Su Kyung An

Macrocystic Neoplasms of the Pancreas: CT Differentiation of Serous Oligocystic Adenoma from Mucinous Cystadenoma and Intraductal Papillary Mucinous Tumor

OBJECTIVE The purpose of our study was to determine useful CT criteria for differentiating serous oligocystic adenomas of the pancreas from other similarly presenting neoplasms, such as mucinous cystadenoma and intraductal papillary mucinous tumor of the branch duct type. MATERIALS AND METHODS Forty-one patients with histologically confirmed macrocystic neoplasms of the pancreas were enrolled: serous oligocystic adenoma in 10 patients, mucinous cystadenoma in 13, and intraductal papillary mucinous tumor in 18. Location, greatest dimension, shape, presence of mural nodules, presence of wall calcification, and the extent and degree of main pancreatic duct (MPD) dilatation were analyzed with CT. The lesions were categorized into seven groups according to their shapes: multicystic, lobulated contour with and without internal septation, smooth contour with and without internal septation, pleomorphic cystic, and clubbed fingerlike cystic. Comparative studies were performed using Fishers exact test and the Mann-Whitney U test. RESULTS Significant differences in lesion shape were found between serous oligocystic adenoma and the other macrocystic neoplasms (mucinous cystadenoma [p < 0.05], intraductal papillary mucinous tumor [p < 0.05]). Serous oligocystic adenoma had a multicystic or lobulated contour with or without septation, whereas mucinous cystadenoma had a smooth contour with or without septation and intraductal papillary mucinous tumor had either a pleomorphic or a clubbed fingerlike cystic shape. Serous oligocystic adenoma showed proximal MPD dilatation from the lesion, whereas intraductal papillary mucinous tumor showed distal or whole MPD dilatation (p < 0.05). No significant difference was apparent among the three diseases in terms of location, greatest dimension, or presence of calcification or mural nodules. CONCLUSION Serous oligocystic adenoma of the pancreas has characteristic CT findings that differentiate it from other cystic tumors. It appears as a multicystic or lobulated cystic lesion with septation.

Gadobenate Dimeglumine-Enhanced Liver MRI as the Sole Preoperative Imaging Technique: A Prospective Study of Living Liver Donors

OBJECTIVE The objective of our study was to determine whether gadobenate dimeglumine-enhanced MRI is practical as the sole preoperative imaging technique for the examination of living liver donors. SUBJECTS AND METHODS Forty-four consecutive living donor candidates underwent liver MRI on a 1.5-T MR unit. The MR examination included in- and opposed-phase T1-weighted gradient-echo imaging, T2-weighted MR cholangiography, MR angiography (MRA) and parenchymal phase imaging after the administration of gadobenate dimeglumine, and 60-minute delayed T1-weighted MR cholangiography. Two abdominal radiologists analyzed the images regarding the depiction of the biliary duct anatomy and the hepatic vascular anatomy and for the presence of focal or diffuse liver disease. The findings were compared with intraoperative cholangiographic and surgical findings in 24 patients who underwent partial hepatectomy. RESULTS In the 24 patients who underwent liver harvesting, 10 had biliary anatomic variants confirmed by intraoperative cholangiography. T2-weighted MR cholangiography allowed a correct diagnosis in 75% (n = 18/24) and T1-weighted MR cholangiography in 79% (n = 19/24) of these patients. When we evaluated the bile duct anatomy using the combined findings of T2- and T1-weighted MR cholangiographic images, the diagnostic accuracy increased to 92% (n = 22/24), but the difference was not statistically significant (p > 0.05). MRA showed a diagnostic accuracy of 79% (n = 19/24) for the hepatic arterial anatomy, 100% (n = 24/24) for the portal venous anatomy, and 96% (n = 23/24) for the hepatic venous anatomy. CONCLUSION Gadobenate dimeglumine-enhanced MRI allows comprehensive assessment of the biliary and hepatic vascular systems and the hepatic parenchyma and can serve as the sole preoperative imaging test for living liver donor candidates.

Enhancement characteristics of cholangiocarcinomas on mutiphasic helical CT: emphasis on morphologic subtypes

PURPOSE The purpose of this study was to characterize the differences in CT enhancement pattern among the morphologic subtypes of cholangiocarcinomas. MATERIALS AND METHODS Unenhanced, hepatic arterial (HAP), and portal venous phase (PVP) CT images of 84 patients with pathologically proven cholangiocarcinoma were retrospectively reviewed. Tumors were of the following types: 27 mass-forming, 39 periductal-infiltrating, and 18 intraductal. The CT attenuation values of tumors were measured at each phase. The tumor enhancement ratio (ER) on HAP and PVP was calculated. RESULTS Each cholangiocarcinoma subtype produced characteristic enhancement relative to liver on HAP and PVP images: mass-forming tumors demonstrated hyperenhancing periphery and hyopenhancing centers; periductal-infiltrating tumors, hyperenhancing; and intraductal tumors, hypoenhancing. The ER of the tumor types was significantly different (P<.001, HAP, PVP): periductal-infiltrating tumors showed the highest ER (2.5; 3.8); the centers of mass-forming tumors, lowest (1.5; 2.2); the peripheries of mass-forming tumors, high (2.1; 3.0); intraductal tumors, low (1.9; 2.6). CONCLUSION Cholangiocarcinoma subtypes tended to exhibit distinct enhancement characteristics. Knowledge of these enhancement patterns may aid diagnosis and surgical planning.

Sonographic Features of an Intraductal Polypoid Mass Differentiation Between Hepatocellular Carcinoma and Intraductal Cholangiocarcinoma

Objective. To identify laboratory and sonographic features capable of differentiating hepatocellular carcinoma (HCC) invading the bile duct from intraductal cholangiocarcinoma (IDCCC). Methods. Nine patients with HCC invading the bile duct and 8 patients with IDCCC were found in our radiologic and pathologic database. Laboratory (α‐fetoprotein, cancer antigen 19‐9, total bilirubin, and alkaline phosphatase) and sonographic findings were retrospectively reviewed by 2 reviewers by consensus. Sonographic findings included the presence and echo texture of parenchymal masses, the margin and echo texture of intraductal masses, continuity between parenchymal and intraductal masses, cystic ductal dilatation or wall thickening of the bile duct, and the presence of associated chronic liver disease. Results. Significant differences were found in the levels of total bilirubin (14 versus 3.5 mg/dL), α‐fetoprotein (2984 versus 5 ng/mL), and cancer antigen 19‐9 (8574 versus 1861 U/mL) in HCC and IDCCC (P < .05). Echogenicity of the intraductal masses was iso or low in 8 (88.9%) of 9 HCCs and 3 (37.5%) of 8 IDCCCs (P < .05). In all 7 patients with HCC but in no patient with IDCCC, the parenchymal masses were contiguous with the intraductal masses (P < .05). Cystic ductal dilatation of bile duct was seen in 8 (88.9%) of 9 HCCs and 3 (37.5%) of 8 IDCCCs (P < .05). All 9 (100%) of 9 HCCs and 3 (37.5%) of 8 IDCCCs were associated with chronic liver disease (P < .05). Parenchymal masses occurred in 7 patients with HCC (77.8%) and in 3 patients with IDCCC (37.5%), but the difference was not statistically significant (P = .153). The margins of the intraductal masses were smooth in all 9 (100%) of 9 HCCs and lobulated in 3 (37.5%) of 8 IDCCCs (P = .082). Conclusions. Combined interpretation of laboratory and sonographic features may help in the differentiation of HCC with bile duct invasion and IDCCC.