MR imaging and MR cholangiopancreatography of multifocal intraductal papillary mucinous neoplasms of the side branches: MR pattern and its evolution

Evolution of incidental branch-duct intraductal papillary mucinous neoplasms of the pancreas: A study with magnetic resonance imaging cholangiopancreatography

AIM

To investigate the type and timing of evolution of incidentally found branch-duct intraductal papillary mucinous neoplasms (bd-IPMN) of the pancreas addressed to magnetic resonance imaging cholangiopancreatography (MRCP) follow-up.

METHODS

We retrospectively evaluated 72 patients who underwent, over the period 2006-2016, a total of 318 MRCPs (mean 4.4) to follow-up incidental, presumed bd-IPMN without signs of malignancy, found or confirmed at a baseline MRCP examination. Median follow-up time was 48.5 mo (range 13-95 mo). MRCPs were acquired on 1.5T and/or 3.0T systems using 2D and/or 3D technique. Image analysis assessed the rates of occurrence over the follow-up of the following outcomes: (1) imaging evolution, defined as any change in cysts number and/or size and/or appearance; and (2) alert findings, defined as worrisome features and/or high risk stigmata (e.g., thick septa, parietal thickening, mural nodules and involvement of the main pancreatic duct). Time to outcomes was described with the Kaplan-Meir approach. Cox regression model was used to investigate clinical or initial MRCP findings predicting cysts changes.

RESULTS

We found a total of 343 cysts (per-patient mean 5.1) with average size of 8.5 mm (range 5-25 mm). Imaging evolution was observed in 32/72 patients (44.4%; 95%CI: 32-9-56.6), involving 47/343 cysts (13.7%). There was a main trend towards small (< 10 mm) increase and/or decrease of cysts size at a median time of 22.5 mo. Alert findings developed in 6/72 patients (8.3%; 95%CI: 3.4-17.9) over a wide interval of time (13-63 mo). No malignancy was found on endoscopic ultrasound with fine-needle aspiration (5/6 cases) or surgery (1/6 cases). No clinical or initial MRCP features were significantly associated with changes in bd-IPMN appearance (P > 0.01).

CONCLUSION

Changes in MRCP appearance of incidental bd-IPNM were frequent over the follow-up (44.4%), with relatively rare (8.3%) occurrence of non-malignant alert findings that prompted further diagnostic steps. Changes occurred at a wide interval of time and were unpredictable, suggesting that imaging follow-up should be not discontinued, though MRCPs might be considerably delayed without a significant risk of missing malignancy.

What Is the Best Way to Identify Malignant Transformation Within Pancreatic IPMN: A Systematic Review and Meta-Analyses

OBJECTIVES

Pancreatic intraductal papillary mucinous neoplasias (IPMNs) represent 25% of all cystic neoplasms and are precursor lesions for pancreatic ductal adenocarcinoma. This study aims to identify the best imaging modality for detecting malignant transformation in IPMN, the sensitivity and specificity of risk features on imaging, and the usefulness of tumor markers in serum and cyst fluid to predict malignancy in IPMN.

METHODS

Databases were searched from November 2006 to March 2014. Pooled sensitivity and specificity of diagnostic techniques/imaging features of suspected malignancy in IPMN using a hierarchical summary receiver operator characteristic (HSROC) approach were performed.

RESULTS

A total of 467 eligible studies were identified, of which 51 studies met the inclusion criteria and 37 of these were incorporated into meta-analyses. The pooled sensitivity and specificity for risk features predictive of malignancy on computed tomography/magnetic resonance imaging were 0.809 and 0.762 respectively, and on positron emission tomography were 0.968 and 0.911. Mural nodule, cyst size, and main pancreatic duct dilation found on imaging had pooled sensitivity for prediction of malignancy of 0.690, 0.682, and 0.614, respectively, and specificity of 0.798, 0.574, and 0.687. Raised serum carbohydrate antigen 19-9 (CA19-9) levels yielded sensitivity of 0.380 and specificity of 0903. Combining parameters yielded a sensitivity of 0.743 and specificity of 0.906.

CONCLUSIONS

PET holds the most promise in identifying malignant transformation within an IPMN. Combining parameters increases sensitivity and specificity; the presence of mural nodule on imaging was the most sensitive whereas raised serum CA19-9 (>37 KU/l) was the most specific feature predictive of malignancy in IPMNs.

The utilization of imaging features in the management of intraductal papillary mucinous neoplasms

Intraductal papillary mucinous neoplasms (IPMNs) represent a group of cystic pancreatic neoplasms with large range of clinical behaviours, ranging from low-grade dysplasia or borderline lesions to invasive carcinomas. They can be grouped into lesions originating from the main pancreatic duct, main duct IPMNs (MD-IPMNs), and lesions which arise from secondary branches of parenchyma, denominated branch-duct IPMNs (BD-IPMNs). Management of these cystic lesions is essentially based on clinical and radiological features. The latter have been very well described in the last fifteen years, with many studies published in literature showing the main radiological features of IPMNs. Currently, the goal of imaging modalities is to identify "high-risk stigmata" or "worrisome feature" in the evaluation of pancreatic cysts. Marked dilatation of the main duct (>1 cm), large size (3-5 cm), and intramural nodules have been associated with increased risk of degeneration. BD-IPMNs could be observed as microcystic or macrocystic in appearance, with or without communication with main duct. Their imaging features are frequently overlapped with cystic neoplasms. The risk of progression for secondary IPMNs is lower, and subsequently an imaging based follow-up is very often proposed for these lesions.

Magnetic resonance imaging spectrum of solid pseudopapillary neoplasm of the pancreas

OBJECTIVE

To describe the magnetic resonance imaging spectrum of solid pseudopapillary tumors (SPTs), with an emphasis on solid SPTs.

METHODS

Thirty-two patients with proven SPTs with preoperative magnetic resonance were included. The SPTs were classified into 3 types: solid, cystic, and mixed; and 2 radiologists analyzed the images regarding the morphologic features and enhancement pattern.

RESULTS

Of 11 solid SPTs, 9 SPTs (81.8%) were less than 3 cm. Alternatively, of the 18 mixed SPTs and 3 cystic SPTs, 15 SPTs (71.4%) were larger than 3 cm. The predominant imaging features were homogeneous hypoenhancement with a gradually incremental enhancement pattern showing a sharp margin without hemorrhage, whereas those of the mixed SPTs were heterogeneous enhancement showing a sharp margin with internal hemorrhage.

CONCLUSION

Solid SPTs frequently present as small, well-defined tumors with a gradual enhancement and without hemorrhage or necrosis, and with features that differ from those of mixed or cystic SPTs.

Three-dimensional contrast-enhanced ultrasonography of intraductal papillary mucinous neoplasms of the pancreas: a comparison with magnetic resonance imaging

OBJECTIVES

The objective of this study was to prospectively compare the diagnostic accuracy of 3-dimensional contrast-enhanced ultrasonography (3D-CEUS) with that of magnetic resonance imaging (MRI) in the study of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas.

METHODS

Thirty consecutive patients with IPMN were studied.

RESULTS

Three patients (10.0%) did not undergo diagnostic 3D-CEUS because of technical problems. Three dimensional CEUS identified 12 (44.4%) main-duct IPMNs versus no cases by MRI (P < 0.001). Intraductal papillary mucinous neoplasm localization showed poor agreement between 3D-CEUS and MRI (κ = 0.058), whereas good agreement was found in detecting the pancreatic calcifications (κ = 1.000). Significant differences between 3D-CEUS and MRI were found regarding the number of lesions detected (1.4 ± 0.8 vs 3.8 ± 3.6; P < 0.001), the detection of mucinous plugs (3.7% vs 50.0%; P < 0.001), chronic pancreatitis (7.4% vs 26.7%; P = 0.031), pancreatic atrophy (0% vs 50.0%; P < 0.001), thick septa (22.2% vs 53.3%; P = 0.004), and mural nodules (25.9% vs 3.3%; P = 0.016). Three dimensional CEUS showed similar results as compared with MRI in evaluating IPMNs smaller than 1 cm of diameter or greater than 2 cm.

CONCLUSIONS

Even if MRI remains the criterion standard technique for the diagnosis of IPMNs, 3D-CEUS can be safely used to follow patients with IPMNs of less than 1 cm.

Multifocal branch-duct intraductal papillary mucinous neoplasms (IPMNs) of the pancreas: magnetic resonance (MR) imaging pattern and evolution over time

PURPOSE

The aim of our study was to follow the evolution over time of multifocal intraductal papillary mucinous neoplasms (IPMN) of the pancreatic duct side branches by means of magnetic resonance imaging (MRI).

MATERIALS AND METHODS

A total of 155 patients with multifocal IPMN of the side branches were examined with MRI and MR cholangiopancreatography (MRI/MRCP). Inclusion criteria were patients with ≥2 dilated side branches involving any site of the parenchyma; presence of communication with the main pancreatic duct and previous investigations by MRI/MRCP within at least six months. Median follow-up was 25.8 months (range, 12-217). Patients with a follow-up period shorter than 12 months (n=33) and those with a diagnosis of multifocal IPMN of the side branches without any follow-up (n=14) were excluded from the study. The final study population thus comprised 108 patients. A double, quantitative and qualitative, analysis was carried out. The quantitative image analysis included: number of dilated side branches in the head-uncinate process and body-tail; maximum diameter of lesions in the head-uncinate process; maximum diameter in the body-tail; maximum diameter of the main pancreatic duct in the head and body-tail. The qualitative image analysis included: presence of malformations or anatomical variants of the pancreatic ductal system; site of the lesions (head-uncinate process, body-tail, ubiquitous, bridge morphology); presence of gravity-dependent intraluminal filling defects; presence of enhancing mural nodules.

RESULTS

At diagnosis, the mean number of cystic lesions of the side branches was 7.09. The mean diameter of the cystic lesions was 13.7 mm. The mean diameter of the main pancreatic duct was 3.6 mm. At follow-up, the mean number of cystic lesions was 7.76. The mean diameter of the cystic lesions was 13.9 mm. The mean diameter of the main pancreatic duct was 3.7 mm. Intraluminal filling defects in the side branches were seen in 18/108 patients (16.6%); enhancing mural nodules were seen in 3/108 patients (2.7%).

CONCLUSIONS

Multifocal IPMN of the branch ducts shows a very slow growth and evolution over time. In our study, only 3/108 patients showed mural nodules which, however, did not require any surgical procedure, indicating that careful nonoperative management may be safe and effective in asymptomatic patients.

Incidentally discovered benign pancreatic cystic neoplasms not communicating with the ductal system: MR/MRCP imaging appearance and evolution

PURPOSE

The authors sought to determine magnetic resonance/magnetic resonance cholangiopancreatography (MR/MRCP) imaging features of incidentally discovered benign, noncommunicating cystic neoplasms (BNCNs) of the pancreas to assess their evolution over time and identify MR/MRCP imaging features predictive of tumour growth.

MATERIAL AND METHODS

This was a retrospective study, so informed consent was waived. Sixty-two patients with a diagnosis of BNCN were assessed. Inclusion criteria were incidentally discovered cystic neoplasm of the pancreas with nonmeasurable walls, no mural nodules and no communication with the pancreatic ductal system and who underwent ≥ 1 MR/MRCP examination. Image analysis, performed at diagnosis and during follow-up, included macroscopic pattern (microcystic/macrocystic/mixed), number of cysts (unicystic/oligocystic/multicystic), BNCN maximum diameter and tumour growth rates.

RESULTS

A total of 64 BNCNs was detected. Macroscopic pattern was mixed in 31/64 (48%), microcystic in 28/64 (44%) and macrocystic in 5/64 (8%). BNCNs appeared multicystic in 38/64 (59%) cases, oligocystic in 22/64 (35%) and unicystic in 4/64(6%). All qualitative parameters remained unchanged during follow-up. At diagnosis, the median maximum BNCN diameter was 35.0 mm and 38.0 mm at the final examination (p<0.001). BNCNs showed a tumour growth rate of 2 mm/year.

CONCLUSIONS

Mixed and microcystic patterns were the most common, accounting for 48% and 44% of cases, respectively, and showed no change over time. MR/MRCP features predictive of lesion enlargement were a mixed/ macrocystic pattern, and lesion size was >3 cm (both p<0.001).

Contrast-enhanced MR cholangiography (MRCP) with GD-EOB-DTPA in evaluating biliary complications after surgery

PURPOSE

We assessed the usefulness of contrast-enhanced magnetic resonance cholangiography (CE-MRC) with liver-specific contrast agent in evaluating the biliary tree after hepatic surgery.

MATERIALS AND METHODS

A total of 142 patients with suspected biliary complications after liver surgery underwent hepatobiliary MR before and after administration of gadolinium ethoxy benzylic diethylenetriamine pentaacetic acid (Gd-EOB-DTPA). Unenhanced MR cholangiopancreatography (MRCP) and postcontrast MRC were obtained in all patients. Blinded image evaluation and semiquantitative analysis comparing MRCP and CE-MRC were performed by two experienced radiologists.

RESULTS

In all cases, optimal postcontrast visualisation of the biliary tract was obtained. In 22 patients, a postsurgical biliary complication was confirmed. MRCP detected 64% of lesions, but in 36% of cases, an alteration was only suspected but not clearly defined. CE-MRC allowed definite diagnosis in 100% of cases.

CONCLUSIONS

Hepatobiliary-specific contrast agents allow for accurate and extensive study of biliary tract alterations, especially in assessing postsurgical complications.

Cystic pancreatic lesions: current evidence for diagnosis and treatment

Pancreatic cystic neoplasms are detected at an increasing frequency due to an increased use and quality of abdominal imaging. There are well known differential diagnostic difficulties concerning these lesions. The aim is to review current literature on the diagnostic options and the following treatment for cystic lesions in the pancreas focusing on serous cystadenomas, primary mucinous neoplasm of the pancreas and mucinous cystadenocarcinomas, as well as intraductal papillary mucinous neoplasms, starting with excluding pseudocysts. A conservative approach is feasible in patients with a clinical presentation suggestive of an asymptomatic serous cystadenoma. Surgical management, as well as follow-up, is discussed for each of the types of neoplastic lesions, including an uncharacterized cyst, based on patient data, symptoms, serum analysis, cyst fluid analysis and morphological features. Aspects for future diagnostics and management of these neoplasia are commented upon.

Diagnostic management of pancreatic cancer

Pancreatic cancer is one of the most deadly solid tumors, with an overall 5-year survival rate of less than 5%. Due to a non-specific clinical presentation, it is often diagnosed at an advanced stage and is rarely amenable for curative treatment. Therefore early diagnosis and appropriate staging are still essential to define the best care and to improve patient survival. Several imaging modalities are currently available for the evaluation of pancreatic cancer. This review focuses on different techniques and discusses the diagnostic management of patients with pancreatic cancer. This review was conducted utilizing Pubmed and was limited to papers published within the last 5 years. The search key words pancreatic cancer, pancreatic adenocarcinoma, pancreatic tumors, diagnosis, radiology, imaging, nuclear imaging, endoscopy, endoscopic ultrasound and biochemical markers were used.

National trends in the management and survival of surgically managed gallbladder adenocarcinoma over 15 years: a population-based analysis

INTRODUCTION

National Comprehensive Cancer Network (NCCN) guidelines recommend hepatic resection and lymphadenectomy (LND) for gallbladder adenocarcinoma (GBA). We sought to evaluate compliance with these recommendations and to assess trends in the management and survival of patients with GBA.

METHODS

Using Surveillance, Epidemiology and End Results (SEER)-Medicare-linked data, we identified 2,955 patients with GBA who underwent cancer-directed surgery from 1991 to 2005. We assessed clinicopathologic data, trends in surgical management, and survival.

RESULTS

From 1991 to 2005, preoperative evaluation included CT (62%), MRI (6%), and PET (2%). Only 383 (13%) patients underwent radical resection/hepatectomy with a temporal increase over the study period (1991-1995, 12%; 1996-1999, 10%; 2000-2002, 12.0%; 2003-2005, 16%; P < 0.001). For patients undergoing radical resection/hepatectomy, LND ≥ 3 nodes was performed in 96 (3%) patients. Among patients who had LND, 47% had nodal metastasis. The overall 1-, 3-, and 5-year survival was 56%, 30%, and 21%. On multivariate analysis, radical resection/hepatectomy (hazard ratio (HR) = 0.71) and LND ≥ 3 nodes (HR = 0.56) were independently associated with increased survival. There was no significant improvement in survival over time (P = 0.60).

CONCLUSIONS

Compliance with NCCN guidelines for GBA remains poor. Survival of patients with surgically managed GBA has not improved over time.

Imaging techniques in pancreatic tumors

Conventional ultrasonography represents the first diagnostic imaging modality for the study of pancreatic tumors. Contrast-enhanced ultrasound has significantly improved the accuracy of first-line examination and may influence the choice of second-line investigations: multidetector computed tomography is considered the gold standard for studying pancreatic solid lesions and tumor staging, while MRI with magnetic resonance cholangiopancreatography allows better study of pancreatic cystic lesions and the ductal system. To definitely diagnose a pancreatic lesion, image-guided fine-needle-aspiration or biopsy are very often required. PET with 18-fluorodeoxyglucose, endoscopic ultrasound and intraoperative ultrasonography remain techniques often employed in the third line. This article reviews the imaging techniques generally used for diagnosing the main pancreatic tumors, and a work-up algorithm is finally proposed.

Pancreatic and extrapancreatic lesions in patients with intraductal papillary mucinous neoplasms of the pancreas: a single-centre experience

PURPOSE

This study was performed to describe the possible presence of extrapancreatic neoplasms in patients with intraductal papillary mucinous neoplasm (IPMN) and to evaluate whether the extrapancreatic tumours were synchronous or metachronous to IPMNs.

MATERIALS AND METHODS

One hundred and forty-two patients (56 men and 86 women; mean age 69.5 years, range 37-98) with IPMN diagnosed using the Sendai criteria were enrolled. Six patients (4.2%) had type I, 103 (72.5%) type II and 33 (23.2%) type III IPMN. All patients were studied using the following imaging techniques: ultrasonography (US), multidetector computed tomography (MDCT) and magnetic resonance cholangiopancreatography (MRCP).

RESULTS

Pancreatic IPMN was localised in the head in 43 patients (30.3%), in the body in 13 (9.2%), in the tail in ten (7.0%), in the head-body in 17 (12.0%), in the body-tail in 15 (10.6%) diffuse throughout the gland in 44 (31.0%). The mean size of the cystic lesions was [(mean+/-standard deviation (SD)] 1.9+/-1.9 cm (range 0.5-8.0 cm). Twenty patients (14.1%) had associated pancreatic or extrapancreatic diseases. In evaluating the distribution of pancreatic or extrapancreatic diseases according to IPMN type, we found that this was not significantly different among types I, II and III (p=0.776).

CONCLUSIONS

The majority of pancreatic and extrapancreatic cancers occur before the diagnosis of IPMNs is made and is not related to the type of IPMN.

Evaluation of the biliary and pancreatic system with 2D SSFSE, breathhold 3D FRFSE and respiratory-triggered 3D FRFSE sequences

PURPOSE

The authors compared biliary and pancreatic imaging obtained through 2D single-shot fast spin-echo (SSFSE), breath-hold 3D fast recovery fast spin-echo (FRFSE) and respiratory-triggered 3D FRFSE sequences.

MATERIALS AND METHODS

A total of 106 magnetic resonance cholangiopancreatography (MRCP) examinations performed between December 2007 and September 2008 were evaluated with a comparison of 2D SSFSE (thin section and thick slab), breath-hold 3D FRFSE and respiratory-triggered 3D FRFSE sequences. The biliary tract was divided into seven segments: right hepatic duct, left hepatic duct, common hepatic duct, cystic duct, common bile duct, cystic duct junction and biliary-pancreatic confluence. The main pancreatic duct was divided into three segments (head, body and tail). Visualisation of biliary variants was also compared. Two blinded radiologists evaluated segment visibility using a quantitative scale. The Student's t test for paired samples was used for statistical analysis.

RESULTS

Compared with 2D SSFSE, respiratory-triggered 3D FRFSE sequences showed better visibility of the right hepatic duct (p=0.0277), the cystic duct (p=0.0081), the cystic duct junction (p=0.0010), the biliary-pancreatic confluence (p=0.0334) and biliary variants (p=0.0198). In the comparison between breath-hold 3D FRFSE and 2D SSFSE, a significant statistical difference was found in visualisation of the cystic duct (p=0.027), the cystic duct junction (p=0.020), the biliary-pancreatic confluence (p=0.0338) and biliary variants (p=0.0311).

CONCLUSIONS

Three-dimensional FRFSE offers a significant benefit over conventional 2D imaging.

MR cholangiopancreatography at 3.0 T: intraindividual comparative study with MR cholangiopancreatography at 1.5 T for clinical patients

OBJECTIVES

To prospectively evaluate the image quality and diagnostic accuracy of magnetic resonance cholangiopancreatography (MRCP) at 3.0 T compared with that at 1.5 T used for patients.

MATERIALS AND METHODS

This study was approved by our institutional review board, and informed consent was obtained from all patients. Three-dimensional MRCP with both a 1.5-T system and a 3.0-T system was administered to 33 consecutive patients suspected of having biliary and/or pancreatic diseases. For 3-dimensional MRCP imaging, a respiratory-triggered Fast Recovery Fast Spin Echo sequence with the parallel imaging technique was used for both systems. The spatial resolution at 1.5 T was matched to that at 3.0 T, and matrix size was 512 x 160, field of view (FOV) 36 x 36 cm, slice thickness 2 mm, and the number of slices ranged from 44 to 54. Repetition time varied according to the patients' respiratory cycles, which ranged from 3000 milliseconds to 6000 milliseconds, and effective echo time, ranging from 391 milliseconds to 482 milliseconds, was automatically determined by the systems. Contrast of imaging of the common bile duct versus that of the periductal tissue was quantitatively evaluated. The image quality for homogeneity of signal intensity, image noise, susceptibility artifacts, and overall imaging quality and diagnostic accuracy for stenoses of bile and main pancreatic ducts and for pancreatic cystic lesions were qualitatively evaluated. The results for 1.5- and 3.0-T were then compared statistically, by using the paired t test for quantitative evaluation of contrast between the common bile duct and the periductal tissue, the Wilcoxon signed rank test for visual evaluation of the image quality, and the McNemar chi2 test for evaluation of sensitivity and specificity for diagnostic purposes. A P value of less than 0.05 was considered to indicate a statistically significant difference.

RESULTS

Contrast of the common bile duct versus that of the periductal tissue at 3.0 T was superior to that at 1.5 T (P < 0.001). In the visual evaluation, image quality at 3.0 T was superior to that at 1.5 T for evaluation of image noise (P < 0.001), overall image quality (P < 0.001), and delineation of intrahepatic bile ducts (P < 0.01) and the main pancreatic duct (P < 0.05), whereas there were no significant differences in homogeneity of signal intensity and in susceptibility artifacts. The diagnostic accuracy for 3.0 T was approximately equivalent to that for 1.5 T.

CONCLUSION

Our results for patients with biliary and pancreatic diseases demonstrate a marked improvement in contrast of the common bile duct versus that of the periductal tissue and image quality including image noise at 3.0 T compared by 1.5 T when identical spatial resolution configuration were used. The results suggest that 3.0 T may allow higher spatial resolution and offer promise for improved diagnosis in MRCP, although further investigations using optimize scan parameters will be needed before its full potential can be achieved.

Main pancreatic duct intraductal papillary mucinous neoplasms: accuracy of MR imaging in differentiation between benign and malignant tumors compared with histopathologic analysis

PURPOSE

To retrospectively determine the accuracy of magnetic resonance (MR) imaging combined with MR cholangiopancreatography (CP) in differentiating benign from malignant intraductal papillary mucinous neoplasms (IPMNs) involving the main pancreatic duct (MPD), with histopathologic analysis as the reference standard.

MATERIALS AND METHODS

The informed consent requirement was waived for this institutional review board-approved study. A total of 51 patients with histopathologically proved IPMNs (MPD IPMN, n = 29; mixed type IPMN, n = 22), underwent MR imaging, MR CP, and surgery, with a mean interval of 2.6 months between MR examination and surgery. Qualitative image analysis included assessment of the site of MPD dilatation (head of the pancreas, body and/or tail of the pancreas, or diffuse), presence or absence of duct wall nodules, and contrast enhancement of the MPD walls. Quantitative image analysis included measurement of the maximum diameter of the MPD. A comparison of adenomas and borderline IPMNs with cancerous IPMNs was performed with the Student t test or the Mann-Whitney U test for continuous variables.

RESULTS

At histopathologic analysis, 27 IPMNs were classified as carcinomas; 13, as borderline tumors; and 11, as adenomas. MPD wall nodules were observed in 16 carcinomas involving the MPD and one adenoma or borderline neoplasm (P < .00001). Duct wall enhancement was observed in 20 MPD or mixed type carcinomas and five adenomas or borderline neoplasms (P = .0001). The median maximal diameter of the MPD was 18 mm in malignant MPD or mixed type IPMNs and 11 mm in benign borderline IPMNs (P = .038). No significant difference in the overall 5-year survival rate of patients with MPD IPMNs and those with mixed type IPMNs was observed (P = .813).

CONCLUSION

Duct wall nodules and enhancement of the MPD walls are signs of malignant MPD or mixed type IPMNs.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.2531080604/-/DC1.