应用生物素-亲和素预定位技术对荷人大肠癌裸鼠模型MR免疫显像的实验研究

目的：探讨抗体生物素化的条件,MR预定位增强方法和增强特点,以达到提高MR免疫成像敏感性的目的：方法（1）将抗癌胚抗原（CEA）单克隆抗体CL－3和生物素酯（NHS－LS－biotin),按1／30－50摩尔比,在碱性条件下活化。（2）GdCl3和二乙三胺五乙酸－生物胞素（diethylene triamine pentaacetic acid-biocyin,DTPA-B）反应后,用G－10凝胶层析法去除游离的Gd^3 离子。（3）将动物分为3组：预定位组,抗体对照组和Gd-DTPA组。进行平扫,注射Gd对比剂增强后20min,2h,8h及24h,共5次扫描,测定各时间点肿瘤信号强度。结果：（1）CL－3单克隆抗体在生物素化后,每个抗体可结合11－23个生物素分子,抗体活性高达94．9％。（2）预定位法对肿瘤有特异性增强作用,在注射钆二乙三胺五乙酸生物素（gadolinium-diethylene triamine pentaacetic acid-biotin,Gd-DTPA-Bt)20min,肿瘤信号强度明显升高,以后呈缓慢下降趋势,在24h后仍可见到有差别。（3）预定位法有信号放大作用,强化率为抗体直接标记法的2．4倍。结论：预定位法对荷人大肠癌裸鼠肿瘤有特异性增强作用和信号放大作用,优于传统的抗体直接标记法。     

经组织间隙注射Dextran Gd-DTPA兔腘窝淋巴结MRI——一种新型MR对比剂的初步应用

目的:经组织间隙注射Dextran Gd-DTPA行兔腘窝淋巴结MR成像,探讨该新型淋巴靶向对比剂在鉴别良、恶性淋巴结病变中的价值.方法:选取22只新西兰大白兔,分成Dextran Gd-DTPA增强组和Gd-DTPA对照组,其中增强组18只,对照组4只.增强组分为3个小组:①反应正常组6只;②反应增生组6只,于双侧兔腓肠肌注射蛋黄乳胶;③肿瘤转移组6只,于双侧兔腓肠肌注射VX2肉瘤细胞混悬液.增强组行MRI平扫后,再经双侧趾蹼间隙注射10μmolGd/kg Dextran Gd-DTPA后30min及1、3、6、12和24h行腘窝淋巴结脂肪抑制T1WI扫描,测量标准化信号强度(SI)及增强率(En%),描绘浓度-信号强度曲线及时间-增强相应曲线.Gd-DTPA对照组4只,平扫后再经双侧趾蹼间隙注射50μmol Gd/kg Gd-DTPA后5、10和20min行腘窝淋巴结脂肪抑制T1WI扫描.同时在体外检测Dextran Gd-DTPA溶液中质子的自旋-晶格弛豫时间T1,并计算R1值.结果:Dextran Gd-DTPA的T1值约0.03556s,R1值约33.37l/(mmol·s),Dextran Gd-DTPA经趾蹼间隙行腘窝淋巴结成像的达峰时间约1h,正常组及反应增生组淋巴结均表现为明显强化,信号可均匀,亦可不均匀;VX2肉瘤转移性淋巴结表现为强化不明显,信号可为环状、不规则偏心缺损等不均匀的强化模式,类似邻近肿瘤的强化特征.定量分析发现,VX2肉瘤转移性淋巴结在脂肪抑制T1WI上的标准化SI和强化率(E%)2个指标均明显低于正常组和反应性增生组.在最佳达峰点,正常组Dextran Gd-DTPA的增强率远高于Gd-DTPA对照组.结论:Dextran Gd-DTPA作为组织间隙淋巴靶向对比剂,用量小,强化效应明显,可以鉴别良恶性淋巴结病变.     

顺磁性对比剂Gd-DTPA-DG 的制备及其在肺癌裸鼠模型活体MR实验研究

目的 合成一种顺磁性脱氧葡萄糖类MR对比剂二乙三胺五乙酸-脱氧葡萄糖钆盐(Gd-DTPA-DG)并探讨其在荷瘤裸鼠体内肿瘤信号改变的规律.方法 首先合成DTPA-DG ,再与Gd2O3螯合,制得Gd-DTPA-DG.采用荷瘤裸鼠体内实验模型,将裸鼠随机分成实验组与对照组(n=10),前者尾静脉注射Gd-DTPA-DG,后者尾静脉注射含相同Gd3+浓度(0.1 mmol/kg)的Gd-DTPA, 测量SE T1WI平扫及引入对比剂30 s、2 min、5 min、 10 min、20 min、30 min、45 min、1 h、2 h后瘤体信号强度,并计算对比度噪声比(CNR).将右侧前肢肌肉组织信号变化作为参照物,并进行统计分析.结果 Gd-DTPA-DG比Gd-DTPA在肿瘤组织内表现为更强且更持久的强化.注射对比剂30 s后,实验组裸鼠瘤体信号增加与扫描前差异没有统计意义(P=0.171),在30 min左右差异性最大(P<0.001).对照组5 min时前后差异最大(P<0.001),但2 h时即与注射前没有显著差异性(P=0.057).结论 Gd-DTPA-DG 可在肺癌模型活体内起到肿瘤强化作用,是一种新型顺磁性Gd(III)类糖代谢MR对比剂.     

二步法预定位技术对荷人肝癌裸鼠模型的MR免疫成像研究

目的利用生物素亲和素系统(biotin avidinsystem,BAS)的靶向定位效应和生物放大作用,提高MR分子免疫成像的敏感性。方法制备生物素化抗人肝癌细胞单克隆抗体HAb18并测定其生物素化程度及抗原结合活性。20只荷人肝细胞癌裸鼠分为3组,二步法预定位组8只,先静脉注射生物素化单克隆抗体600μg,24h后再给予钆喷替酸葡甲胺链霉亲和素(Gd DTPA streptavidin,Gd DTPA SA);HAb18单克隆抗体Gd DTPA组6只,经尾静脉注射Gd DTPA HAb18;Gd DTPA对照组6只,静脉注射Gd DTPA。对实验动物行MR扫描,测量SET1WI平扫及增强后10、30、60min及3、6、12、24、48h图像内肿瘤的信号强度,绘制信号强度时间曲线,并计算肿瘤强化率及对比度噪声比(contrast to noiseratio,CNR)。结果HAb18单克隆抗体经生物素化后,每个抗体分子平均可结合20个分子生物素,其抗原结合活性约为91%。二步法预定位组内,肿瘤信号强度缓慢升高,增强后第6小时,肿瘤的强化率、CNR达到最大值,与其他两组相比较差异有统计学意义。48h后,肿瘤的强化仍肉眼可辨。单克隆抗体组内,肿瘤表现为缓慢轻度强化,增强后24h的强化率达13.5%,肿瘤信号强度、CNR与平扫比较差异均有统计学意义(P值均<0.05)。Gd DTPA对照组内,肿瘤表现为快进快出特点的强化特点。结论二步法预定位技     

Gd-EOB-DTPA在肝脏局部结节性病变诊断中的应用

目的 研究肝细胞特异性对比剂Gd-EOB-DTPA在肝脏结节性病变定性诊断中的应用价值.方法 收集经CT或MR(Gd-DTPA)增强检查证实肝内有结节性病变的患者30例,再进行肝细胞特异性对比剂Gd-EOB-DTPA MR增强扫描,采集T1WI、T2WI、DWI、LAVA动态增强扫描,在注射对比剂后15～20 min采集肝胆特异摄取期图像.结果 30例入组患者,共发现36个病灶.其中中低分化肝细胞癌14个,高分化肝细胞癌8个,再生结节或不良性再生结节9个,局灶性再生结节5个.注射肝细胞特异性对比剂Gd-EOB-DTPA后,病灶在动静脉期强化方式与非特异性钆基对比剂Gd-DTPA相同;在对比剂Gd-EOB-DTPA被肝细胞摄取的特异期内观察,不同分化程度的肝细胞癌均表现为境界清晰的低信号,而不同阶段的肝硬化结节信号强度出现分化,肝局灶性结节均表现为等或稍高信号.结论 Gd-EOB-DTPA在肝脏结节性病变的定性诊断中有重要价值.     

间质性磁共振淋巴成像评估健康小鼠乳腺淋巴引流的价值

【摘要】 目的：探讨对BALB/c小鼠乳腺采用Gd DTPA行间质性磁共振淋巴成像（MRL）的检查技术并评价其可行性;比较BALB/c小鼠和昆明小鼠乳腺间质性MRL的差异。方法：在3只BALB/c小鼠右侧第5组乳腺邻近皮内注射10μL（1.0μmol）Gd-DTPA溶液,用同样方法分别于5只BALB/c小鼠和5只昆明小鼠（雌性,大小约10周）右侧第5组乳腺邻近皮内注射相同剂量Gd-DTPA溶液。每只实验动物均在注射对比剂前及对比剂注射后40s、2min10s、5min10s、8min10s、11min10s、14min10s、17min10s、20min10s行乳腺MRL扫描,测量增强后淋巴结的信号强度并计算淋巴结-肌肉信号强度比（SIR）。绘制时间-信号强度比曲线,比较两种小鼠淋巴结增强效果并进行统计学分析。结果：注射Gd-DTPA后40s,可见BALB/c小鼠右侧腹股沟淋巴结明显强化;时间 信号强度比曲线在注射对比剂后40s内快速上升,随后快速下降,20min时恢复至平扫时的信号强度;对比剂注射前后各时间点BALB/c小鼠与昆明小鼠右侧腹股沟淋巴结SIR的比较采用F检验,差异均无统计学意义（P<0.05）。所有实验小鼠皮内注射Gd-DTPA后未见明显不良反应。结论：①利用Gd-DTPA进行小鼠乳腺间质性MR淋巴成像是一种安全、重复性好的可行性检查技术;②昆明小鼠可代替BALB/c小鼠进行乳腺间质MRL研究。     

顺磁性抗HER2免疫脂质体的制备及MR靶向成像研究

目的：制备顺磁性抗 HER2免疫脂质体,探讨其对荷人乳腺癌裸鼠模型的 MR 特异成像作用。方法：制备顺磁性抗 HER2免疫脂质体,评价其理化特性及体外细胞结合特性。动物试验选择12只荷人乳腺癌裸鼠,分为2组进行磁共振扫描。实验组为顺磁性抗 HER2免疫脂质体组,对照组为钆布醇组。测量平扫及静脉注射对比剂后第10分钟、1小时、6小时后,肿瘤组织在 T1 WI 的信号强度,计算并比较不同实验组内肿瘤组织的强化率和对比度噪声比。结果：顺磁性抗 HER2免疫脂质体的平均粒径为134．2 nm,多分散系数为0．29,Zeta 电位为－32．49 mV,r1弛豫率为4．67／mM·s;与HER2高表达的 SK-BR-3乳腺癌细胞表现为特异性结合,胞浆出现罗丹明红染。注射顺磁性抗 HER2免疫脂质体后,肿瘤组织表现为显著持久的强化;增强10 min 后肿瘤强化率为121％,1 h 后肿瘤强化率为185％,6 h 后肿瘤强化率为224％。对照组在静脉注射钆布醇10 min 后,肿瘤组织表现为显著强化,强化率为153％,1 h 后的信号强度与平扫相近。两组实验动物在注射对比剂后第1、6 h 后,肿瘤组织的强化率、CNR 差异具有统计学意义。结论：顺磁性抗 HER2免疫脂质体具有长循环时间,高 r1弛豫率,对乳腺癌具有特异性靶向作用。     

弥散法MR膝关节造影可行性研究

目的评价MR对比剂静脉内注射、膝关节腔内弥散关节造影的可行性研究并寻找最佳检查参数. 资料与方法选取膝关节正常者24名,按常规方法进行扫描后再将其分为运动组和未运动组.每组再分为3小组.3个小组分别从静脉注入不同剂量的Gd-DTPA.注射完后未运动组受检者静卧于检查床,进行延迟扫描;运动组步行10 min后再进行扫描,并进行延迟.扫描结束后,对平扫和增强图像中的关节腔周围组织及关节腔内信号进行测量.采集后的数据按组归类,并进行统计处理,观察对比剂注射后关节腔内信号增加程度并选取最佳检查方法. 结果弥散法膝关节造影可使关节腔信号强度明显增加,与周围组织产生明显信号差,以采用注射剂量为0.2 mmol/kg体重,注射后受检者正常步行10 min后造影效果最佳. 结论弥散法MR膝关节造影可起到关节造影的效果,造影效果良好,是一种操作简单、危险性小、并发症少的检查方法.     

体素内不相干运动用于评估小鼠对比剂急性肾损伤的病理生理变化过程及其与常规扩散加权成像及动脉自旋标记的比较

正摘要目的探究体素内不相干运动(IVIM)在评估对比剂急性肾损伤的病理生理过程方面的应用价值。方法选择27只大鼠制成对比剂急性肾损伤模型,其中6只分别在注射对比剂前24 h及注射对比剂后30 min、12 h、24 h、48 h、72 h、96 h进行MR成像;另外从剩余大鼠中随机选择3只测     

靶向CT对比剂在结核急性感染动物模型中的初步观察

目的 探讨抗85B和ESAT-6鼠单克隆抗体靶向CT对比剂对小鼠急性感染肺结核动物模型显示的可行性.方法 采用已纯化的抗85B和ESAT-6鼠单克隆抗体与碘原子耦联制备靶向CT对比剂,计算对比剂溶液中抗体含量和结合127Ⅰ含量,稀释后配制成5μg I/ml备用.将20只小鼠急性感染肺结核动物模型通过随机数字表法随机分为4组,每组5只并编号,分别记为靶向对比剂85B组和ESAT-6组、普通对比剂组和对照组.普通对比剂组与85B组注射含碘浓度相同的碘海醇稀释液；对照组注射pH 7.4的磷酸盐缓冲液(PBS).分别于注射对比剂前、后不同时间(即刻,6、12、24 h)行微CT(Micro-CT)扫描,观察小鼠肺内病变的显示情况,判断指标为病变CT值,绘制CT强化-时间曲线,并计算强化率.两样本均数比较用t检验,多个样本均数比较用方差分析.结果 实验所制备的2.52 ml抗85B对比剂溶液中含有210～ 255μg抗体、10.5 ～ 16.6μg 127Ⅰ;2.93 ml抗ESAT-6对比剂溶液中含有抗体147μg、结合127Ⅰ约20.58 μg.靶向对比剂组小鼠肺内病变的CT值随时间延长而逐渐升高,在注射对比剂后12 h(t12)病变强化明显,在注射对比剂24 h(t24)后肺内病变仍有强化,且与普通对比剂组小鼠肺内病变的CT值相比[85B组t12=(-125.04±13.58)HU,t24=(-117.37±12.28)HU和ESAT-6组t12=(-122.14±19.01)HU,t24=(-114.23±17.08)HU],差异均有统计学意义(2组24 ht值分别为4.05和6.39,P值均＜0.05).对照组小鼠肺内病变在注射PBS前后,均未见强化.结论 制备的抗85B和ESAT-6结核特异抗体靶向CT对比剂在小鼠肺结核动物模型中具有一定靶向性,为结核相关靶向对比剂的研究奠定了实验基础.     

SPIO与Gd-DTPA增强对裸鼠肾癌移植瘤显影价值对照研究

目的:比较SPIO与Gd-DTPA增强对裸鼠肾癌移植瘤显影价值.方法:种植人肾癌Ketr-3细胞的雄性裸鼠14只,随机分为2组:SPIO组7只,Gd-DTPA组7只.SPIO组先行T_2 WI平扫,后快速注入Reso-vist,注药后即时、10min重复T_2WI序列.Gd-DTPA组先行T_1WI平扫,后快速注入Gd-DTPA,注药后即时、10rain重复T_1WI序列.扫描结束分别测量两组移植瘤增强前后的信号强度及计算相对增强率.结果:SPIO组注入Resovist后,即时移植瘤T_2信号强度(SI)开始下降,10min后T_2SI逐渐回复.Gd-DTPA组注入Gd-DTPA后,即时移植瘤T_1SI明显增加,10min后T_1SI亦维持于较高水平.结论:Gd-DTPA对于肾癌移植瘤的诊断有着较长的强化时间窗,且强化效果较SPIO更明显.     

Gadolinium-DTPA enhanced MRI demonstrates uterine vascular changes associated with artificially induced decidualization and ovoimplantation in rats

Gadolinium-DTPA enhanced magnetic resonance (MR) imaging has been used to demonstrate uterine vascular changes during ovoimplantation and artificially induced decidualization in rats. Evans blue dye and Gd-DTPA were injected i.v. into rats 10 h after unilateral decidualization was induced by injection of sesame oil into the lumen of one uterine horn. Animals were killed various times later and uteri were removed, T₁-weighted proton imaging was performed, and mean image intensities for stimulated and control uterine horns were calculated by computer-assisted image analysis. Macroscopic bluing confined to stimulated horns was apparent 5 min after tracer injection and increased in intensity until the experiment was terminated at 320 min. Analysis of MR images showed that mean image intensity of control horns did not change significantly at any time after injection of the Gd-DTPA and Evans blue whereas mean image intensity of stimulated horns increased significantly by 5 min after injection, peaked at 20 min, and returned to values not different from controls by 320 min. T₁-weighted images of day 6 pregnant rats injected with Gd-DTPA and Evans blue revealed patterns of image enhancement that matched those of macroscopic bluing. Uterine concentrations of radioactivity after injection of ¹⁵³Gd-DTPA indicated that increased extracellular fluid volume (ECFV) produces the image enhancement of stimulated horns since the tracer permeates the extracellular fluid of both horns. Gd-DTPA-enhanced MR imaging of uteri after deciduogenic stimulation revealed significant image enhancement for stimulated horns at both 9 and 27 h after stimulation. We conclude that Gd-DTPA enhanced MR imaging allows the identification of uterine vascular changes during ovoimplantation and decidualization and that this methodology may be useful in both experimental and clinical settings.     

动态增强磁共振在评价肝细胞癌微血管密度中的意义

目的：将肝细胞癌（HCC）的动态增强MRI与组织学微血管密度（MVD）这一肿瘤预后的可靠指标进行对照性研究。材料和方法：回顾性研究47例经MR检查、治疗性肝癌切除术和病理证实的HCC,应用免疫组化方法计数肿瘤微血管,以其均值分高、低MVD两组。在MRI上测量肿瘤T1WI、SPGR平扫和增强扫描的信号强度,计算对比增强率（CER）,并将动态增强曲线分成四型。结果：47例的MVD值与MR的对比增强率呈正相关,高MVD和低MVD两组的CER值和增强曲线构成具有显著的不同。结论：肝细胞癌的磁共振动态增强曲线和对比增强率能够反映肿瘤微血管形成和谐,从而有助于判断病人的预后。     

MR imaging of tumor angiogenesis using sterically stabilized Gd-DTPA liposomes targeted to CD105

Aim

To depict tumor angiogenesis via the expression of CD105 in tumor-bearing rats using Gd-DTPA liposomes targeted to CD105 (CD105-Gd-SLs) on MR imaging.

Materials and methods

Three Gd-DTPA liposomal nanoparticles were prepared in our trial: liposomes entrapping Gd-DTPA (Gd-SLs), Gd-SLs conjugated to immunoglobulins (IgG-Gd-SLs) and CD105-Gd-SLs. Forty glioma-bearing rats were randomized into four groups: (a) Gd-DTPA; (b) Gd-SLs; (c) IgG-Gd-SLs; (d) CD105-Gd-SLs. Axial T1WI MRI images were collected at baseline and repeated at 5, 30, 60 and 120 min post-intravenous injection of Gd-DTPA or liposome. Enhancement features and contrast-to-noise ratio of each group were analyzed. After imaging, tumors were resected for immunohistochemistry and immunofluorescence staining to assess vascularity and angiogenesis.

Results

The four groups showed different enhancement features. The enhancement area was restricted for group CD105-Gd-SLs, while diffused for the other three. The degree of enhancement over time varied: group Gd-DTPA showed an early contrast enhancement at instant after injection with a peak at 30 min and a decline to baseline values at 60 min. In group CD105-Gd-SLs, the signal intensity (SI) continuously increased over 120 min. In groups IgG-Gd-SLs and Gd-SLs the SI peaked at 60 min, followed by a minor decrease for IgG-Gd-SLs and a rapid decrease for Gd-SLs almost to baseline. Immunohistochemistry and immunofluorescence showed that the enhancement in the CD105-Gd-SLs group resulted mainly from new microvessels. While in the other three groups, mature microvessels and new microvasculature resulted in the enhancement of the tumor.

Conclusion

CD105-Gd-SLs can be used to detect early tumor angiogenesis on MR images. This might provide a means to non-invasively reveal a malignant phenotype of extracerebral F98 tumor and evaluate its progression.     

单克隆抗体磁共振对比剂(Gd-DTPA-chTNT)对荷人肝癌裸鼠模型瘤体信号改变规律的初步探讨

目的 通过探讨单克隆抗体磁共振对比剂(Gd—DTPA—chTNT)对裸鼠瘤体信号改变的规律，评价Gd—DTPA—chTNT诊断肝肿瘤的可行性及有效性。材料与方法 首先chTNT与caDTPA(DTPA环二酸酐)连接，再标记上钆离子，制得Gd—DTPA—chTNT；将5～6周龄SPF级BLAB/C裸鼠皮下接种人肝癌瘤块作为动物模型；将裸鼠随机分成实验组与对照组，前者腹腔注射Gd—DTPA—chTNT1ml，后者腹腔注射含相同Gd^3 浓度的Gd—DTPA，观测注射前后T1WI瘤体信号改变情况。注射后扫描时间点选为6h、24h、36h、48h、60h、72h。结果 注射对比剂36h后，实验组裸鼠瘤体信号增加与扫描前差异有统计意义，48h时差异最大，72h时仍有差异。对照组注射对比剂后任何时间点与扫描前瘤体信号差异均无统计意义。结论 Gd—DTPA—chTNT对裸鼠瘤体信号增加的持续性提高了肝肿瘤定性诊断特异性。     

肝细胞癌射频治疗后的磁共振表现

目的：评价MRI平扫及Gd-DTPA动态增强对射频治疗肝细胞癌疗效随访的价值。材料和方法：回顾性分析了55例RF术前及术后的MRI表现,并与活检及长期随访结果进行对照。结果：RF术前病灶在T1加权上多呈相对低信号、T2加权像上呈相对高信号,RF术后病灶转变成T1加权较高信号、T2加权均匀一致的等低信号,残存的癌结节表现为病灶周围包膜不规整或周边小结节并在动态增强时呈单峰型“快进快出”强化表现,活检提示癌灶残存。结论：MR平扫评价RF的疗效基本可靠,动态增强能进一步提高评价信心及准确率。RF术后定期MR随访具有重要意义。     

Contrast-enhanced MRI of tumors. Comparison of Gd-DTPA and a macromolecular agent

The study aim was to define potential differences and advantages in magnetic resonance (MR) patterns of tumoral contrast enhancement using either a small molecular, extracellular fluid contrast enhancer [Gd-DTPA] or a macromolecular agent [albumin-(Gd-DTPA)20], designed for primary intravascular biodistribution. MR images of 25 mice with implanted fibrosarcomas were obtained before and repeatedly for up to 120 minutes after injection of either Gd-DTPA [0.2 mmol/kg, n = 11] or albumin-(Gd-DTPA) [0.0029 mmol/kg, n = 14]. Histologically, this hypovascular tumor contained zones of viable tissue and non-viable, necrotic tissue. Using either type of contrast media, the viable portions enhanced strongly, up to 152% and the necrotic portions enhanced poorly, less than 31%. However, the time-course of enhancement differed between contrast agents. Gd-DTPA tended to provide maximal enhancement soon after administration with no significant changes over two hours. Enhancement from albumin-(Gd-DTPA) was weak initially, corresponding to tumor hypovascularity, but over two hours the signal of the viable tumor zones progressively increased in intensity. This gradual tumoral accumulation of the macromolecular agent within the tumor was considered to reflect abnormal capillary permeability, associated with neovascularity. Thus, the increasing intensity within the neoplastic tissues over time, reflecting abnormal capillary permeability for macromolecules, may serve as a useful, albeit indirect, marker of neoplasia.     

Chordomas of the skull base: MR features.

PURPOSE: To characterize the MR features of skull base chordomas with regard to signal intensity, size, position, extension, and Gd-DTPA enhancement. PATIENTS AND METHODS: The MR imaging studies of 28 patients with surgically proven chordomas of the skull base were retrospectively reviewed. Twenty-two of these patients received intravenous administration of Gd-DTPA. RESULTS: On short TR/short TE images, chordomas generally had low to intermediate signal. On long TR/long TE images, chordomas generally had very high signal that was heterogeneous in 79%. After Gd-DTPA administration, all chordomas demonstrated some degree of contrast enhancement. In most cases, enhancement was demonstrated throughout most of each tumor in a heterogeneous pattern. Chordomas were associated with MR findings of displacement and encasement of vessels, and frequent extension into adjacent structures such as the cavernous sinus, sella, nasopharynx, and hypoglossal canal. CONCLUSION: The MR characterization of the position and extent of these neoplasms played an important role in determining the optimal surgical approaches for gross total tumor resection.     

MR imaging of hilar cholangiocarcinoma--comparative study with CT]

Magnetic resonance (MR) images of 18 cases of hilar cholangiocarcinoma were evaluated to compare the effectiveness of Gd-DTPA with that of high dose contrast enhancement computed tomography (HCE-CT) in detecting the primary tumor. The primary tumor was demonstrated as having slightly low intensity compared with liver parenchyma and high intensity compared with the dilated bile duct on T1 weighted images. In contrast, MRI using Gd-DTPA, which was carried out in five cases, revealed intense enhancement of the tumor. As the differentiation between cholangiocarcinoma and dilated bile duct was difficult, it was concluded that the use of Gd-DTPA improves the efficacy of MRI in diagnosing cholangiocarcinoma. Gd-DTPA was also effective in differentiating the growth pattern of the tumor: the infiltrating type was demonstrated as thickening of the wall of the bile duct, the polypoid type as a soft tissue mass in the bile duct. Contrast MRI study is effective for the detection of cholangiocarcinoma. It is also expected to be effective in the staging diagnosis of cholangiocarcinoma.