肝纤维化MRI弥散加权成像的初步研究

目的 探讨MRI扩散加权成像对肝纤维化的诊断价值.方法 分别对54例经肝穿刺活检确诊的肝纤维化病人利用扩散加权成像技术分别测定b值为300、500、700s/mm2时的表观扩散系数(ADC值).比较各组ADC值的变化情况,并与病理改变作对照研究.结果 b值取500和700s/mm2时,随肝纤维化分期的增加,ADC值依次...     

3.0T MR弥散加权成像及张量成像评价肝纤维化的临床研究石喻

 目的 探讨MR弥散加权成像(DWI)及张量成像（DTI）对慢性病毒性肝炎患者的肝纤维化程度定量分析的能力。方法 应用3.0T MR对8名志愿者、40例慢性病毒性（乙型或丙型）肝炎患者进行DWI及DTI检查,弥散敏感度(b值)选择0,800 s/mm2,比照肝穿病理结果,计算表观弥散系数（ADC）及平均弥散率（MD）,分析两种方法定量肝纤维化分期的能力。结果 受试者的肝脏ADC和MD分别为(1.26±0.12)×10-3 mm2/s和(1.39±0.14)×10-3 mm2/s,差异有统计学意义（Z=-5.775,P<0.01）。ADC、MD与纤维化分期呈显著负相关（r分别为-0.686,-0.481,P<0.01）;ADC可有效鉴别正常肝脏（S0期）与S2 、S3、S4期纤维化（P<0.05）,肝硬化（S4期）与S1、S2、S3期纤维化（P值分别为 0.003,0.041,0.014）;MD能有效鉴别S4期与S0、S1期纤维化(P值分别为0.002,0.026）,但不能鉴别比较其他各期纤维化(P >0.05）。ADC预测≥S2期、≥S3期及≥S4期纤维化的能力均优于MD（ROC曲线下面积,ADC分别为0.879、0.823、0.866;MD分别为0.796、0.743、0.725）。结论 DWI对肝纤维化分期的定量分析效果全面优于DTI,适合慢性病毒性肝炎患者的纤维化评价。     

常规弥散加权成像和弥散张量成像在肝纤维化和炎症中的诊断效能

目的 探讨MR传统弥散加权成像（DWI）与弥散张量成像（DTI）对慢性病毒性肝炎患者的肝纤维化程度和炎症程度定量分析的能力,评估DWI与DTI在诊断肝纤维化和炎症中的诊断效能。方法 选取笔者医院收治的58例经病理组织学诊断为慢性病毒性肝炎的患者和8例健康志愿者作为研究对象。所有研究对象都进行DWI和DTI检查,采用弥散敏感度（b值）为0、800s/mm²的单次激发快速自旋回波进行DWI和DTI检查。计算表观弥散系数（ADC）及平均弥散率（MD）,分析两种方法定量肝纤维化分期的能力。对慢性肝炎患者肝穿刺病理组织检查,按照肝活检评分系统Metavir评分表对肝实质纤维化和肝炎症程度进行分级。运用Spearman相关分析探讨ADC值MD值变化和纤维化分期、炎症分级之间的相关性。结果 ADC与纤维化分期呈显著负相关（r分别为-0.939、-0.682,P<0.01）;ADC、MD值与炎症分级之间有负相关性（r分别为-0.721、-0.486,P<0.01）。结论 DWI在肝纤维化分期和肝炎炎症分级方面的诊断效能均优于DTI,ADC值可定量评价肝纤维化的分期及肝炎活动的分级。     

磁共振弥散加权成像在肝占位病变中的应用

随着磁共振(MR)技术的发展,磁共振弥散加权成像(diffusion—weighted imaging,DWI)在临床上得以广泛应用。作者就DWI在肝占位病变中的应用和研究现状作一综述。     

磁共振弥散加权成像在不同纤维化程度乙型肝炎患者的诊断及与血清肝纤维化指标相关性分析

目的采用磁共振弥散加权成像(MR-DWI)诊断慢性乙型肝炎肝纤维化程度,并分析血清肝纤维化四项指标与表观弥散系数(ADC)值的相关性。方法选择2017年5月至2019年5月就诊的112例的慢性乙型肝炎患者,其中82例肝纤维化患者作为研究组,30例未发生肝纤维化患者为对照组,检测所有患者血清肝纤维化四项指标,所有患者均接受腹部磁共振成像(MRI)平扫及弥散加权成像(DWI)检查。结果与对照组比较,研究组各纤维化分期患者血清肝纤维化四项指标差异有统计学意义(P0.05),且随着纤维化程度升高也随之升高。当b值为200 s/mm~2时,纤维化患者与非纤维化患者ADC值差异无统计学意义(P0.05);当b值为400 s/mm~2、800 s/mm~2时,S3、S4期患者ADC值显著低于对照组,且800 s/mm~2时效果更好(P0.05)。肝纤维化患者血清肝纤维化四项指标与ADC值均具有相关性,且Ⅳ型胶原(CIV)测定值与ADC值相关性最高,Ⅲ型前胶原氨基端肽(PIII NP)测定值与ADC值相关性最低。结论 ADC值随肝纤维化程度加重而逐渐降低,ADC值与血清肝纤维化指标明显相关,且CIV相关性最高。     

肝纤维化磁共振扩散加权成像Meta分析

目的通过Meta分析研究方法对弥散加权成像磁共振检查方法评价肝纤维化分级诊断的准确性做出分析。方法通过检索国内外公开发表的DWI评价肝纤维化分级诊断准确性的文章,并且采用Metavir、Scheuer、Batts-Ludwig计分系统标准进行分级。两名研究人员按照纳入与排除标准独立选择文献并根据QUADAS评价条目标准进行质量评价。使用MetaDisc软件进行Meta分析,并绘制SROC曲线。结果检索到247篇相关文献,最终纳入了10项1.5 T场强研究和3项3.0 T场强研究,受试者总数为809例。Meta分析结果示各组间存在统计学异质性,采用随机效应模型合并分析。DWI磁共振检查方法对轻度肝纤维化(G1)组、明显肝纤维化(G2)组、严重肝纤维化(G3)组、早期肝硬化(G4)组的合并灵敏度和特异度分别为:0.74和0.74、0.83和0.76、0.78和0.79、0.83和0.79;SROC曲线下面积分别为:0.8363、0.8820、0.8663和0.8719。结论DWI对肝纤维化分级具有较高的诊断效能。     

磁共振弥散加权成像ADC值诊断兔肝脏纤维化模型病理变化

目的 研究磁共振弥散加权成像(MR-DWI)ADC值在诊断肝脏纤维化模型(Liver fibrosis model,LFM)病理变化中的价值和意义.方法 对4只正常和13只LFM兔进行MR-DWI检查,选择b值为200 s·mm-2、500 s·mm-2、300 s·mm-2、600 s·mm-2,分别在肝脏左右侧获得4个ADC值.按照ISHAK肝脏病理组织学评分和纤维化分期标准,对全部兔肝脏标本进行组织病理学评分分级(1～6分为一级、7～12分为二级、13～18分为三级)和纤维化分期(Ⅰ期～Ⅵ期),以此为标准统计分析ADC值的变化情况.统计学分析应用SPSS13.0统计软件包,采用单向方差分析方法(Analysis of variance,ANOVA).P<0.05为差异有统计学意义.结果 兔LFM组中4个ADC值均明显低于正常对照组,统计分析表明正常对照组与模型组、不同病理评分分级和纤维化分期间ADC值差异性均有统计学意义,P=0.000.结论 肝脏发生纤维化时,肝组织的ADC值明显降低,随着病理评分分级和纤维化分期的增加,ADC值降低越加显著.肝细胞变性、肿胀和炎细胞浸润,以及间质内胶原纤维沉积,使水份含量减少,水的自山运动受到限制,是导致ADC值降低的主要病理学基础.     

MR弥散加权成像在纵隔肿瘤中的应用研究

目的 分析不同纵隔肿瘤病变MR弥散成像表现,评价MR弥散加权成像在纵隔肿瘤诊断及鉴别诊断中的价值.方法 对32例纵隔肿瘤性病变行MR弥散加权成像检查(b值取800s·mm-2),并测量表观弥散系数值(apparent diffusion coefficient,ADC);观察不同纵隔肿瘤的弥散加权成像(Diffusion-Weighted Imaging,DWI)表现.结果 良性胸腺瘤10例,在DWI图上表现为低信号,信号均匀;恶性胸腺瘤12例,在DWI图上表现为高信号,信号强度不均匀;6例神经鞘瘤在DWI图上表现为稍低信号,信号强度明显不均匀;4例神经纤维瘤在DWI图上表现为稍高信号,信号强度不均匀.选取b值800s·mm-2时,测得的良恶性胸腺瘤组、神经鞘瘤与神经纤维瘤组之间差异均有统计学意义(P＜0.01).结论 MR弥散加权成像对纵隔肿瘤的诊断及鉴别诊断有一定价值,可作为纵隔MRI检查的有益补充.     

MR弥散加权成像对急性缺血性脑血管病的诊断价值

目的 :讨论磁共振弥散加权成像 (DWI)对急性脑缺血的诊断价值。方法 :30例脑缺血患者行MRDWI检查及常规序列检查 ,其中急性和非急性脑缺血各 15例 ,计算两组缺血病灶的ADC值 ,并进行组间比较。结果 :急性脑缺血组的ADC值平均为 0 .4 7× 10 -3 mm2 /s,ADC图可见异常拟合低信号病灶 ;非急性组的ADC值为 1.38× 10 -3 mm2 /s。两组的ADC值差异非常显著 (P <0 .0 1)。结论 :弥散加权成像对急性脑缺血能较早和较为敏感做出诊断 ,其ADC值能做出定量分析     

脑MR弥散加权成像和弥散张量成像可比较图像参数的研究

目的 研究正常人脑部弥散加权成像(DWI)的表观扩散系数(ADC)和不同弥散方向个数时的弥散张量成像(DTI)的平均扩散系数的异同.方法 应用相控阵神经血管线圈,随机选择正常健康体检者进行DWI成像检查和6、15、25个梯度方向的DTI检查.各取得数据15例.对所有研究对象均进行了头颅常规MRI检查,均未发现异常.然后,用DTI分析软件DtiStiduo 2.4对获得的弥散加权像和弥散张量图像进行处理,得到DWI的平均ADC图像.DTI的张量的导出量--张量的特征值λ1、λ2、λ3.各向同性指标ADC、Trace(MD)的图像.对得到的每个研究对象相应图像中选取10+感兴趣区进行测量,得到相应的参数数值.结果 DWI(X、Y、Z三个方向正交扩散梯度)和6、16、25个扩散梯度方向的DTI所获得的ADC值没有显著性差异(P=0.579);DWI、DTI 的ADC值和MD值无显著性差异.结论 弥散成像q=DWI和DTI中得到的ADC值具有可比性,可作为临床正常参考值.     

磁共振DWI对慢性乙型肝炎肝纤维化程度和活动度的评价

目的：探讨磁共振弥散加权成像（DWI）评价慢性乙型肝炎肝纤维化程度和肝炎活动度的价值。方法设置不同的弥散敏感系数b值对102例慢性乙型肝炎患者（肝炎组）和26例健康志愿者（对照组）进行磁共振DWI检查,测定并比较两组肝脏感兴趣区的表观弥散系数（ADC）值。肝炎组进一步分为纤维化组（n＝74）和无纤维化组（n＝28）。结果设置b值为100和200 s／mm2时,两组ADC值比较差异无统计学意义（P＞0．05）;b值为400、600和800 s／mm2时,肝炎组ADC值低于对照组,肝纤维化组ADC值低于无纤维化组,差异有统计学意义（P＜0．05）;b值为600及800 s／mm2时,肝纤维化组S3及S4期ADC值低于S0及S1期,差异有统计学意义（P＜0．05）;b值为100、200和400 s／mm2时,不同肝纤维化程度分期 ADC值间的差异无统计学意义（P＞0．05）;b值为800 s／mm2时,不同炎症活动度组G1与G4级的ADC值的差异有统计学意义（P＜0．01）,其余组间差异无统计学意义（P＞0．05）。结论磁共振DWI技术在评价不同分期慢性乙型肝炎肝纤维化程度和活动度方面具有较好的应用价值,设置b值为800 s／mm2时,效果最佳。     

Magnetic resonance diffusion-weighted imaging in the diagnosis of diffuse liver diseases in rats

Background The diagnosis of diffuse hepatic lesions in early stage is a tough task at any time for clinical conventional imaging. Magnetic resonance diffusion-weighted imaging (MR DWI) can detect the changes of tissue structure at molecular level. This study was designed to determine the value of DWI in the diagnosis of diffuse liver lesions in early stage.
Methods Diffuse liver lesions were induced by diethylnitrosamine in 42 rats of test group. Fourteen rats in control group were fed with pure water. Dynamic changes of MR DWI were observed every week in both groups during the early stage of diffuse liver lesions (1 to 12 weeks after drug administration in the test group). Apparent diffusion coefficient (ADC) values of liver parenchyma in different stages and pathologic changes were analyzed.
Results The process of diffuse hepatic lesions in the test group was classified into three stages according to pathological changes, namely hepatitis, hepatic fibrosis and cirrhosis. No obvious morphological changes were shown by conventional imaging in both groups during this stage. But MR DWI demonstrated heterogeneous signal changes in early stage of hepatic cirrhosis in the test group. No significant change of ADC values was found in the control group between different weeks (P>0.05). The ADC values of the test group declined from the fifth week, and after the tenth week the ADC values were significantly different between the test and control groups at gradient factor (b) value 300 sec/mm2 (P<0.05). At b value 600 and 1000 sec/mm2, significant difference was seen between the two groups from the sixth week onward. The range of ADC value of the groups was (1.7-0.9)±(0.40-0.04) mm2/sec (b=600) and (1.38-0.75)±(0.07-0.35) mm2/sec (b=1000), respectively. Dominant pathological changes included swelled hepatocytes within 1 to 4 weeks after the administration of diethylnitrosamine in the test group, hyperplasia of fibrous tissues in 5-8 weeks and formation of cirrhotic nodules in 9-12 weeks.
Conclusions MR functional DWI could detect diffuse liver lesions earlier than conventional morphological imaging. ADC value as a marker for early diagnosis of diffuse liver lesions could also be used to inspect changes of the lesions.
     

核磁共振动态增强成像评价肝纤维化的临床应用

摘要：目的探讨核磁共振（MR）动态增强时间信号曲线（TIC）定量参数评价肝纤维化程度的价值。方法患者及健康志
愿者共36人行肝脏MR常规及动态增强扫描,依据肝纤维化程度分为正常组（n=9）、轻度纤维化（n=5）、中重度纤维化（n=
7）及肝硬化（n=15）共4 组。获取门静脉、肝、脾的TIC,评价峰高、TTP、信号上升最大斜率（MSI）和信号下降最大斜率
（MSD）等TIC量化参数与肝纤维化程度的相关性,运用ROC曲线评价TIC斜率指标诊断肝纤维化程度的效力。结果各
ROI的TIC曲线的峰高、MSI、肝脾的MSD均与纤维化程度呈负相关关系（P<0.05,r为-0.446~-0.800）,TTP与之呈较为密
切的正相关关系（P<0.05,r>0.5）。ROC曲线分析显示：诊断轻度肝纤维时,各斜率指标曲线下面积（AUC）依次为0.747~
0.783,其中脾MSD曲线下面积最大;诊断中度以上纤维化（S≥3）时,AUC为0.728~0.877,由小到大对应的指标依次为动
脉期肝MSI、门静脉MSI、门静脉期肝MSI、肝MSD、动脉期脾MSI、脾MSD;诊断肝硬化时,AUC为0.742~0.821,由小到
大对应的指标依次为门静脉期肝MSI、肝MSD、动脉期肝MSI、门静脉MSI、动脉期脾MSI、脾MSD。结论MR动态增强
TIC能反映肝纤维化进程的血流动力学变化,是一种无创评价肝纤维化程度的功能影像学方法。     

弥散加权磁共振成像评价大鼠胶质瘤新生血管的价值

目的 分析大鼠C6脑胶质瘤新生血管与弥散加权磁共振成像(diffusion weighted imaging,DWI)定量参数rADC动态变化特征,探讨DWI评价胶质瘤新生血管的价值.方法 清洁级SD大鼠30只,建立大鼠C6胶质瘤原位移植模型,分别在移植肿瘤细胞后4、8、12、16、20、24d行MR扫描并取大鼠脑组织行病理和免疫组化检查,观察肿瘤新生血管及DWI动态变化特征并分析MR数据与组织性参数相关性.结果 C6原位胶质瘤模型在30只SD大鼠颅内成功建立.T2WI肿瘤呈明显高信号;DWI可见明显弥散受限,并且随着移植时间的延长,肿瘤组织ADC不断升高(F=27.9,P＜0.05).DWI观察不同移植时间胶质瘤新生血管的变化,发现rADC与胶质瘤微血管密度(microvessel density,MVD)呈显著正相关(R2=0.515,P＜0.05);进一步分析不同血管新生类型与rADC相关性,发现血管出芽、血管套叠与rADC显著正相关(R2 =0.586、0.537,P＜0.05).结论 DWI定量参数rADC与C6胶质瘤MVD、血管出芽、血管套叠指数均表现出显著正相关性,可以有效地在体评价胶质瘤新生血管,具有较大的临床应用前景和价值.     

Initial study of biexponential model of intravoxel incoherent motion magnetic resonance imaging in evaluation of the liver fibrosis

Background The diagnosis of liver fibrosis is a difficult task at any time using conventional clinical imaging.Intravoxel incoherent motion （IVIM） can be used to investigate both diffusion and perfusion changes in tissues.This study was designed to determine the value of IVIM in the diagnosis and staging of liver fibrosis.Methods IVIM examinations were performed on a GE 3.0T MR scanner in 25 patients with liver fibrosis and 25 healthy volunteers as the control group.Patients with liver fibrosis diagnosis were confirmed by pathology and staged on a scale of F0-4.The standard ADC values and the values of a biexponential model （slow ADC （Dslow）,fast ADC （Dfast） and fraction of fast ADC （FF）） were measured in three liver regions per person.The mean standard ADC values,Dslow values,Dfast values and FF values from the study group were compared among the right posterior hepatic lobe,right anterior hepatic lobe and medial segment of the left lobe.Receiver Operating Characteristic （ROC） curves and independent-samples t-tests were used to calculate the mean standard ADC values,Dslow values,Dfast values and FF values from the study group and the control group.Spearman rho correlation analysis was used for the stage of liver fibrosis.The liver fibrosis stages between the groups F0-1 and F2-4,the groups F0-2 and F3-4 were compared.Results Among the liver fibrosis,there was no significant difference in the mean standard ADC values,Dslow values,Dfast values,and FF values obtained from the right posterior hepatic lobe,right anterior hepatic lobe and medial segment of the left lobe.Using ROC analysis,the Area Under the Curve （AUC） values of standard ADC,Dslow,Dfast,FF were all between 0.7 to 0.9.The mean standard ADC values,Dslow values,Dfast values and FF values of the liver in the study group were significantly lower than the values in the control group （P ＜0.05）.As the stage of the fibrosis increased,the values decreased by Spearman rho correlation analysis.The mean values （standard ADC,Dslo     

Diffusion weighted magnetic resonance imaging for acute stroke: practical and popular

Aim

To evaluate the feasibility and impact of diffusion weighted magnetic resonance imaging (DW MRI) as the first line neuroimaging of stroke at a district general hospital.

Methods

Prospective audit of all in‐patients admitted with clinically suspected acute stroke and referred for imaging over a consecutive 17 week period. The data collected included scan type, time from cerebral event to imaging request, and time from formal radiological request to neuroimaging. Clinicians'' (general physicians, neurologists, and radiologists) perceptions were assessed by a questionnaire.

Results

148 patients had neuroimaging for clinically suspected stroke during this period. Eighty one per cent of patients (120 of 148) had DW MRI as first line. Ninety two per cent of these patients had DW MRI within 24 hours of the formal radiological request. Twenty eight patients did not undergo DW MRI because lack of MRI safety, clinical state, unavailability because of maintenance service or lack of trained staff. Clinicians found the introduction of the DW MRI based service a significant improvement on computed tomography, especially for equivocal cases.

Conclusion

DW based MRI service is both feasible and sustainable in the setting of a district general hospital and most clinicians feel that this is a significant improvement to stroke services.     

MRI动态增强扫描在肝脏炎性假瘤诊断中的应用

目的 探讨磁共振成像(MRI)平扫及动态增强扫描在肝脏炎性假瘤(IPL)诊断中的应用价值.方法 回顾性分析经临床病理证实的12例肝脏炎性假瘤的MRI表现,并与病理进行对照.结果 术前诊断良性病变10例,2例误诊为恶性肿瘤,其中诊断为炎性假瘤者7例.T1WI上5例为等信号,6例为低信号.T2WI上3例呈低信号,5例呈略高信号,3例呈等信号.多期动态扫描:动脉期均未见明显强化,在静脉期及平衡期可见不同程度强化,强化方式多样,偏心性或周边不均匀环行强化,或呈间隔样强化,强化持续时间较长.结论 MR诊断IPL具有一定的特异性,结合病史,MR平扫及动态增强扫描,可以对肝脏炎性假瘤做出诊断.     

Evaluating transcatheter arterial chemoembolization for primary hepatic cancer by magnetic resonance diffusion-weighted imaging

Hepatic cancer is associated with very high mortality and morbidity, and the world＇s highest morbidity and mortality rates for this malignant tumor are found in China. Each year, the number of people who die of hepatic cancer in China amounts for 53% of the world total. Although resection is the first-choice treatment for hepatic cancer, only 20%-30% of patients have the opportunity to undergo resection. Transcatheter arterial chemoembolization （TACE） is a typical intervention therapy. Its advantages include minimal trauma, precise efficacy,     

磁共振弥散加权成像评价肝纤维化的临床病理对照研究

目的 探讨磁共振弥散加权成像(DWI)评价慢性病毒性肝炎患者纤维化和炎症程度的临床应用价值.方法 对85例慢性肝炎患者和22名健康志愿者进行前瞻性的DWI检查,选用5个不同b值(100、300、500、800、1000 s/mm2),测量不同b值条件下的肝脏表观弥散系数(ADC)值.对慢性肝炎患者肝穿刺病理改变进行纤维化分期和炎症分级.运用单因素方差分析比较不同纤维化分期之间和不同炎症分级之间ADC值的差异,运用Spearman相关分析探讨ADC值变化和纤维化分期、炎症分级之间的相关性.运用受试者工作曲线评估ADC值预测2期及以上肝纤维化、3期及以上肝纤维化、1级及以上炎症活动度的诊断效能.结果 ADC值与纤维化分期之间有中度负相关性,b值取800 s/mm2时相关性最佳(r=-0.697,P=0.000).在不同b值条件下,肝纤维化≤1期与≥12期之间、纤维化≤2期与≥3期之间肝脏ADC值进行比较,差异均有统计学意义(均P<0.05);在b值取800 s/mm2时,DWl诊断≥2期肝纤维化的曲线下面积为0.909,以ADC值≤1.26×10-3mm2/s为标准,敏感性和特异性分别为76.6%和88.3%;DWI诊断≥3期肝纤维化的曲线下面积为0.917,以ADC值≤1.19×10-3mm2/s为标准,敏感性为80.0%,特异性为91.5%.ADC值与炎症分级之间有轻中度负相关性.当b值取500 s/mm2时,诊断≥1级肝脏炎症活动度的曲线下面积为0.781,以ADC值≤1.54×10-3mm2/s为标准,敏感性为60.0%,特异性为86.4%.结论 磁共振弥散加权成像可以初步用于肝纤维化的分期和炎症的分级,为临床肝纤维化的早期诊断和治疗后的随访提供了新的手段.