Magnetic Resonance Imaging versus Computed Tomography for Biliary Tract Intraductal Papillary Mucinous Neoplasm (BT-IPMN): A Diagnostic Performance Analysis

Abstract

BACKGROUND In most cases, biliary tract intraductal papillary mucinous neoplasm (BT-IPMN) is depicted by pathological features rather than on imaging modalities, but fine-needle aspiration cytology cannot provide complete information on tumor(s). Computed tomography (CT) has the advantage of high spatial resolution and multiplanar capabilities, while magnetic resonance imaging (MRI) has greater contrast resolution than CT. The purpose of this study was to compare the diagnostic performance of CT vs. MRI for the diagnosis of BT-IPMN using surgical pathology as the reference standard. MATERIAL AND METHODS Data from CT, MRI, and surgical pathology of 210 patients with complaints of abdominal discomfort, vomiting, and/or jaundice for at least 6 months were included in the analysis. Intra-observer agreements for diagnosis of neoplasm was evaluated by kappa statistics. RESULTS CT and MRI respectively detected 171 and 33 patients with BT-IPMN, 6 and 176 with biliary intraductal tubulopapillary neoplasms (BT-ITPN), and 28 and 6 with inconclusive results. Surgical pathology reported 179 patients with BT-IPMN and 25 patients with BT-ITPN. CT and MRI both had the same accuracy (97.14%) for BT-IPMN. The sensitivities for diagnosis of BT-IPMN were 87.75%, 83.81%, and 81.43% for the surgical pathology, MRI, and CT, respectively. Intra-observer agreements for diagnosis of neoplasm were substantial (k=0.79), perfect (k=0.81), and perfect (k=0.85) for CT, MRI, and surgical pathology, respectively. CONCLUSIONS MRI appears to be a more accurate and reliable method than CT for depicting BT-IPMN.

Figure 1

Flow diagram of the study.

Figure 2

Computed tomography images of a male patient, age 67 years, with recurrent upper abdominal pain and the elevated serum liver enzyme level. Direct enhancement showed that the volume of the left lobe of the liver increased, and a solid non-uniform enhancement shadow was seen inside. The boundary was clear and the size was about 7.7×4.7 cm. The multiple wall nodules were enhanced and the lesion was connected with the left intrahepatic bile duct. There was no abnormal enhancement in the liver parenchyma. The bile duct and common bile duct were significantly expanded. The widest diameter of the common bile duct was about 3.3 cm. The gallbladder volume was increased, no abnormal density appeared in the gallbladder, and the pancreas and spleen were normal. No obvious abnormal enhancement shadows were observed. There was local aortic wall calcification. Sweeping and the left kidney views show a small circle of low-density, non-enhanced shadows, only a few millimeters in diameter, with no obvious enlarged lymph nodes after the retroperitoneum. No signs of ascites were found. (A) Liver left lobe cystic space-occupying lesion with intrahepatic bile duct and common bile duct dilatation, gallbladder enlargement, intraductal papillary myxoma (the contrast-enhanced axial view). (B) Aortic sclerosis (the contrast-enhanced axial view), (C) Left kidney small cyst (the contrast-enhanced sagittal view). (D) The non-enhanced axial view.

Figure 3

The axial view of magnetic resonance imaging of a male patient, aged 67 years, with recurrent upper abdominal pain and elevated serum liver enzyme level. The volume of the left lobe of the liver is increased, and a cystic solid abnormal signal is seen inside. It has a long T1 long T2 signal, and there are multiple nodular T2 signals, with the T1 slightly longer. The boundary is clear and the size is about 7.7×4.7 cm. After the enhancement, the solid part and the wall of the capsule were obviously enhanced. The lesion was connected with the left intrahepatic bile duct. There was no abnormal enhancement in the parenchyma of the remaining liver. The intrahepatic bile duct and common bile duct were obviously dilated. The wide diameter of the common bile duct was about 3.0 cm. The gallbladder volume was increased, no abnormal signal appeared in the gallbladder, there were no abnormalities in the morphology of the pancreas and spleen, and no obvious abnormal enhancement was observed. Sweeping and left kidney views show a small class of circular low signal without enhancement, only a few millimeters in diameter, with no obvious enlarged lymph nodes after the retroperitoneum. No signs of ascites were found. (A) T1-weighted, unenhanced view. (B) T2-weighted unenhanced view. (C) Diffused-weighted image, and (D) Contrast-enhanced view. Liver left lobe cystic space-occupying lesion with intrahepatic bile duct and common bile duct dilatation, gallbladder enlargement, and intraductal papillary myxoma. Left kidney small cyst.

Figure 4

A surgical pathological analysis. (A) Gross appearance of the resected specimen. Intraductal papillary tumor, intestinal type, with low-grade dysplasia. The mass was approximately 0.1 cm from the leading edge of the liver. IHC: Ki67 (+, 30%), p53 (+, 10%), CK7 (small foci +), CK19 (+), CDX2 (+), MUC-1 (cavity +), Muc-2 (+), MUC5 (+), MUC6 (part +) (right half hepatectomy specimen). (B) Histopathology of hepatic lymph nodes of reactive hyperplasia of resected specimen (hematoxylin and eosin staining). Compared with the anterior piece, after drainage of the liver abscess, the drainage area was seen in the operation area, and the VII segment of the liver was seen as a lamellae low-density shadow, which was smaller than the front and had ring-shaped enhancement. During the operation, multiple morphological abnormalities were observed in the liver.

Figure 5

Beneficial score analysis.