Focal hyperechoic liver lesions in children: far beyond hemangiomas - pictorial essay / Lesões hepáticas hiperecogênicas focais em crianças: muito além dos hemangiomas - ensaio iconográfico

Abstract The aim of this report was to present a selection of focal hyperechoic liver lesions of different etiologies, illustrating the wide spectrum of diagnostic possibilities for such lesions in the pediatric population.

Resumo Apresentamos uma seleção de lesões focais hiperecogênicas hepáticas de diversas etiologias, que ilustram o grande espectro de diferentes possibilidades diagnósticas dessas lesões na faixa pediátrica, muito além dos hemangiomas.

Hepatic epithelioid hemangioendothelioma: a report from three university centers / Hemangioendotelioma epitelioide hepático: pesquisa em três centros universitários

Abstract Objective: To determine common imaging findings of hepatic epithelioid hemangioendothelioma on magnetic resonance images. Materials and Methods: A search was made of three institutional databases between January 2000 and August 2012. Seven patients (mean age, 47 years; range, 21-66 years; 6 women) with pathology-confirmed diagnosis of hepatic epithelioid hemangioendothelioma who had undergone magnetic resonance imaging were identified. None of the patients had received any treatment for hepatic epithelioid hemangioendothelioma at the time of the initial magnetic resonance imaging examination. Results: Hepatic epithelioid hemangioendothelioma tumors appeared as focal masses in 7/7 patients, greater than 5 in number, with a coalescing lesion in 1/5, and peripheral localization in 6/7. Capsular retraction was present in 4/7, and was associated with peripherally located lesions. Early ring enhancement was appreciated in the majority of lesions in 7/7 patients. Centripetal progressive enhancement was shown in 5/7 patients on venous phase that exhibited a distinctive thick inner border of low signal on venous phase images, and a central core of delayed enhancement. Small lesions did not show this. Conclusion: The combination of multifocal round-configuration lesions that are predominantly peripheral and exhibit early peripheral ring enhancement and late appearance of an inner thick border of low signal and central core of high signal may represent an important feature for hepatic epithelioid hemangioendothelioma.

Resumo Objetivo: Determinar os achados comuns de hemangioendotelioma epitelioide hepático em imagens de ressonância magnética. Materiais e Métodos: Uma pesquisa foi feita em três bases de dados institucionais entre janeiro de 2000 e agosto de 2012. Sete pacientes (média de idade, 47 anos; variação, 21-66 anos; 6 mulheres) com diagnóstico confirmado por exame patológico de hemangioendotelioma epitelioide hepático submetidos a ressonância magnética foram identificados. Nenhum dos pacientes havia recebido tratamento para hemangioendotelioma epitelioide hepático antes do exame inicial por ressonância magnética. Resultados: Tumores de hemangioendothelioma epitelioide hepático apareceram como massas focais, maiores que 5 em número, em 7/7 pacientes, com uma lesão coalescente em 1/5 e localização periférica em 6/7 pacientes. Retração capsular esteve presente em 4/7 pacientes e foi associada com lesões perifericamente localizadas. Realce precoce em anel foi visto na maioria das lesões, em 7/7 pacientes. Realce progressivo centrípeto foi demonstrado em 5/7 pacientes na fase venosa, que exibia uma borda interna espessa distinta de baixo sinal nas imagens de fase venosa e um núcleo central de realce tardio. As lesões pequenas não mostraram isso. Conclusão: A combinação de lesões de configuração arredondada multifocais que são predominantemente periféricas e exibem realce precoce em anel periférico e aparecimento tardio de uma borda espessa interna de baixo sinal e um núcleo central de alto sinal pode representar uma característica importante para hemangioendotelioma epitelioide hepático.

Liver-specific magnetic resonance contrast medium in the evaluation of chronic liver disease / Aplicações do contraste hepato-específico de ressonância magnética nas hepatopatias crônicas

ABSTRACT The hepatobiliary-specific contrast medium (gadoxetic acid – Primovist®) is primarily used to improve detection and characterization of focal hepatic lesions, such as in chronic liver disease patients with suspected hepatocellular carcinoma. Since the contrast medium is selectively taken up by functioning hepatocytes in the late hepatobiliary phase, it helps to detect typical hepatocellular carcinoma, which show low signal intensity on this phase. This imaging feature also assists in differentiating regenerative/dysplastic nodules from early hepatocellular carcinomas (with over 90% accuracy), as well as hypervascular hepatocellular carcinomas from arterial pseudo-enhancement foci. Future perspectives include its use in quantification of hepatic function and fibrosis.

RESUMO O contraste hepato-específico (ácido gadoxético – Primovist®) tem como utilidade principal melhorar a detecção e a caracterização de lesões hepáticas focais, por exemplo, em hepatopatas crônicos com suspeita de hepatocarcinoma. Por apresentar captação seletiva por hepatócitos funcionantes na fase hepatobiliar tardia, auxilia na detecção de hepatocarcinomas típicos – a maioria dos quais apresentando hipossinal nessa fase. Essa característica de imagem também auxilia na diferenciação entre nódulos regenerativos/ displásicos e hepatocarcinomas precoces (com mais de 90% de acurácia), e entre hepatocarcinomas hipervascularizados e focos de pseudorrealce arterial. Perspectivas futuras promissoras incluem sua utilização na quantificação de função e de fibrose hepáticas.

The use of the increased IL-27 expression as a diagnostic marker in the serum of hepatocellular carcinoma patients / 中国医师杂志

Objective To investigate the clinical significance of IL-27 in hepatocellular carcinoma ( HCC) in the early stage , and to compare it with alpha-fetoprotein ( AFP) in diagnostic performance .Methods Enzyme-linked immunosorbent assay was used to detect the serum level of IL-27 in the HCC group and control group .Receiver operator characteristic ( ROC) curve was used to ana-lyze two indicators and the logistic regression model predicted value ( PRE) was obtained .Results The study indicated the concentra-tion of IL-27 in HCC group [(364.19 ±177.55)pg/ml] was significantly higher than the control group [(255.49 ±94.33)pg/ml], the area under the curve (AUC) of IL-27 and AFP were (0.804) and (0.818), respectively.Logistic regression obtained the regres-sion model PRE that contains AFP and IL-27, with a predicted area under the ROC curve for HCC (0.901), while the diagnostic sen-sitivity (84.8%) and specificity (96.7%) were significantly higher than the capability of individual diagnosis of each indicator .Con-clusions In this study we obtained the model which can be used for clinical diagnosis of hepatocellular carcinoma in future .

Characterization of Focal Liver Lesions with Superparamagnetic Iron Oxide-Enhanced MR Imaging: Value of Distributional Phase T1-Weighted Imaging

OBJECTIVE: To determine the potential value of distributional-phase T1-weighted ferumoxides-enhanced magnetic resonance (MR) imaging for tissue characterization of focal liver lesions. MATERIALS AND METHODS: Ferumoxides-enhanced MR imaging was performed using a 1.5-T system in 46 patients referred for evaluation of known or suspected hepatic malignancies. Seventy-three focal liver lesions (30 hepatocellular carcinomas [HCC], 12 metastases, 15 cysts, 13 hemangiomas, and three cholangiocarcinomas) were evaluated. MR imaging included T1-weighted double-echo gradient-echo (TR/TE: 150/4.2 and 2.1 msec), T2*-weighted gradient-echo (TR/TE: 180/12 msec), and T2-weighted turbo spin-echo MR imaging at 1.5 T before and after intravenous administration of ferumoxides (15 mmol/kg body weight). Postcontrast T1-weighted imaging was performed within eight minutes of infusion of the contrast medium (distributional phase). Both qualitative and quantitative analysis was performed. RESULTS: During the distributional phase after infusion of ferumoxides, unique enhancement patterns of focal liver lesions were observed for hemangiomas, metastases, and hepatocellular carcinomas. On T1-weighted GRE images obtained during the distributional phase, hemangiomas showed a typical positive enhancement pattern of increased signal; metastases showed ring enhancement; and hepatocellar carcinomas showed slight enhancement. Quantitatively, the signal-to-noise ratio of hemangiomas was much higher than that of other tumors (p < .05) and was similar to that of intrahepatic vessels. This finding permitted more effective differentiation between hemangiomas and other malignant tumors. CONCLUSION: T1-weighted double-echo FLASH images obtained soon after the infusion of ferumoxides, show characteristic enhancement patterns and improved the differentiation of focal liver lesions.

Well-Differentiated Hepatocellular Carcinoma: Triple-Phase Helical CT Findings

PURPOSE: To determine the imaging characteristics of well-differentiated hepatocellular carcinomas (HCCs), as seen at triple-phase helical CT. MATERIALS AND METHODS: Thirty-eight well-differentiated HCCs in 29 patients who underwent surgical resection comprised our study population. Triple-phase helical CT images were obtained at 30 seconds, 70 seconds, and 3 minutes after contrast injection, and HCCs were divided into four groups according to their size: smaller than 1 cm (n=12), 1-2 cm (n=15), 2-4 cm (n=8), and larger than 4 cm (n=3), The enhancement patterns of HCCs at triple-phase helical CT were retrospectively analysed. RESULTS: In the smaller than l cm group, the most common enhancement pattern at all three phases was iso-attenuation (n=8; 67%). In the 1-2 cm group, iso-attenuation (n=10; 67%) was most common during the arterial phase and slightly low attenuation during the portal and equilibrium phases while in the 2-4 cm group, high attenuation (n=6; 75%) was most common during the arterial and portal phases, and low attenuation during the equilibrium phase (n=6; 75%). Two (67%) of three cases in the larger than 4 cm group demonstrated low, including fatty, attenuation. The detection rate was 33% (4/12) in the smaller than 1 cm group, 87% (13/15) in the 1-2 cm group and 100% (11/11) in the 2-4 cm and larger than 4 cm groups. CONCLUSION: At triple-phase helical CT, the enhancement patterns of well-differentiated HCCs were diverse, and the detection rate of those larger than 1 cm was 92% (24/26).

Detection of Hepatocelluar Carcinoma on Triple-Phase Images of Liver Using Multi-Detector Row Helical CT

PURPOSE: To determine whether triple-phase multi-detector-row helical CT images of the liver improves the detection rate of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Forty-one patients with 103 HCCs underwent triple-phase multi-detector-row helical CT imaging of the entire liver after contrast administration. Early and late arterial phase images were obtained serially during a single breath-hold, and portal venous-phase images were then obtained. Each image set was independently assessed for the presence of HCC by two radiologists unaware of the possible presence of tumors, and for each phase the detection rate was determined. For each arterial-phase image, lesion conspicuity (attenuation of a tumor compared with that of its parenchyma) was calculated. RESULTS: For reader 1, the detection rates for the early arterial, late arterial, and portal venous phase were 81%, 77%, and 55%, respectively, and for reader 2 were 83%, 81%, and 68%, respectively (p>0.05). When triplephase imaging findings were combined, the detection rate was significantly higher than when only those of the early or late arterial, and portal venous, phase were used (p0.05). CONCLUSION: Triple-phase imaging of the liver, involving the early arterial, late arterial, and portal venous phase, and using multi-detector-row helical CT, increases the detection rate of HCC.

Detection of Malignant Primary Hepatic Neoplasms with Gadobenate Dimeglumine (Gd-BOPTA) Enhanced T1-Weighted Hepatocyte Phase MR Imaging: Results of Off-site Blinded Review in a Phase-II Multicenter Trial

OBJECTIVE: To investigate the efficacy of gadobenate dimeglumine (Gd-BOPTA) enhanced MR imaging for the detection of liver lesions in patients with primary malignant hepatic neoplasms. MATERIALS AND METHODS: Thirty-one patients with histologically proven primary malignancy of the liver were evaluated before and after administration of Gd-BOPTA at dose 0.05 or 0.10 mmol/kg. T1-weighted spin echo (T1W-SE) and gradient echo (T1W-GRE) images were evaluated for lesion number, location, size and confidence by three off-site independent reviewers and the findings were compared to reference standard imaging (intraoperative ultrasound, computed tomography during arterial portography or lipiodol computed tomography). Results were analyzed for significance using a two-sided McNemar's test. RESULTS: More lesions were identified on Gd-BOPTA enhanced images than on unenhanced images and there was no significant difference in lesion detection between either concentration. The largest benefit was in detection of lesions under 1 cm in size (7 to 21, 9 to 15, 16 to 18 for reviewers A, B, C respectively). In 68% of the patients with more than one lesion, Gd-BOPTA increased the number of lesions detected. CONCLUSION: Liver MR imaging after Gd-BOPTA increases the detection of liver lesions in patients with primary malignant hepatic neoplasm.

In vivo Proton MR Spectroscopic Findings of Focal Hepatic Lesions: Initial Experience

PURPOSE: To investigate the in vivo proton MRS features of various focal hepatic lesions and to distinguish these features according to the involved. MATERIALS AND METHODS: Twenty-five hepatic lesions [hepatocellular carcinoma (n=7), cholangiocarcinoma(n=3), metastatic tumor (n=9), hemangioma (n=3), hepatic abscess (n=2), lymphoma (n=1)] underwent proton MR spectroscopy using a 1.5T unit and a localized proton STEAM sequence, without respiratory interruption, The findings of this in-vivo sequence were then reviewed, with particular attention to the presence and location of dominant peaks. RESULTS: In-vivo proton MR spectra were successfully acquired in all cases. A dominant lipid peak appeared in the MR spectra of the hepatocellular carcinomas, metastatic tumors, hepatic abscesses, lymphoma, one hemangioma and one cholangiocarcinoma(88%) at 1.3ppm, but not in two cholangiocarcinomas and one hemangioma. The spectral peaks of other metabolites appeared very irregular and even different in the same disease. CONCLUSION: In focal hepatic lesions, the spectra obtained during in-vivo proton MRS were useful, and a lipid peak was most frequent and dominant. Among the various neoplasms there were, however, no specific MR spectral features, and nor did such features vary according to the specific pathologic entity.

CT Findings of Ciliated Hepatic Foregut Cyst Mimicking Metastasis: A Case Report

Ciliated hepatic foregut cyst (CHFC) is a rare benign lesion consisting of ciliated pseudostratified columnar epithelium, loose subepithelial connective tissue, a smooth muscle layer, and an outer fibrous capsule. We encountered a patient with retroperitoneal and posterior mediastinal neurilemmoma and additional CHFC mimicking metastasis. Abdominal CT examination demonstrated that the posterior mediastinal and retroperitoneal lesions were lobulated, well-defined tumors with a neural foraminal extension that were pathologically confirmed as neurilemmomas. Unenhanced CT indicated that the additional lesion was a slightly hypodense mass relative to surrounding parenchyma at the medial segment of the left lobe of the liver, and after the IV ad-ministration of contrast material, the lesion did not show enhancement.

Comparison between Spiral CT and MR Imaging in Evaluation of Focal Hepatic Masses

PURPOSE: The main aim of this study was to compare spiral CT and MR imaging in the detection and characterization of focal hepatic masses. MATERIALS AND METHODS: Seventy-nine patients with 155 focal hepatic masses confirmed pathologically, or radiologically and clinically [hepatocellular carcinoma(HCC) (n =52), hemangioma (n=36), cysts (n =35), metastasis (n =27), intrahepatic cholangiocarcinoma (n =5)], underwent two- or three-phase spiral CT, and T1-, T2- weighted, and dynamic contrast-enhanced MR imaging. The detection and characterization of focal hepatic masses by these modalities were evaluated and compared. RESULT: The detection rates of spiral CT and MR imaging, respectively, were as follows: HCC, 81%(42/52) and 94%(49/52); hemangioma, 75%(27/36) and 100%(36/36); cysts, 80%(28/35) and 100%(35/35); metastasis, 67%(18/27) and 100%(27/27); and intrahepatic cholangiocarcinoma, 100%(5/5) and 100%(5/5). MR imaging was superior to spiral CT in mass detection of HCC, hemangioma, cysts, and metastasis (p < .05). The characterization rates of spiral CT and MR imaging, respectively, were as follows: HCC, 52%(27/52) and 71%(37/52); hemangioma, 67%(24/36) and 100%(36/36); cysts, 63%(22/35) and 100%(35/35); metastasis, 37%(10/27) and 100%(27/27); and intrahepatic cholangiocarcinoma, 40%(2/5) and 80%(4/5). In the mass characterization of HCC, hemangioma, cysts, and metastasis, MR imaging was superior to spiral CT (p< .05). CONCLUSION: In the detection and characterization of focal hepatic masses, including hepatocellular carcinoma, hemangioma, hepatic cyst and metastasis, MR imaging is superior to spiral CT.

Wedge-shaped Parenc hymal Enhancement Peripheral to the Hepatic Hemangioma: Two-phase Spiral CT Findings

PURPOSE: To determine the incidence of hepatic hemangiomas associated with wedge-shaped parenchymal enhancements adjacent to the tumors as seen on two-phase spiral CT images obtained during the hepatic arterial phase and to characterize the two-phase spiral CT findings of those hemangiomas. MATERIALS AND METHODS: One hundred and eight consecutive hepatic hemangiomas in 63 patients who underwent two-phase spiral CT scanning during an 11-month period were included in this study. Two-phase spiral CT scans were obtained during the hepatic arterial phase(30-second delay) and portal venous phase(65-second delay) after injection of 120mL of contrast material at a rate of 3mL/sec. We evaluated the frequency with which wedge-shaped parenchymal enhancement was adjacent to the hemangiomas during the hepatic arterial phase and divided hemangiomas into two groups according to whether or not wedge-shaped parenchymal enhancement was noted (Group A and Group B). The presence of such enhancement in hemangiomas was cor-related with tumor size and the grade of intratumoral enhancement. RESULTS: In 24 of 108 hemangiomas, wedge-shaped parenchymal enhancement adjacent to hepatic tumors was seen on two-phase CT images obtained during the hepatic arterial phase. Mean hemangioma size was 22mm in Group A and 24mm in Group B. There was no statistically significant relationship between lesion size and the presence of wedge-shaped parenchymal enhancement adjacent to a hemangioma. In 91.7% and 1 00% of tumors in Group A, and in 9.6% and 17.8% in Group B, hemangiomas showed more than 50% intra-tumoral enhancement during the arterial and portal venous phase, respectively. Wedge-shaped parenchymal enhancements peripheral to hepatic hemangiomas was more frequently found in tumors showing more than 50% intratumoral enhancement during these two phases(p<0.01). CONCLUSION: Wedge-shaped parenchymal enhancements is not uncommonly seen adjacent to hepatic heman-giomas on two-phase spiral CT images obtained during the hepatic arterial phase. A hemangioma showing-wedge-shaped parenchymal enhancement tends to show more than 50% intratumoral enhancements during the arterial and portal venous phase.

MR Imaging of Hepatocellular Carcinoma: Usefulness of Four-Phase Dynamic Imaging Including Early ArterialPhase

PURPOSE: To evaluate the usefulness of four-phase dynamic MR imaging technique by analyzing the imagingfeatures of hepatocellular carcinoma(HCC). MATERIALS AND METHODS: We reviewed four-phase dynamic MR images of 63lesions in 38 patients. MR imaging of the whole liver on gradient T1-weighted sequence was obtained at 10seconds(phase I), 35 seconds(phase II), 60 seconds(phase III), and 5 minutes(phase IV) after the start ofGd-DTPA(0.1mmol/kg) hand injection(3-4cc/sec) through the vein. We evaluated the degree of lesional contrastenhancement during each phase by comparing surrounding liver parenchyma, and analyzed signal intensity in lesionsover and less 2cm, respectively. RESULTS: The number of lesions showing high signal intensity compared withsurrounding liver parenchyma was 52(83%)during phase I, 30(48%) during phase II, 12(19%) during phase III, and 4(6%) during phase IV. During each phase, the number of lesions with signal intensity lower than that ofsurrounding liver parenchyma was 7(11%), 2(3%), 7(11%) and 21(33%), respectively. Thirty-four lesions wereenhanced only during phase I and eleven during only phase II. In tumors less than 2cm(n=40), more enhanced lesionswere during phase I(n=33) than more during phase II(n=16)(p=.0020). CONCLUSION: During each phase, four-phasedynamic MR imaging is useful for the effective detection of HCC showing varying degrees of contrast enhancement.

Value of MR Imaging after CT in Patients with Focal Hepatic Lesion

PURPOSE: To determine the usefulness of magnetic resonance imaging (MRI) after computed tomography (CT) inpatients with focal hepatic lesion. MATERIALS AND METHODS: We evaluated 100 patients with 103 focal hepaticlesions. The diagnosis of each lesion was made pathologically (n=19), or radiologically and clinically (n=84), andthe findings were as follows: he-mangioma (n=53), hepatocellular carcinoma (n=17), metastasis (n=10), cyst (n=5),regenerative nodule (n=3), and adenomatous hyperplasia (n=3). The patients underwent conventional CT (n=25),two-phase spi-ral CT (n=17) or three-phase spiral CT (n=61). MRI was performed using conventional T1- andT2-weighted imaging and dynamic contrast enhancement. The value of MRI after CT was assigned to one of fourgrades, according to the consensus of three radiologists: grade I (decisive), grade II (helpful), grade III (notadditional), or grade IV (confused). RESULTS: The outcome of MRI of 103 lesions was grade I in 14 cases(14%), IIin 34 (33%), III in 49 (48%), and IV in 6 (6%). MRI was not helpful (grade III or IV) in 40% (10/25), 47% (8/17),and 61%(31/61) of lesions after conventional, two-phase spiral, and three-phase spiral CT, respectively. Grade IIIor IV lesions were present in 45% of hemangiomas (24/53), 59% of hepatocellular carcinomas (10/17), and 80% ofcases in which metastasis had occurred(8/10). CONCLUSION: MRI after CT in patients with focal hepatic lesion washelpful in less than half of all cases. It was particularly valuable for patients who did not undergo three-phasespiral CT and in whom hemangioma was suspected.

Color Doppler Ultrasound of Hepatocellular Carcinoma: Evaluation of Recurrence after Transcatheter Arterial Chemoembolization

PURPOSE: To evaluate the efficacy of color and pulsed Doppler ultrasound (US) for the detection of arterial revascularization of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE). MATERIALS AND METHODS: One hundred and four histologically proven HCCs (0.7-12.5 cm, mean 4.14 cm) of 87 consecutive patients who had undergone TACE using a Lipiodol-chemoagent suspension were examined using color Doppler equipment. The criteria for diagnosing arterial revascularization of HCC were detection of inward blood vessels within HCC and demonstration by spectral Doppler US of pulsatile arterial flow within the vessel. Color Doppler US was prospectively performed using a multi-Hertz probe (2.5-5 Hz), and was followed by digital subtraction angiography (DSA). RESULTS: In 37 of 104 HCCs in 87 patients treated with TACE, color and spectral Doppler US demonstrated intratumoral arterial flows, with peak systolic velocity of 4.2-220 (mean, 59) cm/sec. DSA revealed neovascularity or tumor stains in 38 HCCs (3.4-12.5 cm, mean 5.9 cm in size) including 37 which on Doppler US showed arterial flow. The remaining 66 of 104 HCCs (0.7-6.3 cm, mean 3.2 cm) did not stain during DSA. Doppler US showed a false negative result in only one HCC (4.6 cm, located at segment VII of the Couinaud classification), which stained faintly during DSA. The sensitivity, specificity, and accuracy of color and spectral Doppler US used for the detection of recurrent HCC were 97.4%, 100%, and 99%, respectively. CONCLUSIONS: Color and spectral Doppler US is an effective method for the evaluation of arterial revascularization of HCC after TACE.

Dual Phase CT Hepatic Arteriography in the Evaluation of Hypervascular Hepatocellular Carcinoma

PURPOSE: To assess the diagnostic accuracy of dual-phase computed tomography during hepaticarteriography(CTHA) in depicting hypervascular hepatocellular carcinoma. MATERIALS AND METHODS: Forty patientswith hepatocellular carcinoma underwent dual-phase CTHA. First-phase data was obtained 6 seconds after contrastmedia was injected into the common hepatic artery, while second-phase data was obtained 35-40 seconds later.Lipiodol CT was performed 10-17 days after 2mL of lipiodol was injected into the proper hepatic artery. As agold-standard of 172 lipiodol-uptaken nodules seen on lipiodol CT, the detectability and positive predictive valueof the first and second phases, and the simultaneous interpretation of both phases, were analysed. RESULTS: Allnodules were detected by first-phase CTHA, 162 (94%) by second-phase CTHA, and 170 (99%) by simultaneousinterpretation of both phases. The detection sensitivities of first-phase CTHA and simultaneous interpretation ofboth phases were statistically superior to that of second-phase CTHA. Positive predictive values were 87% withfirst-phase CTHA, 96% with second-phase CTHA, and 97% with simultaneous interpretation of both phases. CONCLUSION: Dual-phase CTHA was useful for increasing detectability and accuracy in the diagnosis of hypervascularhepatocellular carcinoma.

Post-transplantation Lymphoproliferative Disorder in Transplanted Liver: A Case Report

Post-transplantation lymphoproliferative disorder occurs in transplant recipients in whom immunosuppressivetherapy has compromised the immune system. In patients who have undergone transplants, suppressor T lymphocytefunction is suppressed, leading to unbridled B lymphocyte proliferation. We encountered a case withpost-transplantation lymphoproliferative disorder which manifested as a focal hepatic mass in transplanted liver.This mass was isoechoic, with a peripheral hypoechoic halo on ultrasonogram, while on all three phases of helicalCT scan low attenuation without contrast enhancement was seen.

CT Features of Malignant Hepatic Tumors: the Significance of Capsular Retraction

PURPOSE: To evaluate the prevalence of capsular retraction in malignant hepatic tumors and the factorsinvolved. MATERIALS AND METHODS: Between January 1994 and December 1996, we retrospectively reviewed the CT scansof 152 patients with pathologically-proven, peripherally-located, malignant hepatic tumors. We evaluated size,site, portal and hepatic venous obstruction, bile duct dilatation, and liver atrophy in 18 cases involvingcapsular retraction. RESULTS: The overall prevalence of capsular retraction among malignant hepatic tumors was18/152(12%) ; the prevalence was 9/129(7%) in hepatocellular carcinoma, 6/14(43%) in cholangiocarcinoma and3/9(33%) in metastatic cancer ; among cases of cholangiocarcinoma and metastatic cancer, the prevalence washigh(p <0.05). Portal venous obstruction was seen in six patients with hepatocellular carcinoma (a high incidence ;p=0.041) and one with cholangiocarcinoma. Hepatic venous obstruction was demonstrated in one patient withhepatocellular carcinoma and one with cholangiocarcinoma. Among cholangiocarcinoma patients, bile duct obstructionwas seen in four and liver atrophy in three, but among metastatic cancer cases there were no similar findings. CONCLUSION: The main factors causing capsular retraction were portal venous obstruction in hepatocellularcarcinoma and bile duct obstruction and liver atrophy in cholangiocarcinoma.

Angiosarcoma of the Liver: A Case Report

We report a case of histopathologically confirmed hepatic angiosarcoma. A 29-year old patient was admitted with fever and palpable tender mass in the right upper abdomen. On ultrasonography, a large, well circumscribed mixed echoic mass was seen in the right lobe of the liver. On CT scan, irregular enhancement was seen mainly in the peripheral portion of the mass ; the central portion was not enhanced. The mass showed low signal intensity on T1W1, and high signal intensity on T2WI. Peripheral nodular enhancement was noted on Gd-enhanced MR images; In the peripheral portion of the mass,

Liver Neoplasms: Atypical CT and MR Imaging Findings

The use of advanced imaging techniques in computed tomography(CT) and magnetic resonance imaging (MRI) has established the appearance of most common liver neoplasms. There are, however, considerable overlaps In the appearances of various pathologic entities on CT and MRI, and certain hepatic lesions can show unusual characteristics that may lead to misinterpretation, so it is important for the radiologist to be aware of these uncommon appearances. The purpose of this article is to illustrate the spectra of uncommon patterns and various diagnostic pitfalls encountered on CT and MRI of liver neoplasms.