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An advanced technique for multiple breath-hold volumetric modulated arc therapy (VMAT) has been proposed under fluoroscopic image guidance with a fiducial marker implanted close to a tumor. The marker coordinates on a digitally reconstructed radiography image at a gantry start angle, under a planned breath-hold condition, were transferred to the fluoroscopic image window. Then, a reference lateral line passing through the planned breath-hold marker position was drawn on the fluoroscopic image. Additional lateral lines were further added on both sides of the reference line with a distance of 3 mm as a tolerance limit for the breath-hold beam delivery. Subsequently, the patient was asked to breathe in slowly under fluoroscopy. Immediately after the marker position on the fluoroscopic image moved inside the tolerance range, the patient was asked to hold the breath and the VMAT beam was delivered. During the beam delivery, the breath-hold status was continuously monitored by checking if the deviation of the marker position exceeded the tolerance limit. As long as the marker stayed within the tolerance range, a segmented VMAT delivery continued for a preset period of 15 to 30 seconds depending on the breath-hold capability of each patient. As soon as each segmented delivery was completed, the beam interrupt button was pushed; subsequently, the patient was asked for free breathing. This procedure was repeated until all the segmented VMAT beams were delivered. A lung tumor case is reported here as an initial study. The proposed technique may be clinically advantageous for treating respiratory moving tumors including lung tumor, liver cancer, and other abdominal cancers.

Purpose: The purpose of this work was to clarify the mechanism of peritumoral rim enhancement of metastatic liver cancer. Method: Twenty-nine liver metastases of colon cancer were examined by single-level dynamic CT during hepatic arteriography, which was performed without table feed. We analyzed these findings and correlated them with the histopathologic findings. Results: Eleven metastases were hypervascular and 18 were hypovascular. Early appearance of rim enhancement was seen in 3 of 10 hypervascular metastases and 17 of 18 hypovascular metastases (p < 0.01). The time of appearance and thickness of peritumoral rim enhancement showed no apparent correlation with the desmoplastic reaction or inflammation in the surrounding hepatic parenchyma. Conclusion: Two types of intra- and peritumoral enhancement were observed. Peritumoral rim enhancement was considered to be due mainly to the drainage of blood flow from the tumor to the surrounding hepatic parenchyma in hypervascular metastasis or increased arterioportal shunts surrounding the tumor in hypovascular metastasis.

To compare the effectiveness of biphasic computed tomography (CT) and magnetic resonance (MR) imaging in the detection of pancreatic islet cell tumors.Retrospective quantitative, qualitative, and receiver operating characteristic analyses of biphasic CT and MR imaging were performed in 19 patients with 26 histopathologically proved islet cell tumors. Delayed arterial dominant-phase (AP) and portal venous-phase (PVP) biphasic CT was performed after the administration of contrast material. MR imaging included T1-weighted spin-echo (SE) and T2-weighted SE or fast SE imaging, fat-saturated T1-weighted SE imaging, dynamic contrast material-enhanced T1-weighted gradient-echo imaging, and delayed enhanced T1-weighted SE imaging with or without fat saturation.PVP CT and delayed enhanced T1-weighted MR imaging had the highest A(z) values (0.98 and 0.97, respectively; P.05). Delayed enhanced T1-weighted MR imaging had the highest relative sensitivity (14-15 [74%-79%] of 19 lesions), followed by PVP CT (18-19 [69%-73%] of 26 lesions), AP CT (17-19 [65%-73%] of 26 lesions), fat-saturated T1-weighted MR imaging (eight to 10 [57%-71%] of 14 lesions), T2-weighted (16-17 [62%-65%] of 26 lesions), T1-weighted (15-18 [58%-69%] of 26 lesions) MR imaging, and dynamic MR imaging (nine [56%] of 16 lesions).Biphasic (especially PVP) CT and MR imaging have similar effectiveness in the detection of islet cell tumors if fat-saturated T1-weighted and delayed enhanced T1-weighted MR imaging are included.

The distribution of nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd)-positive neurones was investigated in the chicken caecum. Double staining combined NADPHd histochemistry with immunohistochemistry for neural nitric oxide synthase (nNOS) indicated that NADPHd-positive neurones also showed immunoreactivity for nNOS. NADPHd-positive nerve cell bodies were observed in both the myenteric and the submucous plexuses. Nerve fibres showing enzyme activity were mainly distributed in the circular muscle layer, but only a few fibres in the mucosal layer. Fine nerve fibres showing NADPHd activity were found running between germinal centres in the caecal tonsil. Quantitative analysis showed no significant differences in the number of enzyme-positive nerve cell bodies per ganglion of the myenteric and the submucous plexuses among three different caecal regions; proximal, middle and distal regions. Larger numbers of ganglia were detected in the submucous plexus than the myenteric plexus at all three regions. These data indicate that nitrergic neurones in the submucous plexus mainly project to the circular muscle layer in the chicken caecum. It is possible that nitrergic nerves regulate the motility of the chicken caecum.

Different imaging appearances of giant hyperplastic change of the caudate lobe of the liver are presented in a patient with liver cirrhosis. The mass like caudate lobe was isoechoic on ultrasound, hypodense on postcontrast computed tomography (CT), hyperintense on T1-weighted magnetic resonance, images and isointense on T2-weighted images. These imaging findings are similar to those of dysplastic nodule in cirrhotic liver. The caudate lobe received normal portal flow on CT during arterial portography, but superior mesenteric arteriography showed precocious or early division of the caudate portal branch. We suspect that caudate hyperplastic change may be correlated to anomalous caudate portal vein branch.

The purpose of our study was to assess the efficacy of single-level dynamic CT during hepatic arteriography (D-CTA) in the differentiation between hypervascular hepatocellular carcinoma (HCC) and hypervascular pseudolesion.D-CTA was performed in nine cases with HCC and nine cases with pseudolesion. Findings on D-CTA were retrospectively analyzed.The transition of the stain of pseudolesion on D-CTA was divided into three phases: (1) inflow of the contrast material into the portal vein within the lesion, (2) lesion staining, and (3) fading out of the stain; that of HCC was divided into four phases: (1) inflow of CM into tumor, (2) tumor staining, (3) inflow of CM into the adjacent liver, and (4) coronal stain of adjacent liver. The coronal stain was seen in all HCCs but not in any pseudolesions.The present study suggest that D-CTA is a helpful option in the differentiation between HCC and pseudolesion.

To assess the intrahepatic portal flow in patients with Budd-Chiari syndrome (BCS) by computed tomography (CT) during arterial portography (CTAP).Five patients with BCS [with (n = 3) and without (n = 2) inferior vena cava (IVC) obstruction] underwent both CTAP and postcontrast CT following CTAP. CTAP and postcontrast CT after angioplasty were also performed in one patient. Findings on CTAP and postcontrast CT were analyzed retrospectively.Patients with IVC obstruction and a patent large hepatic vein showed homogeneous hepatic enhancement on CTAP. Patients without IVC obstruction and with no patent large hepatic veins showed heterogeneous hepatic enhancement, which consisted of patchy enhancement and more definite enhancement in the central part of the liver. On postcontrast CT, the patchy enhancement was enlarged compared with that on CTAP in these patients. The heterogeneous hepatic enhancement became homogeneous in the patient who underwent angioplasty.We suggest that the more marked the blood congestion, the more heterogeneous the hepatic enhancement becomes on CTAP. Heterogeneous hepatic enhancement on CTAP is seen in such cases without any patent hepatic veins.

To determine the anatomy of the portal venous system in the posterior aspect of segment IV of the liver by using helical computed tomography (CT) during arterial portography (CTAP).One hundred consecutive patients underwent CTAP. Helical CT during hepatic arteriography was performed in 20 patients. In seven patients with hepatocellular carcinoma in the posterior aspect of segment IV, the feeding arteries were also analyzed.A venule from the intrahepatic portal vein to segment IV was seen in all patients. Other findings included a tiny venule from the distal part of the main left portal vein (n = 36), from the proximal left main portal vein (n = 20), and from the right portal vein (n = 18). Aberrant right gastric venous drainage and/or parabiliary venous drainage directly into the posterior aspect was present in 14 patients. In two patients, a tiny accompanying artery was seen on images from CT during hepatic arteriography. In seven patients with hepatocellular carcinoma, the main feeding artery branched from the right (n = 2) or left (n = 5) hepatic artery.CTAP adequately demonstrates the tiny portal venous and arterial branches from the main right or left portal vein that distribute to the posterior aspect of segment IV. Knowledge of this vascular anatomy is clinically important.

Background: Aberrant gastric venous drainage (AGVD) into the posterior edge of the medial segment of the liver (segment IV) is the main cause of pseudolesion on computed tomography (CT) during arterial portography. We estimated the prevalence of AGVD into the medial segment of the liver with color and power Doppler ultrasound (US).

To evaluate the causes of intrahepatic segmental areas of signal hypointensity [corrected] on T1- and T2-weighted spin-echo (SE) and gradient-echo (GRE) magnetic resonance (MR) images.Six patients in whom wedge-shaped hypointense areas were seen on hepatic MR images underwent examination with ultrasound (US), computed tomography (CT), angiography, and CT during arterial portography (CTAP). Histologic examination was performed in three patients.The affected liver parenchymas were best depicted as segmental or lobar hypointense areas on GRE images. Angiography and CTAP revealed that portal blood supply to the hypointense areas was absent or decreased due to portal vein tumor thrombus and arterioportal shunt (n = 1), compression of a portal branch by tumor (n = 2), portal vein thrombosis (n = 1), or arterioportal shunt (n = 2). Iron deposition in the hepatocytes was evident in all three patients with histologic correlation.Segmental signal hypocoagulability was generally due to hepatocyte iron deposition and was accompanied and possibly caused by a disturbance in portal flow.

Our aim was to clarify whether copper or copper-binding protein (CBP) in hepatocytes makes adenomatous hyperplasia of the liver (AH) hyperintense on T1-weighted magnetic resonance (MR) image, using 40 AHs arising in cirrhotic livers. Copper was detected in 33 AHs (82.5%) and CBP in 29 AHs (72.5%). Copper and CBP were more numersous than in the surrounding liver in 7 and 11 AHs, respectively, while in the remaining cases, both copper and CBP were similarly observed or absent in AH and the surrounding cirrhotic liver. Copper and CBP were generally small in their amount, when present, and were not evenly located. On the other hand, on T1-weighted MR image, eight surgically resected AHs were evenly hyperintense. Further, in four of all eight hyperintense AHs, neither copper nor CBP increased compared with those in the surrounding liver. That is, we could not find any differences on T1-weighted image among AHs which contained more copper and CBP than the surrounding liver, those which contained as much copper and CBP as the surrounding liver, and those which contained neither copper nor CBP. In this study it was suggested that on T1-weighted MR image, copper- (and/or CBP-) accumulating AH is not discernible from copper- (and/or CBP-) free AH.

Results of orcein staining and findings obtained with non-contrast-medium-enhanced computed tomography (CT) and magnetic resonance (MR) imaging (T1- and T2-weighted images) were compared for 53 histologically confirmed hepatocellular carcinomas (HCCs). HCCs were 5 cm in the largest diameter. Three lesions with diffuse and strong orcein staining were highly attenuating on nonenhanced CT images. Electron x-ray microanalysis of one of them revealed copper. The high attenuation value at nonenhanced CT may have been due to the abundant copper-binding protein in the cancer cells. The difference between orcein staining results and attenuation patterns at CT was statistically significant (chi 2, P less than .001). It could not be concluded that the paramagnetic effects of copper in HCC had an influence on signal intensity on MR images. The difference between orcein staining results and signal-intensity patterns on T1- and T2-weighted images was not statistically significant.

To examine the frequency of the right hepatic arterial supply to the posterior aspect of segment IV (PASIV) of the liver shown on computed tomography (CT) during hepatic arteriography (CTHA).Seventy-four patients who underwent CTHA from the right and/or left hepatic artery were studied. The right arterial supply to the PASIV was determined when the PASIV was stained on CT during right hepatic arteriography without any opacified arteries originating from the right hepatic artery and distributing to segment IV through the left hepatic hilum or when no staining was seen in the PASIV on CT during left hepatic arteriography. The frequency of the right hepatic arterial supply to the PASIV demonstrated on CTHA was analyzed.In six of 74 patients (8%), the PASIV was supplied from the right hepatic artery.This PASIV was supplied by the right hepatic artery in a significant proportion of cases.

We present a case of asymptomatic bronchial artery aneurysm that formed a fistula with part of the pulmonary artery (there was no definite fistula with the pulmonary vein). We were able to catheterize the feeding vessel but could not reach the aneurysm. We therefore injected a mixture of N-butyl-2-cyanoacrylate (NBCA; Histoacryl, B. Braun, Melsungen, Germany) and iodized oil (Lipiodol; Guerbet, Aulnay-sous-Bois, France) from the feeding vessel. The fistula, aneurysm, and feeding vessel were almost totally occluded. After embolization, the patient coughed a little; there were no other definite side effects or complications. One and 3 months later, on chest CT, the aneurysm was almost completely occupied with hyperattenuating NBCA-Lipiodol embolization. NBCA is a liquid embolization material whose time to coagulation after injection can be controlled by diluting it with Lipiodol. It is therefore possible to embolize an aneurysm, feeding vessels, and efferent vessels (in our case, it was a fistula) by using an NBCA-Lipiodol mixture of an appropriate concentration, regardless of whether the catheter can reach the aneurysm or not.

The purpose of this study was to determine the relationship between segmental hyperintensity of the liver on T1-weighted images and segmental cholestasis in patients with obstructive jaundice. T1-weighted and T2-weighted MR images were obtained of 73 patients with obstructive jaundice caused by various diseases. Fat-suppressed T1-weighted images were also obtained of 10 patients. Eleven patients with segmental intrahepatic bile duct dilatation (cholestasis) showed segmental hyperintensity on T1-weighted images and/or fat-suppressed T1-weighted images and no signal intensity difference on T2-weighted images. Sixty-two patients with widespread intrahepatic bile duct dilatation showed no intensity difference on T1-weighted and T2-weighted images (P < .01). Segmental hyperintensity on T1-weighted images was correlated with intrahepatic cholestasis.

To clarify the correlation between aberrant gastric venous drainage and a focal spared area at the posterior edge of segment IV in fatty liver by using color Doppler ultrasound (US).Seventeen patients with fatty liver were examined with gray-scale, color Doppler, and power Doppler US. In one patient with a focal spared area, arteriography and computed tomography (CT) were performed during injection of contrast medium into the right gastric artery.Focal spared areas of fatty liver at segment IV were shown in five of 17 patients. In all five patients with a focal spared area, aberrant gastric venous drainage was observed with color Doppler US. Power Doppler US depicted aberrant gastric venous drainage more clearly than color Doppler US. On the other hand, no definite aberrant gastric venous drainage was seen in the 12 patients who had no focal spared area. In one patient who underwent selective arteriography of the right gastric artery and CT arteriography, aberrant gastric venous drainage into segment IV was directly demonstrated.Focal spared areas at segment IV in fatty liver correlate strongly with aberrant gastric venous drainage. Noninvasive imaging methods such as color and power Doppler US are useful for depicting these aberrant drainage veins.

Gallbladder varices were correctly diagnosed by color Doppler sonography and computed tomography during arterial portography (CTAP) in two patients with portal vein thrombosis. One patient with multiple hepatocellular carcinomas showed extrahepatic and intrahepatic portal vein occlusion by a tumor thrombus. The other patient, with liver cirrhosis, had a portal vein thrombosis. Color Doppler sonography clearly showed the portal vein occlusion, cavernous transformation of collateral veins, and gallbladder varices that drained into the intrahepatic portal venous branches. The intrahepatic portal venous branch, connecting to the gallbladder varices, exhibited reverse flow from the periphery to the hilum of the liver. CTAP also demonstrated gallbladder varices communicating directly with the intrahepatic portal vein branches in both patients. Gallbladder varices developed as a venous collateral because of extrahepatic portal vein occlusion. Color Doppler sonography and CTAP are useful for detecting these varices and planning biliary surgery in patients with portal vein thrombosis.

Purpose: After transcatheter arterial embolization (TAE) with iodized oil (Lipiodol), a relatively dense accumulation of Lipiodol is often seen in the nontumorous liver adjacent to a hypervascular hepatocellular carcinoma (HCC) nodule. We compared this phenomenon with the findings obtained with single-level dynamic CT during hepatic arteriography (SLDCTHA) and presumed its possible mechanism. Methods: Fifty-six patients with HCC underwent hepatic angiography including SLDCTHA followed by segmental or subsegmental TAE with a mixture of an anticancer drug and Lipiodol. We compared the drainage area of the HCC depicted on SLDCTHA with the Lipiodol accumulation in the nontumorous liver adjacent to the HCC on CT after TAE (LpCT). Results: In 26 of the 56 patients, a definite corona enhancement around the HCC, suggesting the drainage of blood from the tumor into the surrounding liver parenchyma, was seen on the late phase of SLDCTHA. In 17 of these 26 patients (65.4%), LpCT showed a more intense accumulation of Lipiodol in the nontumorous liver adjacent to the HCC that corresponded to the drainage area revealed on SLDCTHA. Conclusion: The drainage of blood from the HCC was considered to be a possible mechanism of the accumulation of Lipiodol in the nontumorous liver adjacent to the HCC.

It is imperative to understand the intraand perinodular hemodynamics of hepatocellular carcinoma (HCC) for precise imaging diagnosis and determination of treatment strategies. For this purpose, the combination of computed tomography (CT) and selective arteriography, such as CT during hepatic arteriography (CTHA) and CT during arterial portography (CTAP), is most valuable and precise. We introduced CTAP as a part of an arteriographic examination for preoperative evaluation of HCC in the 1980s [1], and, after the development of helical CT system, simultaneous performance of CTAP and CTHA became possible [2]. In this article, the intraand peritumoral hemodynamics analyzed by CTHA and CTAP are compared with histology.

To compare the appearance of small hepatic hemangiomas at nonenhanced and contrast material-enhanced helical computed tomography (CT) with that of small (3-cm) hypervascular malignant liver tumors and to evaluate the accuracy of multiphase helical CT for differentiating small hemangiomas from small hypervascular malignant tumors.Radiologists reviewed multiphase helical CT liver images in 86 patients with 37 hemangiomas and 49 malignant liver tumors. They evaluated lesion type and degree of enhancement for change from arterial to portal venous phase. They rated their confidence in the discrimination of hemangiomas from malignant tumors.At arterial phase CT, enhancement similar to aortic enhancement was observed in 19%-32% of hemangiomas and 0%-2% of malignant tumors; globular enhancement, in 62%-68% and 4%-12%, respectively. At portal venous phase CT, enhancement similar to blood pool enhancement was observed in 43%-54% of hemangiomas and 4%-14% of malignant tumors; globular enhancement, in 46%-49% and 0%-2%, respectively. For all readers and all phases of enhancement, the area under the receiver operating characteristic curves was 0.81-0.87, indicating that inherent accuracy of CT is high and that there was no significant difference (P.28) in overall accuracy. Readers diagnosed hemangiomas with 47%-53% mean sensitivity with all enhancement phases and diagnosed malignant lesions with 95% mean specificity.Small hemangiomas frequently show atypical appearances at CT. Two-phase helical CT does not improve sensitivity but does improve specificity for differentiating hemangiomas from hypervascular malignant tumors.

We experienced a case of focal fatty infiltration in the anteromedial edge of the medial segment of the liver adjacent to the falciform ligament associated with advanced esophageal cancer. By using CT during selective right internal thoracic arteriography, we confirmed that the inferior vein of Sappey drained into the area of focal fatty infiltration. This is the first case to directly establish the relationship between drainage of the inferior vein of Sappey and occurrence of focal fatty infiltration of the liver.

The purpose of this study was to evaluate dynamic CT findings of hepatic abscesses, especially segmental hepatic enhancement, and to clarify the cause.Twenty-four abscesses in eight patients were examined by early (30 sec) and late phase (90 sec) dynamic CT. Patients underwent abscess drainage (n = 1), hepatic resection (n = 2), or antibiotic therapy (n = 5). CT during arterial portography and CT during hepatic arteriography were performed in one patient. We retrospectively observed the frequency and changes of segmental hepatic enhancement on dynamic CT and determined its cause using radiologic and pathologic correlation.Sixteen abscesses (67%) showed transient segmental hepatic enhancement and three abscesses showed only segmental hepatic enhancement in the early phase. Four abscesses in one patient who underwent CT during arterial portography and CT during hepatic arteriography showed a segmental perfusion defect on CT during arterial portography and segmental enhancement on CT during hepatic arteriography. On follow-up dynamic CT performed 10-17 days after the initial CT, segmental hepatic enhancement surrounding hepatic abscesses decreased or disappeared in all abscesses. Pathologic examination of two patients showed marked inflammatory cell infiltration with stenosis of portal venules within the portal tracts surrounding hepatic abscesses without definite inflammation in the liver parenchyma.Segmental hepatic enhancement on dynamic CT is frequently associated with hepatic abscesses and may be caused by decreased portal flow resulting from inflammation of the portal tracts.

We report a case of segmental hepatic iron deposition in the parenchyma peripheral to a tumor-thrombosed intrahepatic portal vein. On MR imaging, especially fast low-angle shot image, the liver parenchyma was demonstrated as a hypointense area with segmental and wedge-shaped configuration. Absence of portal blood flow may cause such segmental hepatic iron deposition.

Purpose: The goal of our study was to assess the prevalence of pseudolesion in segment IV of the liver on MRI in patients with and without liver cirrhosis. Method: Patients were divided into three groups: 10 patients with angiographically confirmed aberrant gastric venous drainage and liver cirrhosis (Group 1). 250 consecutively selected patients with liver cirrhosis (Group 2), and 250 with normal liver (Group 3). The signal intensity of pseudolesion in segment IV on T1- and T2-weighted MRI in the 510 patients was analyzed. Results: In Group I. five pseudolesions were visible and hyperintense on T1-weighted images. On T2-weighted images, four were visible and hypointense. In Group 2, 11 were seen (4.4%). All were hyperintense on T1-weighted images. Five were hypointense on T2-weighted images. In Group 3. one pseudolesion was seen (0.4%). Conclusion: The prevalence of pseudolesion in segment IV on MRI is higher in liver cirrhosis than in normal liver. The lesion is hyperintense on T1-weighted images when visible.

Single shot fast spin echo (SSFSE) pulse sequence provides us with a thick single-slice MR cholangiopancreatography (MRCP) as well as thin multi-slice MRCP, and T2-weighted images are also obtained with SSFSE sequences. In comparison with conventional spin-echo and fast spin-echo sequences, T2-weighted image using SSFSE sequence has the advantages of the abscence of motion artifacts and the extremely short acquisition times. MRCP using SSFSE sequence is useful in the conspicuity of bile duct, pancreatic duct, and cystic lesions. However, T2 weighted image using SSFSE is superior to MRCP not only for the differentiation between solid and cystic lesions but also for the visualization of contour of different organs and lesions.

The value of delayed magnetic resonance (MR) imaging (6 min) and ultradelayed MR imaging (1-4 h) for differentiating of hepatic tumors was studied.Postcontrast delayed and ultradelayed MR images were obtained after administration of 0.1 mmol/kg of Gd-DTPA in 30 patients with various malignant hepatic tumors.Delayed enhancement in the center of the tumors was seen in 13 patients on the delayed MR images and in 22 patients on the ultradelayed MR images. On the ultradelayed images, peripheral hypointense rim was seen in 12 patients and central focal hypointense area was seen in eight patients. Pathologically, the portion showing delayed enhancement corresponded to abundant fibrous stroma, the hypointense rim to rich proliferation of tumor cells, and the central hypointense areas to coagulative necrosis.Ultradelayed MR imaging can characterize different tissue components within various hepatic tumors.

Aberrant gastric venous drainage (AGVD) into the posterior edge of the medial segment of the liver (segment IV) is the main cause of pseudolesion on computed tomography (CT) during arterial portography. We estimated the prevalence of AGVD into the medial segment of the liver with color and power Doppler ultrasound (US).Screening gray-scale and color Doppler and power Doppler US were performed in 100 consecutive patients. AGVD was defined as a venous structure that ascended parallel to the main portal vein and drained independently into segment IV.AGVDs were observed in eight of 100 patients (8%) with color and power Doppler US. Power Doppler US depicted these veins more clearly than did color Doppler US. Gray-scale US did not show any AGVDs. Two of eight patients with AGVDs detected by color Doppler US underwent celiac arteriography and CT during arterial portography (CTAP). In these two patients, celiac arteriography directly demonstrated AGVDs draining into segment IV, which revealed nontumorous perfusion defects (pseudolesions) on CTAP.Color and power Doppler US are useful imaging methods for demonstrating AGVDs.

Objective : The purpose of this study is to demonstrate the relation between focal hepatic fatty infiltration and aberrant gastric venous drainage (AGVD) in the posterior edge of the medial segment (PEMS) of the liver. Materials and Methods : We present two cases of focal hepatic fatty infiltration with AGVD in the PEMS and discuss their imaging features. Results : In both cases the focal fatty infiltration areas were hyperechoic on sonography, hypodense on CT, and hyperintense on T1-weighted MRI. Computed tomography during arterial portography (CTAP) showed nodular perfusion defects corresponding to the areas in both cases, and early enhancement of the area was observed with dynamic MRI in one case. Although the findings on CTAP and dynamic MRI suggested a neoplastic nature for the lesions, focal fatty infiltration was confirmed with surgical resection in one case and with imaging follow-up in the other. Aberrant gastric venous drainage into the area was demonstrated on arteriography in both cases. Conclusion : The variation in blood supply caused by AGVD may play an important role in fatty metabolism in the PEMS of the liver and may influence imaging features.

To analyze imaging finding in focal areas of liver parenchyma with aberrant gastric venous drainage (AGVD) in cirrhotic livers.Eighteen patients with AGVD confirmed with computed tomography (CT) during arterial portography and arteriography underwent ultrasound (US) (n = 18), CT (n = 18), magnetic resonance (MR) imaging (n = 12), dynamic CT (n = 14), and dynamic MR imaging (n = 8). Imaging and histologic (n = 2) findings were analyzed.The focal area with AGVD was hypoechoic on US scans (n = 7), hypoattenuating on CT scans (n = 4), hyperintense on T1-weighted MR images (n = 6), and hypointense on T2-weighted MR images (n = 5). Early enhancement was seen with dynamic CT (n = 8) and with dynamic MR imaging (n = 6), without definite staining on arterial phase of arteriography. Histologic findings revealed hyperplastic changes of liver.The imaging findings, except for early enhancement, were very similar to those of adenomatous hyperplasia or well-differentiated hepatocellular carcinoma. The early enhancement was considered due to early venous return compared with that of the surrounding liver.

The potential of superparamagnetic ferrite particles in magnetic resonance (MR) imaging to help differentiate between hyperplastic nodular lesions in the liver and hepatocellular carcinomas was evaluated with chemically induced liver tumors in cirrhotic rats. Ferrite particles decreased the signal intensity of hyperplastic nodules but not that of hepatocellular carcinomas, and stainable iron was found in the former but not in the latter with Prussian blue iron stain. T1-weighted spin-echo images made little contribution to the differentiation between these two lesions, while T2-weighted spin-echo images were effective for this purpose, since ferrite particles cause T2 shortening. Ferrite-enhanced MR imaging may be useful in differentiating these two lesion types according to their signal intensity changes on images, because Kupffer cells are present in hyperplastic nodular lesions but rarely in hepatocellular carcinomas.

Tuberculous involvement of the liver is usually a diffuse process, associated with miliary tuberculosis. However, localized tuberculosis of the liver producing a macronodular tuberculoma or an abscess is rare [1 , 2]. Several reports have described the CT findings in such localized hepatic tuberculosis [3, 4]; however, the findings of MR imaging have not been widely published. We describe the CT and MR findings in a case of macronodular tuberculoma of the liver.

This report describes three patients whose cystic portions were filled with intravenously injected Gadolinium-DTPA. Four cystic portions showed contrast enhancement of the whole wall on early MR images and enhancement of the content on delayed MR images. Two cystic portions showed no enhancement of content. We speculate that the difference is based upon the composition of the cyst walls.