7.0T磁共振对磁标记单细胞的成像研究

目的 7.0T MR系统对氧化铁纳米粒子标记单细胞进行体外成像,并对成像参数进行探讨.方法 3D-FLASH序列对磁标记单细胞计数,对比梯度回波序列与自旋回波序列成像差异,对比梯度回波序列不同回波时间、不同分辨率成像差异.结果 7.0T MR能对磁标记单细胞进行成像,MR图像对细胞浓度为2×103/ml的琼脂糖模型进行细胞计数为1.7×103/ml,与实际浓度一致.2D-FLASH较SE序列对磁标记单细胞导致的T2*WI信号改变明显,差异有统计学意义;3D-FLASH序列随TE时间延长T2*效应增强,但图像伪影逐渐明显;分辨率降低单细胞导致的信号缺失明显降低,在200 μm时单细胞导致的信号波动已基本接近琼脂糖背景的内源性波动.结论 7.0T MR系统可对氧化铁纳米粒子标记的单细胞进行探测,选择适合的序列、优化序列内参数可有效提高磁标记细胞的探测敏感性.     

超顺磁性氧化铁标记大鼠骨髓间充质干细胞的磁共振成像研究

目的:探讨超顺磁性氧化铁纳米粒子(Superparamagnetic iron oxide,SPIO)体外标记大鼠骨髓间充质干细胞(Bone marrow mesenchymal stem cells,BMSCs)的适当浓度和不同标记浓度对细胞的生物学活性影响,以及经MR成像的特征等.方法:选取第5代细胞进行不同浓度SPIO标记,运用光学显微镜观察铁颗粒在细胞内的位置、分布及标记率;选取适当浓度标记量,使用1.5T磁共振进行T1wI、T2WI、T2*WI扫描,测量不同扫描序列标记细胞管的信号强度改变,并进行统计学分析.结果:标记后的铁颗粒均位于细胞质内;含量在25～50μg Fe/ml的培养液是SPIO标记干细胞的安全浓度,在此浓度阈值标记后孵育24 h即可有效标记细胞97%～100%;SPIO标记的MSCs在T1WI,T2WI及T2*WI序列信号均降低.结论:SPIO可以简便标记MSCs.并且在适当浓度下对MSCs的生物学活性没有影响,MR T2WI和T2*WI序列可有效显像磁性标记的干细胞,为下一步活体试验奠定基础.     

USPIO在中枢神经系统的应用进展

USPIO是一种新型顺磁性磁共振对比剂,具有颗粒小、血浆半衰期长、能透过血脑屏障等特点,在网状内皮系统、组织灌注、磁共振血管成像及淋巴结成像等方面取得了良好效果。与传统Gd螯合对比剂相比,USPIO在很多方面存在优势,但在中枢神经系统的应用方面研究相对较少。本文就目前USPIO在中枢神经系统的应用情况进行综述。     

菲力磁增强磁共振诊断急性放射性肝损伤的实验研究

目的探讨菲力磁在肝脏急性放射性损伤磁共振诊断中的应用价值。方法成年家兔12只,于40GyX线半肝照射后第10天,行肝脏菲力磁增强前后磁共振成像和病理学研究。结果菲力磁增强前磁共振,家兔肝脏信号均匀。菲力磁增强自旋回波序列T1WI、T2WI扫描分别检出11只、9只阳性家兔,肝脏照射区呈高或相对高信号改变。200倍光镜下,家兔肝脏照射区均出现不同程度小叶中央静脉血管闭塞性损伤;400倍光镜下肝脏照射区具有吞噬功能的Kupffer细胞较未照射区有明显减少。结论肝脏在受单次大剂量照射后,早期病理以小叶中央静脉血管闭塞性损伤为主要特征,菲力磁增强MRI是评价肝脏急性放射性损伤的有效手段。     

大鼠骨髓源神经干细胞的Sinerem体外标记及磁共振成像研究

目的 应用超小超顺磁性氧化铁(USPIO)Sinerem和转染试剂多聚赖氨酸(PLL)复合物标记大鼠骨髓源神经干细胞,初步评价磁共振成像活体示踪Sinerem标记干细胞的可行性.方法 分离SD大鼠骨髓基质干细胞,体外培养诱导成骨髓源神经干细胞.将制备的Sinerem-PLL复合物以浓度Sinerem 200μg/ml和干细胞共孵育培养过夜.采用普鲁士蓝染色和透射电镜确定细胞内铁的摄取、定位情况;并对细胞增殖、凋亡检测评价.体内外以SE序列T2WI与T2*WI行4.7T磁共振干细胞成像.结果 该方法标记干细胞效率为95%以上,普鲁士蓝染色显示铁颗粒存在胞质中,电镜显示铁颗粒集中于内涵体和溶酶体中;该浓度时Sinerem对细胞的活性影响与未标记细胞相比差异无统计学意义(P＞0.05).标记后细胞体内外的T2WI与T2*WI信号强度明显降低.结论 利用Sinerem对比剂经PLL介导标记骨髓源神经干细胞高效易行,磁共振可用于活体示踪神经干细胞.     

USPIO增强MRI在兔动脉粥样硬化斑块模型的观察研究

目的 探讨单纯高脂饮食建立兔动脉粥样硬化模型的可行性以及超小顺磁性氧化铁(USPIO)增强磁共振成像(MRI)在兔动脉粥样硬化(AS)斑块研究中的价值.方法 挑选30只健康的雄性新西兰大白兔作为研究对象,使用随机分组法分为两组,其中实验组20只,对照组10只.实验组通过单纯高脂饲料饲养的方法建立兔AS模型,对照组不作其他干预.观察USPIO增强前后动脉斑块的MRI表现,与病理结果进行比较和分析.结果 实验组成功建立兔AS模型,其中14例形成AS斑块,USPIO增强T2W1序列表现为斑块中央信号减低,血管壁信噪比值在96 h降低最低,较增强前信号差异有统计学意义(P＜0. 05),而对照组在增强前后管壁信号无变化.USPIO增强PJN 2D-TOF序列表现为管壁点状充盈缺损.病理检查显示USPIO颗粒主要沉积在内膜下.结论 单纯高脂饮食可以建立兔AS模型,USPIO增强MRI能反映出兔AS斑块情况,有助于对AS病变诊断作出评估.     

肝纤维化的SPIO增强磁共振成像研究

目的旨在通过动物肝纤维化模型的超顺磁性氧化铁（SPIO）增强磁共振（MR）研究,分析不同程度肝纤维化对SPIO增强效应的影响。方法肝纤维化大鼠21只及正常大鼠8只于注射SPIO前及60min后行T2加权MR扫描。测量图像的信号强度（SI）,计算信噪比（SNR）和信号强度变化百分比。肝脏标本行组织学检查,根据Scheuer的肝纤维化分期标准将大鼠分为4组。结果正常及肝纤维化组的SI及SNR于增强前后差异有显著性（P〈0.01）。肝纤维化分期与信号强度变化百分比的Spearman相关分析显示无相关性存在（P=0.212,r=0.239）。结论SPIO在肝纤维化与正常肝脏具有同样有效的增强作用。SPIO对肝脏增强效果的降低与慢性肝脏疾病的损害程度无显著相关。     

超顺磁性氧化铁MR成像检测兔动脉粥样硬化斑块的实验研究

目的探讨超顺磁性氧化铁(SPIO)作为磁共振成像(MRI)示踪剂使动脉粥样斑块成像的可行性。方法采用高脂饲养结合球囊损伤颈动脉血管内皮的方法,建立兔颈动脉粥样硬化模型。10只动脉粥样硬化模型兔分为2组,实验组(A)5只,经外周静脉注射SPIO(1 mmol/kg);对照组(B)5只,经外周静脉注射等量生理盐水。分别于24 h、48 h及72 h后行MRI扫描检查,然后行损伤颈动脉的病理组织学检查。结果在外周静脉注射超顺磁性氧化铁24 h后,A组中3只兔的T2*WI显示损伤的血管壁呈明显低信号区,血管腔明显呈"管腔扩大样"改变;B组则无明显异常信号改变;病理学检测显示A组5只MR信号改变实验兔的损伤血管内膜及斑块组织中有Perl’s蓝染色阳性颗粒;B组粥样斑块组织中则无该染色阳性颗粒,2组间Perl’s蓝染色阳性颗粒差异有统计学意义(P<0.05)。结论超顺磁性氧化铁可以靶向动脉粥样硬化斑块中的巨噬细胞,可作为MRI示踪剂使活体兔的动脉粥样硬化斑块成像,为动脉粥样硬化斑块的临床分子成像提供了实验依据。     

磁共振胰胆管成像术扫描方法及影响图像质量的因素

目的探讨磁共振胰胆管成像术（MRCP）检查前准备、扫描方法及影响图像质量的因素。方法40例MRCP检查者,30例空腹,10例口服超顺磁性氧化铁（SPIO）10min后扫描,扫描时病人平静呼吸。结果30例空腹者,其中25例有不等量的胃肠液储留。高信号的胃肠液体影响MRCP图像质量,10例口服SPIO能抑制胃肠道内液体信号,使胰胆管显影更加清楚,获得高质量的MRCP图像小。40例MRCP受检者中,2例呼吸渡均匀度差,有移动伪影,影响MRCP图像质量。结论检查前进行呼吸训练,可以提高MRCP图像质量。口服SPIO可以抑制胃肠道液体信号,使MRCP图像显示更佳。     

不同浓度超小超顺磁性氧化铁粒子在兔炎症淋巴结模型中的磁共振强化特征

目的 研究不同浓度超小超顺磁性氧化铁粒子(USPIO)在兔炎性淋巴结中的增强磁共振特征,建立USPIO淋巴结显像的常规注射及扫描方案.方法 12只健康新西兰兔于足垫注射完全弗氏佐剂,建立腘窝淋巴结的炎性增生模型.静脉注射不同剂量(45、90、135 μmol Fe/kg)的USPIO,注射前后行磁共振扫描,观察不同浓度组及90 μmol Fe/kg浓度组在不同时间点淋巴结强化特征,测量各组淋巴结T2信号强度、T1信号强度、T2*值及T2值变化并计算T2强化率.结果 炎症淋巴结在USPIO增强后24 h,90和135 μmol Fe/kg浓度组T2加权像序列强化效果及强化率差异无显著性,但均显著优于45 μmol Fe/kg浓度组(P<0.05);90 μmol Fe/kg组在6～24 h T2信号强度、T1信号强度、T2值及T2强化率差异无显著性 (P>0.05),90 μmol Fe/kg组淋巴结信号强度降低在18 h达峰值,于18～24 h均能获得较好的图像.结论 90 μmol Fe/kg可以较好地强化淋巴结,注射USPIO后18～24 h采集淋巴结图像可以达到满意的强化效果.     

超顺磁性葡聚糖氧化铁纳米颗粒的研制及表征

目的 制备葡聚糖包被的超顺磁氧化铁（SPIO）纳米粒子,并对其主要物理性质和磁学性质进行研究。探讨它作为磁共振造影剂的可能性。方法 通过共沉淀法获得SPIO纳米粒子,分别采用透射电镜和光子相关光谱仪测定其粒径大小,利用邻苯二氮菲比色法测定铁的浓度,同时用核磁共振仪测定弛豫率等参数。结果 X-射线衍射分析确定所制备的葡聚糖磁性粒子主要为Fe3O4晶体,粒子体均粒径为85．9nm,氧化铁核心大小为15nm左右,具有超顺磁性,其弛豫率和质量磁饱和度分别达到0．1567mmol／ms和80emu／gFe。结论 所制备的SPIO粒子稳定,其物理性质表明其具有作为磁共振造影剂的特性。     

Epidermal growth factor receptor-targeted ultra-small superparamagnetic iron oxide particles for magnetic resonance molecular imaging of lung cancer cells in vitro

Background  Magnetic resonance (MR) molecular imaging can detect abnormalities associated with disease at the level of cell and molecule. The epidermal growth factor receptor (EGFR) plays an important role in the development of lung cancer. This study aimed to explore new MR molecular imaging targeting of the EGFR on lung cancer cells.

Methods  We attached ultra-small superparamagnetic iron oxide (USPIO) particles to cetuximab (C225) anti-human IgG using the carbodiimide method. We made the molecular MR contrast agents C225-USPIO and IgG-USPIO, the latter as a control reagent, and determined concentrations according to the Fe content. Lung cancer A549 cells were cultured and immunocytochemistry (SP) was used to detect the expression of EGFR on cells. We detected the binding rate of C225-USPIO to A549 cells with immunofluorescence staining and flow cytometry. We cultured A549 cells with C225-USPIO at a Fe concentration of 50 μg/ml and assayed the binding of C225-USPIO after 1 hour with Prussian blue staining and transmission electron microscopy (TEM). We determined the effects on imaging of the contrast agent targeted to cells using a 4.7T MRI. We did scanning on the cells labeled with C225-USPIO, IgG-USPIO, and distilled water, respectively. The scanning sequences included axial T1WI, T2WI.

Results  Immunocytochemical detection of lung cancer A549 cells found them positive for EGFR expression. Immunofluorescence staining and flow cytometry after cultivation with different concentrations of C225-USPIO showed the binding rate higher than the control. Prussian blue staining and transmission electron microscopy revealed that in the C225-USPIO contrast agent group of cells the particle content of Fe in cytoplasmic vesicles or on surface was more than that in the control group. The 4.7T MR imaging (MRI) scan revealed the T2WI signal in the C225-USPIO group of cells decreased significantly more than in unlabeled cells, but there was no significant difference between the time gradients.

Conclusions  We successfully constructed the molecular imaging agent C225-USPIO targeting the EGFR of A549 lung cancer cells. The imaging agent showed good targeting effect and specificity, and reduced MRI T2 value significantly, thus such molecular contrast agents could provide a new way to measure EGFR levels.

     

超顺磁性氧化铁纳米粒子标记成肌细胞方法研究

目的:使用超顺磁性氧化铁纳米粒子(SPIO)对成肌细胞进行体外标记,探讨SPIO标记方法及SPIO对细胞的影响.方法: 常规方法进行成肌细胞培养,应用脂质体包被的SPIO标记成肌细胞,用光镜及电镜观察标记效率及对细胞增殖的影响,台盼蓝染色及JC-1观测SPIO对细胞活力的影响.结果: 普鲁士蓝染色证实了每个标记细胞胞质内有多少不等的蓝染铁颗粒,单纯SPIO标记有效率为50%,脂质体包被的SPIO标记有效率为100%,电镜也观测到细胞内的SPIO颗粒.SPIO标记对细胞无毒性,不影响细胞的增殖及活性.结论: 脂质体包被SPIO标记成肌细胞方法简单、高效、无毒,可用于磁共振对标记细胞进行活体内外无创动态示踪研究.     

Efficiently tracking of stem cells in vivo using different kinds of superparamagnetic iron oxide in swine with myocardial infarction

Background  Superparamagnetic iron oxide (SPIO) particles have shown much promise as a means to visualize labeled cells using molecular magnetic resonance imaging (MRI). Micrometer-sized superparamagnetic iron oxide (MPIO) particles and nanometer-sized ultrasmall superparamagnetic iron oxide (USPIO) are two kinds of SPIO widely used for monitoring stem cells migration. Here we compare the efficiency of two kinds of SPIO during the use of stem cells to treat acute myocardial infarction (AMI).

Methods  An AMI model in swine was created by 60 minutes of balloon occlusion of the left anterior descending coronary artery. Two kinds of SPIO particles were used to track after intracoronary delivered 10⁷ magnetically labeled mesenchymal stem cells (MR-MSCs). The distribution and migration of the MR-MSCs were assessed with the use of 3.0T MR scanner and then the results were confirmed by histological examination.

Results  MR-MSCs appeared as a local hypointense signal on T₂^*-weighted MRI and there was a gradual loss of the signal intensity after intracoronary transplantation. All of the hypointense signals in the USPIO-labeled group were found on T₂^*-weighted MRI, contrast to noise ratio (CNR) decreased in the MPIO-labeled group (16.07±5.85 vs. 10.96±1.34) and USPIO-labeled group (11.72±1.27 vs. 10.03±0.96) from 4 to 8 weeks after transplantation. However, the hypointense signals were not detected in MPIO-labeled group in two animals. MRI and the results were verified by histological examination.

Conclusions  We demonstrated that two kinds of SPIO particles in vitro have similar labeling efficiency and viability. USPIO is more suitable for labeling stem cells when they are transplanted via a coronary route.

     

超微超顺磁性氧化铁在中枢神经系统疾病磁共振影像诊断中的应用

超微超顺磁性氧化铁(USPIO)作为磁共振对比剂具有血浆半衰期长、能够特异性结合巨噬细胞两个重要特性。相对于目前临床普遍使用的钆螯合物对比剂,USPIO对部分中枢神经系统疾病的诊断具有一些独特的优势,但仍有待进一步的临床研究确证。本文就近年来USPIO在部分中枢神经系统疾病磁共振影像诊断中的应用研究进展作一综述。     

Specific targeting of angiogenesis in lung cancer with RGD-conjugated ultrasmall superparamagnetic iron oxide particles using a 4.7T magnetic resonance scanner

Background Angiogenesis is an essential step for tumor development and metastasis. The cell adhesion molecule αvβ3 integrin plays an important role in angiogenesis and is a specific marker of tumor angiogenesis. A novel αvβ3 integrin-targeted magnetic resonance (MR) imaging contrast agent utilizing Arg-Gly-Asp (RGD) and ultrasmall superparamagnetic iron oxide particles (USPIO) (referred to as RGD-USPIO) was designed and its uptake by endothelial cells was assessed both in vitro and in vivo to evaluate the angiogenic profile of lung cancer.

Methods USPIO were coated with ?NH3+ and conjugated with RGD peptides. Prussian blue staining was performed to evaluate the specific uptake of RGD-USPIO by human umbilical vein endothelial cells (HUVECs). Targeted uptake and subcellular localization of RGD-USPIO in HUVECs were confirmed by transmission electron microscopy (TEM). The ability of RGD-USPIO to noninvasively assess αvβ3 integrin positive vessels in lung adenocarcinoma A549 tumor xenografts was evaluated with a 4.7T MR scanner. Immunohistochemistry was used to detect αvβ3 integrin expression and vessel distribution in A549 tumor xenografts.

Results HUVECs internalized RGD-USPIO significantly more than plain USPIO. The uptake of RGD-USPIO by HUVECs could be competitively inhibited by addition of free RGD. A significant decrease in T2 signal intensity (SI) was observed at the periphery of A549 tumor xenografts at 30 minutes (P <0.05) and 2 hours (P <0.01) after RGD-USPIO was injected via the tail vein. Angiogenic blood vessels were mainly distributed in the periphery of tumor xenografts with positive αvβ3 integrin expression.

Conclusions RGD-USPIO could specifically label αvβ3 integrin and be taken up by HUVECs. This molecular MR imaging contrast agent can specifically evaluate the angiogenic profile of lung cancer using a 4.7T MR scanner.

     

超顺磁性氧化铁增强MRI检测转移性淋巴结的实验研究

目的探讨超顺磁性氧化铁粒子(SPIO)增强MRI检测转移性淋巴结的价值。方法取新西兰兔12只,6只于后腿肌肉接种VX2癌细胞,用于建立肿瘤转移性淋巴结模型;6只作为正常对照组。皮下间隙注射SPIO(每肢10 μmol Fe),在注射前和注射后12 h行MRI扫描,序列包括自旋回波(SE )T1WI、SE T2WI和梯度回波(GRE)T2WI,并与病理结果对照。结果平扫时,正常淋巴结和VX2转移淋巴结在三个序列图像上均表现出相似的信号特点。在增强SE T1WI 上,两组淋巴结的信号强度均未见变化;在增强SE T2WI上,正常淋巴结的信号强度不均匀降低,VX2转移组淋巴结的信号强度未见明显变化;在增强GRE T2WI上,正常淋巴结的信号强度明显地均匀降低,而VX2转移组有4个淋巴结信号强度未见降低,2个淋巴结不均匀降低。结论SPIO增强MR成像可用于检测转移性淋巴结。     

体外纳米磁标记骨髓间充质干细胞生物学特性及其MR成像

目的 研究超顺磁性氧化铁粒子(superparamagnetic iron oxide particles,SPIO)体外标记兔骨髓间充质干细胞(mesenchymal stem cells,MSCs)及MR细胞成像示踪可行性.方法 从兔骨髓中分离培养MSCs,体外不同浓度SPIO联合硫酸鱼精蛋白标记,未标记细胞设为对照组.普鲁士蓝染色和电镜检查鉴定细胞内铁颗粒,台盼蓝染色检测细胞存活,MTF法测定细胞生长曲线的变化,磁标记MSCs转入成骨、成脂肪培养基中进行诱导培养后进行鉴定,应用1.5T MR梯度回波T2加权(GRE T2 *WI)扫描序列和自旋回波T2加权(SE T2WI)扫描序列对磁标记细胞成像示踪.结果 普鲁士蓝染色和电镜检查显示细胞质内含致密铁颗粒,磁标记对MSCs活性和增殖无统计学差异(P<0.05),标记细胞可正常成骨、成脂肪分化.GRE T2*WI序列和SE T2WI序列提示与未标记细胞信号强度(sI)相比,1×106(标记细胞)、5×105(标记细胞)SI均显著性下降(P<0.05),其中GRE T2*WI的信号强度衰减率(△SI)显著高于T2WI序列(P<0.05).在2个序列中1×106(标记细胞)△SI均高于5×105(标记细胞)△SI,但不具有显著性差异(P>0.05).结论 SPIO联合硫酸鱼精蛋白转染剂能成功标记MSCs,磁标记对细胞存活、增殖及潜在多向分化能力无影响.磁标记细胞在MR上产生特征性的低信号改变.应用1.5T MR成像示踪标记细胞可行,以GRE T2*WI序列成像最为敏感.     

SPIO纳米药物载体联合碘化油经肝动脉栓塞治疗兔VX2肝癌

目的：评价超顺磁性氧化铁(superparamagnetic iron oxide, SPIO)纳米药物载体联合碘化油(lipiodol,LIP) 经肝动脉栓塞治疗兔VX2肝癌的可行性及效果。方法：新西兰大白兔24只,肝内种植VX2瘤组织制作VX2肝癌模型, 将荷瘤兔随机分为阿霉素(DOX)组、DOX-LIP组、SPIO-DOX组、SPIO-DOX-LIP组共4组,每组6只,行肝动脉栓塞 治疗。于术前以及术后1,3,5,7 d检测血清ALT和AST水平;术后0,5,15,30,60,120 min检测血清DOX浓度; 术后7 d行MRI及CT扫描观察SPIO及LIP在肝组织及其肿瘤中的分布和沉积情况;术后7 d取肝及其肿瘤组织检测组织 DOX浓度,同时行病理学检查,包括HE染色、普鲁士兰染色及TUNEL染色,计算肿瘤坏死率和凋亡指数。结果： 与DOX组相比,其他3组术后1和3 d血清AST和ALT水平均明显升高(P<0.05);术后7 d DOX组、DOX-LIP组和SPIODOX- LIP组血清AST和ALT水平恢复至术前水平,3组间差异无统计学意义(P>0.05);SPIO-DOX-LIP组术后120 min内 各时间点的血清DOX浓度均明显低于其他3组(P<0.05);SPIO-DOX-LIP组术后7 d肿瘤组织DOX浓度明显高于其他3组 (P<0.05)。术后7 d T2加权像(T2WI)示SPIO-DOX组和SPIO-DOX-LIP组肿瘤信号降低,CT示DOX-LIP组和SPIO-DOX-LIP 组肿瘤区域LIP沉积。术后7 d病理结果示SPIO-DOX-LIP组肿瘤中心大部分区域凝固性坏死,肿瘤坏死率和凋亡指数均 高于其他3组(P<0.05)。结论：SPIO纳米药物载体联合LIP是一种安全、可行的化学治疗栓塞体系,具有良好的MRI和 CT可视性,可提高兔VX2肝癌的化学药物栓塞治疗的效果。     

使用SPIO对大鼠肝癌模型进行MR增强显像的实验研究

目的评价超顺磁氧化铁(SPIO)增强MR成像对肝脏占位性病变的诊断价值。方法制作20只大鼠肝癌模型,注射SPIO前后行MR扫描,扫描序列包括SE T1WI(390 ms/14 ms)、TSE T2WI(4 100 ms/99 ms)、SE PDWI和T2WI(1 800 ms/20 ms/70 ms)、FLASH T2*WI(600 ms/15 ms/15°)、FLASH T1WI(150 ms/14 ms/70°),分析不同病灶的强化特点。5只正常大鼠作为空白对照,扫描序列与实验组相同。结果注射SPIO后,正常肝组织和硬化肝组织的信号强度都下降,以GRE T2*WI最为显著。SPIO增强T1WI上,肝细胞癌、肝硬化再生结节、灶性结节增生都出现阳性强化;T2WI上,肝细胞癌仍保持较高的信号强度,而再生结节、灶性结节增生出现负性强化现象。SPIO增强后GRE T2*WI中,肝细胞癌的增强噪声比高于其他扫描序列,TSE和SE T2WI在显示肝细胞癌的信噪比、增强噪声比方面没有显著性差异。结论SPIO对比剂在T1、T2WI的强化特性有助于肝脏占位性病变的显示,对于良、恶性结节的定性诊断有着重要意义。