MRI功能性成像诊断肝纤维化的研究进展

肝纤维化（HF）是多种慢性肝病发展的共同病理基础,在一定情况下可被逆转。但若病因持续存在,肝纤维化逐渐加重,即可发展为不可逆转的肝硬化。早期HF等弥漫性病变的诊断一直是临床诊断的难题之一。MR]近年来用于HF的诊断,但常规MRI成像仅可对形态学进行观察。MRI功能成像包括磁共振扩散加权成像（DWI）、磁共振波谱分析（MRS）、磁共振扩散张量成像（DTI）、     

磁共振弥散成像在肝纤维化中的研究进展

我国慢性肝病患者在逐年增多, 评价患者肝纤维化及肝硬化的严重程度是当前研究的热点之一. 长期以来, 临床多以肝活检组织病理学检查作为诊断肝纤维化的金标准, 但其有一定的创伤性及盲目性. 血清肝纤维化指标和常规影像学方法在肝纤维化的研究中未发现较敏感和特异性的指标, 而近年磁共振弥散成像为肝纤维化的诊断带来了曙光. 本文就磁共振扩散加权成像在评价慢性肝病肝纤维化的严重程度中的应用现状予以综述.     

肝纤维化患者肝脏形态学改变的CT、MR评价

目的 评价肝纤维化患者肝脏形态学改变ＣＴ、ＭＲ表现。方法 对１６８例经肝穿刺活检病理证实的肝纤维化患者行ＣＴ和／或ＭＲ检查。根据肝纤维化炎症活动度分级和纤维化程度分期进行肝脏形态学改变和相关指标的统计分析。结果 肝左叶体积、肝表面形态和肝裂增宽等肝脏形态学改变随着肝纤维化严重程度的加重而有统计学差异。结论 无创伤性的ＣＴ、ＭＲ检查是临床评价肝脏形态学改变和动态观察肝纤维化病程演进的有效手段。     

家兔肝纤维化模型的建立及三维全肝动态磁共振灌注成像对纤维化分期的量化价值

目的 探索家兔肝纤维化模型的建立方法,评价三维全肝动态磁共振灌注成像对肝纤维化分期量化研究的可行性及价值. 方法分别用5%CCl4油溶液和纯CCl4,按0.1 ml/kg剂量每周1次腹腔注射,并于6、8、10、12周分组行磁共振灌注成像检查,量化分析门静脉和肝实质的峰值时刻、达峰时间、信号上升最大斜率和最大相对信号增加率的变化规律并与病理结果对照.不同浓度CCl4造模对比采用卡方检验;实验组灌注参数的多组问比较采用单因素方差分析,组间两两比较采用最小显著差法. 结果 5%CCl4h浓度组和纯CCl4组成模率分别为40%和75%,两组家兔死亡率差异有统计学意义(χ2=5.013,P<0.05).31只家兔均顺利完成磁共振灌注成像检查,肝脏灌注的基线平稳,均得到了较满意的时间-信号强度曲线.随着肝纤维化程度的加重,门静脉和肝实质的峰值时刻南SO期的(22.62±1.80)s和(29.04±0.60)s上升至S4期的(39.84±0.44)s和(45.44±1.95)s;达峰时间由(11.06±0.92)S和(13.19±1.06)S上升至(25.57±0.36)S和(28.81±2.92)s;信号上升最大斜率由(322.49±88.13)/s和(191.79±60.00)/s下降至(147.97±40.83)/s和(70.20±10.59)/s;最大相对信号增加率由4.47%±0.63%和2.69%±0.36%下降至2.54%±0.30%0和1.20%0±0.16%,S0～S2期与S3、S4期差异均有统计学意义(P值均<0.01).结论 按0.1 ml/kg剂量纯CCl4每周1次腹腔注射,家兔肝纤维化成模率高.高质量的三维全肝动态磁共振灌注成像,能够对肝纤维化程度进行量化评估.     

磁共振扩散成像在诊断家兔肝纤维化中的应用

目的 评价磁共振扩散成像在诊断家兔肝纤维化中的作用.方法 选用普通级家兔58只,随机分为对照组和实验组.实验组腹腔注射四氯化碳建立家兔肝纤维化模型,然后行磁共振扩散成像.磁共振扩散成像采用自旋-回波平面成像序列,分别取扩散敏感梯度(b值)为300、500进行扫描,通过软件处理获得表观扩散系数(ADC)值以及指数表观扩散系数(EADC)值,磁共振检查后取家兔肝脏行病理检查,并按病理学分期分组,用SPSS 11.0统计软件分析.结果 在磁共振扩散成像结果中,b值为300时,对照组(SO)ADC值为(2.460±0.424)×10-3,实验组(S1～S4)ADC值分别为(2.170±0.311)×10-3,(1.950±0.248)×10-3,(1.635±0.296)×10-3,(1.566±0.353)×10-3,对照组EADC值为0.102±0.044,实验组(S1-S4)EADC值分别为0.167±0.047,0.183±0.042,0.216±0.054,0.219±0.048.对照组和实验组ADC值以及EADC值差异有统计学意义(F=12.13,P=0.0006;F=10.06,P=0.004).b值为500时,对照组ADC值为(2.044±0.215)×10-3,实验组(S1～S4)ADC值分别为(1.907±0.223)×10-3,(1.785±0.232)×10-3(1.542±0.268)×103(1.312±0.212)×10-3.对照组EADC值为0.1106±0.069,实验组(S1～S4)EADC值分别为0.1764±0.073,0.1889±0.056,0.2421±0.079,0.2657±0.037.对照组和实验组ADC值以及EADC值差异有统计学意义(F=14.57,P=0.0002;F=10.42,P=0.003).同时,b值为300、500时,实验组中S1组与S4组ADC值差异均有统计学意义(P=0.03,P=0.044),其余实验组间差异无统计学意义(P>0.05).结论 ADC值以及EADC值可能是肝纤维化诊断和量化的一个潜在标准.     

肝纤维化的影像学研究进展

长期以来,临床多以肝活检组织病理学检查作为诊断肝纤维化的金标准,但其有一定的创伤性及盲目性。超声、CT、MRI及核医学等多种影像学检查在肝纤维化、肝硬化的诊断、治疗及预后的评价方面发挥着重要的作用,它们各有其优缺点,应进行合理的选用及相互对照验证。     

肝纤维化的影像学研究进展

肝纤维化如能作出早期诊断、及时评估其病情的进展情况,对于慢性肝病的治疗和预后有重要意义. 影像学检查已开始从过去单纯的形态学检测向功能形态学检测方面和分子影像学检测方面转变,使其在肝纤维化检测和评估中发挥了更多的作用.     

肝纤维化影像学诊断研究进展

通过影像学方法诊断肝纤维化是肝纤维化无创诊断的重要组成部分,包括超声波、CT、磁共振等,但传统的影像学方法对肝纤维化的检测缺乏敏感性。近些年发展起来的弹性成像技术可较敏感地检测肝纤维化,成为传统影像学方法诊断肝纤维化的重要补充。此文将对这些影像学方法的优劣分别进行介绍。     

瞬时弹性成像用于肝纤维化的无创评价

肝活组织检查是肝纤维化诊断的黄金标准。但肝活组织检查是有创的，标本仅占整个肝脏容积的1／50000，由于纤维化分布的不均匀性，可能引起采样误差，不同操作人员的结果可能不一致，存在准确度和可重复性问题，费用也较高。     

肝纤维化模型磁共振成像T1、T2和ADC值与肝功能和肝纤维化指标相关性研究

探索非创伤性检查方法进行肝纤维化的诊断成为众多肝病学者研究和关注的热点问题。本研究以肝纤维化动物模型为研究对象,通过定量检测磁共振成像（MRI）中的T1值、T2值和弥散加权成像（MR—DWI）中的表观扩散系数（ADC值）,与部分血清生化和肝纤维化四项指标检测结果进行相关性分析,探讨MRI对肝纤维化诊断的临床意义。     

Perfusion magnetic resonance imaging of the liver

Perfusion magnetic resonance imaging (MRI) studies quantify the microcirculatory status of liver parenchyma and liver lesions, and can be used for the detection of liver metastases, assessing the effectiveness of antiangiogenic therapy, evaluating tumor viability after anticancer therapy or ablation, and diagnosis of liver cirrhosis and its severity. In this review, we discuss the basic concepts of perfusion MRI using tracer kinetic modeling, the common kinetic models applied for analyses, the MR scanning t...     

Quantitative assessment of hepatic fibrosis in chronic hepatitis B and C: T1 mapping on Gd-EOB-DTPA-enhanced liver magnetic resonance imaging

AIM To assess the accuracy of Look-Locker on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(GdEOB-DTPA)-enhanced magnetic resonance imaging(MRI) for staging liver fibrosis in chronic hepatitis B/C(CHB/C).METHODS We prospectively included 109 patients with CHB or CHC who underwent a 3.0-Tesla MRI examination, including T1-weighted and Look-Locker sequences for T1 mapping. Hepatocyte fractions(He F) and relaxation time reduction rate(RE) were measured for staging liver fibrosis. A receiver operating characteristic analysis using the area under the receiver operating characteristic curve(AUC) was used to compare thediagnostic performance in predicting liver fibrosis between He F and RE.RESULTS A total of 73 patients had both pathological results and MRI information. The number of patients in each fibrosis stage was evaluated semiquantitatively according to the METAVIR scoring system: F0, n = 23(31.5%); F1, n = 19(26.0%); F2, n = 13(17.8%); F3, n = 6(8.2%), and F4, n = 12(16.4%). He F by EOB enhancement imaging was significantly correlated with fibrosis stage(r =-0.808, P 0.05). AUC values for diagnosis of any(≥ F1), significant(≥ F2) or advanced(≥ F3) fibrosis, and cirrhosis(F4) using He F were 0.837(0.733-0.913), 0.890(0.795-0.951), 0.957(0.881-0.990), and 0.957(0.882-0.991), respectively. He F measurement was more accurate than use of RE in establishing liver fibrosis staging, suggesting that calculation of He F is a superior noninvasive liver fibrosis staging method.CONCLUSION A T1 mapping-based He F method is an efficient diagnostic tool for the staging of liver fibrosis.     

Magnetic resonance-based total liver volume and magnetic resonance-diffusion weighted imaging for staging liver fibrosis in mini-pigs

AIM:To determine whether and how magnetic resonance imaging(MRI)-based total liver volume(TLV) and diffusion weighted imaging(DWI) could predict liver fibrosis.METHODS:Sixteen experimental mature mini-pigs(6 males,10 females),weighing between 20.0 and 24.0 kg were prospectively used to model liver fibrosis induced by intraperitoneal injection of 40% CCl4 dissolved in fat emulsion twice a week for 16 wk,and by feeding 40% CCl4 mixed with maize flour twice daily for the subsequent 5 wk.All the survival animals underwent percutaneous liver biopsy and DWI using b = 300,500 and 800 s/mm2 followed by abdominal gadolinium-enhanced MRI at the 0,5th,9th,16th and 21st weekend after beginning of the modeling.TLV was obtained on enhanced MRI,and apparent diffusion coefficient(ADC) was obtained on DWI.Hepatic tissue specimens were stained with hematoxylin and Masson' s trichrome staining for staging liver fibrosis.Pathological specimens were scored using the human METAVIR classification system.Statistical analyses were performed to determine whether and how the TLV and ADC could be used to predict the stage of liver fibrosis.RESULTS:TLV increased from stage 0 to 2 and decreased from stage 3(r = 0.211;P 0.001).There was a difference in TLV between stage 0-1 and 2-4(P = 0.03) whereas no difference between stage 0-2 and 3-4(P = 0.71).TLV could predict stage ≥ 2 [area under receiver operating characteristic curve(AUC) = 0.682].There was a decrease in ADC values with increasing stage of fibrosis for b = 300,500 and 800 s/mm2(r =-0.418,-0.535 and-0.622,respectively;all P 0.001).Differences were found between stage 0-1 and 2-4 in ADC values for b = 300,500 and 800 s/mm2,and between stage 0-2 and 3-4 for b = 500 or 800 s/mm2(all P 0.05).For predicting stage ≥ 2 and ≥ 3,AUC was 0.803 and 0.847 for b = 500 s/mm2,and 0.848 and 0.887 for b = 800 s/mm2,respectively.CONCLUSION:ADC for b = 500 or 800 s/mm2 could be better than TLV and ADC for b = 300 s/mm2 to pre-dict fibrosis stage ≥ 2 or ≥ 3.     

Three-Tesla magnetic resonance elastography for hepatic fibrosis: Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging.METHODS: Forty-two patients were included in the study. On MRE, mean stiffness values were measured on the elastograms in kilopascals. The apparent diffusion coefficient (ADC) of the liver was measured using DWI. On gadoxetic acid enhanced MR, the contrast enhancement index (CEI) was calculated as signal intensity (SI)_post/SI_pre, where SI_post is liver-to-muscle SI ratio on hepatobiliary phase images and SI_pre is that on nonenhanced images. Correlation between aspartate aminotransferase to the platelet ratio index (APRI) and three MR parameters was assessed. Each MR parameter was compared between a hepatic fibrosis (HF) group and non-hepatic fibrosis (nHF) group.RESULTS: Liver stiffness showed strong positive correlation with APRI [Spearman correlation coeffiecient (r) = 0.773, P < 0.0001], while ADC and CEI showed weak or prominent negative correlation (r = -0.28 and -0.321, respectively). In the HF group, only liver stiffness showed strong correlation with APRI (r = 0.731, P < 0.0001). Liver stiffness, ADC, and APRI were significantly different between the HF group and nHF group.CONCLUSION: MRE at 3-Tesla could be a feasible method for the assessment of hepatic fibrosis.     

Multiparameter magnetic resonance imaging of liver fibrosis in a bile duct ligation mouse model

BACKGROUNDBile duct ligation (BDL) in animals is a classical method for mimicking cholestatic fibrosis. Although different surgical techniques have been described in rats and rabbits, mouse models can be more cost-effective and reproducible for investigating cholestatic fibrosis. Magnetic resonance imaging (MRI) has made great advances for noninvasive assessment of liver fibrosis. More comprehensive liver fibrotic features of BDL on MRI are important. However, the utility of multiparameter MRI to detect liver fibrosis in a BDL mouse model has not been assessed.AIMTo evaluate the correlation between the pathological changes and multiparameter MRI characteristics of liver fibrosis in a BDL mouse model.METHODSTwenty-eight healthy adult male balb/c mice were randomly divided into four groups: sham, week 2 BDL, week 4 BDL, and week 6 BDL. Multiparameter MRI sequences, included magnetic resonance cholangiopancreatography, T1-weighted, T2-weighted, T2 mapping, and pre- and post-enhanced T1 mapping, were performed after sham and BDL surgery. Peripheral blood and liver tissue were collected after MRI. For statistical analysis, Student’s t-test and Pearson’s correlation coefficient were used.RESULTSFour mice died after BDL surgery; seven, six, five and six mice were included separately from the four groups. Signal intensities of liver parenchyma showed no difference on TI- and T2-weighted images. Bile duct volume, ΔT1 value, T2 value, and the rate of liver fibrosis increased steadily in week 2 BDL, week 4 BDL and week 6 BDL groups compared with those in the sham group (P < 0.01). Alanine aminotransferase and aspartate transaminase levels initially surged after surgery, followed by a gradual decline over time. Strong correlations were found between bile duct volume (r = 0.84), T2 value (r = 0.78), ΔT1 value (r = 0.62), and hepatic fibrosis rate (all P < 0.01) in the BDL groups.CONCLUSIONThe BDL mouse model induces changes that can be observed on MRI. The MRI parameters correlate with the hepatic fibrosis rate and allow for detection of cholestatic fibrosis.     

胃食管反流病与功能磁共振技术

随着对胃食管反流病研究的深入,大脑和食管感觉及胃排空的相互作用越来越受到重视,功能磁共振成像技术,有助于进一步了解胃食管反流病的发病机制。     

Liver magnetic resonance imaging: State of the art

Magnetic resonance imaging (MRI) has now been used for about three decades to characterize the human liver in a non-invasive way, that is without the need of using ionizing radiation or removing tissue samples. During the past few years, technical progress has been considerable and novel applications of MRI have been implemented in the clinic. The beginning of a new decade offers an excellent opportunity for having fi ve experts to present their view on the current status of MRI (and magnetic resonance spec...