HASTE MR cholangiopancreatography in the evaluation of intraductal papillary-mucinous tumors of the pancreas

Imaging features to distinguish malignant and benign branch-duct type intraductal papillary mucinous neoplasms of the pancreas: a meta-analysis

OBJECTIVE

To systematically determine the imaging findings for distinguishing malignant and benign branch-duct type intraductal papillary mucinous neoplasms (BD-IPMNs), including mixed type, and their diagnostic value through meta-analysis of published studies.

BACKGROUND

Management of BD-IPMNs, including mixed type, largely relies on imaging findings. The current knowledge on imaging findings to distinguish malignant and benign BD-IPMNs has weak evidence and is mostly from scattered individual retrospective studies.

METHODS

Thorough literature search in Ovid-MEDLINE and EMBASE databases was conducted to identify studies where findings of computed tomography, magnetic resonance imaging, and endoscopic ultrasonography of BD-IPMNs with or without main pancreatic duct (MPD) dilatation were correlated with surgical/pathological findings. Review of 1128 article candidates, including full-text review of 102 articles, identified 23 eligible articles with a total of 1373 patients for meta-analysis. Dichotomous data regarding distinction between malignant and benign BD-IPMNs were pooled using random effects model to obtain the diagnostic odds ratios (DORs) and their 95% confidence intervals (CIs) of various individual imaging findings for diagnosing malignant BD-IPMN.

RESULTS

Presence of mural nodules revealed the highest pooled DOR (95% CI) of 6.0 (4.1-8.8) followed by MPD dilatation [3.4 (2.3-5.2)], thick septum/wall [unadjusted, 3.3 (1.5-6.9); publication bias-adjusted, 2.3 (0.9-5.5)], and cyst size greater than 3 cm [2.3 (1.5-3.5)]. Multilocularity and multiplicity of the cystic lesions did not reveal statistically significant association with malignancy.

CONCLUSIONS

Presence of mural nodules should be regarded highly suspicious for malignancy warranting a surgical excision whereas cyst size greater than 3 cm, MPD dilatation (5-9 mm), or thick septum/wall may better be managed by careful observation and/or further evaluation.

Development of a novel fusion imaging technique in the diagnosis of hepatobiliary-pancreatic lesions

INTRODUCTION

Multi-row detector computed tomography (MDCT) and magnetic resonance cholangiopancreatography (MRCP) play an important role in the imaging diagnosis of hepatobiliary-pancreatic lesions. Here we investigated whether unifying the MDCT and MRCP images onto the same screen using fusion imaging could overcome the limitations of each technique, while still maintaining their benefits. Moreover, because reports of fusion imaging using MDCT and MRCP are rare, we assessed the benefits and limitations of this method for its potential application in a clinical setting.

METHODS

The patient group included 9 men and 11 women. Among the 20 patients, the final diagnoses were as follows: 10 intraductal papillary mucinous neoplasms, 5 biliary system carcinomas, 1 pancreatic adenocarcinoma and 5 non-neoplastic lesions. After transmitting the Digital Imaging and Communication in Medicine data of the MDCT and MRCP images to a workstation, we performed a 3-D organisation of both sets of images using volume rendering for the image fusion.

RESULTS

Fusion imaging enabled clear identification of the spatial relationship between a hepatobiliary-pancreatic lesion and the solid viscera and/or vessels. Further, this method facilitated the determination of the relationship between the anatomical position of the lesion and its surroundings more easily than either MDCT or MRCP alone.

CONCLUSION

Fusion imaging is an easy technique to perform and may be a useful tool for planning treatment strategies and for examining pathological changes in hepatobiliary-pancreatic lesions. Additionally, the ease of obtaining the 3-D images suggests the possibility of using these images to plan intervention strategies.

Interdisciplinary management of an intraductal papillary mucinous neoplasm of the pancreas

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is less common than classic invasive ductal adenocarcinoma of the pancreas but is being diagnosed with greater frequency since its clinicopathologic features are now clearly defined. Often multifocal in its existence along the pancreatic duct, IPMN is associated with a significant risk for recurrence and warrants vigilant surveillance, even after a margin-negative resection.

METHODS

The authors present a case highlighting important features in the diagnosis, workup, and management of IPMN. They also review existing literature highlighting epidemiology, findings of molecular studies, and current treatment recommendations.

RESULTS

Physicians and patients must carefully weigh the risks and benefits associated with treatment options. Limited resection in a patient with a high likelihood of multifocal disease preserves pancreatic parenchyma and reduces the risk of developing pancreatic endocrine and exocrine insufficiency. Though the risk of developing invasive cancer in the remnant is small, the prognosis is worse if it does develop. Conversely, total pancreatectomy eliminates the risk of future malignancy but involves life-long insulin and exogenous pancreatic enzyme dependence and significant associated morbidity.

CONCLUSIONS

Decision making for effective treatment of IPMN is complex and requires attention to detail by an interdisciplinary team with experience in the diagnosis and management of these tumors. Treatment must be individualized based on patient life expectancy in terms of remaining years and overall quality. Molecular profiling of these lesions may allow for more precise tailoring of treatment in the future.

Magnetic resonance cholangiopancreatography: current use and future applications

Magnetic resonance pancreatography (MRCP) is now established as a robust noninvasive tool for the evaluation of biliary and pancreatic pathology. Its diagnostic performance is comparable with endoscopic retrograde cholangiopancreatography without the associated risks. This article aims to familiarize the reader with the technique, clinical indications, and limitations of the investigation. Common pitfalls in interpretation also are addressed. Emerging applications and techniques are discussed that include recent advances in technology and the development of functional imaging.

CT vs MRCP: optimal classification of IPMN type and extent

INTRODUCTION

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are being diagnosed with increased frequency. CT scanning commonly serves as the primary imaging modality before surgery. We hypothesized MRCP provides better characterization of IPMN type/extent, which more closely matches actual pathology.

METHODS

Of 214 patients treated with IPMN (1991-2006), 30 had both preoperative CT and MRCP. Of these, 18 met imaging study criteria. Independent readers performed retrospective, blinded analyses using standardized criteria for IPMN type and extent.

RESULTS

A ductal connection was detected on 73% of MRCP scans and only 18% of CT. IPMN type was classified differently in seven (39%); four (22%) of which were read on CT as having main duct involvement where this was not appreciated on MRCP or found on surgical pathology. MRCP showed multifocal disease in 13(72%) versus only 9(50%) on CT. A different disease distribution was seen in 9(50%). Finally, 101 branch lesions were identified on MRCP compared to 46 on CT.

CONCLUSIONS

CT falls short of MRCP in detecting a ductal connection, estimating main duct involvement, and identification of small branch duct cysts. These factors influence diagnostic accuracy, cancer risk stratification and operative strategy. MRCP should be employed for optimal management of patients with IPMN.

Differentiation of intraductal papillary mucinous neoplasms from other pancreatic cystic masses: comparison of multirow-detector CT and MR imaging using ROC analysis

PURPOSE

To compare the diagnostic performance of multirow-detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the differentiation of intraductal papillary mucinous neoplasms (IPMNs) from other pancreatic cystic masses.

MATERIALS AND METHODS

A total of 53 patients with pathologically proven pancreatic cystic lesions who had undergone MDCT and MRI were included in this study. Two radiologists analyzed the morphologic features of the lesions and graded the lesion conspicuity on each examination. The readers assigned their confidence level regarding the differentiation of IPMN from other lesions and predicting ductal communication of the lesion. The radiologists' diagnostic confidence was compared using receiver operating characteristic (ROC) analysis.

RESULTS

The Az values for each observer for predicting ductal communication of the lesion and differentiating IPMN from other lesions were as follows: For MRI they were respectively 0.949 and 0.995 for reader 1, and 0.916 and 0.932 for reader 2. For MDCT they were respectively 0.790 and 0.875 for reader 1, and 0.774 and 0.850 for reader 2. In addition, for differentiating IPMNs from other lesions, MRI was significantly more accurate than MDCT (P < 0.05) for one observer, but for the other observer there was no significant difference between the two examinations (P = 0.059). For predicting ductal communication of the cystic lesions for both observers, MRI was significantly more accurate than MDCT (P < 0.05). The weighted kappa values indicate good agreement (kappa = 0.61) between observers for MDCT, and excellent agreement (kappa = 0.82) for MRI.

CONCLUSION

Pancreatic MRI shows better diagnostic performance than MDCT for differentiating IPMNs from other cystic lesions of the pancreas.

Collateral branches IPMTs: secretin-enhanced MRCP

Recently, the fantastic evolution of imaging modalities (especially MR, MDCT, EUS) has raised many issues regarding the correct classification of smaller and smaller lesions, their preoperative evaluations, and indications of most appropriate treatment. However, it is still debated which technique should be employed for the diagnosis and the follow-up of intraductal papillary mucinous tumours (IPMTs). Despite the superb spatial resolution of MDCT, nowadays most of the authors agree on considering MR with magnetic resonance cholangiopancreatography (MRCP) the imaging modality of choice in studying IPMTs. In particular, MRCP is rapid, non-invasive, and accurate in detecting, localizing, and correctly classifying IPMT. The diagnostic performance of MRCP is even improved after the introduction of secretin stimulation. In fact, dynamic MRCP studies after secretin administration, besides facilitating the depiction of the structural characteristics of the lesions, make easier the detection of the communicating duct of branch duct IPMTs with the main pancreatic duct, especially if the newest high resolution 3D heavily T2-weighted sequences are utilized. Secretin stimulation is also useful in the demonstration of early changes of associated chronic pancreatitis. Consequently, we believe that secretin-enhanced MRCP is the most suitable imaging modality in the diagnosis and follow-up of IPMTs of the collateral branches.

Intraductal papillary mucinous neoplasms of the pancreas: correlation of helical CT and dynamic MR imaging features with pathologic findings

BACKGROUND

We assessed the imaging features of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas paying special attention to underlying pancreatic fibrosis on three-phase helical computed tomography (CT) and dynamic magnetic resonance (MR) imaging.

METHODS

Sixteen patients with histopathologically proven IPMNs underwent three-phase helical CT and dynamic MR imaging.

RESULTS

IPMNs were seen as a cluster of cyst-like structures in branch duct (n = 5) and combined types (n = 10), and as a fusiform appearance in the main duct type (n = 1). IPMN shape was most easily visualized at the portal venous dominant phase or delayed phase owing to rim-like enhancement of the dilated ducts. Pathologically mild to severe fibrosis was seen on this enhanced rim replacing the surrounding pancreatic parenchyma. Communication between the dilated branch ducts and main pancreatic duct was identified in 15 patients on helical CT and 14 patients on dynamic MR imaging. In patients with fibrosis of pancreatic parenchyma surrounding this, communication was most easily visualized at the later phase on CT and MR imaging. Adenocarcinomas were depicted as papillary projections in eight of nine patients on CT and MR imaging. Invasion of the pancreatic parenchyma was seen in five of six patients as a solid mass in the pancreatic parenchyma. These masses were most easily visualized at the arterial dominant phase on both CT and MR imaging.

CONCLUSION

Three-phase helical CT and dynamic MR imaging were useful in the diagnosis of IPMN of the pancreas.

Magnetic resonance cholangiopancreatography: A useful tool in the evaluation of pancreatic and biliary disorders

Magnetic resonance cholangiopancreatography (MRCP) is being used with increasing frequency as a noninvasive alternative to diagnostic retrograde cholangiopancreatography (ERCP). The aim of this pictorial review is to demonstrate the usefulness of MRCP in the evaluation of pancreatic and biliary system disorders. Because the recently developed techniques allows improved spatial resolution and permits imaging of the entire pancreaticobiliary tract during a single breath hold, MRCP is of proven utility in a variety of pancreatic and biliary disorders. It uses MR imaging to visualize fluid in the biliary and pancreatic ducts as high signal intensity on T2 weighted sequences and is the newest modality for pancreatic and biliary duct imaging. Herein, we present the clinical applications of MRCP in a variety of pancreaticobiliary system disorders and conclude that it is an important diagnostic tool in terms of imaging of the pancreaticobiliary ductal system.

The clinicopathologic features of intraductal papillary mucinous neoplasms of the pancreas

Since first described in 1982, intraductal papillary mucinous neoplasm (IPMN) has been the preferred term to describe the proliferation of the pancreatic ductal epithelium. It is totally different from pancreatic carcinoma in epidemiology, histology, pathology and prognosis. According to the site of involvement, IPMNs are classified into three categories, i.e. main duct type, branch duct type, and combined type. Most branch duct IPMNs are benign, whereas the other two types are often malignant. A large branch duct IPMN and marked dilation of the main pancreatic duct indicate the presence of adenoma at least. The additional existence of large mural nodules increases the possibility of malignancy in all types. The prognosis is more favorable after complete resection of benign and non-invasive malignant IPMNs. Malignant IPMNs that become more aggressive after parenchymal invasion necessitate adequate lymph node dissection. On the other hand, asymptomatic branch duct IPMNs without mural nodules can be observed without the need for resection for a considerable period of time. Our review addresses available data, current understanding, controversy, and future directions about IPMNs.

Intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND/AIMS

Intraductal papillary mucinous neoplasms (IPMNs) are neoplasms of the pancreatic duct epithelium characterized by intraductal papillary growth and thick mucin secretion. Quantities of mucin fill the main and/or branches of pancreatic ducts and cause ductal dilatation. This review encompasses IPMNs, including symptoms, diagnosis, management, and prognosis.

METHODS

A Pubmed database search was performed. All abstracts were reviewed and all articles in which cases of IPMNs could be identified were further scrutinized. Further references were extracted by cross-referencing.

RESULTS

Only one-third of all patients are symptomatic. According to the site of involvement, IPMNs are classified into three types: main duct type, branch duct type, and combined type. Most branch type IPMNs are benign, while the other two types are frequently malignant. The presence of large mural nodules increases the possibility of malignancy in all types. Presence of a large branch type IPMN and marked dilatation of the main duct indicate the existence of adenoma at least. Synchronous or metachronous malignancies may be developed in various organs. Endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography, and intraductal ultrasonography clearly demonstrate ductal dilatation and mural nodules, while magnetic resonance pancreatography best visualizes the entire outline of IPMNs.

CONCLUSIONS

Prognosis is excellent after complete resection of benign and non-invasive malignant IPMNs. The extent of pancreatic resection and the intraoperative management of resection margins remain controversial. Total pancreatectomy should be reserved for patients with resectable but extensive IPMNs involving the whole pancreas; its benefits, however, must be balanced against operative and postoperative risks. Regular monitoring for disease recurrence is important after surgery.

Pancreatic Tumors: Diagnostic Patterns by 3D Gradient-Echo Post Contrast Magnetic Resonance Imaging with Pathologic Correlation

Magnetic resonance (MR) imaging has considerable potential in characterizing pancreatic masses. Certain features can be used by the radiologist to establish a definitive diagnosis for most pancreatic tumors including ductal adenocarcinoma, islet cell tumors, solid and papillary epithelial neoplasms, micro- and macrocystic adenoma, and metastases. Recognition of these tumors on imaging is important since it often changes the treatment approach and may obviate the need for surgery. Recent introduction of 3D gradient recalled echo (GRE) sequence such as volumetric interpolated breath hold examination (VIBE) has dramatically improved MR imaging by providing dynamic enhanced thin-slice images with fat saturation and high signal-to-noise ratio. In this article, special emphasis will be placed on the impact of 3D GRE sequence in the diagnosis of pancreatic neoplasms with pathologic correlation.

Screening for early pancreatic neoplasia in high-risk individuals: a prospective controlled study

BACKGROUND & AIMS

Individuals with a strong family history of pancreatic cancer and persons with Peutz-Jeghers syndrome (PJS) have an increased risk for pancreatic cancer. This study screened for early pancreatic neoplasia and compared the pancreatic abnormalities in high-risk individuals and control subjects.

METHODS

High-risk individuals with PJS or a strong family history of pancreatic cancer were prospectively evaluated with baseline and 12-month computed tomography (CT) scan and endoscopic ultrasonography (EUS). If EUS was abnormal, EUS-fine-needle aspiration and endoscopic retrograde cholangiopancreatography (ERCP) were performed. Surgery was offered to patients with potentially neoplastic lesions. Radiologic findings and pathologic diagnoses were compared. Patients undergoing EUS and/or ERCP for benign non-pancreatic indications were concurrently enrolled as control subjects.

RESULTS

Seventy-eight high-risk patients (72 from familial pancreatic cancer kindreds, 6 PJS) and 149 control patients were studied. To date, 8 patients with pancreatic neoplasia have been confirmed by surgery or fine-needle aspiration (10% yield of screening); 6 patients had 8 benign intraductal papillary mucinous neoplasms (IPMNs), 1 had an IPMN that progressed to invasive ductal adenocarcinoma, and 1 had pancreatic intraepithelial neoplasia. EUS and CT also diagnosed 3 patients with 5 extrapancreatic neoplasms. At EUS and ERCP abnormalities suggestive of chronic pancreatitis were more common in high-risk patients than in control subjects.

CONCLUSIONS

Screening EUS and CT diagnosed significant asymptomatic pancreatic and extrapancreatic neoplasms in high-risk individuals. IPMN should be considered a part of the phenotype of familial pancreatic cancer. Abnormalities suggestive of chronic pancreatitis are identified more commonly at EUS and ERCP in high-risk individuals.

Intraductal papillary mucinous neoplasms of the pancreas: A surgical perspective

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas represent a relatively "new", but increasingly recognized entity. The emergence of this entity is due primarily to the widespread use of modern imaging methods, but also to a heightened awareness of physicians regarding this cystic neoplasm of the pancreas. No signs or symptoms are pathognomonic of IPMNs, but frequently, patients have a pancreatitis-like abdominal pain. Fully one-third of patients with IPMN are asymptomatic at the time of diagnosis. Cross-sectional imaging (ultrasonography, computed tomography, magnetic resonance cholangiopancreatography), endoscopic retrograde cholangiopancreatography, and endoscopic ultrasonography are the diagnostic and staging methods of choice in the evaluation of patients with IPMNs. IPMNs show a wide spectrum of histologic changes, ranging from adenoma to invasive neoplasm, even within the same neoplasm, suggesting a "field defect" predisposing major segments or even the entire ductal epithelium to the development of IPMN. Fine-needle aspiration/cytology and/or analysis of the cystic fluid may be useful diagnostic tools; however, these examinations are associated with high false-negative rates. Complete surgical resection is the therapeutic method of choice. The extent and type of pancreatectomy remain somewhat controversial but should be based on morphologic changes of the pancreas. Even the role of adjuvant therapy remains unclear; however, being "duct-derived" neoplasms of potential malignant character, some form of adjuvant chemo- or ratio-therapy seems indicated in the presence of invasive disease, despite a "curative" resection. In the absence of invasive disease, prognosis after R0 resection is highly favorable with recurrences of 5-10%. However, invasive IPMNs behave quite similar to ductal adenocarcinoma of the pancreas when analyzed stage-by-stage, with a slightly better prognosis; however, even after an R0 resection, recurrence is common.

Intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is a new pathological entity. It is diagnosed with increasing frequency. However, its natural history and management are still not well defined.

METHODS

A Medline search was undertaken to identify articles using the keywords "intraductal papillary mucinous neoplasms of pancreas", "pancreatic neoplasms", and "pancreatic cyst". Additional papers were identified by a manual search of the references from the key articles.

RESULTS

Surgical resection is the only treatment which can produce a cure. The reported overall 5-year survival for IPMN after surgical resection varies from 36% to 77%; for non-invasive IPMN, 77% to 100% and for invasive IPMN, 27% to 60%. The overall recurrence rate was 7% to 43%. IPMN can recur either as disseminated disease or as isolated pancreatic remnant recurrence even after surgical resection with negative margins.

CONCLUSIONS

Based on the available evidence, patients with IPMN should undergo complete surgical resection. The extent of pancreatic resection and the intra-operative management of resection margins remain controversial. Balancing the risk of recurrence and the morbidity of total pancreatectomy, routine total pancreatectomy for IPMN is not recommended. Total pancreatectomy should only be reserved for patients with resectable but extensive IPMN which involves the whole pancreas. Regular monitoring for disease recurrence is important after surgery as there is a risk of recurrence in both non-invasive and invasive IPMN, and repeat resection for an isolated recurrence in the pancreatic remnant gives good results.

State-of-the-art computed tomographic and magnetic resonance imaging of the gastrointestinal system

Among the major innovations in radiology of the gastrointestinal (GI) system are the replacement of classic invasive diagnostic methods with noninvasive ones and the improvement in lesion characterization and staging of pancreatobiliary malignancies. Developments in imaging technology have led to many improvements in the field of diagnostic GI radiology. With its fast and thin-section scanning abilities, multidetector-row CT (MDCT) strengthens the place of CT as the most efficient tool to diagnose, characterize, and preoperatively stage pancreatic neoplasms. MR cholangiopancreatography has widely replaced endoscopic retrograde cholangiopancreatography in the diagnosis and staging of pancreatobiliary malignancies. MR imaging, using phased-array or endorectal coils, demonstrates local tumor invasion accurately in rectal cancers and thus allows an improved surgical planning. Virtual colonoscopy with MDCTs is an efficient screening method for colon cancer, and MDCT enterography is becoming the standard imaging technique for many small bowel disorders. The continuing developments in CT and MR technology will most probably further improve the accuracy of these and other imaging applications in the near future.

Aspect radiologique des tumeurs intracanalaires pancréatiques mucineuses et papillaires

IPMTP is a pancreatic duct disease that can better be diagnosed due to advances in imaging techniques. This probably explains the recent increased frequency of this disease. Enlargement of the main pancreatic duct and/or branch ducts is a typical feature. CT and MRI with MRCP are useful for diagnosis. Features of malignant degeneration are better known. Preoperative staging is performed at CT. Differential diagnosis includes main pancreatic duct dilatation and pancreatic cysts. Recent papers indicate that isolated side branch IPMTP is less frequently malignant. Surgery is indicated in the presence of acute pancreatitis or suspicion of malignant degeneration. Imaging is useful for the follow up of patients with isolated side branch IPMTP. In this paper, the diagnostic, staging and malignant features of IPMTP will be reviewed.

Coexistence of annular pancreas with carcinoma in the dorsal part of pancreas divisum: diagnostic value of magnetic resonance cholangiopancreatography

We report on the incidental observation of a pancreas divisum coexistent with an annular pancreas in a 88-year-old woman presenting with jaundice due to a pancreatic carcinoma. This case report discusses the embryologic hypotheses underlying this peculiar association, highlights the capacities of imaging techniques to depict them, and enhances the performance of magnetic resonance imaging.

Differential diagnosis of benign and malignant intraductal papillary mucinous tumors of the pancreas: MR cholangiopancreatography and MR angiography

Objective

To compare the usefulness of magnetic resonance cholangiopancreatography (MRCP) and MR angiography (MRA) in differentiating malignant from benign intraductal papillary mucinous tumors of the pancreas (IPMTs), and to determine the findings which suggest malignancy.

Materials and Methods

During a 6-year period, 46 patients with IPMT underwent MRCP. Morphologically, tumor type was classified as main duct, branch duct, or combined. The diameter of the main pancreatic duct (MPD), the extent of the dilated MPD, and the location and size of the cystic lesion, septum, and communicating channel were assessed. For all types of IPMTs, enhanced mural nodules and portal vein narrowing were evaluated at MRA.

Results

Combined-type IPMTs were more frequently malignant (78%) than benign (42%) (p < 0.05). Compared with benign lesions, malignant lesions were larger, and the caliber of the communicating channel was also larger (p < 0.05). Their dilated MPD was more extensive and of greater diameter (p < 0.05), and the presence of mural nodules was more frequent (p < 0.001).

Conclusion

Combined MRCP and MRA might be useful for the differential diagnosis of malignant and benign IPMTs of the pancreas.

ERCP and MRCP in the differentiation of pancreatic tumors

The introduction of endoscopic retrograde cholangiopancreatography (ERCP) in the early 1970s provided gastroenterologists with a number of diagnostic as well as therapeutic possibilities for examining biliopancreatic systems. In the meantime, magnetic resonance cholangiopancreatography presents a non-invasive alternative to diagnostic ECRP providing the advantage of a lower rate of possible complications. This article addresses the two methods presently available for differentiating pancreatic tumors. The objective of this article is to describe the advantages and disadvantages as well as the possibilities inherent in both methods.

Natural History of Pancreatic Intraductal Papillary Mucinous Tumor of Branch Duct Type

OBJECTIVE

The purpose of this study was to elucidate the natural history of branch duct type pancreatic intraductal papillary mucinous tumor (IPMT) by evaluating serial changes in the magnetic resonance cholangiopancreatography (MRCP) findings of patients diagnosed with pancreatic IPMT of branch duct type.

METHODS

Thirty-five patients had branch duct type IPMT, including 9 patients with separate lesions, and underwent initial and follow-up MRCP over a period of more than 12 months. The maximum diameter of the cystic lesion, the presence of associated main pancreatic duct (MPD) dilatation, and the presence of a filling defect were evaluated. Serial changes in these findings were analyzed.

RESULTS

Tumor enlargement on follow-up MRCP was observed in 7 cases. Of the 29 branch duct IPMTs without associated MPD dilatation or a filling defect identified on initial MRCP, only 1 showed gradual tumor enlargement. In 4 cases, the cyst size decreased on follow-up MRCP.

CONCLUSIONS

Branch duct type IPMTs grow slowly and can be monitored without operation provided that the tumor shows no associated MPD dilatation or filling defect.

Molecular pathogenesis of precursor lesions of pancreatic ductal adenocarcinoma

Precursor lesions are assuming greater importance in the study of pancreatic ductal adenocarcinoma. As pancreatic cancer is almost universally fatal due to late clinical presentation and biological aggressiveness, characterisation of its precursor lesions may create scope for early diagnosis and improved outcome with conventional therapies as well as the development of novel therapeutic and preventative strategies. Pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous tumours (IPMTs) are thought to be precursor lesions of ductal adenocarcinoma of the pancreas. Recent work has focused on the molecular aberrations associated with these lesions leading to the formulation of a progression model for pancreatic cancer. Progressive histopathological changes along the progression model are associated with aberrations of cell cycle regulatory and growth factor signalling molecules that occur in pancreatic cancer at high frequency and are common to many cancers. Characterisation of these molecular aberrations provides scope for the development of novel diagnostic and treatment strategies that will ultimately impact on the outcome for people who develop pancreatic cancer.

Intraductal papillary mucinous tumors of the pancreas. Comparison of helical CT and MR imaging

PURPOSE

To compare the effectiveness of thin-section helical CT and MR imaging with gadolinium-enhanced dynamic technique and MR cholangiopancreatography (MRCP) in the examination of patients with intraductal papillary mucinous tumors.

MATERIAL AND METHODS

Helical CT, dynamic MR imaging, and MRCP of 25 intraductal papillary mucinous tumors were compared with ERCP and surgical findings.

RESULTS

The duodenal papilla was identified by helical CT and dynamic MR imaging in 11 (44%) and 20 (80%) of the 25 patients, respectively (p<0.05). The main pancreatic duct was visualized on helical CT, dynamic MR imaging, and MRCP in all patients (100%): 25 (96.2%), 24 (92.3%), and 26 (100%) cystic lesions were depicted, respectively. A communicating duct between the main pancreatic duct and the cystic lesion was visualized on helical CT, dynamic MR imaging, and MRCP in 14 (53.8%), 11 (42.3%), and 15 (55.7%) lesions, respectively. The papillary projections corresponding to 3 mm or larger papillary neoplasms were depicted on helical CT and MR imaging in 7 patients (25%).

CONCLUSION

MR imaging was equal or slightly superior to thin-section helical CT in the evaluation of intraductal papillary mucinous tumors.

Mucus is a predictor of better prognosis and survival in patients with intraductal papillary mucinous tumor of the pancreas

The aim of our study was to examine the case histories of patients with intraductal papillary mucinous tumor (IPMT) treated with resection to determine predictors of prognosis. Between 1989 and 2000, all patients treated with pancreatic resection for IPMT (n = 63) were analyzed. The diagnosis of IPMT was made using the surgical specimen and the World Health Organization definition. Predictors were determined using univariate and multivariate analysis. The pathologic findings were benign (n = 30), carcinoma in situ (CIS; n = 5), and invasive carcinoma (n = 28). After univariate analysis, predictors of malignancy (invasive plus CIS) were jaundice (odds ratio = 10.32), elevated serum CA19-9 (odds ratio = 15.0), any abnormal liver function test (odds ratio = 7.69), and p53 overexpression. The only predictor of benign disease was gross mucus observed during endoscopy (odds ratio = 4.35). After multivariate analysis, predictors of malignancy were any abnormal liver function test (odds ratio = 5.09) and p53 overexpression, whereas the only predictor of benign disease was still gross mucus (odds ratio = 5.88). Actuarial 3- and 5-year survival for benign disease was 95% and 83% and for malignant disease 52% and 44%, respectively (P = 0.0048). Survival curves also favored p53-negative tumors vs. p53-positive tumors (P = 0.0055). In the 33 patients with malignant disease (mean follow-up time = 35 months), the presence of gross mucus was a predictor of prolonged survival after univariate and multivariate analysis (odds ratio = 4.34 and 4.55, respectively), whereas alcohol abuse was a predictor of poor survival (odds ratio = 3.41 and 3.60, respectively). Gross mucus observed during endoscopy is a predictor of benign IPMT and, within the group with malignant IPMT; the presence of gross mucus was associated with better survival. Survival was also strongly associated with either benign IPMT or negative staining for p53 overexpression.

Intraductal papillary mucinous tumor of the pancreas: computerized tomography and magnetic resonance imaging features

The aim of this study was to analyze the computerized tomography (CT) and magnetic resonance imaging (MRI) features of intraductal papillary mucinous tumor (IPMT) of the pancreas. The cases of eight patients with pathologically proven IPMT (1 papillary hyperplasia, 7 adenocarcinoma) of the pancreas were retrospectively reviewed. There were five men and three women with ages ranging from 42 to 82 years. Imaging studies included six thin-section dynamic CT scans, seven MRI scans, one MR cholangiopancreatography scan, and two endoscopic retrograde cholangiopancreatography scans. There was only one benign IPMT, which presented as a unilocular cyst in the pancreatic body with no mural nodules and no dilatation of the main pancreatic duct (MPD). All seven patients with malignant IPMT had multilocular cysts with papillary projections in the pancreatic head and/or uncinate process accompanied by dilated MPD (5 diffuse, 2 segmental). Communication between the cystic lesions and the MPD were evident in all seven patients. One patient had small mural nodules in the branch ducts of the pancreatic body and five had a bulging papilla with a patulous orifice. A mass effect resulting in biliary obstruction was shown in one patient. One patient had a ruptured cyst with mucin leakage into the right anterior pararenal space following sono-guided aspiration. In conclusion, the main imaging feature of IPMT in our patients was a multilocular cyst with papillary projections located in the pancreatic head and uncinate process. Although CT and MRI cannot differentiate mucin content from pancreatic juice, communication between the cystic lesion and the dilated MPD and a bulging papilla with a patulous orifice are characteristics of IPMT.

MR cholangiopancreatography: evaluation of common pancreatic diseases

In the evaluation of common pancreatic diseases, MRCP is a noninvasive alternative to ERCP. Ductal anatomy can be ascertained without risk of complications. MRCP is valuable in defining common anatomic variants, determining the state of the pancreatic duct in pancreatitis, and characterizing neoplasms, especially combined with other MR imaging sequences. With the advent of MRCP, techniques requiring endoscopy and percutaneous access are largely reserved for histologic diagnosis and treatment, or for cases in which MRCP fails to establish a diagnosis.

Cystic pancreatic neoplasms

Cystic pancreatic neoplasms are uncommon, but are being seen more frequently due to the widespread use of cross-sectional imaging. In this article, we will address the clinical and imaging features of the more commonly seen neoplasms. Points of differentiation between these neoplasms, the use of cyst fluid analysis and an approach to the incidentally discovered cystic mass will be addressed.

Update on magnetic resonance cholangiopancreatography

MRCP is a useful tool in the diagnosis of a wide variety of pathologic entities including congenital anomalies, biliary obstruction and stricture, biliary calculi, pancreatitis, neoplasms, and trauma. ERCP and MRCP both have important roles in the management of patients with suspected pancreaticobiliary disease. Knowledge of the advantages and disadvantages of each technique is needed to determine the appropriate work-up of patients with these pathologies.

ERCP and MRCP--when and why

Since the introduction of endoscopic retrograde cholangiopancreatography (ERCP) in the 1970s, gastroenterologists have a wide spectrum of diagnostic and therapeutic options in the biliopancreatic ductal system at their disposal. With its arrival in the 1990s, magnetic resonance cholangiopancreatography (MRCP) developed as a potent diagnostic tool in biliopancreatic pathology. Currently, MRCP is widely replacing diagnostic ERCP and thereby avoiding complications related to endoscopic technique.We summarize evidence-based data and demonstrate indications and differential indications for MRCP and ERCP in pancreatic disease. Complications related to the procedures and possible medical prevention are discussed. The feasibility of interventional endoscopy in pancreatic disease is reported in detail. The role of gastroenterologists in performing MRCP is outlined on the basis of practical examples.

Pancreatic duct: morphologic evaluation with MR cholangiopancreatography after secretin stimulation

PURPOSE

To evaluate the pancreatic duct after administration of secretin.

MATERIALS AND METHODS

Single-shot turbo spin-echo T2-weighted dynamic magnetic resonance cholangiopancreatography (MRCP) was performed in 85 patients who did not have pancreatic diseases (group 1) and in 50 patients who had focal severe stenosis of the main pancreatic duct (group 2). The visualization and diameter of the pancreatic duct before and after secretin administration were assessed.

RESULTS

In group 1, after secretin administration, the best visualization of the main pancreatic duct in the head, body, accessory pancreatic duct, and branch ducts was achieved in 4.7 minutes +/- 1.6 (SD), 4.8 minutes +/- 1.6, 4.6 minutes +/- 1.6, and 4.7 minutes plus minus 1.3, respectively. Improvement in the delineation of the main pancreatic duct in the head (78 [92%] patients), body (80 [94%] patients), accessory pancreatic duct (35 [41%] patients), and branch ducts (14 [16%] patients) was achieved. Overlap of fluid in the organ and the pancreatic duct was observed in 20 (24%) of 85 patients. Overlap was especially observed after 5 minutes of secretin injection. In group 2, the best visualization of the distal main pancreatic duct was achieved 4.9 minutes +/- 1.4 after secretin administration. Improvement in the delineation of the distal main pancreatic duct was achieved in 17 (85%) of 20 patients.

CONCLUSION

MRCP is best performed during the first 5 minutes after secretin administration.

Intraductal papillary mucinous tumors of the pancreas: features with multimodality imaging

The radiologic diagnosis of intraductal papillary mucinous tumor (IPMT) of the pancreas is important to establish because of its malignant potential and in order to determine the site of tumor origin and its extent. These pancreatic tumors are recognized more often now than previously because of the increasing use of imaging modalities such as computed tomography and magnetic resonance cholangiopancreatography. The main features of IPMT are given in this pictorial essay, with illustrations provided from a series of 50 patients with a surgically proven diagnosis of IPMT.

MR cholangiopancreatographic differentiation of benign and malignant intraductal mucin-producing tumors of the pancreas

OBJECTIVE

The purpose of this study was to establish MR cholangiopancreatographic criteria for discriminating benign from malignant intraductal mucin-producing tumors of the pancreas.

MATERIALS AND METHODS

Thirty-one patients with 34 intraductal mucin-producing tumors underwent MR cholangiopancreatography. Tumors were classified as either main duct type (n = 10) or branch duct type (n = 24). In patients with the main duct type, the maximum diameter and the location of the main pancreatic duct, the extent of main pancreatic duct dilatation, and the presence of a filling defect were evaluated. For branch duct type, the location and maximum diameter of the cystic lesion, the presence of a filling defect, and the presence of associated main pancreatic duct dilatation were evaluated.

RESULTS

In patients with the main duct type, the main pancreatic duct was significantly narrower when associated with benign rather than malignant tumors. All malignant tumors showed diffuse main pancreatic duct dilatation, whereas all benign tumors showed segmental dilatation. Among patients with branch duct type, the cyst was smaller when it was a benign rather than malignant tumor. All but one malignant tumor showed mild associated main pancreatic duct dilatation, whereas benign tumors were not associated with main pancreatic duct dilatation. Filling defects suggested malignancy, although half of the malignant tumors had no filling defects.

CONCLUSION

In patients with intraductal mucin-producing tumors of the pancreas, filling defects are indicative of malignancy. Diffuse main pancreatic duct dilatation greater than 15 mm (main duct type), or any main pancreatic duct dilatation (branch duct type), is strongly associated with malignancy.