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Purpose: To clarify the variations of the intrahepatic artery and portal vein and to verify the proper segmentation for the right anterior section of the liver., Materials and Methods: CT during arterial portography and CT angiography were performed on 64-slice multi detector row CT in 147 patients. All images were transferred to a workstation for analysis using multi-image-fusion mode. We investigated the spatial relationship between hepatic artery and portal vein in the right hemiliver and the segmentation of the right anterior hepatic artery and portal vein., Results: The spatial anatomy of right hepatic arteries and portal vein was (1) anterior and posterior hepatic artery run superior and inferior to anterior portal vein, respectively (47.6%), (2) one anterior hepatic artery runs superior to and another one runs inferior to anterior portal vein (15%), (3) anterior and posterior hepatic arteries run superior to anterior portal vein (11.6%), (4) anterior and posterior hepatic arteries run inferior to anterior portal vein (7.5%), and (5) one posterior hepatic artery runs superior to and another one runs inferior to anterior portal vein (6.8%). The combined anatomy of right anterior artery and portal vein with regard to segmentation was classified as (1) dorso-ventral (26.5%), (2) dorso-ventral and inferior (10.9%), (3) multiple (18.4%), and (4) superior and inferior segments (1.4%)., Conclusion: There are various types of spatial anatomy of intrahepatic artery and portal vein. The hepatic arteries as well as portal veins of right anterior section of the liver could be divided into dorsal and ventral, not superior and inferior., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To investigate the imaging features of portal biliopathy with emphasis on MR cholangiopancreatography (MRCP). The ancillary vascular findings of portal biliopathy were also evaluated by accompanying MR portography, dynamic contrast-enhanced (CE) CT, and dynamic CE MRI studies., Materials and Methods: Sixteen patients with portal cavernoma were included in the study. Patients had undergone MRCP (n=16) studies accompanied by MR portography (n=13), dynamic CE CT (n=3) or dynamic CE MRI (n=2) of the liver. Two patients had undergone both dynamic CE CT and dynamic CE MRI. Two radiologists evaluated all the examinations together, retrospectively. MRCP images were analyzed for the presence of biliary stenosis, upstream (prestenotic) dilatation, wavy appearance of the bile ducts, angulation of the common bile duct (CBD), and choledocholithiasis. MR portography, dynamic CE CT and dynamic CE MRI studies were evaluated for the existence of portal cavernomas, and the presence of gall bladder/choledochal varices., Results: All patients had signs of portal biliopathy on MRCP. Frequencies of the biliary findings on MRCP were as follows: biliary stenosis, 93.7%; upstream dilatation, 68.7%; wavy appearance of the biliary tree, 87.5%; angulation of the CBD, 75%. None of the patients had choledocholithiasis. Frequencies of the ancillary vascular findings detected on CE studies were as follows: gall bladder varices, 100%, choledochal varices, 93.7%., Conclusion: MRCP features of portal biliopathy in order to their frequencies were as follows: biliary stenosis, wavy appearance of the bile ducts, angulation of the CBD, and upstream dilatation of the bile ducts.

The aim of this study was to evaluate multidetector helical computed tomography (MDCT), superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging, and CT arterial portography (CTAP) and CT during hepatic arteriography (CTHA) for the detection and diagnosis of hepatocellular carcinomas (HCC). This included visual correlations of MDCT and SPIO-MR imaging in the detection of HCC using receiver operating characteristic (ROC) analysis. Twenty-five patients with 57 nodular HCCs were retrospectively analyzed. A total of 200 segments, including 49 segments with 57 HCCs, were reviewed independently by three observers. Each observer read four sets of images (set 1, MDCT; set 2, unenhanced and SPIO-enhanced MR images; set 3, combined MDCT and SPIO-enhanced MR images; set 4, combined CTAP and CTHA). The mean Az values representing the diagnostic accuracy for HCCs of sets 1, 2, 3, and 4 were 0.777, 0.814, 0.849, and 0.911, respectively, and there was no significant difference between sets 3 and 4. The sensitivity of set 4 was significantly higher than those of set 3 for all the lesions and for lesions 10 mm or smaller (p<0.05); however, for lesions larger than 10mm, the sensitivities of the two sets were similar. No significant difference in positive predictive value and specificity was observed between set 3 and set 4. Combined MDCT and SPIO-enhanced MR imaging may obviate the need for more invasive CTAP and CTHA for the pre-therapeutic evaluation of patients with HCC more than 10mm.

Superparamagnetic iron oxide (SPIO) particles are as MR contrast media composed of iron oxide crystals coated with dextran or carboxydextran. These particles are sequestered by phagocytic Kupffer cells in normal reticuloendothelial system (RES), but are not retained in tumor tissue. Consequently, there are significant differences in T2/T2* relaxation between normal RES tissue and tumors, which result in increased lesion conspicuity and detectability. The introduction of SPIO has been expected to substantially increase the detectability of hepatic metastases. For focal hepatocellular lesions, it has been documented that SPIO-enhanced MR imaging exhibits slightly better diagnostic performance than dynamic helical CT in the detection of hypervascular hepatocellular carcinoma (HCC). A combination of dynamic and static MR imaging technique using T1- and T2 imaging criteria appears to provide clinically more useful patterns of enhancement. SPIO-enhanced MR imaging also provides information useful for differential diagnosis, via enhancement of RES-containing tumors. With the exploitation of rapid T2*-sensitive sequences, SPIO-enhanced dynamic MR imaging may become comparable to gadolinium-enhanced dynamic MR imaging and dynamic studies with multidetector-row CT. SPIO-enhanced MR imaging plays an important role in therapeutic decision-making for patients with HCC.

The radiologic diagnosis of liver metastasis involves detection, characterization, and tumor staging. Knowledge of the histopathologic changes that occur with metastases provides the best approach to the accurate interpretation of radiologic imaging findings, and in particular, radiologists need to choose appropriate imaging methods based on such knowledge. Because the majority of metastases are hypovascular, the merits of the routine acquisition of hepatic arterial dominant-phase images by contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI) are disputable. Hepatic arterial dominant-phase images may be obtained when hypervascular tumors are suspected or three-dimensional CT angiography is necessary. And, imaging during the portal venous phase is essential for detecting metastases, evaluating intrahepatic vessel invasion, and for assessing intratumoral necrosis or fibrosis. Equilibrium- to delayed-phase imaging 3-5 min after contrast administration may improve the detection of intratumoral fibrosis, and occasionally lead to more accurate tissue characterization. MRI offers diagnostic information on vascularity, amount of free water, hemorrhage, fibrosis, necrosis, and water molecule diffusion in metastases. And, liver-specific contrast agents like superparamagnetic iron oxide, liposoluble gadolinium chelate, and manganese may improve the MRI-based diagnosis of liver metastases.

Objective: To determine whether there is a difference in the prevalence of non-tumoral perfusion defects (NTPD) in left hepatic lobe during CT arterial portography (CTAP) through splenic (SA) and superior mesenteric artery (SMA) injection., Methods and Patients: For the preoperative evaluation, 59 patients (20 females, 39 males) who either have colorectal carcinoma metastasis (n: 42) or hepatocellular carcinoma (n: 17) underwent CTAP examination. Patients were divided into two groups (SA and SMA) according to the injection artery. The presence and type of NTPD in the left hepatic lobe were determined and compared., Results: There were significant differences in peripherally located wedge shaped, perihilar-periligamentous and pericholecystic NTPD, but no significant difference was found in lobar/segmental defects between the groups., Conclusions: Our study demonstrated lower prevalence of NTPD in the left hepatic lobe in CTAPs performed through SA injection and we think that this could be explained by the streamlining of portal blood flow.

Computed tomography (CT) examination of the liver has continually been improving our understanding and assessment of liver disease since its introduction into clinical practice. The hallmark of the advances in CT imaging has undoubtably been helical CT, which made a great impact on body imaging with its many advantages, the most important being optimization of multiphasic enhanced studies, CT hepatic angiography (CTHA), and CT arterial portography (CTAP). Various applications and protocols of CT imaging rendering advantages and drawbacks to the technique are highlighted in this review article.

A case of an unusual form of hepatodiaphragmatic portosystemic shunt arising from the periphery of left posterosuperior portal vein branch, running beneath the inferior aspect of left hemidiaphragm and draining into the left lateral abdominal wall is demonstrated and assessed with digital subtraction portography, maximum-intensity-projection images reconstructed from helical CT during arterial portography and pulsed Doppler sonography with flow velocity measurement. This is a reported case of this unusual intrahepatic portosystemic shunt and discussion on the utility of current radiological techniques.

To attempt to determine the characteristic imaging features of intrahepatic cholangiocarcinoma on spiral CT during arterial portography (CTAP), spiral CTAP examinations of 17 patients with pathologically confirmed intrahepatic cholangiocarcinoma were reviewed in consensus by three radiologists. The diameter of the tumors ranged from 1 to 12 cm (mean diameter, 6.6 cm). All tumors (100%) were hypoattenuating masses on spiral CTAP. In 11 cases, the tumor was homogeneous in attenuation (65%). Tumor margins were smooth and regular in 11 cases (65%). Vascular invasion was found in 14 cases (82%). Intrahepatic bile duct dilatation was present in seven cases (41%). This review shows that intrahepatic cholangiocarcinoma is associated with a constellation of findings on spiral CTAP. The presence of a low attenuation homogeneous intrahepatic mass with vascular invasion and intrahepatic bile duct dilatation on spiral CTAP images should raise the possibility of intrahepatic cholangiocarcinoma. However, these findings can be associated with other types of primary and secondary malignant hepatic tumors.

Right anterior caudocranial oblique (RACCO) projections were evaluated for transarterial portography with digital subtraction angiography. For RACCO projection, the image intensifier was tilted 25 degrees caudally and 30 degrees to the patient's right with the patient in the supine position. The abnormal findings imaged in 20 patients were analyzed by types of abnormalities and their locations in the portal venous systems by comparing RACCO and PA projections. The RACCO view was superior to the PA projection for demonstrating either encasements or tumor thrombi in relatively proximal segments of the portal venous branches. Two encasement lesions and a tumor thrombus were imaged only on the RACCO projection. However, the RACCO projection had no definite advantage over the PA view for showing encasements or tumor thrombi in the distal segmental branches. The RACCO projection was superior to the PA view for demonstrating defects in the hepatograms of some hepatic segments (S5 and S8). We concluded that the RACCO view is extremely useful and is indicated for angiographic work-ups of hepatic or biliary lesions when abnormalities are suspected in proximal portal venous branches.