肝细胞急性坏死与凋亡的磁共振扩散加权成像活体检测实验研究

 目的 评价MRI、DWI检测及鉴别肝细胞凋亡和坏死两种病理改变的价值.方法 72只S-D大鼠随机分成假手术对照组、右侧肝动脉与门静脉分支均结扎组(HA+PV组)和单独右侧门静脉分支结扎组(PV组),各24只.每组再分成4个亚组,每个亚组6只,分别于术后3 h、12 h、24 h、72 h行MRI、DWI检查,检查结束后取肝标本作HE染色、TUNEL染色,将病理结果与影像检查进行对照分析.结果 右侧门静脉与肝动脉均结扎后,肝右叶于术后3 h在T2WI上即表现为高信号,ADC值下降.单独肝右侧门静脉结扎后12 h,肝右叶ADC值出现升高,至24 h肝细胞凋亡数达最高,ADC值也达最高.结论 T2WI和DWI可早期检测发生坏死的肝组织.而组织中细胞发生凋亡后,DWI较T1WI、T2WI早期检测到凋亡组织.     

大鼠右肝血供不同程度阻断后的病理变化及磁共振表现

目的:探讨用磁共振新技术活体检测肝细胞凋亡和坏死的可能性。方法:①体重为0.25～0.3kg的SD大鼠90只随机分成A、B、C三组,每组30只,分别行右肝门静脉结扎(A组)、右肝门静脉及肝动脉双结扎(B组)及假手术(C组),术后3h、1天、3天、7天、14天作为5个时间点,各观察6只。②每组大鼠进行磁共振成像(MRI)、磁共振扩散加权成像(DWI)、1H磁共振波谱(1H-MRS)及磁共振灌注成像(PWI)检查。③取肝脏标本行病理学及电镜检查。④将磁共振检查结果同病理学及电镜对照分析。结果:①A组病理学及电镜检查证实肝细胞发生凋亡;B组肝组织发生凝固性坏死。②A组T1WI信号增高,T2WI信号刚开始略减低,后呈小片状增高;DWI呈小片状高信号,表观扩散系数(ADC)图则相反;MRS表现为胆碱(Choline,Cho)、肌酸(Creatine,Cr)、谷氨酸(Glutamate,Glx)峰稍下降,乳酸(Lactate,Lac)峰、脂质(Lipid,Lip)峰增加;PWI灌注曲线下降;③B组T1WI信号减低,T2WI信号增高;DWI呈高信号;Cho峰下降明显,Cr、Glx峰下降,Lac峰明显升高,Lip峰略增高;PWI曲线低平。结论:右肝血供不同程度阻断后肝细胞分别发生凋亡和坏死;磁共振检查(DWI、MRS、PWI)具有特征性表现,可活体检测细胞凋亡和坏死的存在。     

大鼠肝细胞凋亡和坏死动物模型的建立及评价

目的:通过大鼠肝右叶血供干预分别建立肝细胞凋亡和坏死动物模型,为进一步的磁共振成像实验奠定基础。方法:选取体重为250-300克的SD大鼠90只,随机分为A、B、C三组,每组30只,分别行肝右叶门静脉和肝动脉结扎术、门静脉结扎术及假手术,各组在术后3 h及1、3、7和14 d分别处死6只大鼠,取肝脏标本送病理及电镜检查。结果: A组30只大鼠肝右叶发生凝固性坏死,光镜及电镜下均呈典型的坏死改变,TUNEL染色呈阴性;B组30只大鼠肝右叶发生小灶性凋亡,光镜下可见肝细胞核固缩改变,电镜下见肝组织核边集和凋亡小体,TUNEL染色呈阳性改变。术后3 h 即可见凋亡细胞,24 h时凋亡细胞数最多,7 d后肝组织开始发生小灶性坏死;C组30只大鼠肝右叶未发生凋亡和坏死的病理改变。结论:大鼠肝右叶门静脉和肝动脉双结扎可建立胆脏凝固性坏死模型,单纯肝右叶门静脉结扎能构建肝细胞小灶性凋亡模型。     

肝组织大面积凋亡的磁共振成像和病理对照研究

目的:通过手术结扎大鼠门静脉右支的方法制作肝组织大面积凋亡的动物模型,并通过MRI和病理学方法对其进行对照研究,评价MRI、DWI和增强MRI对肝脏大面积凋亡的诊断价值.材料和方法:采用S-D大鼠42只,随机分7组.A组为假手术对照组,B、C、D、E、F、G组大鼠分别于门静脉右支结扎后3h、12h、24h、3d、7d、14d进行磁共振成像,检查结束后进行肝脏标本病理检查,包括HE染色、TUNEL染色.将病理结果与MRI、DWI和增强MRI资料进行对照分析.结果:通过门静脉分支结扎成功制作肝细胞大片凋亡的动物模型.肝细胞大片凋亡早期在T1WI上呈略高信号,T2WI上为中等略低信号,随时间延长至72h,T2WI上肝右叶内可见斑片状稍高信号灶,在T1WI上仍为低信号.在DWI上以等低信号或肝叶内出现斑片状稍高信号影为主.增强MRI早期,病灶部位表现为明显均匀强化,但是在门脉期增强明显低于肝左叶.结论:肝组织发生大片细胞凋亡后在普通MRI、增强MRI成像和DWI上均有较明显的特征性表现,各种序列综合表现可以较早期和较敏感地显示肝组织细胞大片凋亡的存在.     

肝组织坏死和凋亡MRI鉴别诊断的实验研究

目的:通过对大鼠肝右叶坏死和凋亡的动物模型进行磁共振T1WI、T2WI、DWI和ADC等检查,观察形态和信号变化特点,探索MRI新技术对肝脏组织坏死或凋亡的鉴别诊断能力。材料和方法:78只大白鼠随机分成13组,每组6只,A1、B1、C1、D1、E1、F1六组动物同时结扎肝动脉右支和门静脉右支。A2、B2、C2、D2、E2、F2六组动物单独结扎门静脉右支,另6只大鼠为假手术对照组。各组实验大鼠于手术后3h、12h、24h、3d、7d、14d进行MRI检查,然后处死动物并取得肝脏标本,进行HE染色、TUNEL染色、透视电镜等病理检查。每例均进行常规MRI和DWI、ADC图成像。结果:动物麻醉和结扎手术成功率93.8%。右侧肝动脉与门静脉分支均结扎后,病理显示肝右叶发生凝固性坏死。单独右侧门静脉分支结扎后,3h即出现凋亡细胞,24h达高峰。坏死肝组织在DWI上早期即呈高信号,中晚期呈长T1和中等T2表现。单纯门静脉右支结扎的A2、B2、C2组大鼠肝右叶在T1WI上呈特征性较高信号,T2WI呈等信号,72h后出现斑点状高信号,DWI上早期呈信号减低改变,后期呈等信号或小片状高信号。结论:肝组织细胞坏死和凋亡在T1WI和T2WI上有明显的信号差异表现。结合DWI和ADC检查表现,可以区分肝脏细胞发生坏死或凋亡的不同病理改变。     

热射病患者小脑的磁共振波谱研究

目的 应用磁共振波谱技术(MRS)探讨热射病(HS)患者小脑的代谢物变化.方法 研究对象来源于2013年8月滨州医学院烟台附属医院重症医学科收治的8例HS患者和同期7名年龄相匹配的健康志愿者(对照组),采用化学位移成像采集MRS数据,测量HS患者及正常对照组小脑的代谢物比值NAA/Cr、NAA/Cr2、Cho/Cr、Cho/Cr2、NAA/Cho,采用Mann-Whitney U检验比较两组间MRS代谢参数之间的差异,HS患者小脑的代谢物比值并与Glasgow昏迷评分法(GCS)进行Pearson相关性分析.结果 HS患者小脑的NAA/Cr显著低于对照组(0.79±0.10 vs 1.03±0.11,P=0.004),Cho/Cr低于对照组(0.85 ±0.13 vs 0.99 ±0.05,P=0.032),NAA/Cr2、Cho/Cr2、NAA/Cho与对照组差异无统计学意义(均P＞0.05);HS患者小脑的NAA/Cr与其GCS评分存在显著正相关(r=0.748,P=0.033).结论 应用MRS技术可敏感地探测HS患者小脑的代谢物异常,并可通过小脑的代谢物比值NAA/Cr判断病情的轻重.     

肝细胞癌的1H-MRS和DWI研究

目的 分析肝细胞癌(hepatoceliular carcinoma,HCC)的氢质子磁共振波谱(1H-MRS)及扩散加权成像(DWI)表现,评价HCC代谢物变化与表观扩散系数(ADC)值的相关性.资料与方法 对经手术病理证实的29例30个HCC病灶分别进行DWI及单体素波谱分析,测量HCC胆碱峰(Cho)、脂质峰(Lip)的相对浓度及HCC的ADC值,对Cho/(Cho+Lip)比值与ADC值进行线性相关分析.结果 30个HCC的Cho/(Cho+Lip)比值及ADC值分别为(0.25±0.21)和(1.49±0.27)mm2/s.HCC的Cho/(Cho+Lip)比值与ADC值呈负相关(P<0.05).质地均一、无明显出血坏死HCC(n:10)的Cho/(Cho+Lip)比值明显升高,ADC值明显下降;不均质局灶出血坏死HCC(n=13)的Cho/(Cho+Lip)比值轻度下降,ADC值轻度升高;明显脂肪变性(n=2)及透明细胞型(n=2)HCC的Cho/(Cho+Lip)比值很低,但是ADC值无明显升高;纤维基质丰富、无明显坏死、质地均一HCC(n=3)的Cho/(Cho+Lip)比值及ADC值均较低.结论 1H-MRS与ADC值结合能基本反映HCC的肿瘤组织成分变化,有助于HCC的诊断、鉴别诊断和活体肿瘤成分分析.     

单侧门静脉栓塞诱导家兔肝细胞凋亡及对侧肝叶增生的实验研究

目的探讨家兔门静脉栓塞后同侧肝细胞凋亡及对侧肝叶增生的最佳时间。方法健康家兔40只,随机分成5组,每组8只。一组做对照,余剖腹细针穿刺行肝右叶选择性门静脉栓塞。分别于栓塞前、栓塞后第3、7、14、21天各处死1组,依次为A、B、C、D、E组。处死后测量肝左、右叶体积,右肝取病理切片观察肝细胞凋亡、坏死情况及肝功能改变。结果栓塞后肝右叶体积逐步减少,A到E组平均体积分别为46．4、46．0、44．4、42．0、39．7 cm~3。肝左叶体积逐步增大,A到E组平均体积分别为54．0、54．5、56．3、61．7、63．9 cm~3。剩余肝比例逐步增加,A到E组分别为53．8%、54．2%、55．9%、59．0%、61．0%。肝细胞凋亡指数A到E组分别为8．1%、12．2%、19．4%、20．1%、14．2%。结论选择性门静脉栓塞可引起同侧肝叶萎缩及诱导肝细胞凋亡和对侧肝叶体积代偿性增生,最佳时间为7～14 d。     

MRS在鉴别前列腺外周带T2低信号炎症和肿瘤中的作用

目的用磁共振波谱分析方法定量评价造成前列腺外周带T2信号减低的前列腺炎和前列腺癌的代谢变化.方法24例MRI检查示外周带T2信号减低的病人,经超声引导下穿刺活检分为前列腺炎和前列腺癌2组,根据T2低信号区在外周带设定兴趣区后利用三维磁共振波谱测定各兴趣区(胆碱+肌酸)/枸橼酸盐[(Cho+Cre)/Cit]的比值.计算并比较各组(Cho+Cre)/Cit比值的差异.结果前列腺炎组(Cho+Cre)/Cit平均值为0.98±0.17;前列腺癌组(Cho+Cre)/Cit平均值为1.4l±0.31,2组比值的组间差别具有统计学意义,t=8.89,P＜0.05,但有29%的比值重叠.结论用MRS定量评价造成外周带T2低信号的前列腺炎和前列腺癌的代谢变化是可行的,MRS与其它方法结合提高诊断的准确性是有可能的.     

1H-MRS在原发性中枢神经系统淋巴瘤与高级别胶质瘤鉴别诊断中的价值

目的 探讨单体素不同回波时间(TE =30 ms/135 ms)和多体素长回波(TE=135 ms) MRS在原发性神经系统淋巴瘤(PCNSL)与高级别胶质瘤(HGG)鉴别诊断中的价值.方法 回顾性分析19例PCNSL(13例经病理证实,6例经诊断性治疗确诊)和22例HGG(均经病理证实)患者影像资料.19例PCNSL均行单体素短和长回波MRS检查,其中15例行多体素长回波MRS检查.22例HGG均行单体素短和长回波MRS及多体素长回波MRS检查.分析不同TE时间单体素MRS在瘤体中的不同代谢物相对比值,同时分析多体素长回波MRS在瘤体及瘤周中的不同代谢物相对比值.结果 单体素短回波MRS的Cho/Cr和NAA/Cr在PCNSL与HGG的鉴别诊断中差异均有统计学意义(P＜0.05);Cho/NAA和(Lac+ Lip)/Cr在两者的鉴别诊断中差异均无统计学意义(P＞0.05).单体素长回波MRS的Cho/Cr、NAA/Cr和Cho/NAA在两者的鉴别诊断中差异均有统计学意义(P＜0.05).多体素长回波MRS瘤体的Cho/Cr、NAA/Cr和Cho/NAA在两者的鉴别诊断中差异均无统计学意义(P＞0.05);瘤周的Cho/Cr、NAA/Cr和Cho/NAA在两者的鉴别诊断中差异均无统计学意义(P＞0.05).结论 单体素MRS代谢物是鉴别诊断PCNSL与HGG的有效指标,多体素长回波MRS鉴别诊断价值有限.     

How does alteration of hepatic blood flow affect liver perfusion and radiofrequency-induced thermal lesion size in rabbit liver?

The purpose of this study was to test the hypothesis that decreasing liver perfusion in rabbits results in an increase in thermal lesion size and that these effects can be accurately monitored using magnetic resonance imaging (MRI). We additionally tested the hypothesis that the increase in thermal lesion size would depend on the particular vessel or vessels occluded (hepatic artery, portal vein, or both). Using an Institutional Animal Care and Use Committee approved protocol, 20 New Zealand white rabbits were randomly assigned to four treatment groups (five in each group): control and ligation of portal vein (PV), hepatic artery (HA), or both PV and HA (HAPV). Surgical ligation of the appropriate vessel was performed under general anesthesia. Immediately after ligation, the rabbits were placed in a 0.2-T open MR system, and an 18-G copper radiofrequency (RF) electrode with a 2-cm exposed tip was inserted into the liver. RF was applied for 10 minutes with the tip temperature maintained at 90 degrees +/- 2 degrees C. Before and after ablation, perfusion data were obtained for 90 seconds using 30 3-second sequential single oblique-slice fast imaging with steady-state progression (FISP) acquisitions after injection of gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) via the inferior vena cava. Postablation scanning included axial and oblique turbo spin-echo (TSE) T2-weighted (T2w), STIR, and Gd-enhanced T1w sequences. Lesion size was determined perpendicular to the RF electrode using software calipers on the imager. The rabbits were sacrificed after completion of the post-therapy scans, and their livers were harvested for histologic analysis. The liver showed a mean increase in signal amplitude (SA) of 76% 24 seconds after Gd contrast injection in the control group. After contrast injection, the SA increased to a mean of only 66% in the group with ligated hepatic arteries, with no difference in the time to peak compared with the control group. No significant SA increase over baseline could be found in the groups with ligated PV or ligated PV and HA. T2-weighted images demonstrated the highest lesion-to-liver contrast-to-noise ratios (CNRs; mean -5.5) on postprocedure images, followed by STIR images (mean -2.2) in the control group. The lesions were poorly delineated on the Gd-enhanced images. Average maximum lesion sizes (mean +/- 95% confidence interval) were 22 +/- 4.3 mm after ligation of PV, 22 +/- 2.6 mm after ligation of both PV and HA, 14 +/- 2.0 mm after ligation of HA, and 13 +/- 1.9 mm in the control group. We accept the hypothesis that the diameter of the region of coagulation necrosis achieved by standardized RF ablation in the liver increases with reduced organ perfusion and that this effect can be accurately monitored using MRI. The major factor influencing the size of the coagulation area is the portal venous flow. Occlusion of the hepatic artery alone does not significantly increase lesion size. T2w sequences are best suited for postprocedure imaging due to the high lesion-to-liver CNR in rabbits with normal hepatic perfusion. J. Magn. Reson. Imaging 2001;13:57-63.     

MRI 3D-VIBE序列全肝灌注应用探讨

目的：探讨磁共振三维客积式内插法屏气检查（3D-VIBE）序列对人全肝灌注的可行性及其临床应用价值。方法：30例健康志愿者行常规MRI T1WI、T2WI轴面及true-FISP冠状面扫描后,采用经改良的3D-VIBE序列行全肝灌注扫描,然后在肝左、右叶、腹主动脉及门静脉区分别选择兴趣区（ROI）,测量其在注射Gd—DTPA后不同灌注时间及延迟期的信号强度值,最后绘制时间-浓度曲线。结果：每个志愿者分别得到4条关于肝左、右叶、腹主动脉及门静脉的时间-浓度曲线。Od—DTPA在肝左、右叶、腹主动脉和门静脉的动态浓度范围分别为0～0．6mmol／l、0～0．6mmol／l、0～1．7mmol／l和0～1．0mmol／l。肝左、右叶及门静脉时间-浓度曲线较柔和,缓慢达峰并缓慢下降;腹主动脉时间-浓度曲线有2个峰值,且达峰时间快。结论：应用改良的3D-VIBE序列行全肝灌注的技术切实可行,能从中获得时间-浓度曲线,使肝血流灌注参数量化,对评估肝血流灌注异常具有重要临床意义。     

DCE-MRI在评估肝硬化血流动力学与肝功能关系中的应用

目的:探讨3.0T磁共振增强技术在对比研究正常肝脏及肝硬化肝脏血流变化与肝功能的相关性中的应用价值。方法:分别对53例肝硬化患者(肝硬化组)及46例健康人(正常对照组)进行MR对比剂动态增强扫描,连续扫描10期。分别测量肝、脾、门静脉及腹主动脉的最大上升斜率(MSI)、信号增强率(SER)、正性增强积分(PEI)、最大下降斜率(MSD)和峰值(PV)。比较肝硬化组与正常对照组血流参数,同时分析以上测量指标与肝硬化、Child-Pugh分级以及临床肝功能血清标记物之间的关系。结果:在肝硬化组,肝脏的PEI及PV,门静脉的PV,以及腹主动脉的MSI、PEI及PV均小于正常对照组(P值均<0.05)。在肝硬化组,肝脏的MSI、SER、PEI、MSD及PV,门静脉的PEI及PV,腹主动脉的MSD均随着Child-Pugh分级的增加而下降,差异具有统计学意义(P值均<0.05)。但脾脏的MSI、SER、PEI、MSD及PV在肝硬化组与正常对照组之间、不同Child-Pugh分级之间差异均无统计学意义(P值均>0.05)。另外,肝硬化组MSI、MSD和PV均分别与TBIL总胆红素和IBIL间接胆红素呈负相关(P值均<0.05),PEI与IBIL呈负相关(P=0.019,r=0.486),其余动态参数与肝功能血清标记物未见相关性(P>0.05)。结论:MR对比剂动态增强技术可无创评估肝硬化血流动力学的变化,在肝功能的评估方面也具有一定的价值。     

与TIPSS相关的影像学解剖关系的研究

目的应用多种医学影像学及解剖学方法，研究与经颈静脉肝内门腔静脉内支架分流术（ＴＩＰＳＳ）密切相关的解剖学改变，以提高操作的成功率、可靠性及安全性，并探索新的导向方式及分流途径。材料与方法采用ＭＲＩ、ＣＴ、血管造影、肝脏血管铸型等手段，研究肝动脉、胆管和门静脉的伴行情况及相互空间关系，估计各种穿刺途径对其损伤的可能性。分析肝段下腔静脉与门静脉的空间关系。结果胆管和肝动脉主要位于门静脉分叉及主干的前方、前上方；在右干分叉部及左干角部、矢状部分布不规则，可位于其后上或左右方。肝动脉，特别是肝右动脉和门静脉关系密切，可作为穿刺导向。肝段下腔静脉距门静脉分叉及左右干均较近，穿刺有较大的安全范围，可作为新的分流途径。结论熟悉肝脏血管解剖、应用有效导向、避免胆道和肝动脉损伤可提高ＴＩＰＳＳ疗效     

肝内门静脉和肝静脉的解剖与变异(三维动态增强磁共振血管成像分析)

目的用三维动态增强磁共振血管成像（３ｄｉｍｅｎｔｉｏｎａｌｄｙｎａｍｉｃｃｏｎｔｒａｓｔｅｎｈａｎｃｅｄＭＲＡ,３ＤＤＣＥＭＲＡ）前瞻性地观测肝内门静脉（简称门脉）和肝静脉的解剖和变异。方法共进行１４２例门脉和肝静脉３ＤＤＣＥＭＲＡ检查。对肝内门脉和肝静脉的解剖和变异做分型,计算每一型所占总调查人数的比例,并计算右后下肝静脉的显示率。结果１４２次成像中,８例（５．６％）显示门脉呈三分叉状,７例（４．９％）门脉先分出右后支,然后上行分为左支和右前支,４例（２．８％）门脉右前支源于左支,未发现有门脉左支水平段或右支缺如,余下１２３例（８６．６％）显示正常门脉分支。绝大多数情况下（９５．１％）肝中、肝左静脉合并,而三大支肝静脉单独汇入下腔静脉仅占４．９％。右后下肝静脉的显示率为７．７％。结论肝内门脉变异并不少见。肝中和肝左静脉多合并后汇入下腔静脉。部分病人有较为粗大的右后下肝静脉。３ＤＤＣＥＭＲＡ能方便而清楚地显示上述血管的解剖和变异     

Portal vein ligation is as effective as sequential portal vein and hepatic artery ligation in inducing contralateral liver hypertrophy in a rat model

PURPOSE: Dual embolization of the hepatic artery and portal vein (PV) has been proposed to enhance contralateral liver regeneration before resection. The aim of this study was to evaluate the effect of PV ligation compared with simultaneous or sequential dual ligation on regeneration, proinflammatory response, and liver damage. MATERIALS AND METHODS: Single hepatic artery ligation (HAL), PV ligation (70%), or dual ligation of the hepatic artery and PV (70%) simultaneously or sequentially within a 48-hour interval was performed in a rat model. Liver regeneration, proinflammatory mediators, hepatocellular synthetic function and injury, histopathology, and apoptosis were assessed at a maximum of 14 days after surgery. RESULTS: Sequential dual ligation resulted in a faster increase in hepatocyte proliferation at 24 hours without additional increase in liver mass compared with PV ligation after 14 days. Both dual ligations significantly increased proinflammatory response in plasma and in the regenerating liver compared with PV ligation alone. Fourteen days after PV ligation, the hepatic parenchyma was completely restored, whereas fibronecrosis was seen in the sequentially dual-ligated groups and complete necrosis was seen in simultaneously ligated groups. Increased apoptosis in the regenerating liver and prolonged hepatic dysfunction were observed after both dual ligations. CONCLUSIONS: PV ligation is as effective as dual ligation in inducing liver regeneration. No additional benefit of arterial ligation was observed.     

Tracer input for kinetic modelling of liver physiology determined without sampling portal venous blood in pigs

Purpose  

Quantification of hepatic tracer kinetics by PET requires measurement of tracer input from the hepatic artery (HA) and portal vein (PV). We wished to develop a method for estimating dual tracer input without the necessity to sample PV blood.