Imaging considerations in intraductal papillary mucinous neoplasms of the pancreas

Abstract

With the widespread use of cross-sectional imaging, particularly computed tomography (CT) and magnetic resonance imaging (MRI), and the continuous improvement in the image quality of these techniques, the diagnosis of incidental pancreatic cysts has increased dramatically in the last decades. While the vast majority of these cysts are not clinically relevant, a small percentage of them will evolve into an invasive malignant tumor making their management challenging. Mucinous cystic neoplasms and intraductal papillary mucinous neoplasms (IPMN) are the most common pancreatic cystic lesions with malignant potential. Imaging findings on CT and MRI correlate tightly with the presence of malignant degeneration in these neoplasms. IPMN can be classified based on their distribution as main duct, branch duct or mixed type lesions. MRI is superior to CT in demonstrating the communication of a branch duct IPMN with the main pancreatic duct (MPD). Most branch duct lesions are benign whereas tumors involving the MPD are frequently associated with malignancy. The presence of solid nodules, thick enhancing walls and/or septae, a wide (> 1 cm) connection of a side-branch lesion with the MPD and the size of the tumor > 3 cm are indicative of malignancy in October 27, 2010|Volume 2|Issue 10| a branch and mixed type IPMN. A main pancreatic duct > 6 mm, a mural nodule > 3 mm and an abnormal attenuating area in the adjacent pancreatic parenchyma on CT correlates with malignant disease in main duct and mixed type IPMN. An accurate characterization of these neoplasms by imaging is thus crucial for selecting the best management options. In this article, we review the imaging findings of IPMN including imaging predictors of malignancy and surgical resectability. We also discuss follow-up strategies for patients with surgically resected IPMN and patients with incidental pancreatic cysts.

Assessment of Malignant Potential in Intraductal Papillary Mucinous Neoplasms of the Pancreas: Comparison between Multidetector CT and MR Imaging with MR Cholangiopancreatography

“…Given that CT has advantages over MR imaging with MRCP in terms of spatial resolution and wider availability and that MRCP is more useful than CT in evaluating ductal communication and abnormalities, at many institutions, both modalities are equally used to evaluate patients with IPMNs and interchangeably used to follow-up patients with IPMNs (12,13,20,22,23). Although several previous studies demonstrated that both CT and MR imaging can be useful in determining the malignant potential of IPMNs, until now, there were no studies that assessed the intermodality agreement for depicting stigmata and worrisome features at CT or MR imaging (13,20,(24)(25)(26)(27)(28)(29). On the basis of our study results, which showed good intermodality agreement between multidetector CT and MR imaging, we believe that multidetector CT and MR imaging can be interchangeably used for the evaluation of malignant potential in IPMNs, as well as for follow-up.…”

Added value of diffusion‐weighted imaging to MR cholangiopancreatography with unenhanced mr imaging for predicting malignancy or invasiveness of intraductal papillary mucinous neoplasm of the pancreas

“…The MR criteria used in our study for the diagnosis of malignant IPMNs or invasive IPMCs were established based on the reported findings or suggested criteria from the previous studies (1,8,10,(19)(20)(21)(22)(23), which were based mainly on the features of main cystic tumor lesions, and associated findings such as the changes in the main pancreatic duct and the bile duct and pancreatic parenchymal changes (Figs. 1, 2).…”

“…Multirow detector computed tomography (MDCT) or magnetic resonance imaging (MRI) is often the first imaging ordered when the diagnosis of a pancreatic cystic neoplasm is considered (6,7). Several previous studies (1,4,(8)(9)(10)(11) on MRI and CT have demonstrated that a tumor size greater than 3-5 cm, MPD dilation greater than 5-10 mm, a thick septum, mural nodule or a parenchymal mass, and local invasion are associated with malignancy. Therefore, to stratify a malignancy and for therapeutic decision-making, it is necessary to precisely evaluate ductal changes as well as the presence of mural nodules or parenchymal involvement as seen on imaging studies.…”

Intraductal Papillary Mucinous Neoplasms of the Pancreas: Evaluation of Malignant Potential and Surgical Resectability by Using MR Imaging with MR Cholangiography

“…Even though CT is still a mainstay in the evaluation of the surgical resectability of pancreatic IPMNs with a strong preference among pancreatic surgeons, MR imaging with MRCP has come into wide acceptance in recent days (7,14,(19)(20)(21)(22)(23)(24)(25)(26)(27).…”