Microcystic features at US: a nonspecific sign for microcystic adenomas of the pancreas

Intraoperative ultrasonography of the pancreas

Intraoperative ultrasonography (US) of the pancreas is a versatile technique that provides excellent spatial and contrast resolution and real-time imaging capabilities, making it useful for diagnostic imaging as well as for guidance of laparoscopic and open operative procedures. Intraoperative US may be used for applications such as staging and localizing tumors; performing regional metastatic surveys; documenting arterial and venous patency; identifying endocrine tumors; distinguishing pancreatitis from a neoplasm; and guiding biopsy, duct cannulation, and drainage of abscesses or cysts. The scanning approach and technique vary according to the application, with many different equipment and transducer options and sterilization methods available. With increasing clinical demands for intraoperative US, it is essential that radiologists be familiar with its uses and technique. In addition, to properly perform intraoperative US and accurately interpret the images, knowledge of normal and variant pancreatic and vascular anatomy and relevant landmarks is needed. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.307105051/-/DC1.

Intraoperative ultrasound of the pancreas

Intraoperative ultrasound provides spatial resolution of the pancreas superior to computed tomography, magnetic resonance imaging, and transabdominal sonography. This pictorial essay will review common benign and malignant pancreatic processes including the following: pancreatic ductal adenocarcinoma, pancreatitis, endocrine tumors, mucinous cystic neoplasm, intraductal papillary mucinous neoplasm, serous cystadenoma, and solid pseudopapillary tumor. The use of intraoperative ultrasound in specific surgical situations will be discussed, which include the following: (1) identification of insulinoma(s) which are not detectable preoperatively, (2) identification of the pancreatic duct to determine dissection planes for chronic pancreatitis surgery (eg, Puestow procedure) and for tumor resection, and (3) staging purposes for malignant disease.

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.

The Spectrum of Cystic Masses of the Pancreas: Imaging Features and Diagnostic Difficulties

Cystic masses of the pancreas comprise a diverse group of pathologic entities ranging from pseudocysts to cystic tumors. Although their presentations may be similar, the appropriate treatment and patient management can differ greatly. There is an overlap in radiologic features, but the clinical context and some imaging findings are useful in differentiating among these entities; the differential diagnosis could be considerably reduced and it is generally possible to reach the correct diagnosis. In this article, we review imaging characteristics and radiologic patterns of both common and uncommon cystic masses of the pancreas. An algorithmic approach for the management of cystic pancreatic lesions is proposed.

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.