identification of G2-3 and stage III-IV tumors (90.3% and 96%, 95%CI: 73.1-97.5 and 77.7-99.8). The mean apparent diffusion coefficient value was significantly lower in G2-3 and stage III-IV lesions compared to well differentiated and low-stage tumors (1.09 × 10-3 mm2/s vs 1.45 × 10-3 mm2/s and 1.10 × 10-3 mm2/s vs 1.53 × 10-3 mm2/s, P = 0.003 and 0.001). Receiving operator characteristic analysis determined optimal cut-offs of 1.21 and 1.28 × 10-3 mm2/s for the identification of G2-3 and stage III-IV tumors, with sensitivity and specificity values of 70.8/80.7% and 64.5/64% (95%CI: 48.7-86.6/60-92.7 and 45.4-80.2/42.6-81.3).CONCLUSIONMR features of PanNENs vary according to their grade of differentiation and their stage at diagnosis and could predict the biological behavior of these tumors.

Comparison of endoscopic ultrasound, computed tomography and magnetic resonance imaging in assessment of detailed structures of pancreatic cystic neoplasms

AIM To evaluate the advantages of endoscopic ultrasound(EUS) in the assessment of detailed structures of pancreatic cystic neoplasms(PCNs) compared to computed tomography(CT) and magnetic resonance imaging(MRI).METHODS All patients with indeterminate PCNs underwent CT, MRI, and EUS. The detailed information, including size, number, the presence of a papilla/nodule, the presence of a septum, and the morphology of the pancreatic duct of PCNs were compared among the three imaging modalities. The size of each PCN was determined using the largest diameter measured. A cyst consisting of several small cysts was referred to as a motherdaughter cyst. Disagreement among the three imaging modalities regarding the total number of mother cysts resulted in the assumption that the correct number was the one in which the majority of imaging modalities indicated.RESULTS A total of 52 females and 16 males were evaluated. The median size of the cysts was 42.5 mm by EUS, 42.0 mm by CT and 38.0 mm by MRI; there was no significant difference in size as assessed among the three imaging techniques. The diagnostic sensitivity and ability of EUS to classify PCNs were 98.5%(67/68) and 92.6%(63/68), respectively. These percentages were higher than those of CT(73.1%, P < 0.001; 17.1%, P < 0.001) and MRI(81.3%, P = 0.001; 20.3%, P < 0.001). EUS was also able to better assess the number of daughter cysts in mother cysts than CT(P = 0.003); however, there was no significant difference between EUS and MRI in assessing mother-daughter cysts(P = 0.254). The papilla/nodule detection rate by EUS was 35.3%(24/68), much higher than those by CT(5.8%, 3/52) and MRI(6.3%, 4/64). The detection rate of the septum by EUS was 60.3%(41/68), which was higher than those by CT(34.6%, 18/52) and by MRI(46.9%, 30/64); the difference between EUS and CT was significant(P = 0.02). The rate of visualizing the pancreatic duct using EUS was 100%, whereas using CT and MRI it was less than 10%.CONCLUSION EUS helps visualize the detailed structures of PCNs and has many advantages over CT and MRI. EUS is valuable in the diagnosis and assessment of PCNs.

Magnetic resonance cholangiopancreatography for the detection of pancreatic duct stones in patients with chronic pancreatitis

AIM:To assess the role of magnetic resonance cholangiopancreatography(MRCP) in detection of pancreatic duct stones(PDS) in patients with chronic pancreatitis(CP).METHODS:Clinical data of 78 CP patients who were treated at the First Affi liated Hospital of Xi'an Jiaotong University(China) between January 2004 and July 2008 were retrospectively analyzed.A predictive model of pancreatic duct stones was established through logistic regression and its effectiveness was verifi ed.Among these patients, MRCP was performed in 60 patients who served as a control group, while 44 patients with a higher predictive value than the entry threshold of the predictive model served as an experimental group.RESULTS:The positive rate of PDS in the 78 patients with CP was 19.2%(15/78).The predictive entry threshold of the predictive model was 5%(P < 0.05).The possibility of existence of PDS could be predicted according to the following 4 indexes:gastrointestinal symptoms, intermittent abdominal pain, diabetes mellitus(DM)/impaired glucose tolerance(IGT) and positive B-mode ultrasound results.The incidence of PDS in the experimental group was higher than that in the control group(P < 0.05).CONCLUSION:MRCP is strongly suggested for the detection of PDS in patients with gastrointestinal symptoms, intermittent abdominal pain, DM/IGT and positive B-mode ultrasound results.

Role of abdominal ultrasound for the surveillance follow-up of pancreatic cystic neoplasms: a cost-effective safe alternative to the routine use of magnetic resonance imaging

BACKGROUND Patients with pancreatic cystic neoplasms(PCN), without surgical indication at the time of diagnosis according to current guidelines, require lifetime imagebased surveillance follow-up. In these patients, the current European evidencedbased guidelines advise magnetic resonance imaging(MRI) scanning every 6 mo in the first year, then annually for the next five years, without reference to any role for trans-abdominal ultrasound(US). In this study, we report on our clinical experience of a follow-up strategy of image-based surveillance with US, and restricted use of MRI every two years and for urgent evaluation whenever suspicious changes are detected by US.AIM To report the results and cost-efficacy of a US-based surveillance follow-up for known PCNs, with restricted use of MRI.METHODS We retrospectively evaluated the records of all the patients treated in our institution with non-surgical PCN who received follow-up abdominal US and restricted MRI from the time of diagnosis, between January 2012 and January 2017. After US diagnosis and MRI confirmation, all patients underwent US surveillance every 6 mo for the first year, and then annually. A MRI scan was routinely performed every 2 years, or at any stage for all suspicious US findings.In this communication, we reported the clinical results of this alternative followup, and the results of a comparative cost-analysis between our surveillance protocol(abdominal US and restricted MRI) and the same patient cohort that has been followed-up in strict accordance with the European guidelines recommended for an exclusive MRI-based surveillance protocol.RESULTS In the 5-year period, 200 patients entered the prescribed US-restricted MRI surveillance follow-up. Mean follow-up period was 25.1 ± 18.2 mo. Surgery was required in two patients(1%) because of the appearance of suspicious features at imaging(with complete concordance between the US scan and the on-demand MRI). During the follow-up, US revealed changes in PCN appearance in 28 patients(14%). These comprised main pancreatic duct dilatation(n = 1), increased size of the main cyst(n = 14) and increased number of PNC(n = 13). In all of these patients, MRI confirmed US findings, without adding more information.The bi-annual MRI identified evolution of the lesions not identified by US in only11 patients with intraductal papillary mucinous neoplasms(5.5%), largely consisting of an increased number of very small PCN(P = 0.14). The overall mean cost of surveillance, based on a theoretical use of the European evidenced-based exclusive MRI surveillance in the same group of patients, would have been 1158.9± 798.6 € per patient, in contrast with a significantly lower cost of 366.4 ± 348.7 €(P < 0.0001) incurred by the US-restricted MRI surveillance used at our institution.CONCLUSION In patients with non-surgical PCN at the time of diagnosis, US surveillance could be a safe complementary approach to MRI, delaying and reducing the numbers of second level examinations and therefore reducing the costs.

Functional magnetic resonance imaging in an animal model of pancreatic cancer

AIM: To test the hypotheses that diffusion weighed (DW)and transcatheter intraarterial perfusion (TRIP)magnetic resonance imaging (MRI) can each be used to assess regional differences in tumor function in an animal pancreatic cancer model.METHODS: VX2 tumors were implanted in pancreata of 6 rabbits. MRI and digital subtraction angiography (DSA) were performed 3 wk following implantation. With a 2-French catheter secured in the rabbit's gastroduodenal artery, each rabbit was transferred to an adjacent 1.5T MRI scanner. DWand TRIP-MRI were performed to determine if necrotic tumor core could be differentiated from viable tumor periphery. For each, we compared mean differences between tumor core/ periphery using a 2-tailed paired t-test (α = 0.05). Imaging was correlated with histopathology. RESULTS: Tumors were successfully grown in all rabbits, confirmed by necropsy. On DW-MRI, mean apparent diffusion coeffi cient (ADC) value was higher in necrotic tumor core (2.1 ± 0.3 mm2/s) than in viable tumor periphery (1.4 ± 0.5 mm2/s) (P < 0.05). On TRIP-MRI, mean perfusion values was higher in tumor periphery (110 ± 47 relative units) than in tumor core (66 ± 31 relative units) (P < 0.001). CONCLUSION: Functional MRI can be used to differentiate necrotic from viable tumor cells in an animal pancreatic cancer model using ADC (DW-MRI) and perfusion (TRIP-MRI) values.

Application Progress of Intravoxel Incoherent Motion Diffusion Weighted Magnetic Resonance Imaging in Pancreatic Cancer

Intravoxel incoherent motion imaging (IVIM), on the traditional diffusion weighted imaging (DWI) technology, uses the biexponential model and adopts the multi-b-value analysis to obtain the perfusion information of water molecule diffusion and microcirculation without the use of contrast agent. It is more and more used in pancreatic diseases, which is of great significance for the diagnosis and identification of pancreatic cancer. This article will review the principles of IVIM imaging and its application in pancreatic diseases, especially in pancreatic cancer diagnosis, the prediction of pathological grade of pancreatic ductal adenocarcinoma, the judgment of lymph node metastasis, and differentiation of pathological classification.

Value of CA19-9, CA125 and CEA combined magnetic resonance imaging in the diagnosis of pancreatic cancer

Objective:To study the value of CA19-9, CA125 and CEA combined magnetic resonance imaging (MRI) in the diagnosis of pancreatic cancer, and to provide a reference for clinical diagnosis and treatment.Methods:A total of 110 cases of pancreatic cancer admitted to our hospital from November 2015 to November 2017 were selected as the observation group, and another 80 normal pancreas organizers who participated in the physical examination in the same period were selected as the control group. The change of magnetic resonance scanning parameters and serum CA19-9, CA125 and CEA detection were compared between the two groups of subjects at the same time, contrast scan and serum magnetic resonance detection of CA19-9, CA125 and CEA positive rate, and to evaluate the four alone and in combination with the diagnosis of pancreatic cancer specificity, sensitivity, negative predictive value and positive predictive value.Results:The T1WI of the observation group was low or slightly low signal, T2WI was slightly high signal, and the tumor of fat suppression sequence was low signal, which was in line with the typical characteristics of pancreatic cancer. The serum levels of CA19-9, CA125 and CEA in the observation group were significantly higher than those in the control group, and the difference was statistically significant. Compared with the two groups, the positive rates of MRI and serum CA19-9, CA125 and CEA in the observation group were higher than those in the control group, and the difference was statistically significant. The sensitivity and accuracy of MRI scan combined with three serological markers were higher than those of single detection. The specificity was between four.Conclusion: CA19-9, CA125 and CEA combined magnetic resonance imaging (MRI) have good sensitivity and accuracy in diagnosis of pancreatic cancer, but their specificity is common, which should be used for reference.

Magnetic resonance imaging for local complications of acute pancreatitis: A pictorial review

Acute pancreatitis is a common disease characterized by sudden upper abdominal pain and vomiting. Alcoholism and choledocholithiasis are the most common factors for this disease. The choice of treatment for acute pancreatitis might be affected by local complications, such as local hemorrhage in or around the pancreas, and peripancreatic infection or pseudoaneurysm. Diagnostic imaging modalities for acute pancreatitis have a significant role in confirming the diagnosis of the disease, helping detect the extent of pancreatic necrosis, and for diagnosing local complications. Magnetic resonance imaging (MRI) might be indicated in acute pancreatitis for detecting and characterizing local complications of acute pancreatitis that involve necrotic, hemorrhagic, infectious, vascular, and pseudocyst disorders. The general MRI sequences for pancreatitis require the combined use of T1-weighted, T2-weighted sequences, and magnetic resonance chol-angiopancreatography. For imaging of pancreatic necrosis, the combination of T1-weighted and T2-weighted findings with dynamic contrast-enhanced imaging gives a comprehensive evaluation of the extent of necrosis and full range of inflammatory extension. For imaging of infectious complications, dynamic contrast-enhanced examinations might help differentiate pancreatic cellulitis or abscesses, from pancreatic fluid collection or simple pseudocysts. For vascular abnormalities, the combination of cross-sectional pancreatic parenchyma imaging with MRA represents a single diagnostic modality for the full evaluation of peripancreatic artery and vein involvement, such as arterial pseudoaneurysms and venous thromboses. The purpose of this pictorial review is to examine the MRI appearances of various local complications of acute pancreatitis and to discuss the practical setup of MRI in local complications of acute pancreatitis.

Morphological and functional evaluation of chronic pancreatitis with magnetic resonance imaging

Magnetic resonance imaging(MRI)techniques for assessment of morphology and function of the pancreas have been improved dramatically the recent years and MRI is very often used in diagnosing and follow-up of chronic pancreatitis(CP)patients.Standard MRI including fat-suppressed T1-weighted and T2-weighted imaging techniques reveal decreased signal and glandular atrophy of the pancreas in CP.In contrast-enhanced MRI of the pancreas in CP the pancreatic signal is usually reduced and delayed due to decreased perfusion as a result of chronic inflammation and fibrosis.Thus,morphological changes of the ductal system can be assessed by magnetic resonance cholangiopancreatography(MRCP).Furthermore,secretin-stimulated MRCP is a valuable technique to evaluate side branch pathology and the exocrine function of the pancreas and diffusion weighted imaging can be used to quantify both parenchymal fibrotic changes and the exocrine function of the pancreas.These standard and advanced MRI techniques are supplementary techniques to reveal morphological and functional changes of the pancreas in CP.Recently,spectroscopy has been used for assessment of metabolite concentrations in-vivo in different tissues and may have the potential to offer better tissue characterization of the pancreas.Hence,the purpose of the present review is to provide an update on standard and advanced MRI techniques of the pancreas in CP.

Magnetic resonance imaging for acute pancreatitis

Acute pancreatitis is characterized by acute chemical injury of the pancreatic parenchyma and peripancreatic tissue.The increased frequency of death in acute pancreatitis is directly correlated with the degree and progress of pancreatic necrosis.Moreover,the occurrence of some local complications in acute pancreatitis,such as pancreatic hemorrhage,peripancreatic abscess or large pseudocyst,and pseudoaneurysm,could influence the choice of treatment for these patients.Magnetic resonance imaging(MRI) can be used to help evaluate the presence and degree of pancreatic necrosis,and is crucial for identifying complications of acute pancreatitis and predicting prognosis.The purpose of this article is to describe MRI techniques for acute pancreatitis,to review the spectrum of pancreatic and peripancreatic patterns,as well as to survey various complications secondary to acute pancreatitis on MRI.The role of MRI in the initial evaluation and staging of acute pancreatitis is emphasized.