磁共振弥散加权成像在肝硬化诊断中的应用

目的探讨磁共振弥散加权成像对肝硬化的诊断价值。方法采用GEHDx1．5TMRI扫描仪对100例临床诊断肝硬化患者（肝硬化组）及30名健康对照者（对照组）行轴位屏气弥散加权成像扫描（扩散敏感系数b值选用800mm^2／s）,比较2组表观弥散系数（apparent diffusion coefficient。ADC）值。结果对照组与肝硬化组肝脏ADC值分别为（1．842±0．173）和（1．380±0．137）×10^-3mm^2/s,后者低于前者,2组差异有统计学意义。结论肝硬化患者肝脏ADC值下降,磁共振弥散加权成像可望成为无创肝硬化诊断的手段之一。     

Guidelines for imaging focal lesions in liver cirrhosis

Imaging cirrhotic patients for early detection of hepatocellular carcinoma remains a challenging issue despite many technological advances. In fact, nonmalignant hepatocellular lesions, such as regenerative or dysplastic nodules, may mimic a small tumor. Imaging protocols are aimed at showing the different vascular supply to the lesion. It is accepted that dynamic contrast-enhanced imaging techniques, including contrast ultrasound, multidetector computed tomography and magnetic resonance imaging, can establish the diagnosis of hepatocellular carcinoma in nodular lesions larger than 1 cm showing arterial hypervascularization with venous washout. Magnetic resonance imaging in combination with liver-specific contrast agents, including hepatocyte-targeted and reticuloendothelial system-targeted agents, may be useful to clarify questionable cases, due to its ability to show changes in hepatobiliary function or Kuppfer cell content associated with malignancy. However, even optimized imaging techniques remain relatively insensitive for the detection of tiny satellite nodules associated with the main tumor.     

Prediction of liver cirrhosis,using diagnostic imaging tools

Early diagnosis of liver cirrhosis is important. Ultrasoundguided liver biopsy is the gold standard for diagnosis of liver cirrhosis. However, its invasiveness and sampling bias limit the applicability of the method. Basic imaging for the diagnosis of liver cirrhosis has developed over the last few decades, enabling early detection of morphological changes of the liver by ultrasonography(US), computed tomography, and magnetic resonance imaging(MRI). They are also accurate diagnostic methods for advanced liver cirrhosis, for which early diagnosis is difficult. There are a number of ways to compensate for this difficulty, including texture analysis to more closely identify the homogeneity of hepatic parenchyma, elastography to measure the stiffness and elasticity of the liver, and perfusion studies to determine the blood flow volume, transit time, and velocity. Amongst these methods, elastography using US and MRI was found to be slightly easier, faster, and able to provide an accurate diagnosis. Early diagnosis of liver cirrhosis using MRI or US elastography is therefore a realistic alternative, but further research is still needed.     

不同Child-Pugh分级的血吸虫病性肝硬化患者肝脏CT灌注成像参数分析

目的 探讨不同Child-Pugh分级的血吸虫病性肝硬化患者肝脏CT灌注成像参数的变化。方法 2016年5月～2018年10月我院诊治的血吸虫病性肝硬化患者40例(Child A级12例,B级16例和C级12例)和同期健康人40例,接受螺旋CT检查,应用 CT Perfusion 4D肝脏灌注软件包处理肝脏灌注的相关数据,包括平均通过时间(MTT)、肝动脉分数(HAF)、肝动脉灌注量(HAP)、血容量(BV)和肝血流量(BF)等参数。结果 健康人肝脏CT检测的BV、BF、MTT、HAF和HAP分别为(45.7±8.4)mL/100g、(212.6±43.3)mL/min·100g、(13.5±2.3) s、(0.2±0.0)和(16.3±8.3)mL/min·100g,而Child A级患者分别为(41.0±15.3)mL/100g、(185.6±38.4)mL/min·100g、(15.2±1.2) s、(0.2±0.0)和(20.5±8.0)mL/min·100g,Child B级分别为(38.5±20.6)mL/100g、(126.6±90.5)mL/min·100g、(19.4±11.4) s、(0.3±0.0)和(26.7±2.0)mL/min·100g,Child C级分别为(23.3±8.7)mL/100g、(129.4±46.6)mL/min·100g、(27.5±2.7) s、(0.4±0.1)和(35.2±12.6)mL/min·100g,肝硬化与健康人及不同Child分级的肝硬化患者之间,差异显著(P<0.05)。结论 血吸虫病性肝硬化肝脏CT检查能提供形态学改变信息,CT灌注成像参数可以较好地评估肝硬化程度。     

磁共振扩散加权成像评价肝硬化的应用价值

目的探讨肝硬化磁共振扩散加权成像（DW I）表观弥散系数（ADC）值变化与肝硬化程度之间的相关性。方法对54例肝硬化患者及48例正常肝脏行扩散加权成像,并测量ADC值,DW I序列所选用弥散敏感度（b值）分别为（0,400,600,800）s/mm2。在b1和b2（ADC1）、b1和b3（ADC2）及b1和b4（ADC3）计算肝脏ADC值。结果肝硬化平均ADC1、ADC2、ADC3均显著低于正常肝脏（P〈0.05）;Ch ild A、B、C各级肝硬化与正常肝脏相比,ADC值均明显降低（P〈0.05）;ADC值随肝硬化程度的加重而降低（P〈0.05）;各组ADC值随b值增大而降低（P〈0.05）;b值为600 s/mm2、800 s/mm2时,认为（1.30×10-3）s/mm2可能为正常肝脏与肝硬化的分界点,低于此值即可考虑为肝硬化。结论DW I-ADC值的测定可辅助临床诊断早期肝硬化并反映肝硬化的动态变化,是评价肝硬化的有价值的参考指标。     

Intrapulmonary right-left shunt associated with liver cirrhosis: diagnosis by contrast echocardiography

The hypoxaemia associated with hepatic cirrhosis is classically attributed to an intrapulmonary shunt caused by small vascular abnormalities. Severe hypoxaemia (47 mmHg) associated with dyspnoea, cyanosis and clubbing was observed in a 57-year old man who presented with cirrhosis of the liver. At contrast echocardiography, a right-to-left shunt was demonstrated by the appearance of microcavities in the left atrium and ventricle after peripheral intravenous injection of the contrast medium. The intrapulmonary location of the shunt was determined by a 4 cardiac cycles interval between the arrival of the microcavities in the right heart and their appearance in the left heart. The right-to-left shunt was confirmed by the pure oxygen ventilation test and by pulmonary perfusion scintigraphy with radiolabelled albumin microaggregates. Pulmonary angiography proved normal. Thus, contrast echocardiography is capable of diagnosing right-to-left shunts associated with hepatic cirrhosis and to demonstrate their intrapulmonary location.     

Intrahepatic circulatory time analysis of an ultrasound contrast agent in liver cirrhosis.

OBJECTIVE: To assess the diagnostic accuracy and advantages of intrahepatic circulatory time analysis of an ultrasound contrast agent using pulse-inversion imaging as compared with recently reported noninvasive diagnostic tests for cirrhosis. METHODS: Forty patients divided into noncirrhotic (nonLC) (n = 20) and compensated cirrhotic (LC) (n = 20) groups were studied prospectively. After intravenous administration of a contrast agent, the arrival times at the hepatic artery (HA), portal vein (PV), and hepatic vein (HV) were measured by pulse-inversion imaging. Intrahepatic circulatory time was calculated as the difference between the HV and HA arrival times (HV-HA interval time) or the HV and PV arrival times (HV-PV interval time). RESULTS: The HV-HA and HV-PV interval times were significantly shorter in the LC group (7.4 +/- 1.7 and 1.9 +/- 1.5 s, respectively) compared with those in the nonLC group (normal: 15.6 +/- 2.1 and 11.1 +/- 1.7 s, respectively; P < 0.001 and P < 0.001, respectively, and hepatitis: 12.8 +/- 4.1 and 7.8 +/- 4.4 s, respectively; P < 0.001 and P < 0.002, respectively). Each intrahepatic circulatory time showed the highest accuracy rate for cirrhosis in other noninvasive diagnostic tests. CONCLUSIONS: This analysis, which is considered to reflect intrahepatic hemodynamic changes, is a useful noninvasive diagnostic test for compensated cirrhosis.     

Detection of hepatopulmonary syndrome in patients with liver cirrhosis using 3D contrast echocardiography

Background and study aimsHepatopulmonary syndrome (HPS) is characterised by the triad of advanced liver disease, arterial hypoxaemia and intrapulmonary vascular dilatation (IPVD). The present study aimed to evaluate HPS in patients with liver cirrhosis and the role of three-dimensional (3D) contrast echocardiography in the detection of this syndrome.Patients and methodsA total of 78 chronic liver disease patients aged 42 ± 11 years fulfilled the criteria for this study and were subjected to clinical examination, laboratory investigations, arterial blood gases measurement, pulmonary function tests, upper gastrointestinal endoscopy, 3D contrast echocardiography and computed tomography (CT) pulmonary angiography.ResultsAccording to 3D contrast echocardiography results, we divided the patients into a positive group (n = 26) in which patients showed a delayed appearance of contrast in left heart chambers and a negative group (n = 52). Among 26 patients of the positive group, nine had hypoxaemia (partial pressure of oxygen (PaO₂) <70 mm Hg) and were diagnosed as having hepatopulmonary syndrome (HPS), the other 17 who had shown echocardiographic evidence of IPVDs but without hypoxaemia were diagnosed as having sub-clinical HPS. This study showed significant correlation between positive contrast echocardiography findings and duration of liver disease, Child score, cyanosis, clubbing, orthodeoxia, portal vein diameter, spleen size and oesophageal varices grades. No significant correlation was found between 3D contrast echocardiography findings and age, sex, spider naevi and pulmonary function tests. Multivariate logistic regression showed that cyanosis, clubbing, orthodeoxia, Child score and portal vein diameter are independent predictors of HPS.ConclusionCyanosis, clubbing and platypnoea-orthodeoxia are suggestive indicators of HPS, which can be easily detected by 3D contrast echocardiography which can replace the trans-oesophageal echocardiogram (TEE) in cirrhotic patients.     

Non-invasive diagnosis of liver cirrhosis: magnetic resonance imaging presents special features

OBJECTIVE: Liver cirrhosis and its complications constitute a daily clinical challenge. The diagnosis of cirrhosis is traditionally established with the invasive method of liver biopsy. We undertook the present study in order to investigate the sensitivity and specificity of magnetic resonance imaging (MRI) in diagnosing cirrhosis. MATERIAL AND METHODS: A total of 56 patients were included in our retrospective study. The liver cirrhosis group comprised 30 patients and the control group 26 patients. All cases were histologically verified. A 1.5T MRI unit was used. Twelve radiological features of cirrhosis (enlargement of segment one, narrowing of hepatic veins, enlargement of spleen, fibrosis, nodular liver surface, ascites, regenerative nodules, enlargement of hilar periportal space, atrophy of right lobe, portosystemic collaterals, expanded gallbladder fossa, iron depositions) and tumour-load were evaluated by consensus reading. The ratio between segment one and right lobe was measured and the livers were classified as cirrhotic or non-cirrhotic. The chi2-test and t-test were used to indicate statistical difference. RESULTS: The sensitivity of MRI in diagnosing liver cirrhosis was 87% and the specificity 92%. The most characteristic MRI features were enlargement of segment one (83%), narrowing of hepatic veins (83%), signs of portal hypertension (77%), fibrosis (77%), and nodular liver margin (67%). There were statistical differences in all MRI signs between the cirrhosis and control groups. The ratio between segment one and right lobe also showed statistical significance between the two groups. All occult hepatocellular carcinomas were detected in the cirrhosis group. CONCLUSION: MRI has high sensitivity and specificity in the diagnosis of liver cirrhosis.     

Non-invasive diagnosis of liver cirrhosis: Magnetic resonance imaging presents special features

Objective Liver cirrhosis and its complications constitute a daily clinical challenge. The diagnosis of cirrhosis is traditionally established with the invasive method of liver biopsy. We undertook the present study in order to investigate the sensitivity and specificity of magnetic resonance imaging (MRI) in diagnosing cirrhosis. Material and methods A total of 56 patients were included in our retrospective study. The liver cirrhosis group comprised 30 patients and the control group 26 patients. All cases were histologically verified. A 1.5T MRI unit was used. Twelve radiological features of cirrhosis (enlargement of segment one, narrowing of hepatic veins, enlargement of spleen, fibrosis, nodular liver surface, ascites, regenerative nodules, enlargement of hilar periportal space, atrophy of right lobe, portosystemic collaterals, expanded gallbladder fossa, iron depositions) and tumour-load were evaluated by consensus reading. The ratio between segment one and right lobe was measured and the livers were classified as cirrhotic or non-cirrhotic. The χ²-test and t-test were used to indicate statistical difference. Results The sensitivity of MRI in diagnosing liver cirrhosis was 87% and the specificity 92%. The most characteristic MRI features were enlargement of segment one (83%), narrowing of hepatic veins (83%), signs of portal hypertension (77%), fibrosis (77%), and nodular liver margin (67%). There were statistical differences in all MRI signs between the cirrhosis and control groups. The ratio between segment one and right lobe also showed statistical significance between the two groups. All occult hepatocellular carcinomas were detected in the cirrhosis group. Conclusion MRI has high sensitivity and specificity in the diagnosis of liver cirrhosis.     

MR imaging of the basal ganglia in chronic liver disease: correlation of T1-weighted and magnetisation transfer contrast measurements with liver dysfunction and neuropsychiatric status

Conventional T₁-weighted spin echo (T₁WSE) and T₁-weighted magnetization transfer (MT) images were obtained in 26 patients with biopsy-proven cirrhosis (nine Child's grade A, 10 Child's grade B and seven Child's grade C). Four subjects showed no evidence of neuropsychiatric impairment on clinical, psychometric and electrophysiological testing, seven showed evidence of subclinical hepatic encephalopathy and 15 were classified as having overt hepatic encephalopathy. Signal intensities of basal ganglia nuclei (head of caudate, putamen, globus pallidus and thalamus) and adjacent brain parenchyma were measured and contrast calculated. On T₁WSE imaging, contrast measurements of the globus pallidus were significantly greater in patients with neuropsychiatric dysfunction than in those who were unimpaired (p<0.05). This was not observed in the other basal ganglia nuclei. Patients with subclinical and overt hepatic encephalopathy could not be distinguished on the basis of contrast measurements of the globus pallidus or of any other nucleus. T₁WSE contrast measurements of the globus pallidus were increased with elevations in blood ammonia levels (p<0.05) and with the severity of liver dysfunction, when graded according to the Pugh's score (p<0.05). Those patients with the worst liver injury (Child's grade C) had significantly greater T₁WSE pallidal contrast measurements (p<0.05) than those patients with minimal liver injury (Child's grade A). The patients with intermediate liver damage (Child's grade B) could not be distinguished from the other two groups. While MT imaging highlighted the basal ganglia and showed a correlation between globus pallidus contrast and blood ammonia levels (p<0.05), no other relationship between MT contrast measurements and either the degree of hepatic encephalopathy or the severity of liver dysfunction was found.     

Parametric imaging of contrast ultrasound for the evaluation of neovascularization in liver tumors

Aim: To assess the efficacy of parametric imaging for the diagnosis of neovascularization in liver tumors. Methods: The subjects were 17 rabbits (five with normal liver and 12 with VX2 tumor implanted in the liver). The contrast agents used were SonoVue (Bracco, Milan, Italy). A diagnostic ultrasound system was used with a programmable replenishment sequence. The images obtained between the initial frame after the high mechanical index (MI) scan, which diminishes microbubbles in the scan volume, and the current frame were coded in color according to the arrival and peak times. After the experiment, the tumors were excised and sectioned. Sections were prepared for light microscopy with hematoxylin-eosin (HE) staining and CD31 staining to evaluate vascular density. Results: Arrival time imaging (ATI) delineated the fine blood vessels (100-200 mum in diameter) in all of the rabbits. Tortuous and meandering tumor vessels were visualized in the VX2 tumors. Differences of perfusion velocity between tumor tissue and tumor-free areas were shown in peak time imaging (PTI). Vascularity evaluated on the ATI and perfusion speed recognized on the ATI and PTI were related to the vascular density measured by pathological investigation. Conclusion: Parametric imaging is a promising new method for the visualization of perfusion and the estimation of tumor blood vessels.     

CT图像自动识别系统诊断肝炎肝硬化的研究

目的探讨肝炎肝硬化早期诊断方法。方法基于肝脏CT平扫图像，采用计算机图像自动识别及测量技术．计算乙型肝炎患者肝叶比例，通过统计对照数据库中的历史数据，对早期肝硬化做出诊断。结果肝硬化组与乙型肝炎组比较，本系统L1／L2和R1／L1比值均有显著性差异（P〈0．05）；建立判别方程：D=1．650LI／L 2＋0．509R1／L1-5．019；确定判别的临界值为0．0795；D〉0．0795为肝硬化，D〈0．0795为乙型肝炎；判别效果分析（回代），结果诊断肝硬化的正确率为68．42％，诊断乙型肝炎或判断为无肝硬化的正确率为89．8％。结论可以利用肝脏各叶的比例变化来预测和早期诊断肝炎肝硬化。     

Current status of superparamagnetic iron oxide contrast agents for liver magnetic resonance imaging

Five types of superparamagnetic iron oxide(SPIO), i.e. Ferumoxides(Feridex~ Ⅳ, Berlex Laboratories), Ferucarbotran(Resovist~, Bayer Healthcare), Ferumoxtran-10(AMI-227 or Code-7227, Combidex~, AMAG Pharma; Sinerem~, Guerbet), NC100150(Clariscan~, Nycomed,) and(VSOP C184, Ferropharm) have been designed and clinically tested as magnetic resonance contrast agents. However, until now Resovist~ is current available in only a few countries. The other four agents have been stopped for further development or withdrawn from the market. Another SPIO agent Ferumoxytol(Feraheme~) is approved for the treatment of iron deficiency in adult chronic kidney disease patients. Ferumoxytol is comprised of iron oxide particles surrounded by a carbohydrate coat, and it is being explored as a potential imaging approach for evaluating lymph nodes and certain liver tumors.