Diffuse und vaskul?re Lebererkrankungen

In addition to focal liver lesions, diffuse and vascular disorders of the liver represent a wide spectrum of liver diseases which are from the radiological point of view often difficult or nearly impossible to diagnose. Classical diagnostic methods are computed tomography and magnetic resonance imaging in addition to ultrasound. Diffuse parenchymal damage caused by diseases of various etiologies is therefore difficult to evaluate because it often lacks characteristic morphological features. For hepatic steatosis, hemochromatosis/siderosis as an example of a diffuse storage disease and sarcoidosis and candidiasis as infectious/inflammatory diseases, an image-based diagnosis is appropriate in some cases. For most diffuse liver diseases, however only nonspecific changes are visualized. Vascular pathologies of the liver, such as the Budd-Chiari syndrome and portal vein thrombosis, however, can usually be diagnosed very clearly using radiology and there is also a very effective interventional radiological treatment. Chronic diseases very often culminate in liver cirrhosis which is highly associated with an increased risk of liver cancer.     

瞬时弹性成像的研究进展及临床应用

慢性肝纤维化是肝病进展的重要过程,是机体对各种病因所致慢性肝损伤的一种修复反应,是慢性肝病共有的病理变化,也是肝硬化发展的中间环节.肝纤维化在早期乃至后期都可以发生逆转,越早确定肝纤维化的程度,越有利于临床治疗及患者的预后.目前,肝活检仍是诊断肝纤维化的“金标准”,但因其为有创检查,患者不易接受.近年来,肝纤维化无创诊...     

Quantification of liver iron with MRI: State of the art and remaining challenges

Liver iron overload is the histological hallmark of hereditary hemochromatosis and transfusional hemosiderosis, and can also occur in chronic hepatopathies. Iron overload can result in liver damage, with the eventual development of cirrhosis, liver failure, and hepatocellular carcinoma. Assessment of liver iron levels is necessary for detection and quantitative staging of iron overload and monitoring of iron‐reducing treatments. This article discusses the need for noninvasive assessment of liver iron and reviews qualitative and quantitative methods with a particular emphasis on magnetic resonance imaging (MRI). Specific MRI methods for liver iron quantification include signal intensity ratio as well as R2 and R2* relaxometry techniques. Methods that are in clinical use, as well as their limitations, are described. Remaining challenges, unsolved problems, and emerging techniques to provide improved characterization of liver iron deposition are discussed. J. Magn. Reson. Imaging 2014;40:1003–1021 . © 2014 Wiley Periodicals, Inc .     

Bildgebende Diagnostik der Leberzirrhose

For the diagnosis of liver cirrhosis ultrasound, computed tomography, magnetic resonance imaging, and angiography are recommended as imaging modalities. Ultrasound of the liver is used as a screening imaging tool in cases of patients suspicious for diffuse liver disease and is helpful in the term of follow-up examinations. Computed tomography is mainly performed to clarify the presence of liver disease detected by ultrasound. In this context, accurate examination of the vascular structures of the liver as well as extrahepatic situation, is of the essence. Diagnosis of diffuse liver disease and characterization of morphologic changes is improved using contrast-enhanced MR imaging with liver specific contrast media. Combined magnetic resonance imaging can provide comprehensive evaluation of cirrhosis. An improved detection rate and characterization of regenerating nodules can be achieved compared to imaging modalities such as ultrasound and computed tomography. MR imaging can be performed in a one-stop-technique using unenhanced and liver-specific-contrast-enhanced sequence protocols to evaluate the liver parenchyma itself, MR cholangiography to verify the bile duct system, and MR angiography to specify the vascular situation. This technique is the optimal protocol for diagnostic imaging in patients suffering from liver cirrhosis and the method of choice to reach the final diagnosis.     

A knowledge-based technique for liver segmentation in CT data

Liver cancer is one of the major death factors in the world. Transplantation and tumor removal are two main therapies in common clinical practice. Both tasks need image assisted planning and quantitative evaluations. Automatic liver segmentation is required for corresponding quantitative evaluations. Conventional approaches in liver segmentation consist of finding the initial liver border followed by tuning the border to the final mask. Finding the liver initial border is of great importance as the latter step largely depends on the initial step. In the previous works, the liver initial border was determined by applying thresholding and morphological filters. In order to estimate the liver initial boundary, we have proposed a technique based on anatomical knowledge of liver, its surrounding tissues as well as the approach that a clinician follows in screening liver in a CT dataset. Based on the above reasoning, we developed a multi-step heuristic technique to segment liver from other tissues in multi-slice CT images. The proposed technique can deal with various shapes, locations, and liver sizes. The method was evaluated in the presence of 50 actual liver data sets and the results were encouraging.     

99mTc-GSA scintigraphy with SPECT for assessment of hepatic function and functional volume during liver regeneration in a rat model of partial hepatectomy.

Small-animal models are crucial to gain insights in the complex recovery mechanisms of liver function during liver regeneration. (99m)Tc-Mebrofenin hepatobiliary scintigraphy (HBS) has been introduced for noninvasive assessment of liver function in the clinical setting as well as in experimental research. However, HBS is restricted to planar modalities in small animals because hepatic kinetics are generally too fast for SPECT acquisition. (99m)Tc-DTPA-galactosyl serum albumin (where DTPA is diethylenetriaminepentaacetic acid) ((99m)Tc-GSA) scintigraphy is an alternative, receptor-mediated, noninvasive liver function test. After hepatic uptake, (99m)Tc-GSA remains trapped in the liver, which readily enables additional SPECT for the assessment of both liver function and liver functional volume within one test. In this study we evaluated the use of (99m)Tc-GSA scintigraphy combined with SPECT for the assessment of liver function and liver functional volume in normal and regenerating rat livers. METHODS: The reproducibility of (99m)Tc-GSA scintigraphy and SPECT was investigated by repeated measurements within the same rat. For the assessment in a regenerating liver, (99m)Tc-GSA scintigraphy with SPECT was performed on 1, 3, 5, and 7 d (n = 6 rats per time point) after 70% partial hepatectomy (PH). RESULTS: The correlation between repeated (99m)Tc-GSA measurements was strong (r = 0.75, P = 0.019). In normal rat livers, there was a strong, significant correlation between liver functional volume and conventional liver volume (r = 0.93; < 0.0001). The correlation between (99m)Tc-GSA uptake and liver volume was moderate (r = 0.62, P = 0.043). During the regeneration process, (99m)Tc-GSA uptake was significantly lower compared with both liver volume (P < 0.001) and liver functional volume (P < 0.001), when expressed as a percentage of baseline levels. There was a strong correlation between liver functional volume and conventional liver volume in the regenerating liver (r = 0.92, P < 0.0001). CONCLUSION: (99m)Tc-GSA scintigraphy combined with SPECT is a feasible, noninvasive method to assess hepatic functional volume in normal rat liver as well as in the regenerating rat liver. However, the hepatic (99m)Tc-GSA uptake as a liver function test seems to underestimate hepatic regeneration in comparison to liver volume.     

Primary malignant tumours in the non-cirrhotic liver

Intrahepatic chlangiocarcinomas (CCs), the second most common primary malignant liver tumours, usually occur in non-cirrhotic liver, and can be classified into three types based on gross morphology: mass-forming; periductal infiltrating; and intraductal growing. Among them, mass-forming intrahepatic CCs are the most common type and characterized by homogeneous mass with an irregular but well-defined margin with peripheral enhancement on late arterial phase and delayed enhancement in central portion of tumours corresponding to the fibrous stroma. Several imaging features such as enhancement pattern and degree of diffusion restriction have been suggested as prognostic markers for mass-forming CCs. Hepatocellular carcinomas (HCCs) are the most common primary malignant liver tumors, and usually arise from the cirrhotic liver. However, approximately 20% of HCCs involve the non-cirrhotic liver (hereafter, non-cirrhotic HCC), and non-cirrhotic HCCs are often detected at an advanced stage due to the lack of surveillance for patients with non-cirrhotic liver. Other primary malignant liver tumours other than CCs and HCCs including angiosarcoma, undifferentiated embryonal sarcoma are quite rare, and imaging diagnosis is often difficult. This review offers a brief overview of epidemiology, risk factors and imaging features of primary malignant tumours in non-cirrhotic liver. Understanding of radiologic appearance and predisposing clinical features as well as differentials of primary malignant tumour in non-cirrhotic liver can be helpful for radiologists to adequately assess these tumours, and subsequently to make optimal management plan.     

肝特异性生物活性肽研究进展

肝脏是人体内最重要的器官之一,具有强大的再生能力。肝再生的调控机制非常复杂,众多因子参与其中,但大多数因子,类似肝细胞生长因子（HGF）、表皮生长因子（EGF）都不具备肝细胞作用的特异性。近年来,本实验室从新生小牛的肝脏中分离得到了能够特异性地促进肝细胞增殖、促进70%肝切除小鼠肝再生的物质并将其命名为HPPCn。因此,结合本实验室的工作对肝刺激物（HSS）、肝再生增强因子（ALR）、HPS、HPPCn等具有肝特异性作用的生物活性肽的研究进展以及相互之间的异同加以综述。     

胆管细胞囊腺瘤(癌)的临床特征及诊治方法研究

 目的 了解胆管细胞囊腺瘤(癌)的发病情况,分析该病诊治特点.方法 回顾性分析我院近10年来明确诊断的39例胆管细胞囊腺瘤(癌)患者的临床资料,对该病的发病率及诊断、治疗情况进行系统研究.结果 胆管细胞囊腺瘤(癌)在肝脏占位性病变中约占0.35%,在肝脏囊实性占位中约占1.70%,手术切除后复发率为2.6%.结论 胆管细胞囊腺瘤(癌)是一种少见的肝脏占位性病变,患者大多缺乏典型临床症状,影像学是主要的术前诊断方法,漏诊及误诊率高,对肿瘤实施完整手术切除是确切有效的治疗办法,术后复发率较低,预后较好.     

Inflammatory pseudotumor of the liver in a patient with congenital granulocytopenia and HCV infection

Inflammatory pseudotumor (IPT) of the liver is a rare pathologic lesion. Although IPTs within the liver shows spontaneous regression, these lesions are frequently misdiagnosed as malignant on the basis of the clinical manifestation and the results of diagnostic imaging. With special regard to magnetic resonance imaging (MRI), differential diagnosis such as hepatocellular or cholangiocellular carcinoma (HCC/CCC) as well as regenerative liver lesions are discussed in a case of IPT with concomitant hepatitis C virus (HCV) infection and congenital granulocytopenia.     

Liver cysts in autosomal-dominant polycystic kidney disease: clinical and computed tomographic study

Hepatic CT findings were analyzed in 44 patients with autosomal-dominant polycystic kidney disease and were correlated with liver and renal function tests and liver, splenic, and renal CT volume measurements. CT showed many large liver cysts in 31.8% of patients, small liver cysts in 25%, and no liver cysts in 43.2%. Patients with many large cysts often showed increased liver volumes. Splenic volumes did not differ significantly in patients with and without liver cysts, suggesting that portal hypertension is rarely associated with cystic liver disease. There was no correlation between severity of liver involvement and extent of renal cystic disease as determined from urea nitrogen and creatinine levels and renal volumes. Liver function tests were normal except in two patients, one with a cholangiocarcinoma, which may have arisen from a cyst, and the other with an infected liver cyst and chronic active hepatitis. Accordingly, if liver function tests are abnormal, an attempt should be made to identify complications of polycystic liver disease such as tumor, cyst infection, and biliary obstruction. Such complications are rare but may be seen in patients whose lives are prolonged by dialysis and renal transplantation. CT is a useful method for detecting liver cysts and identifying patients at risk for these complications.     

Liver abscess as a complication of TAE--risk factors and prevention

Transcatheter hepatic arterial embolization for not only hepatocellular carcinoma but metastatic liver cancers is nowadays prevalent. Gall bladder infarction, cholangitis, peptic ulcers, pancreatitis, and aneurysm are reported as complications of it. But the liver abscess following it is rare. We reviewed three cases of liver abscesses after transcatheter hepatic arterial embolization. Biliary tract congestion and inflammation, and iatrogenic contaminations are supposed to major factors that caused liver abscesses. We think we should refrain from the embolization until biliary tract disorders are resolved and take care not to contaminate the proceeding materials in addition to mixing antibiotics with embolus.     

Technetium-99m DISIDA hepatobiliary tract imaging in pseudotumors of the liver

Tc-99m sulfur colloid images of the liver are frequently falsely reported as tumor or metastases in certain space occupying lesions of the liver. Whether a primary malignancy is known or not, every suspicious space-occupying lesion of the liver should be given the benefit of alternate diagnostic studies before a firm diagnosis of neoplasia is made. This is critical when the decision regarding chemotherapy has to be made. Timely intervention by other diagnostic modalities may obviate the consideration of chemotherapy in cases where there are no liver metastases. The case presented below illustrates the value of hepatobiliary tract imaging in pseudotumors of the liver.     

Quantitative Assessment of Liver Fat with Magnetic Resonance Imaging and Spectroscopy

Hepatic steatosis is characterized by abnormal and excessive accumulation of lipids within hepatocytes. It is an important feature of diffuse liver disease, and the histological hallmark of non-alcoholic fatty liver disease (NAFLD). Other conditions associated with steatosis include alcoholic liver disease, viral hepatitis, HIV and genetic lipodystrophies, cystic fibrosis liver disease, and hepatotoxicity from various therapeutic agents. Liver biopsy, the current clinical gold standard for assessment of liver fat, is invasive and has sampling errors, and is not optimal for screening, monitoring, clinical decision making, or well-suited for many types of research studies. Non-invasive methods that accurately and objectively quantify liver fat are needed. Ultrasound (US) and computed tomography (CT) can be used to assess liver fat but have limited accuracy as well as other limitations. Magnetic resonance (MR) techniques can decompose the liver signal into its fat and water signal components and therefore assess liver fat more directly than CT or US. Most magnetic resonance (MR) techniques measure the signal fat-fraction (the fraction of the liver MR signal attributable to liver fat), which may be confounded by numerous technical and biological factors and may not reliably reflect fat content. By addressing the factors that confound the signal fat-fraction, advanced MR techniques measure the proton density fat-fraction (the fraction of the liver proton density attributable to liver fat), which is a fundamental tissue property and a direct measure of liver fat content. These advanced techniques show promise for accurate fat quantification and are likely to be commercially available soon.     

Magnetic resonance imaging: Review of imaging techniques and overview of liver imaging

Magnetic resonance imaging (MRI) of the liver is slowly transitioning from a problem solving imaging modality to a first line imaging modality for many diseases of the liver. The well established advantages of MRI over other cross sectional imaging modalities may be the basis for this transition. Technological advancements in MRI that focus on producing high quality images and fast imaging, increasing diagnostic accuracy and developing newer function-specific contrast agents are essential in ensuring that MRI succeeds as a first line imaging modality. Newer imaging techniques, such as parallel imaging, are widely utilized to shorten scanning time. Diffusion weighted echo planar imaging, an adaptation from neuroimaging, is fast becoming a routine part of the MRI liver protocol to improve lesion detection and characterization of focal liver lesions. Contrast enhanced dynamic T1 weighted imaging is crucial in complete evaluation of diseases and the merit of this dynamic imaging relies heavily on the appropriate timing of the contrast injection. Newer techniques that include fluoro-triggered contrast enhanced MRI, an adaptation from 3D MRA imaging, are utilized to achieve good bolus timing that will allow for optimum scanning. For accurate interpretation of liver diseases, good understanding of the newer imaging techniques and familiarity with typical imaging features of liver diseases are essential. In this review, MR sequences for a time efficient liver MRI protocol utilizing newer imaging techniques are discussed and an overview of imaging features of selected common focal and diffuse liver diseases are presented.     

糖尿病性脂肪肝B超声像图与脂蛋白代谢异常关系的探讨

目的：探讨糖尿病脂肪肝的发生与患者的血糖、血脂水平的关系。方法：分析了120例糖尿病患者肝脏B超声像图改变与血糖(GLU)、胆固醇(CH)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)水平的关系，并与200例正常对照组进行了比较。结果：糖尿病组脂肪肝发生率远远高于对照组，二者比值为7．59：1；120例糖尿病患者中，78例确诊为糖尿病脂肪肝，糖尿病致脂肪肝的发病率为65％。结论：糖尿病脂肪肝的发生与患者的血糖、血脂水平有直接关系。合并脂肪肝组的GLU、CH、TG、LDL-C水平均高于未合并脂肪肝组；HDL-C水平低于未合并脂肪肝组，两组比较差异显著。     

Focal liver lesions: role of contrast-enhanced ultrasound

The introduction of microbubble contrast agents and the development of contrast-specific techniques have opened new possibilities in liver imaging. Initially, only intermittent imaging with Doppler detection was available. Second-generation contrast agents and low mechanical index real-time scanning techniques are decisive advances that enable convenient liver examinations with high sensitivity and specificity. Hepatic lesions usually show typical perfusion and enhancement patterns through the various contrast phases, which help their characterization. Several published studies and the daily clinical routine show that, as opposed to conventional ultrasound (US), contrast-enhanced US can substantially improve detection and differentiation of focal liver lesions. Today, contrast-enhanced US is the dynamic imaging modality of choice for differentiation of focal liver lesions. Contrast uptake patterns of the most relevant liver lesions, as well as important clinical indications are presented and discussed.     

Invited. Hepatitis,cirrhosis, and hepatoma

Virus hepatitis and liver cirrhosis are found at high incidence in Asia, and they require not only biochemical examination of blood but also subsequent imaging, because they are often complicated by hepatocellular carcinoma (HCC). It is, therefore, very important to know the specific appearances of hepatitis, liver cirrhosis, and HCC when we diagnose these diffuse liver diseases. Liver necrosis due to severe hepatitis is seen as high intensity on T2-weighted spin echo images. Regeneration is seen as low intensity on T2-weighted images. Morphologic and pathologic changes of cirrhotic liver are well demonstrated by MR imaging techniques. Fibrotic septum with inflammatory cell infiltration or rich pseudo bile duct show high intensity on T2-weighted images, and regenerating nodules shows low intensity. Gradient echo images show regenerating nodules with iron deposition as low-intensity nodules due to susceptibility artifact. MRI also has the potential to evaluate function of diffuse liver disease, cirrhosis, and hepatitis. MRI can visualize and diagnose HCC objectively. Dynamic MRI is very useful for diagnosing HCC. It is also applied for evaluation of effect after transcatheter arterial chemoembolization, because it shows enhancement only in the viable region at an arterial phase. MRI is less invasive and is thus an extremely important form of liver imaging.     

Liver metastases: Detection and staging

The liver is more often involved with metastatic disease than primary liver tumors. The accurate detection and characterization of liver metastases are crucial since patient management depends on it. The imaging options, mainly consisting of contrast-enhanced ultrasound (CEUS), multidetector computed tomography (CT), magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI), extra-cellular contrast media and liver-specific contrast media as well as positron emission tomography/computed tomography (PET/CT), are constantly evolving. PET/MRI is a more recent hybrid method and a topic of major interest concerning liver metastases detection and characterization. This review gives a brief overview about the spectrum of imaging findings and focus on an update about the performance, advantages and potential limitations of each modality as well as current developments and innovations.     

肝移植术后并发症与介入治疗一、肝动脉血栓形成

肝移植术(LT)后并发症的有效处理很大程度上决定手术的成败。LT后肝动脉血栓形成(HAT)可直接导致移植肝坏死、胆汁瘤与肝功能衰竭。及早发现并明确诊断对预后至关重要,多普勒超声可作为首选的普查方式,CTA、MRA及血管造影可以进一步明确诊断。肝动脉血栓形成后局部溶栓简便易行,与球囊扩张、支架置入技术联合应用通常取得较好的疗效,同时需寻求规范化诊疗方案;血管重建术与加压舱治疗也是有效方法,不得已时,肝脏再移植仍是重要的最后治疗措施。