SPIO与Gd-DTPA联合增强检测大鼠肝癌病灶的实验研究

目的 :观察联合使用SPIO和Gd DTPA对大鼠肝癌模型的增强特点。材料和方法 :制作 3 0只大鼠肝癌模型 ,增强前后行MR扫描 ,平扫序列包括SE、TSE、GRE的T1、T2WI序列。增强扫描分为 4组 ,其中Gd +SPIO联合增强组 10只 ,先注射Gd DTPA ,行SE、GRET1WI扫描 ,随后给予SPIO造影剂 ,扫描序列同平扫 ;SPIO +Gd联合增强组 10只 ,先注射SPIO ,行SE、GRET1WI扫描 ,12min后再给予Gd DTPA ,扫描序列同平扫 ;Gd、SPIO增强组各为 5只 ,增强扫描序列同平扫。分析各增强扫描组中病灶的增强特点。结果 :两种联合增强方法中 ,肝脏信号强度在所有扫描序列中均较平扫时下降 ,但与SPIO增强组无差异 ;病灶的SNR、CNR在SE、GRET1WI中明显高于平扫和SPIO、Gd DTPA增强法 ;在T2WI中病灶的SNR、CNR和单独使用SPIO无显著性差异。两种联合增强方法之间的SNR和CNR在每种扫描序列中没有显著性差异。结论 :SPIO和Gd DTPA联合增强方法利用了两种造影剂的优势 ,增加了肿瘤病变的对比 ,可提高发现病变的几率。     

不同MR扫描序列在SPIO增强大鼠肝癌模型的对比研究

目的：比较多种扫描序列超顺磁氧化铁（SPIO）增强扫描对显示大鼠肝癌病灶的能力，找出最佳扫描方案。TSE T2WI、SE双回波的T2WI＋PDWI、GRE T1WI、T2^＊WI，分析增强前后大鼠肝癌病灶的强化特征，并进行病理学检查对照分析。结果：注射SPIO对比剂后，所有扫描序列均显示肝脏的信号强度较增强前有不同程度的下降，肝癌病灶CNR均分别高于平扫。增强后GRE T2^＊WI中病灶的CNR明显高于其它序列，但增强后TSE T2WI和常规SE T2WI在显示病变的SNR、CNR方面没有显著性差异。结论：SPIO增强后检测肝癌病灶的各种序列中，以GRE T2^*WI最为敏感，其次是双回波的T2WI＋PDWI序列。     

为什么部分肝脏局灶病变在超顺磁氧化铁增强T1WI上呈现高信号

目的:探讨肝脏病变在SPIO增强扫描T1WI上呈现高信号的机制.方法:肝脏局灶病变39例(56个病灶),其中33个恶性病灶(肝细胞癌10个、转移瘤21个、胆管细胞癌2个)和良性病灶23个(海绵状血管瘤9个,肝囊肿14个).平扫序列包括SE T1WI、FSPGR T1WI及FSE T2WI.SPIO(菲立磁)增强扫描序列包括FSE T2WI、SE T1WI(TE值分别为8 ms、20 ms)和 FSPGR T1WI(TE值分别为1.5 ms、4.2 ms).分析不同序列图像上病灶及肝实质的的信号变化.结果:在SPIO增强T1WI上,随着TE的延长,肝实质信号降低,肝内局灶病变信号相对增高.在SPIO增强长TE T1WI上,大部分恶性病灶及全部血管瘤呈相对高信号.结论:在SPIO增强T1WI上,SPIO对肝实质的T2*效应可能是部分局灶病变呈高信号的主要原因.     

脑肿瘤T_1WI-FLASH 3D序列直接增强扫描的伽玛刀定位价值

目的探讨T1WI-FLASH 3D(fast low angle shot,FLASH)序列直接增强扫描作为伽玛刀定位图像的价值。方法回顾性的分别对60例颅脑肿瘤患者的增强扫描SE T1WI图像与T1WI-FLASH 3D图像对比研究。由2名放射主任医师、2名放射技师双盲法对两组图像进行分析,分别测量病灶个数、信噪比(SNR)、对比噪声比(CNR),并对两组图像显示程度进行评分。两组图像SNR、CNR比较采用配对样本t检验。结果 T1WI-FLASH 3D图像SNR为87.2±18.8,SE T1WI图像SNR为60.3±9.4,低于T1WI-FLASH3D图像,差异具有统计学意义(t值=9.913,P0.05)。T1WI-FLASH3D图像CNR为40.3±12.6,SE T1WI图像CNR为30.2±3.1,低于T1WI-FLASH3D图像,差异有统计学意义(t值=6.029,P值0.05)。结论以T1WI-FLASH 3D序列直接增强扫描图像作为伽玛刀定位序列优于SE T1WI图像。     

磁共振成像诊断肝脏病变:四种序列的比较

鉴于钆增强快速小角度激发成像(FLASH)对肝结节病变的检查已表现出优于常规T_2WI自旋回波成像以及超顺磁性铁氧化物对比剂(SPIO)的使用增强了MR检查的灵敏性等状况。作者比较了以下四种MR成像序列对于肝脏病变检查的价值。四种序列是脂肪抑制T_2WI SE,动态钆增强FLASH,非增强快速SE和SPIO增强快速SE。26例患者中男16例,女10例,年龄22～76岁。21例源于结肠、     

超顺磁性氧化铁MR成像评估大鼠非酒精性脂肪肝炎枯否细胞功能的初步研究

目的 初步探讨超顺磁性氧化铁(SPIO)作为MRI对比剂评估大鼠非酒精性脂肪肝炎(NASH)枯否细胞(KC)功能的可行性.方法 20只雄性SD大鼠按完全随机法分为实验组和对照组,每组10只,实验组喂养高脂饲料,对照组喂养普通饲料.8周后对所有大鼠行肝脏MRI及SPIO增强扫描,计算肝脏组织平均信号强度下降百分比(PSIL)和SPIO增强前后肝脾对比信号强度比值(RSIR),测定血清总胆固醇(TC)和甘油三酯(TG)值,并取肝脏标本行HE和普鲁士蓝染色分析病理表现.采用两组独立样本均数t检验比较2组不同序列SPIO增强后PSIL和RSIR值的差异.结果 实验组1只大鼠因麻醉过深死亡,其余9只血清TC及TG值分别为(6.58±1.25)和(1.53±0.23)mmoL/L,较对照组[分别为(1.64±0.22)和(0.55±0.14)mmol/L]均明显升高(t值分别为11.716和11.588,P值均＜0.01).SPIO增强扫描后两组肝实质信号强度在各序列明显下降,在PDWI及T_1WI上实验组PSIL分别为(34.78±4.51)%和(60.38±3.49)%,较实验组[分别为(64.96±2.42)%和(81.08±1.66)%]小,差异有统计学意义(t值分别为-18.451和-16.240,P值均＜0.01).PDWI、T_2WI、T_2~*WI和T_1WI序列实验组RSIR分别为1.002±0.141、5.000±0.516、20.004±1.490和2.601±0.077,均较对照组(0.400±0.102、1.500±0.115、0.503±0.105和-0.300±0.058)大(t值分别为10.745、19.800、39.168和92.785,P值均＜0.01).实验组肝脏组织中普鲁士蓝染色阳性颗粒积分(2.33±0.50)分较对照组(4分)明显减少(t=-10.000,P＜0.01).结论 高脂饮食诱导的SD大鼠NASH模型接近人类发病情况且容易建立,临床应用型1.5 T MR通过SPIO增强肝脏扫描可评估KC的功能,提示NASH的发病机制与KC功能的下降有关.     

肝胆特异性对比剂Gd-EOB-DTPA对正常肝脏及其肿瘤ADC值的影响

目的探讨肝胆特异性对比剂钆塞酸二钠(Gd-EOB-DTPA)对正常肝实质及肿瘤组织的表观扩散系数(ap-parent diffusion coefficient,ADC)值的影响。方法 20例患者共检出肝脏肿瘤性病变灶21个,在静脉注射Gd-EOB-DTPA前、后20 min分别行肝脏容积加速快速成像(liver acquisition with volume acceleration,LAVA))和扩散加权成像(diffusionweighted imaging,DWI)扫描(b值=0及800 s/mm2),分别测量增强前后T1WI图像的信噪比(signal-to-noise ratio,SNR)、肝脏及肿瘤的对比噪声比(contrast-to-noise ratio,CNR)、正常肝实质及肿瘤组织的ADC值,应用配对t检验比较增强前、后SNR、CNR、ADC值的变化。结果静脉注射Gd-EOB-DTPA 20 min后T1WI图像的SNR(186.67±59.64)显著高于增强前(102.79±26.95),差异有统计学意义(t=6.841,P<0.01);增强后CNR(84.86±46.2)显著高于增强前(33.09±21.79),差异有统计学意义(t=5.758,P<0.01);增强前、后肿瘤的ADC值分别为(1.45±0.57)×10-3mm/s和(1.37±0.48)×10-3mm/s,差异无统计学意义(t=1.320,P=0.202);增强后正常肝实质的ADC值(1.27±0.23)×10-3mm/s较增强前(1.34±0.25)×10-3mm/s降低,差异有统计学意义(t=2.189,P=0.033)。结论静脉注射Gd-EOB-DTPA 20 min后肝脏T1WI的SNR和CNR均显著高于增强前,故有利于病变的显示及检出;增强前、后肝脏肿瘤的ADC值未见显著差异,而正常肝实质的ADC值较增强前降低,静脉注射Gd-EOB-DTPA20 min后会影响正常肝实质的ADC值的测量。     

诱发性大鼠肝硬化性肝癌超顺磁性氧化铁增强MRI与电镜表现

目的 研究诱发性大鼠肝硬化性肝癌超顺磁性氧化铁(SPIO)增强MRI与电镜表现. 材料与方法 16只由二乙基亚硝胺(DENA)诱导的肝硬化性肝癌大鼠行肝脏SPIO增强前后MR扫描,再行肝脏病理学及电镜检查. 结果 肝癌在T1WI上为低或等低信号,T2WI为较高信号.SPIO增强T2WI上,正常肝实质、肝硬化组织信号强度(SI)较增强前明显下降,肝癌SI较增强前无明显下降,其对比噪声比(CNR)升高,病变显示清晰.SPIO增强T1WI上正常肝实质及硬化肝组织SI无明显下降,肝癌SI较增强前升高,其CNR较增强前降低,病变显示不清楚.电镜下正常肝组织枯否细胞(KC)内溶酶体丰富,可见较多黑色颗粒状SPIO粒子,胞浆内可见大的SPIO簇.肝硬化组织细胞间隔增宽,胶原纤维明显增多,KC数量无明显减少,其内溶酶体有所减少,可见散在SPIO粒子,胞浆内可见较大的SPIO簇.肝癌组织KC数量减少或消失,癌细胞内细胞器基本消失,核异型. 结论 诱导性大鼠肝硬化性肝癌MR信号表现与人类肝癌相似.SPIO增强肝脏信号改变和KC数量及吞噬功能有一定关系.SPIO增强T2WI不仅能提高肝癌的对比,且能间接反映KC数量,可以预测肝癌组织学分级.     

大鼠正常肝脏Mn-DPDP增强磁共振研究

目的 :探讨大鼠正常肝脏磁共振表现与Mn DPDP注射剂量、扫描延迟时间和扫描序列的关系。方法 :将 2 0只健康SD雄性大鼠随机分为 3组 ,每组经尾静脉注射Mn DPDP ,剂量分别为 5、10和 2 5 μmol/kg ,对肝脏进行FMPSPGR和SET1WI序列扫描。扫描延迟时间为 5、15、3 0、60、12 0、180和 2 40min。MRI检查后取肝脏大体标本HE染色进行病理学对照观察。结果 :大鼠肝脏信号随Mn DPDP注射剂量增加而升高 ,但两者并不存在线性相关。 2 5 μmol/kg组增强后各时间点肝脏信号净增加百分率比 5 μmol/kg和 10 μmol/kg组明显 ,且具有显著性差异 (P <0 .0 5 ) ,后二者之间无显著性差异 (P >0 .0 5 )。同一注射剂量组FMPSPGR序列肝脏信号绝对值在相同时间点上较SET1WI序列高 ,两序列肝脏净信号增加百分率无显著性差异 (P >0 .0 5 )。结论 :大鼠正常肝脏MRI检查选择梯度回波序列 (FMPSPGR序列 )和SET1WI序列在Mn DPDP( 2 5 μmol/kg)注射后 60min内可以获得较佳图像。     

MRI不同的扫描序列对肩袖撕裂的诊断价值

目的 探讨MRI在肩袖撕裂的诊断中最佳序列的选择.方法 对22例24肩关节疼痛患者,使用1.5T MR扫描仪进行肩关节磁共振检查,所有患者均采用SE/T1WI、FSE/T2WI、GRE/T2*、STIR及PDWI扫描,比较SE/T1WI、FSE/T2WI、GRE/T2*、STIR及PDWI序列在诊断肩袖撕裂诊断中的敏感性.结果 22例患者24肩关节经手术及临床治疗证实肩袖完全撕裂5例、肩袖部分撕裂15例、肩袖结构完整者4例,在SE/T1WI、FSE/T2WI序列分别为1例、16例、7例;PDWI组为6例、14例、4例;STIR序列为8例、12例、4例.结论 PDWI在提高肩袖撕裂诊断敏感性上是最好的成像序列.     

大鼠肝癌模型LAC-BSA-SPIO增强MR成像研究

目的：探讨LAC-BSA-SPIO对检出肝脏病灶,尤其是微小病灶的潜在价值及其对病灶良恶性鉴别诊断的价值。方法：建立大鼠肝硬化肝癌模型,分别测试LAC-BSA-SPIO最佳注射剂量和最佳扫描时间。28只大鼠MRI平扫序列为SET2map、FSET2WI、SET1WI、FRFSET2WI、GRE、3DFIESTA、SWI,注射LAC-BSA-SPIO（50μmolFe/kg）后30min行增强扫描。结果：成功建立大鼠肝硬化肝癌模型28只,共检出≥2mm的病灶63个,包括36个为肝细胞癌（HCC）,19个腺瘤性增生结节（AHN）,8个炎症性肌纤维母细胞瘤（IMT）。CNR最高的是50μmolFe/kgLAC-BSA-SPIO组;CNR最高的是30min组。增强扫描后AHN、IMT和HCC之间的T2值差异有显著性意义（P〈0.05）。SNR下降最明显的依次是GRE、3DFIESTA、FSET2WI、FRFSET2WI。在所有的序列上,HCC、AHN、IMT增强扫描前后的CNR差异均有显著性意义,所有序列增强扫描前后的差值在HCC、AHN、IMT之间差异有显著性意义（P〈0.05）。结论：LAC-BSA-SPIO有助于提高肿瘤-肝脏的CNR,对于肝硬化性肝癌的病灶有较高的鉴别诊断价值;最佳剂量为50μmolFe/kg,最佳扫描时间为静脉注射后30min。     

Performance of Gd-EOB-DTPA and superparamagnetic iron oxide particles in the detection of primary liver cancer: A comparative study by alternative free-response receiver operating characteristic analysis

The performance of gadolinium-ethoxybenzyl-dieth-ylenetriaminepentaacetic acid (Gd-EOB-DTPA) and superparamagnetic iron oxide (SPIO) particles in detecting liver cancer was compared using alternative free-response receiver operating characteristic (AFROC) analysis, which allowed observers to indicate both the confidence level and the locations of all perceived abnormalities. Axial T1-weighted MR images (1.5 T) pre/post Gd-EOB-DTPA (25 μmol/kg) injection were obtained for 12 rats with chemically induced liver tumors (64 tumors). T2-weighted images (T2WI) were obtained pre/post SPIO (10 μmol/kg) injection for the same animal. Liver signal-to-noise ratio (SNR), tumor-liver contrast-to-noise ratio (CNR), and histopathologic sections corresponding to MR images were obtained. In AFROC, the location and the confidence level for each tumor were indicated independently on MR images by four radiologists. By plotting true-positive fraction and probability of false-positive per image, the area under the AFROC curve (A1) was estimated and statistically analyzed between each sequence. Either drug significantly improved tumor-liver CNR (P < .001) and tumor detection (diameter ≤ 6 mm; P < .05). Gd-EOB-DTPA significantly (P < .05) improved the A1 in T1WI. There was no A1 difference between T2WI + SPIO and T1WI + Gd-EOB-DTPA. Gd-EOB-DTPA-enhanced T1WI showed the same performance as SPIO-enhanced T2WI in detecting liver tumors.     

对比剂铁羧葡胺在正常兔MR脑灌注的初步实验研究

目的 探讨铁羧葡胺(Resovist)应用于脑MR灌注加权成像(PWI)的可行性、给药方法以及最佳剂量.方法 健康新西兰大白兔30只,随机数字法平均分为A、B、C、D、E组.其中A、B、C、D 4组分别给予4、8、16、32 μmol Fe/kg;E组设为对照,给予0.2 mmol/kg的钆喷替酸葡甲胺(Gd-DTPA).所有动物均行MR PWI,获得相应信号强度一时间曲线图,并分别计算脑灰质、白质的最大信号下降百分比(SRRmax)、局部脑血容量(rCBV)和灰质与白质rCBV之比(QRCBV)、SRRmax之比(QRR max).所得数据,根据资料性质,行配对t检验和单因素方差分析.结果 Resovist能快速团注,4组均获得满意的信号强度一时间曲线图;4种剂量的Resovist对实验兔脑灰质和白质均有良好的分辨率.A、B、C、D、E 5组脑灰质和白质的rCBV分别为(50.48±3.84)、(25.57±2.10),(94.69±2.60)、(45.33±3.14),(141.13±6.26)、(67.67±4.65),(243.75±5.90)、(162.06±5.14),(84.60±3.60)、(41.36±2.18)ml/100 g;灰质和白质的SRRmax分别为:(13.70±1.50)%、(7.38±0.41)%,(31.01±4.06)%、(16.49±2.35)%,(43.81±3.42)%、(21.64±4.14)%,(64.49±5.35)%、(43.61±5.78)%,(27.78±2.98)%、(14.42±2.25)%;各组脑灰质与白质检测数据比较差异均有统计学意义(P值均<0.01).A、B、C、D、E 5组QrCBV分别为1.98±0.07、2.09±0.11、2.09±0.07、1.50±0.01、2.05±0.03;QSRRmax分别为:1.85±0.11、1.88±0.06、2.06±0.25、1.49±0.09、1.94±0.12;5组间差异均有统计学意义(QrCBV的F值为85.076,QSRR max的F值为13.915,P均<0.01).A、B、C 3组QrCBV值和QSRR max值差异无统计学意义(P>0.05);而D组QrCBV值和QSRR max值显著低于A组(P<0.01).结论 Resovist应用于MR脑灌注是可行的,适宜剂量4～16 μmol Fe/kg.     

Contrast-enhanced MR imaging of liver and spleen: First experience in humans with a new superparamagnetic iron oxide

The aim of this prospective study was to obtain the first human safety and magnetic resonance (MR) imaging results with a new formulation of superparamagnetic iron oxide (SPIO) (SHU 555 A). The SPIO was tested at four iron doses, from 5 to 40 μmol/kg. Laboratory tests and clinical measurements were done in 32 healthy volunteers for up to 3 weeks after administration. MR imaging at 1.5 T was performed before and 8 hours to 14 days after fast intravenous injection (500 μmol Fe/min) of the SPIO (six subjects per dose). Results of this phase I study demonstrate that SHU 555 A at a concentration of 0.5 mol Fe/L was well tolerated. A dose-dependent minor increase in activated partial thromboplastin time, which remained within the normal range, was seen. All doses of SPIO caused a signal loss in both liver and spleen (P <.05) with a spin-echo sequence (TR = 2,300 msec, TE = 45 msec). The signal losses in the liver 8 hours after contrast agent injection were 58%, 79%, 82%, and 87% for the 5, 10, 20, and 40 μmol Fe/kg doses, respectively. The corresponding signal losses in the spleen were 23%, 45%, 65%, and 78%, respectively. The doses that reduced signal intensity by half were 3.1 μmol Fe/kg for the liver and 12.8 μmol Fe/kg for the spleen. The results suggest that the new SPIO formulation is a safe and efficient MR contrast agent.     

荷人结肠癌裸鼠注射负载超顺磁性氧化铁聚合物纳米囊泡后的MRI表现

目的 制备负载油性超顺磁性氧化铁(SPIO)、水性SPIO聚合物纳米囊泡,并观察负载油性SPIO、水性SPIO聚合物纳米囊泡对结肠癌的MR显像能力.方法 通过多步化学反应制备聚乙二醇-聚D,L-丙交酯(PEG-PDLLA)纳米囊泡,并分别负载油性、水性SPIO.18只荷结肠癌裸鼠模型采用数字表法随机分为3组,每组6只,分别从尾静脉注射单纯SPIO水溶液、负载油性SPIO聚合物纳米囊泡和水性SPIO聚合物纳米囊泡,行MRI动态扫描观察肿瘤、肝脏、肌肉的T2WI信号和T2值.采用重复测量设计的方差分析比较3组间肿瘤、肝脏、肌肉的T2WI信号强度改变,两两比较采用Bonferroni法.结果 静脉注射负载油性、水性SPIO聚合物纳米囊泡后引起肿瘤T2WI信号强度下降,两者引起肿瘤信号强度下降最大百分比分别为11.00%、11.40%;单纯SPIO水溶液未能引起肿瘤信号强度下降,3组间比较差异有统计学意义(F=10.96,P＜0.01),负载油性、水性SPIO聚合物纳米囊泡引起的信号强度下降比单纯SPIO水溶液明显(P＜0.05);而负载油性和水性SPIO聚合物纳米囊泡间的差异无统计学意义(P＞0.05).3种对比剂均引起肝脏T2WI信号强度下降,单纯SPIO水溶液、负载油性、水性SPIO聚合物纳米囊泡引起肝脏信号强度下降的最大百分比分别为32.85%、52.77%、56.89%,3组间比较差异有统计学意义(F=161.18,P＜0.01),负载油性、水性SPIO聚合物纳米囊泡引起的信号强度下降比单纯SPIO水溶液明显(P＜0.01);负载水性SPIO聚合物纳米囊泡比负载油性SPIO聚合物纳米囊泡引起的信号强度下降更明显(P＜0.01).3种对比剂均未引起肌肉组织的T2WI信号强度下降,测量各组间肌肉的信号强度改变的差异无统计学意义(F=0.59,P＞0.05).结论 负载SPIO聚合物纳米囊泡在体内可以引起肿瘤的T2WI信号强度下降,可做为肿瘤显像的对比剂.

Abstract：

Objective To synthesize the hydrophobic supraparamagnetic ironic oxide(SPIO) loaded and hydrophilic SPIO loaded polymeric nano-vesicles and to investigate the feasibility of using hydrophobic SPIO loaded and hydrophilic SPIO loaded polymeric nano-vesicles to display the tumor in MRI in vivo through animal experiments. Methods The polymeric nano-vesicles were prepared from poly (D, L-lactic acid) (PDLLA) and poly (ethylene glycol) (PEG) by a multiple emulsion/solvent evaporation method.The hydrophobic SPIO and hydrophilic SPIO were loaded in the polymeric nano-vesicles respectively.Eighteen nude mice models with human colorectal carcinoma xenograft were established. They were divided equally into three groups (n = 6). The three groups of nude mice models were injected with water-soluble SPIO, hydrophobic SPIO loaded and hydrophilic SPIO loaded vesicle via the mice caudal vein respectively.Dynamic MRI scan were performed in all the mice models. T2WI signal intensity and T2 relaxation time were measured in the tumor, liver and muscle by using T2 mapping software. ANOVA of repeated measurement was used to analyze if there were significant differences of signal intensity changes among the three groups, while Bonferroni method was used for pair-wise comparison. Results On T2 WI, tumors showed decrease in signal intensity after hydrophobic or hydrophilic SPIO loaded polymeric nano-vesicle injection, while no signal intensity decrease was found in the tumor after water-soluble SPIO administration. The maximum percentage of signal intensity decrease in tumor caused by hydrophobic SPIO loaded and hydrophilic SPIO loaded vesicle were 11.00%, 11.40%, respectively. There was statistical significant difference of signal intensity changes among these three groups (F = 10. 96, P ＜ 0. 01). The decrease in signal intensity in the groups with hydrophilic or hydrophobic SPIO loaded polymeric nano-vesicles injection were more pronounced as compared with that of water-soluble SPIO (P ＜ 0. 05), but there was no significant difference in signal intensity decrease between the groups of hydrophilic and hydrophobic SPIO-loaded polymeric vesicles injection (P ＞0. 05). The three agents could lead to signal intensity decrease in the liver. The maximum percentage of signal intensity decrease in liver caused by water-soluble SPIO, hydrophobic SPIO loaded and hydrophilic SPIO loaded vesicle were 32. 85%, 52. 77%, 56. 89%, respectively. There was statistical significant difference between these groups (F = 161.18, P ＜ 0. 01) . The groups of injecting hydrophilic and hydrophobic SPIO loaded polymeric nano-vesicles had the more obvious signal decrease than the one with water-soluble SPIO (P ＜ 0. 01). Hydrophilic SPIO loaded polymeric nano-vesicles exhibited more signal intensity decrease than hydrophobic SPIO loaded polymeric nano-vesicles (P ＜ 0. 01). All three agents could not lead to T2WI signal decrease in the muscle, and there was no significant difference in signal change on T2 WI among three groups (F = 0. 59, P ＞ 0. 05). Conclusion SPIO loaded polymeric nano-vesicles can cause significant T2WI signal loss in human colonic carcinoma on MR imaging in vivo. It can be used as tumor imaging contrast agents.     

胰腺MRI:技术及诊断研究

目的 :探讨MR不同序列在胰腺病变诊断中的应用价值。方法 :84例胰腺检查包括 5 0例正常胰腺及 3 4例临床怀疑有病变的胰腺 ,其中包括 15例胰腺癌 ,2例胰岛细胞瘤 ,1例粘液性囊腺瘤 ,4例胰周肿瘤 ,12例胰腺炎。MR扫描序列包括常规SET1WI ;FSET2 WI ;增强前、后的脂肪抑制T1WI和GRE。结果 :3 4例异常胰腺中的 2 7例 ,增强前、后T1WI脂肪抑制像提供了最好的诊断信息 ,其次为增强后立即扫描的GRE像。未增强的GRE像极好地显示了急性胰腺炎的特征 ,SET2 WI像对胰岛细胞瘤及胰腺癌的肝转移显示较为敏感。结论 :增强前、后T1WI脂肪抑制序列及动态增强的GER序列 ,应为胰腺MRI的标准序列。     

梯度回波反相位T1WI对口腔颌面部疾病的诊断价值

目的探讨梯度回波反相位T1WI(GRE-OP-T1WI)对口腔颌面部疾病的诊断价值. 资料与方法对10名健康志愿者(对照组)绘制GRE-T1WI的回波时间-信号强度(TE-SI)曲线以确定0.5T场强中GRE-OP-T1WI的最小TE值,然后对23例口腔颌面部疾病患者(研究组)进行GRE-OP-T1WI与常规MRI序列对病灶显示程度的比较研究. 结果 0.5T MR仪实际最小TEOP值为21ms; 平扫和增强GRE-OP-T1WI与T2WI、平扫和增强T1WI相比能显著提高病灶显示程度. 结论 GRE-OP-T1WI可以抑制少量脂肪,对口腔颌面部疾病的诊断是常规MRI序列的有效补充,尤其对中、低场MR设备具有极大的应用价值.