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Background: The goal of this study was to investigate the frequency of inhomogeneous parenchymal enhancement of the liver in magnetic resonance imaging during arterial portography (MRAP) versus computed tomography during arterial portography (CTAP)., Methods: CTAP and MRAP were performed in 29 and in 21 patients, respectively, who had suspected primary or secondary liver tumors on clinical or biological grounds. We evaluated the frequency of inhomogeneous hepatic parenchymal enhancement not related to a decrease of portal blood supply due to compression or obstruction by the tumor and physiologic variation in portal perfusion. Inhomogeneous parenchymal enhancement of the liver was classified as segmental or subsegmental and as nonsegmental., Results: Segmental or subsegmental inhomogeneous parenchymal enhancement was seen in six of 29 patients (20.1%) on CTAP and in one of 21 patients (4.8%) on MRAP. Nonsegmental inhomogeneous parenchymal enhancement was seen in five of 29 patients (17.2%) on CTAP images and in none of the patients (0%) on MRAP images. The incidence of nonsegmental inhomogeneous parenchymal enhancement was significantly lower on MRAP than on CTAP., Conclusion: MRAP was superior to CTAP in achieving homogeneous parenchymal enhancement of the liver.

New color Doppler sonography with high resolution improves the detection of liver tumors and provides better information on the hepatic vessels. Echo contrast agents which pass through the lungs open up new fields of application in the investigation of blood flow.

Purpose: Our goal was to determine the MR features of intrahepatic cholangiocarcinoma and to correlate them with pathologic findings in a surgical series., Method: MRI in 14 patients with intrahepatic cholangiocarcinoma who had undergone resection was reviewed. All patients had T1- and T2-weighted SE sequences. Contrast-material-enhanced MRI was performed in 12 cases. Comparison between findings at MRI and pathologic examination was made., Results: MRI depicted all the lesions but one satellite nodule of 2 cm diameter. All lesions were hypointense relative to the liver on T1-weighted images. On T2-weighted images, the tumors were predominantly isointense or slightly hyperintense relative to liver parenchyma in nine cases (64%) and were strongly hyperintense in five cases (36%). Central hypointense areas or bands were seen in eight cases. No capsule was detected. On contrast-enhanced MR studies, all lesions had progressive and concentric filling with contrast material. Associated findings such as vascular encasement, focal liver atrophy, or dilatation of intrahepatic bile ducts were observed in 10 cases (71%). Comparison with pathologic examination revealed that lesion signal intensity on T2-weighted MR images was due mostly to the amount of fibrosis, necrosis, and mucous secretion within the lesion. The nine isointense or slightly hyperintense lesions contained abundant fibrosis and had a low content of mucous secretion or necrosis, whereas the five hyperintense lesions contained low or moderate fibrosis and prominent mucous secretion and/or necrosis., Conclusion: Our study suggests that the MR features of intrahepatic cholangiocarcinoma are well correlated with pathologic findings, but are nonspecific. Associated findings may strengthen the diagnosis of intrahepatic cholangiocarcinoma at MRI.

The recent improvements in magnetic resonance (MR) imaging using the new ultrafast echo-planar technique for diagnosis of hepatobiliary lesions are outstanding. Besides the detection and preoperative evaluation of benign and malignant hepatobiliary tumors, angiography and cholangiography can be simultaneously performed using the techniques of MR angiography or MR cholangiography. Looking ahead, further advantages such as three-dimensional image reconstruction, no X-ray exposure, and short examination time, this MR technique will become the preferred diagnostic procedure for evaluating hepatobiliary lesions.

The frequent detection of benign liver lesions during ultrasound routine examination and a possible curative therapy of early detected malignant tumors require a reliable method of differentiation. Conventional gray-scale ultrasound, according to this problem, has been extended by the Duplex technique and color Doppler ultrasound. Measurement of blood flow velocity by Doppler in the center and at the periphery of liver lesions is not reliable enough to distinguish between benign and malignant lesions. Color Doppler ultrasound possesses some reliable criteria for differentiation. A central spot could be detected in 2 out of 12 hemangiomas, a giant spot in 1 out of 3 giant cavernous hemangiomas. The halo sign without detectable blood flow is considered to be specific for malignancy. We found this sign in 26 out of 81 malignant liver lesions and only in one benign lesion (sensitivity 32%, specificity 97%). The vascularization of focal liver lesions is excellently demonstrated with color Doppler ultrasound. This is very helpful for the diagnosis (e.g. "chaotic blood vessel architecture' in malignant tumors) and for the therapy of focal liver lesions (e.g. follow-up examinations after chemotherapy or chemoembolization). Therefore, application of Duplex and color Doppler ultrasound is highly recommended as a noninvasive diagnostic method of first choice for unknown liver lesions.

A 69-year-old female was admitted to our hospital for further examination of an intrahepatic mass which had been found while undergoing a complete physical examination. The mass measured 4 cm in size and was located in the medial segment (S4) of the liver. On computed tomography (CT), S4 was observed to be 'atrophied' and was well enhanced segmentally. A celiac angiogram showed segmental staining, and a transarterial portogram demonstrated portal stoppage of S4 from the left branch. However, no segmental intensity difference was seen on magnetic resonance imaging (MRI). An aspiration biopsy showed adenocarcinoma and thus an operation was performed under a tentative diagnosis of intrahepatic cholangiocarcinoma. The postoperative diagnosis of the tumor was combined hepatocellular and cholangiocellular carcinoma. However, no histological abnormality was seen in S4, contrary to the expectation of Zahn's infarct. In this study, we discuss the mechanism and imaging findings of Zahn's infarct, the possible reasons as to why no pathological change was seen in S4, as well as stress the rarity of reports on Zahn's infarct in cases of portal thrombus due to hepatocellular carcinoma.

In order to investigate the diagnostic value in differential diagnosis of primary liver tumors, color Doppler sonography was used preoperatively in 30 patients. Without difference, tumor hypervascularization was found in patients with hepatocellular carcinoma (2 of 4), cholangiocellular carcinoma (4 of 4), hemangioma (3 of 8), focal nodular hyperplasia (8 of 8), adenoma (3 of 4), and neuroendocrine tumor (n = 1). No vascular signal could be detected in 1 case of adenomatous hyperplasia and 2 cases of hepatocellular carcinoma, one after previous chemoembolization. Hemangioma appeared hypo- or even avascular in 5 of 8 patients. Therefore, according to our experience, the yield of color Doppler sonography is rather low for differential diagnosis and prediction of the tumor dignity. With regard to the surgical procedure, valuable information about tumor extension can be obtained particularly in central lesions close to hilar structures or liver vein confluence. Further indications result from follow-up of tumor vascularization after chemoembolization and chemotherapy.