CT in hepatic cirrhosis and chronic hepatitis.

Cirrhosis is a diffuse liver disease with premalignant potential in which hepatocellular carcinoma (HCC) frequently develops. The hemodynamics of contrast material are the key to diagnosis of focal liver lesions with computed tomography (CT). Lesions with arterial-dominant vascularity, such as HCC, show brisk enhancement during the arterial phase, whereas lesions with portal blood supply can appear as hyperenhancing lesions in the portal phase. The advent of helical CT has significantly improved the CT examination of the liver because the arterial phase can be displayed independently of the portal phase. The addition of arterial phase imaging to conventional portal phase imaging seems to improve tumor detection and characterization. Although HCC is the single most frequent tumor seen in chronic liver disease, other lesions such as peripheral cholangiocarcinoma and hemangioma should be considered in the differential diagnosis. Optimization of helical CT techniques may allow better detection and characterization of these lesions. In addition to tumor detection, CT plays an important role in preoperative staging of HCC as well as in preoperative assessment of patient candidates to hepatic transplantation. The use of CT angiography with maximum intensity projection techniques may allow for better preoperative work-up and vascular mapping in HCC patients. This article shows the spectrum of helical CT findings in chronic liver disease and specifically in the imaging of HCC and other focal lesions.     

肿瘤性肝灌注异常现象在肝癌中的影像学表现

目的明确肿瘤性肝灌注异常(HPD)在肝细胞癌患者中的发生率、影像学形态特征以及与动-门脉瘘、门脉癌栓之间的关系,探讨其可能发生机制。方法对780例肝细胞癌患者中出现肿瘤性肝灌注异常50例的临床资料、双期CT表现、动态MR增强及肝动脉造影进行回顾性分析,肿瘤性灌注异常的影像诊断标准为:CT、MR增强动脉期表现为病灶周围肝实质楔形或不规则形一过性强化,门静脉期恢复正常,肝动脉造影表现为动脉期病灶周围肝实质一过性染色,门静脉期恢复正常。结果780例肝细胞癌中出现肿瘤性灌注异常50例(6.4%),伴发门脉癌栓者HPD的发生率较不伴发门脉癌栓者高(P<0.01);伴发动-门脉瘘者较不伴者高(P<0.01)。结论肿瘤性灌注异常现象的出现与伴发肝癌动-门脉瘘、门脉癌栓有关。     

Hepatocellular carcinoma: Prospective assessments of the T-factor with CT, US, and MR imaging

The capabilities of computed tomography (CT), ultrasonography (US), and magnetic resonance (MR) imaging were studied in order to determine the role of each of these noninvasive examinations for estimating the T-factor of hepatocellular carcinomas (HCCs). Fifty-one patients with surgically proven HCCs received CT (50 patients), US (46 patients), and MR (44 patients). The images of CT, US, and MR were prospectively evaluated for main tumor size, intrahepatic metastases, and vascular invasion, which compose the T-factor of HCC, and compared to pathological results. The sizes of the main tumor were estimated correctly by all examinations. For estimating intrahepatic metastases, US (74%) and MR (73%) were superior to CT (65%). For estimating portal invasion, CT (79%) was superior to US (70%) and MR (66%), because CT could demonstrate the segmental staining caused by portal invasion. The estimates of hepatic venous invasion were difficult during any of the examinations. We conclude that presurgical evaluations of the T-factor require the use of US and CT or MR and CT.     

Hepatocellular nodules in liver cirrhosis: contrast-enhanced ultrasound

Contrast-enhanced ultrasound (CEUS) using microbubble contrast agents has expanded the role of US in the diagnosis of liver nodules in high risk patients for hepatocellular carcinoma (HCC). HCC is typically characterized by arterial hypervascularity and later washout (negative enhancement). Washout in the portal phase is often not obvious until late (>90 s). Benign nodules such as regenerative nodules or dysplastic nodules are usually isoechoic or slightly hypoechoic in the arterial and portal venous phases. However, there are occasional cases with overlap of imaging features between benign and malignant nodules, including hypovascular HCC and hypervascular HCC without washout. CEUS is helpful to characterize potential mimickers of HCC on imaging such as nontumorous arterioportal shunt or hemangioma. CEUS is also useful for a guidance of percutaneous local therapy of HCC and post-procedure monitoring of therapeutic response. CEUS can be effectively used in the diagnostic algorithm of small (1–2 cm) newly detected nodules during HCC surveillance.     

The role of CEUS in the characterization of hepatocellular nodules detected during the US surveillance program--current practices in Europe

The basic pathological feature for the differential diagnosis between hepatocellular carcinoma (HCC) and non-malignant hepatocellular nodules in cirrhotic patients detected during ultrasound (US) is the vascular supply to the nodule. Computed tomography (CT) and magnetic resonance imaging (MRI) are considered reference imaging techniques for depicting hepatocellular nodule vascularity in the noninvasive diagnosis of HCC. Contrast-enhanced US (CEUS) improves the diagnostic performance of unenhanced US in the diagnosis of HCC, giving an overall diagnostic accuracy that is similar to that of CT, even for nodules smaller than 2 cm. An additional diagnostic feature of CEUS relative to CT is the possibility to visualize contrast wash-in to hepatic nodules during the arterial phase and contrast washout during the portal venous and late phases. Sensitivity for the diagnosis of HCC with combined assessment of CEUS and CT is higher than for separate assessments of CEUS and CT due to the reduction of false-negative findings. CEUS represents a competitive imaging method from an economic point of view, and is an effective imaging tool for assessing the therapeutic outcome after surgery, ablation therapy, and transarterial chemoembolization (TACE).     

Staging of hepatocellular carcinoma by ultrasonography,computed tomography,and angiography: The role of CT combined with arterial portography

A series of 60 patients with hepatocellular carcinoma (HCC) were evaluated over a 2-year period of ultrasonography (US), computed tomography (CT), and angiography. The angiographic studies carried out with intraarterial digital technology were compared to both US and CT of the liver. In 16 of 60 patients, we observed discordance of the findings obtained with angiography, CT, and US. We therefore compared these three methodologies in those cases where diagnostic discordance was noted. In our experience, US had a sensitivity of 73.4%, 76.7% for CT, and 95% for angiography. In 13 of 60 patients, we performed CT with arterial portography (CTAP) which demonstrated a better resolution than conventional CT. In view of the sensitivity of US — comparable to that of CT — and for the even greater sensitivity of intraarterial digital angiography, we performed an US study of patients at risk of HCC. CT was found to play a diagnostic/staging role after angio graphic study has been performed, especially when enhanced by arterial portography.     

肝细胞癌多层螺旋CT灌注成像肝血流变化定量研究

目的 应用多层螺旋CT（MSCT）灌注成像技术研究肝细胞癌（HCC）血流灌注参数变化。方法 HCC患者30例，其中手术切除6例，穿刺活检证实4例，其余为临床综合诊断。正常对照组30例。所有对象均依次行常规全肝平扫、CT灌注扫描及常规全肝增强扫描。高压注射器注射非离子型对比剂50ml，流率4.0ml/s，曝光时间50s，采用去卷积模型，通过灌注参数图获得多种灌注参数。结果 肝癌组灌注参数HBF、HBV、HPP降低与癌旁肝组织和正常肝脏相比有统计学差异（P〈0.05）。肝癌组HAP、HAI明显升高，与癌旁肝组织和正常肝组织相比有显著差异（P〈0.01），各灌注参数在癌旁和正常肝组织中无显著差异（P〉0.05）。结论 多层螺旋CT灌注成像能定量反映HCC的肝动脉和门静脉血流灌注信息。     

Imaging of malignant liver masses: characterization and detection

Noninvasive characterization of focal liver lesions is largely based on their enhancement patterns on contrast-enhanced imaging. The use of microbubble contrast agents combined with specialized ultrasound (US) techniques has significantly expanded the role of US in the diagnosis of focal liver lesions based on their vascularity and specific enhancement features. With the advantage of real-time scanning, contrast-enhanced ultrasound (CEUS) can evaluate small lesions that are indeterminate on computed tomography (CT) or magnetic resonance imaging (MR), because CEUS is far less affected by timing issues. Hepatocellular carcinoma is typically characterized by increased arterial flow with frequent dysmorphic tumor vessels and decreased portal venous flow. However, negative enhancement in the portal phase is often not obvious until late (>2 minutes). On the other hand, metastasis shows prompt brief arterial hypervascularity, with either a rim or diffuse pattern and rapid washout, seen as perfusion defects during the portal venous phase. This pattern of complete rapid washout of metastases within the homogeneously enhanced background liver parenchyma can improve their detection and also improve differentiation from hepatocellular carcinoma or benign focal lesions. All malignant lesions generally show negative enhancement or washout during the extended portal venous phase, and this pattern is useful to differentiate them from benign lesions. Microbubble agents, confined to the intravascular space, may infrequently characterize malignancy by showing washout whereas CT or MR shows persistent enhancement due to interstitial distribution.     

肝细胞肝癌门静脉癌栓介入分型及其临床应用价值

目的:探讨适合指导介入治疗的肝细胞肝癌门静脉癌栓介入分型。方法:根据肝细胞肝癌合并门静脉癌栓患者的动态增强CT或MR影像学表现,将门静脉癌栓分为Ⅰ~Ⅴ共5型,包括Ⅰ型、Ⅱa型/Ⅱb型、Ⅲa型/Ⅲb型/Ⅲc型、Ⅳa型/Ⅳb型、Ⅴ型,其中将Ⅰ~Ⅳ型同时合并肝动脉门静脉瘘归为Ⅴ型。观察不同分型患者经肝动脉化疗栓塞(transcatheter arterial chemoembolization,TACE)联合门静脉支架+放射性碘-125粒子条植入治疗的效果。结果:117例入选患者介入分型为Ⅰ型占10.2%(12/117)、Ⅱ型占17.1%(20/117)、Ⅲ型占53%(62/117)、Ⅳ型占19.6%(23/117)、Ⅴ型占16.2%(19/117)。所有患者均接受介入治疗,术后即刻造影显示,68例(93.1%)患者门静脉灌注明显改善。术后1~3个月增强MR/CT随访显示,植入碘-125粒子部位的癌栓均较术前明显萎缩,有效控制。结论:肝细胞肝癌合并门静脉癌栓的介入分型有助于指导临床制定个体化的介入治疗策略,使患者获益,值得临床推广。     

Parenchymal changes of the liver in cholangiocarcinoma: CT evaluation

We evaluated parenchymal changes of the liver in 92 patients (41 peripheral types and 51 hilar types) with cholangiocarcinomas studied by bolusenhanced computed tomography (CT). In 39% of patients with the peripheral type, a wedge-shaped increased enhancement of the liver was observed peripheral to the tumor on bolus-enhanced CT. Tumor was observed in all cases. In 58.8% of patients with the hilar type, a segmental or lobar increased degree of enhancement of the liver was observed, but the tumor was demonstrated in only 58.8%. Atrophy was accompanied by areas of increased enhancement in 80% of hilar type and 25% of peripheral type. Areas of increased degree of enhancement corresponded to a wedged-shaped perfusion defect on CT during arterial portography. On magnetic resonance imaging (MRI), those lesions showed hyperintensity on T2-weighted images. Most of these changes were considered to be due to reversible hepatic parenchymal ischemia secondary to portal vein invasion by the tumor.     

Utility of Compact Ultrasound in a Mass Surgical Selection Program in Africa

Compact ultrasound (US) was introduced in an austere setting with no other available imaging for an annual mass surgical screening day. Compact US examinations were performed on 25 patients from more than 7000 potential patients, as deemed possibly useful by the screening surgeons. Of the 20 patients with recorded data, compact US was helpful in 14 of 20 as a decision‐making tool, obviating computed tomography for preoperative planning. Compact US was helpful in most cases, saving resources (computed tomography), technologist time, and radiation risk in this select population.     

原发性肝细胞癌的多层CT血管造影表现及临床应用价值

目的探讨原发性肝细胞癌的多层螺旋双期CT血管造影表现及后处理技术.方法所有42例于MX8000 4层螺旋CT机上进行增强扫描,有效层厚3.2 mm,重建间隔1.6 mm,对比剂用量1.5 ml/kg体重,注射速率3 ml/s,延迟时间分别为25 s、50～55 s.进行最大密度投影(MIP)、多平面重组(MPR)、容积再现(VR)处理.结果动脉期显示肿瘤染色者18例,肿瘤血管23例.12例进行了DSA检查,MSCT所显示的肿瘤染色、肿瘤血管及供血动脉的来源与分布与DSA检查一致.门静脉期,检出门静脉瘤栓12例,门静脉闭塞14例,动-静脉分流8例.MIP、MPR及VR有利于检出肝癌的肿瘤染色、肿瘤血管、供血动脉、门静脉闭塞及动-静脉分流.结论 MSCT肝脏双期血管造影可以提供有关肝癌本身、供血动脉及门静脉改变的信息.     

Hepatocellular nodules in liver cirrhosis: MR evaluation

Liver cirrhosis is a major public health problem worldwide. Common causes of cirrhosis include hepatitis C virus, hepatitis B virus, alcohol consumption, and nonalcoholic steatohepatitis. Cirrhotic livers are characterized by advanced hepatic fibrosis and the development of hepatocellular nodules such as regenerative nodules, dysplastic or neoplastic nodules. Cirrhosis is the strongest predisposing factor for hepatocellular carcinoma (HCC). For example, viral hepatitis is the main risk factor for cirrhosis and is associated with the increased incidence (1%–4% per year) of HCC after development of cirrhosis. Currently, a variety of imaging modalities, including ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), and positron-emission tomography (PET) are used in noninvasive evaluation of patients with chronic liver disease and suspected HCC. With technological development of MR scanners, MR imaging has emerged as an important imaging modality for assessing cirrhosis and its complications such as HCC. The recent advance in MR is the introduction of faster sequences which have allowed high-quality imaging of the entire liver with high intrinsic soft-tissue contrast, and also multiphasic dynamic MRI that is essential for the detection and characterization of HCC. In addition, functional MRI including diffusion-weighted MRI, MR elastography, and new MR contrast agent with dual function have been investigated for the clinical utility of detection and characterization of HCCs. In this article, we provide an overview of the state-of-the-art MR imaging techniques being used for noninvasive assessment of hepatocellular nodules including conventional dynamic imaging, liver-specific contrast-enhanced MR imaging, diffusion-weighted imaging, MR spectroscopy, and MR elastography.     

Imaging diagnosis of portal tumor thrombus secondary to gastric cancer

Tumor thrombus in the portal vein secondary to advanced gastric cancer was diagnosed by ultrasound (US) and computed tomography (CT), and was confirmed at autopsy in a 54-year-old man. The register data for 3176 patients of resected gastric cancer disclosed that there was no patient with portal tumor thrombus secondary to gastric cancer.     

肝细胞性肝癌超声造影的增强模式 --低机械指数连续实时成像技术的应用研究

目的　分析采用低机械指数连续实时成像技术时肝细胞性肝癌 (HCC)超声造影的增强模式。方法　 6 8例 HCC患者共 72个病灶接受了超声造影检查。采用对比脉冲序列 (CPS)成像技术 ,造影剂为 Sono Vue。结果　静脉注射 Sono Vue后 ,全部病灶均可见强化 ,绝大多数病灶 (70 /72 ,97.2 % )增强早于肝实质及门静脉 ;增强形态主要为均匀或不均匀增强 ;增强程度在动脉期高于肝实质 ,门静脉期和肝窦期则低于肝实质 ;动脉期 30 .6 % (2 2 /72 )的病灶可见包膜强化。结论　 HCC在各时相的增强模式具有特征性 ,采用 CPS技术及造影剂 Sono Vue能实时连续地描述 HCC的增强特点。     

Atypical large well-differentiated hepatocellular carcinoma with benign nature: a new clinical entity

Based on intranodular hemodynamic studies of nodular lesions associated with liver cirrhosis using computed tomography (CT) during arteriography, CT during arterial portography (CTAP) and angiography under ultrasonography, relatively large hepatocellular nodules with portal perfusion have been depicted. We report 17 such nodules in a total of 663 patients who underwent CTAP. Large well-differentiated hepatocellular carcinomas (HCCs) are characterized by the presence of intranodular portal perfusion even if they measure more than 2.5 cm in diameter. Such nodules display a benign nature clinically as well as pathologically. These nodules, called 'atypical large well-differentiated HCC or dysplastic nodules', show extremely slow growth. Pathological study showed extremely peculiar findings; the nodules consisted of homogeneously hyperplastic or well-differentiated HCC without the component of moderately or poorly differentiated HCC, and without fibrous capsules, vessel invasion or intrahepatic metastasis, all of which are commonly found in typical overt HCC. The incidence of such nodules is not rare; it was 2.6% (17/663) in our HCC patients who underwent CTAP over a period of 7 years. During the 7-year observation period, none of 10 such nodules developed into arterial supply-dominant overt HCC. The recognition of these benign-nature nodules (or large low-grade malignant nodules) is extremely important for the following three reasons. First, the knowledge that such large atypical nodular lesions exist is important for clinicians. Second, regarding the treatment strategy for such nodular lesions, it should be kept in mind that these nodules show a benign nature, and rarely cause death. Finally, considering the etiology and clinical significance of such atypical large benign-nature nodules, the recognition of these nodules provides an important suggestion regarding the pathogenesis of progression from dysplastic nodule to early HCC and finally to overt HCC during multistep human hepatocarcinogenesis. These atypical large benign-nature nodules do not seem to be the nodules in a sequence of multistep progression. The early step of hepatocarcinogenesis includes mainly hyperplastic change, whereas the late step includes mainly an angiogenic process. Although the detailed molecular pathogenesis of both the early and late steps of hepatocarcinogenesis is not clear, it is speculated that these atypical benign-nature nodules do not undergo the phenotypic change of late-step hepatocarcinogenesis. In that sense, these atypical benign-nature nodules are suggestive for the clarification of the mechanism of multistep human hepatocarcinogenesis based on the intranodular vascular supply or hemodynamics. From the viewpoint of clinical practice as well as pathogenesis of human hepatocarcinogenesis, these nodular lesions should be managed as a different disease from overt HCCs; atypical large HCCs or dysplastic nodules with benign nature should be regarded as a new clinical entity.     

Delayed enhancement of hepatocellular carcinoma on dynamic CT: sign of extrahepatic collaterals after transcatheter arterial chemoembolization or transcatheter arterial chemoinfusion

BACKGROUND: We examined the factors of delayed enhancement of hepatocellular carcinoma (HCC) on dynamic computed tomography (CT). METHODS: Dynamic CT and angiography were compared in 113 patients who had undergone transcatheter arterial chemoembolization or transcatheter arterial chemoinfusion and were suspected of developing new HCCs. RESULTS: Eight of 113 patients had HCC nodules that enhanced gradually from the arterial phase to the portal venous phase on dynamic CT and were fed by extrahepatic arteries on angiography. The feeding artery was an omental branch of the splenic artery in one lesion, an omental branch of the gastroduodenal artery in five, and the intercostal artery in two. CONCLUSION: We believe that the recurrence of HCCs delayed enhancement on dynamic CT because the hepatic artery was hidden and long narrow extrahepatic collaterals fed the tumor.     

原发性肝癌合并门静脉癌栓血液动力学变化的MSCTP定量研究

目的探讨原发性肝癌合并门静脉癌栓血液动力学变化的多层螺旋CT灌注成像(MSCTP)各参数的变化规律。方法应用美国GE公司LightSpeed 16型16层螺旋CT对84例受试对象经右侧肘静脉以4mL/s的速率注射对比剂40mL行MSCT灌注扫描。应用去卷积算法模式计算肝血流量(HBF)、肝血容量(HBV)、平均通过时间(MTT)、毛细血管表面通透性(PS)和肝动脉灌注指数(HAF)等。结果实验A组肿瘤组织的HBF、HAF明显高于阳性对照B组,实验A组PVTT组织的HBV、HAF也明显高于阳性对照B组,而实验A组肿瘤组织的MTT值却短于阳性对照B组。实验A组异常灌注组织的HBF、HBV和HAF值均明显高于阴性对照C组。结论MSCTP灌注参数可定量评价原发性肝癌合并门静脉癌栓血液动力学变化特点。     

多层螺旋CT对肝细胞癌合并门静脉癌栓的诊断价值

目的：探讨多层螺旋CT扫描对肝细胞癌合并门静脉癌栓的诊断价值.材料与方法：回顾性分析25例经手术病理证实的肝细胞癌合并门静脉癌栓患者的三期动态增强CT表现,通过兴趣区（Region of interest,ROI）分析定性和定量评估肿瘤动脉期、静脉期和延迟期图像.另外也通过ROI分析定量评价肝左叶和右叶背景强化情况.结果：定性分析发现40％（10/25）的肝细胞癌表现为动脉期快速不均质血管强化,而64％（16/25）的肿瘤表现为门脉期快速洗脱,另外40％（10/25）的肝细胞癌表现为动脉期快速不均质血管强化和门脉期快速洗脱.定量分析提示动脉期血管强化肝细胞癌从强化前到动脉期的绝对增强值为49.1 ±17.1HU,而动脉期无血管强化肿瘤为23.8±16.6HU,差异具有统计学意义（P＜0.01）.动脉期血管强化肝细胞癌的肝实质背景在动脉期的绝对增强值为13.79±7.9HU,而动脉期无血管强化肿瘤的肝实质背景为36.6±30.6HU,差异具有统计学意义（P=0.03）.结论：很大一部分合并门静脉癌栓的肝细胞癌缺乏特征性的动脉期快速不均质血管强化,可能是背景肝实质动脉血供继发性代偿增加所致,这是应用影像学标准诊断肝细胞癌的一个潜在陷阱.     

肝细胞癌的CT灌注成像研究

目的探讨肝细胞癌(HCC)的CT灌注成像特点。方法已确诊的HCC患者26例,在治疗前进行肝脏CT灌注成像,测量病灶、病灶周围肝组织、以及远处肝组织的灌注参数。结果HCC病灶的肝动脉灌注量(HAP)、肝脏灌注指数(HPI)显著高于远处的肝组织(P<0.01),而其门脉灌注量(PVP)和总肝灌注量(TLP)低于远处的肝组织(P<0.01)。边缘清晰的病灶周围肝组织的各项灌注参数均与远处肝组织无显著性差异(P>0.05)。边缘模糊的病灶周围肝组织与癌灶类似,其HAP明显升高,是远处肝组织的2倍,而PVP则降低,TLP无显著性变化。结论HCC在CT灌注成像上具有一定的特征性,根据CT灌注成像可以确定其实际范围。