The role of MRI in the diagnosis and follow-up for cystic pancreatic laesions

Introduction: With the widespread use of cross-sectional imaging and the technical developments 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 in the last decades. These techniques have allowed improved spatial and contrast resolution especially. MR cholangiopancreatography demonstrating the morphologic features of the cyst (septa and mural nodules), the presence of communication between the cystic lesion and the pancreatic duct, and evaluating the extent of pancreatic ductal dilatation. The cystic lesions includes non-neoplastic lesions (i.e. pseudocyst) and cystic neoplasms [serous cystadenomas(SCA), mucinous cystic neoplasms and intraductal papillary mucinous neoplasms (IPMN)]. Mucin-producing neoplasms, except side branch IPMN(Sb-IPMN), have malignant potential.

Materials and Methods: During two years eight patients with serous cystadenoma (pps: 5), or with side-branch IPMN (pps: 3) were examined. Male to female ratio 1:1, mean age: 70 years (61 – 77). All patients were diagnosed by ultrasound, ERCP, CT and MRCP, and followed by ultrasound and MRCP.

Results: US was able to demonstrate the internal architecture in these cysts, however, the presence of air in overlying bowel limited the utility of this technique transabdominally. The CT protocol of the pancreas with multiplanar and curved reconstructions seems to be recommended for the presurgical evaluation of pancreatic cysts, similar to patients with pancreatic adenocarcinoma, and offers accurate information about tumor staging and vascular anatomy. MRCP was superior to MDCT for demonstrating the communication between the main pancreatic duct (MPD) IPMN and a branch duct. According to literature (Sendai criteria) the presence of clinical symptoms, mural nodules, the diameter of the laesion > 3 cm are indicative of malignancy in a branch and mixed type IPMN, but we have not observed such a development in this short period.

Conclusion: Follow-up of Sb-IPMN and SCA every six months by US, and 1 – 2 years by MRCP is a feasible strategy. In these cases, the consideration of surgical techniques, as partial resection of the pancreas is a preferred strategy instead of the long term follow-up. The Sendai criteria are useful for indication of surgery in due time.