钆特醇及钆喷替酸葡甲胺在1.5、3.0 TMR下鼠脑胶质瘤模型增强扫描中的应用比较研究

目的 对比钆特醇及Gd-DTPA在1.5及3.0 T MR下的增强效果,比较两者在增强扫描中的应用价值.方法 42只CDF Fisher 344雄性大鼠,采用经皮导管脑内接种胶质瘤细胞,培育1周,制作鼠脑胶质瘤模型.将大鼠采用数字表法随机分为4组,分别为12、10、10、10只,进行1.5及3.0 T MR下注射钆特醇及Gd-DTPA增强效果对比、注射钆特醇在1.5及3.0 T两种场强下增强效果对比、1.5 T MR下使用标准剂量钆特醇与3.0 T下使用半剂量增强效果对比.两次扫描间隔24 h.选取注射对比剂前及注射后第1、3、5、7、9分钟时间点的T1加权图像,利用影像工作站分析计算各图像的信噪比(signal to noise ratio,SNR),对比噪声比(contrast to noise ratio,CNR)及对比增强比(contrast enhancement,CE),所得数据选用Student配对双尾t检验行统计学分析.结果 1.5 T MR下,注射Gd-DTPA后各时间点图像SNR、CNR和CE平均值分别为54.4±3.2、17.0±3.3、20.8±3.4;注射钆特醇后各值分别为53.2±3.2、17.2±3.1、20.8±3.2,两者差异无统计学意义(t值分别为2.247、0.403、0.076,P值均＞0.05).3.0 T MR下,注射Gd-DTPA后各时间点图像SNR、CNR和CE平均值分别为94.8±7.1、38.0±6.0、45.0±6.3;注射钆特醇后各值分别为95.5±2.9、37.2±2.7、45.6±2.8,两者差异亦无统计学意义(t值分别为0.303、0.573、0.357,P值均＞0.05).注射钆特醇在1.5 T MR下增强扫描后各时间点图像SNR、CNR和CE平均值分别为51.9±3.0、15.6±3.0、18.6±3.0;在3.0 T MR下图像各值分别为86.1±4.9、27.4±5.0、37.3±5.3,均高于1.5 T MRI图像,差异有统计学意义(t值分别为36.227、11.977、17.106,P值均＜0.05).1.5 T MR下注射标准剂量钆特醇增强扫描后,各时间点图像SNR、CNR和CE平均值分别为53.8±1.6、17.7±1.7、20.3±1.6;3.0 T MR下注射半剂量钆特醇增强图像各值分别为72.2±2.4、15.4±2.4、21.1±2.4,两者SNR、CNR均值差异有统计学意义(t值分别为31.503、5.137,P值均＜0.05),而两者CE均值差异无统计学意义(t=2.033,P＞0.05).结论 利用鼠脑胶质瘤模型,在1.5及3.0 T MR下注射钆特醇和Gd-DTPA行增强扫描,两者增强效果无明显差异;3.0 T MR下注射钆特醇行增强扫描,效果明显优于在1.5 T条件下使用;3.0 T MR下使用半剂量钆特醇与在1.5 T下使用标准剂量增强效果相仿,同样能取得满意的增强效果.因此,使用钆特醇可在保证增强效果的同时,在一定程度上降低使用MRI对比剂的风险,增加安全性.     

原发性颅内畸胎瘤的MRI诊断

目的　探讨MRI对畸胎瘤的诊断价值。方法　 9例经手术和病理证实的畸胎瘤患者 ,对其MR表现进行分析。结果　本组术前MRI诊断定位正确率为 10 0 % ,定性正确率 (8/9)为 88.8%。其MRI特征性表现为 :(1)肿瘤形态以分叶状为主 ,边界清楚。(2 )肿瘤信号多不均匀 ,表现复杂。 (3 )Gd -DTPA增强肿瘤呈不均匀强化。结论　MRI的多轴位成像及Gd -DTPA应用有助于畸胎瘤的诊断与鉴别诊断     

靶向TSPO显像剂99Tcm-DTPA-CB86的制备及其对关节炎症的SPECT/CT显像研究

目的制备99Tcm标记的转运蛋白（TSPO）配体CB86[99Tcm-DTPA（二亚乙基三胺五乙酸）-CB86],探讨其作为TSPO靶向关节炎症显像新型分子探针的可行性。方法通过偶联双功能螯合剂制备DTPA-CB86,进行99Tcm标记,经高效液相色谱纯化,测定其放化纯度和体外稳定性。选用巨噬细胞RAW264.7进行体外细胞结合实验,测定99Tcm-DTPA-CB86的结合率和外排率。采用弗氏佐剂建立左踝关节炎症小鼠模型,对其行99Tcm-DTPA-CB86 Micro SPECT/CT显像,并观察探针的体内分布情况。采用SPSS 18.0统计软件对符合正态分布及方差齐性的数据进行t检验。结果99Tcm-DTPA-CB86的标记率为（95.86 ±2.45）%,放化纯度为（97.45 ±0.69）%,其在室温下的磷酸盐缓冲液中的稳定性良好,放置4 h后,其标记率仍>90%。99Tcm-DTPA-CB86能与巨噬细胞RAW264.7特异性结合,3 h的摄取率达到最高峰[（36.45 ±2.18）%],在加入过量未标记的DTPA-CB86后,RAW264.7细胞对99Tcm-DTPA-CB86的摄取明显受到抑制[（10.43 ±2.01）%],与未阻断时相比差异具有统计学意义（t=6.217,P < 0.05）;RAW264.7细胞对99Tcm-DTPA-CB86外排较少,摄取率从4.5 h时的（33.31 ±2.34）%到8 h时的（19.32 ±2.01）%,减少了13.99%。Micro SPECT/CT显像结果显示,99Tcm-DTPA-CB86在小鼠左踝关节炎症部位清晰可见,且能被过量的DTPA-CB86明显抑制;体内生物学分布结果表明,其具有较好的炎症靶向性;注射后3 h踝关节炎症部位的摄取仍可达（2.35 ±0.10）% ID/g。结论99Tcm标记CB86易于制备,具有较好的理化性质及体内代谢学性质,同时具有较好的关节炎症摄取,有望发展成新的TSPO靶向SPECT关节炎症显像分子探针。     

68Ga-DOTA-NOC胰腺癌生长抑素受体靶向显像的实验研究

目的 研究68 Ga-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸-1-萘丙氨酸-奥曲肽(DOTA-NOC)在小鼠体内的生物分布,并进行荷胰腺癌小鼠的68Ga-DOTA-NOC SSTR靶向显像.方法 37 MBq 68GaCl2加入20μl羟乙基哌嗪乙硫磺酸(HEPES,0.1 mmol/L)溶液和10～50 μg DOTA-NOC,于95℃水浴加热15 min制备68Ga-DOTA-NOC.采用HPLC法分析68 Ga-DOTA-NOC的标记率及体外稳定性.予正常BALB/c小鼠尾静脉注射68Ga-DOTA-NOC 3.7 MBq,分别在5、15、30、60和120 min后解剖分离小鼠脏器,测放射性生物分布(％ID/g)情况.将人CFPAC-1胰腺癌细胞与68Ga-DOTANOC共同孵育后,测定放射性计数并计算摄取率.建立CFPAC-1荷瘤裸鼠模型,行microPET显像,勾画ROI,获得肿瘤及主要脏器TAC,计算T/NT(NT为对侧肌肉).用流式细胞术检测CFPAC-1细胞及瘤体SSTR表达水平,采用直线相关分析对SSTR表达率与T/NT行相关性研究.结果 68 Ga-DOTA-NOC标记率为(98.8±1.0)％,无需纯化.正常小鼠体内68Ga-DOTA-NOC肾摄取最多,5 min为(11.20±0.32) ％ID/g,随时间延长减少,60 min为(4.11±0.21)％ID/g,胰腺、肺、胃相对摄取较高,脑几乎无摄取.人CFPAC-1细胞可特异性摄取68Ga-DOTA-NOC.荷瘤鼠microPET显像示CFPAC-1肿瘤部位呈异常放射性摄取,T/NT在120 min达3.2±0.2.CFPAC-1细胞和肿瘤组织SSTR1、2、4、5表达量分别为(96.83±1.23)％、(99.73±0.98)％、(90.42±0.63)％和(92.96±0.71)％,SSTR2、5的表达水平与T/NT均呈正相关(r=0.71、0.80,均P＜0.05).结论 68 Ga-DOTA-NOC易标记,生物分布理想,可靶向结合SSTR阳性的CFPAC-1肿瘤组织.68Ga-DOTA-NOC是新型SSTR靶向显像剂,有利于胰腺肿瘤的早期诊断并为生长抑素介导靶向治疗提供依据.     

131I标记17-丙烯胺基-17-去甲氧基格尔德霉素的制备及生物分布

目的 建立131I标记17-丙烯胺基-17.去甲氧基格尔德霉素(17-AAG)的方法,并观察其在动物体内的生物分布.方法 采用过氧化氢法对17-AAG进行131I标记.测定131I.17.AAG注射后0.5,1,4,8和24 h在ICR健康小鼠体内的生物分布,通过显像动态观察131I-17-AAG在兔Vχ2肝癌模型中的分布.结果 建立了131I过氧化氢法标记17-AAG的最佳条件,131I-17-AAG标记率达85.65%,纯化后其乙酸乙酯相、生理盐水水溶液和4℃下放置5 d的生理盐水水溶液的放化纯分别为(96.51±0.80)%,(95.57±0.09)%和(90.96±1.29)%.尾静脉注射131I-17-AAG,健康ICR小鼠胆囊的摄取(每克组织百分注射剂量率,%ID/g)在0.5 h达到峰值(3.0963±1.3394)%ID/g,胃和小肠的摄取均在4 h达到高峰,24 h时肠道放射性明显减少,肝、肾摄取较少.瘤体给药后于2 h和4,6,14 d进行显像,可见131I-17-AAG在兔肿瘤中持续浓聚,肿瘤/非肿瘤组织放射性(T/NT)比值分别为10.36,3.62,4.32和3.50,其他脏器未见显影.结论 成功建立了131I-17-AAG标记方法,标记物保留了17-AAG生物学活性,体外稳定性好.兔肝肿瘤间质给药提示131I-17-AAG对肿瘤具有理想靶向性作用.     

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。     

新型肠道对比剂Gd- nanoCPs对大鼠溃疡性结肠炎靶向MRI成像的实验研究

目的:建立右旋葡聚糖硫酸钠(DSS)诱导的大鼠溃疡性结肠炎模型,探索经直肠灌注Gd - nanoCPs检测炎性肠病的预临床方法.方法:采用改良的乳化凝结技术合成Gd - nanoCPs.采用5％葡聚糖硫酸钠诱导溃疡性结肠炎大鼠模型.对正常组(n=1 4)、结肠炎组(n=14)分别灌注Gd - nanoCPs混悬液(10只),Gd - DTPA水溶液(2只)及尾静脉注射Gd - DTPA(2只),于灌肠前和灌肠20～ 120min后行结肠MR扫描.对结肠上段、中段及下段肠壁分别进行灌肠前后结肠壁、盆壁肌肉和图像背景MR信号强度进行测量,计算灌肠前后肠壁与盆壁肌肉的相对信号值及强化率,并采用配对t检验进行组间比较.结果:直肠灌注Gd - nanoCPs混悬液20～120min内肠黏膜均有强化,20～ 120min内下段、中段及上段结肠黏膜强化率分别为1.8％～35.2％、1.6％ ～26.4％、1.8％ ～ 27.3％和25.2％～71.1％、20.8％ ～ 55.7％、9.4％～35.1％.两组差异有统计学意义(P＜0.05).结论:Gd - nanoCPs作为一种新型肠道MRI对比剂,具有成为检测炎性肠病的特异性靶向MRI造影剂的潜能.     

减影钆增强MR用于头颈部成象

钆(Gd)作为MRI的增强剂已被广泛应用于检测头颈部肿瘤或其它病变。颅底部位解剖结构复杂,不易发现该部位肿瘤的浸润,为此,作者将1961年Des Plantes提出的减影技术应用于MR检查。方法为应用短弛豫时间,静脉内给Gd-DTPA前后立即作T_1加权自旋回波脉冲序列成象。为避免在扫描通道上移动病人,选择足背静脉为注射部位,而且在病人进入扫描机前就将针插入静脉,     

Gd- DTPA对肝脏、脾脏及肾脏1.5T MR弥散加权成像的影响

目的:探讨钆喷酸葡胺(Gd-DTPA)在1.5T MR机对正常肝脏、脾脏、肾脏弥散加权成像(DWI)的影响.方法:30例健康体检者在1.5T MR机做上腹部MRI.除常规MR平扫和增强外,在增强前和增强后7min采用b值=500 s/mm2单次激发自旋回波平面成像序列(SE- EPI)分别行DWI扫描.测量增强前后肝脏、脾脏、肾脏在DWI上的信噪比(SNR)、脾脏-肝脏对比噪声比(CNR)、信号强度值和ADC值,并进行统计分析.结果:30例健康体检者检查结果均正常.正常肝脏、脾脏DWI的SNR、CNR、信号强度值、ADC值增强后7min与增强前比较差异无统计学意义(P＞0.05),肾脏DWI SNR、信号强度值、ADC值增强后7min较增强前降低,差异有统计学意义(P＜0.05).结论:Gd-DTPA增强后7min对肝脏、脾脏DWI的图像质量和ADC值无明显影响,而肾脏DWI的图像质量和ADC值降低.     

靶向血栓MR分子探针的构建及初步鉴定

目的构建一种靶向血栓MR分子探针并对其相关特性进行鉴定。方法采用双乳化法,以端羧基聚乳酸/羟基乙酸(PLGA-COOH)为载体包裹MR对比剂钆喷酸葡胺(Gd-DTPA)制备Gd-PLGA微球,再采用碳二亚胺法共价结合血小板膜上GPⅡb/Ⅲa受体拮抗剂精氨酸-甘氨酸-天冬氨酸-丝氨酸(Arg-Gly-Asp-Ser,RGDS)短肽片段,构建靶向血栓MR分子探针。观察其理化性质、体外靶向特异性,于1.5 T MRI测量并计算MR纵向弛豫率。结果采用本方法成功构建了靶向血栓MR分子探针,其形态规则,大小较均一,平均粒径为2.04μm,RGDS携带率达89.69%,Gd-DTPA包封率为39.53%;体外寻靶实验显示其对离体血栓具有较强的靶向性及稳定性;在1.5 TMR成像仪上能实现显像,同时随着Gd-DTPA浓度的增加,纵向弛豫率增加。结论成功构建靶向血栓MR分子探针,有望为分子水平诊断血栓提供新技术、新方法。     

Glomerular filtration rate measured using the Patlak plot technique and contrast-enhanced dynamic MRI with different amounts of gadolinium-DTPA

We determined the optimum gadolinium (Gd)-DTPA dose and time window for calculating the glomerular filtration rate (GFR) using contrast-enhanced (CE) dynamic MRI and the Patlak plot technique. Twelve adult volunteers with healthy kidneys were included in the study. As a reference method the GFR was measured by iopromide plasma clearance. A three-dimensional gradient-echo (GRE) sequence with a flip angle of 50 degrees was used for MRI. Signal was measured using a body surface coil with four elements. Each volunteer was examined on four days using 2 mL, 4 mL, 8 mL, or 16 mL of Gd-DTPA 0.5 mmol/mL dissolved with sodium chloride (NaCl) 0.9% to a total of 60 mL. The injection rate was 1 mL/second. A Patlak plot was calculated from the kidney and aorta signals. The mean reference GFR was 133 mL/min (min-max, 116-153 mL/min). The best correlation of GFR calculated from MRI data compared to the reference method was found in a time window 30-90 seconds after aortic signal rise using 16 mL Gd-DTPA. Pearson's correlation coefficient was r = 0.83, and the standard deviation (SD) from the line of regression was 10.5 mL/minute. We found a significantly lower average GFR(MR) using 16 mL Gd-DTPA compared to 4 mL and 2 mL in the late time window 60-120 seconds post aortic rise. A dose of 16 mL Gd-DTPA was optimal for measuring GFR using dynamic MRI and the Patlak plot technique. The slope should be measured in a time window of 30-90 seconds post aortic rise.     

Measurement of single-kidney glomerular filtration rate using a contrast-enhanced dynamic gradient-echo sequence and the Rutland-Patlak plot technique

PURPOSE: To determine the accuracy of single-kidney glomerular filtration rate (GFR) determination using contrast-enhanced dynamic magnetic resonance imaging (MRI) and the Rutland-Patlak plot technique. MATERIALS AND METHODS: Twenty-eight adult patients were included. As reference method, the GFR was measured by plasma clearance using a small bolus injection of iopromide. A three-dimensional gradient-echo (GRE) sequence with a flip angle of 50 degrees was used for MRI; this showed a good linear relationship between gadolinium (Gd)-DTPA concentration and signal change when measured up to a Gd-DTPA concentration of 10 mmol/liter. A slab containing both kidneys and the abdominal aorta was measured 30 times in approximately 3.5 minutes. During this measurement, 15 mL of Gd-DTPA, 0.5 mol/liter diluted to a volume of 60 mL, was injected over 60 seconds. A Rutland-Patlak plot was calculated from the signal changes in the aorta and the renal parenchyma. Single-kidney GFR was calculated for different time windows from the Rutland-Patlak plot slope. RESULTS: The best correlation compared to the reference method was found with the GFR calculated from the slope of the Rutland-Patlak plot 40-110 seconds postaortic rise. Pearson's correlation coefficient was r = 0.86, SD was 14.8 mL/minute. In many of the patients, a decrease of the renal signal was observed in the excretory phase, which was probably caused by very high Gd-DTPA concentrations in the collecting tubules. CONCLUSION: Single-kidney GFR can be calculated from dynamic contrast-enhanced MRI. We found a promising correlation of global GFR calculated by MRI compared to the reference method. In any future study, the amount of Gd-DTPA should by reduced to avoid artificial signal drop in the excretory phase induced by the T2* effect.     

Dyke Award. Europium-DTPA: a gadolinium analogue traceable by fluorescence microscopy

A lanthanide series chelate, europium(Eu)-DTPA, was synthesized to serve as a histochemical analogue for the widely used MR contrast agent gadolinium(Gd)-DTPA. Eu and Gd, being neighboring elements on the periodic table, share many fundamental properties, including ionic radius, valence, and chemical reactivity. Eu-DTPA, however, possesses one important physical property not shared by Gd-DTPA: luminescence under ultraviolet light. The feasibility of detecting Eu-DTPA in animal tissues under fluorescence microscopy was systematically evaluated and documented. Distinctive orange-red luminescence of Eu-DTPA could be observed in the kidneys, livers, dura, choroid, and pituitary glands of rats after intravascular injection. No luminescence was detected in areas of brain beyond an intact blood-brain barrier. When the brain was locally injured by an experimental laceration, however, leakage of Eu-DTPA was detected. Electron probe microanalysis confirmed the parallel presence or absence of simultaneously injected Eu-DTPA and Gd-DTPA in all tissues studied. Fluorescence microscopy with Eu-DTPA has thus been validated as a method for tracing the distribution of Gd-DTPA at the microscopic level.     

Contrast-enhanced MRI of the central nervous system: Comparison between gadodiamide injection and gadolinium-DTPA

Gadodiamide injection, a new nonionic, MRI contrast medium, was compared with the ionic agent gadolinium (Gd)-DTPA at 0.1 mmol/kg body weight in a double-blind, randomised trial in 60 patients, 30 receiving each substance, with known or suspected lesions of the central nervous system. The patients were closely questioned about adverse events. In the Gadodiamide injection group, four patients reported six adverse advents, three of which were judged to be related to the contrast medium. In the Gd-DTPA group, two patients each reported one adverse event, both of which had an uncertain relation to the contrast medium. All events were mild and no medical treatment was needed. No significant change in neurological findings, blood pressure, pulse rate or blood parameters were noted in any patient. Both contrast media were effective; no difference in overall efficacy or safety was observed.     

静脉注射钆类对比剂对乳腺正常腺体及肿瘤组织MR扩散加权成像的影响

目的 探讨乳腺MR DWI质量及正常腺体与癌组织的ADC值是否受到钆类对比剂增强扫描的影响.方法 对25例已经针吸穿刺或粗针活检病理证实为乳腺癌的患者在静脉注射Gd-DTPA前、后行DWI扣描,将R01分别置于癌灶及正常腺体,应用配对t检验及非参数检验比较b值=0及1000 s/mm2时增强前后图像中癌灶和正常腺体的信噪比(SNR)、对比噪声比(CNR)及ADC值的变化.结果 增强前、后癌灶的SNR(34.56±11.34和33.60±14.34)与正常腺体的SNR(9.88±3.16和10.42±4.18)以及图像CNR(24.16±9.05和22.26±10.05)的差异无统计学意义(P癌灶SNR=0.70,P正常腺体SNR=0.11;PCNR=0.17);增强前后癌灶的ADC值分别为(0.96±0.13)×10-3和(0.95±0.14)×10-3mm2/s,正常腺体分别为(1.90±0.47)×10-3 和(1.91±0.61)×10-3mm2/s,两者在增强后ADC值与其增强前差异均无统计学意义(P=0.20和0.97).结论 乳腺痛组织和正常腺体DWI的质量及ADC测量值不会受到Gd-DTPA的影响,故在乳腺MR扫描中,DWI可以在增强扫描后进行.     

Delayed gadolinium-enhanced magnetic resonance imaging (dGEMRIC) of hip joint cartilage: better cartilage delineation after intra-articular than intravenous gadolinium injection

PURPOSE: To investigate and compare delayed gadolinium (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) in the hip joint using intravenous (i.v.) or ultrasound-guided intra-articular (i.a.) Gd-DTPA injection. MATERIAL AND METHODS: In 10 patients (50% males, mean age 58 years) with clinical and radiographic hip osteoarthritis (OA; Kellgren score II-III), MRI of the hip was performed twice on a clinical 1.5T MR scanner: On day 1, before and 90-180 min after 0.3 mmol/kg body weight i.v. Gd-DTPA and, on day 8, 90-180 min after ultrasound-guided i.a. injection of a 4 mmol/l Gd-DTPA solution. Coronal STIR, coronal T1 fat-saturated spin-echo, and a cartilage-sensitive gradient-echo sequence (3D T1 SPGR) in the sagittal plane were applied. RESULTS Both the post-i.v. and post-i.a. Gd-DTPA images showed significantly higher signal-to-noise (SNR) and contrast-to-noise (CNR) in the joint cartilage compared to the non-enhanced images (P < 0.002). I.a. Gd-DTPA provided significantly higher SNR and CNR compared to i.v. Gd-DTPA (P < 0.01). Furthermore, a better delineation of the cartilage in the synovial/cartilage zone and of the chondral/subchondral border was observed. CONCLUSION: The dGEMRIC MRI method markedly improved delineation of hip joint cartilage compared to non-enhanced MRI. The i.a. Gd-DTPA provided the best cartilage delineation. dGEMRIC is a clinically applicable MRI method that may improve identification of early subtle cartilage damage and the accuracy of volume measurements of hip joint cartilage.     

Intraindividual comparison of gadopentetate dimeglumine,gadobenate dimeglumine,and gadobutrol for pelvic 3D magnetic resonance angiography

RATIONALE AND OBJECTIVES: To compare the effect on image quality of a 1.0 mol/L gadolinium chelate with that of two 0.5 mol/L gadolinium compounds. MATERIALS AND METHODS: Five healthy volunteers underwent a mono-station 3D MRA exam (Siemens SONATA, Erlangen, Germany) four times using four separate gadolinium preparations. All subjects first received a fixed volume of undiluted gadobutrol (1 mol/L), which corresponded to a dose between 0.1 and 0.15 mmol/kg body weight. This gadobutrol dosage was then diluted with saline into twice the volume and administered as a bolus at twice the injection rate. For Gd-DTPA and Gd BOPTA, because these contrast agents are 0.5 mol/L preparations, the volume and flow rate were doubled to match diluted gadobutrol volume and concentration. Quantitative and qualitative analysis of the angiographic data sets was performed on nine arterial segments. RESULTS: Image quality was rated diagnostic for all image data sets without statistically significant differences between any of the compounds (P > 0.3). Quantitative measurements of Gd BOPTA (SNR: 81.15; CNR: 68.91) and both standard and diluted forms of gadobutrol (SNR: 84.33; CNR: 71.62; SNR(diluted): 79,23; CNR(diluted): 66.26) yielded significantly higher results (P < 0.02) in comparison with Gd-DTPA (SNR: 49.55; CNR: 38.24). The difference between either form of gadobutrol and Gd BOPTA was not shown to be statistically significant (P > 0.3), whereas both the SNR and CNR of standard gadobutrol were significantly higher than diluted gadobutrol. CONCLUSION: Gadobutrol- and Gd BOPTA-MRA exams lead to improved delineation of the pelvic arterial morphology compared with MRA exams performed with Gd-DTPA.     

快速注射结合缓慢融入对比剂在冠状动脉MR血管成像中的应用

目的 评价快速注射结合缓慢融入对比剂Gd-DTPA对血池T1弛豫效果的影响.方法 对15例冠心病患者行冠状动脉MRA检查.先以1.50 ml/s流率注射对比剂Gd-DTPA 10 ml,再以0.05 ml/s流率注射20 ml,然后对冠状动脉同1支血管行2次扫描,获得注射对比剂后5和15 min的图像.计算增强前后图像的信噪比(SNR)和对比噪声比(CNR),并以t检验进行比较.结果 注射对比剂后5 min图像的SNR和CNR(35.37±6.84和21. 57±6.08)明显高于增强前图像的SNR和CNR(27.38±6.24和13.19±6.50).注射对比剂15 min后图像的SNR(33.81±9.43)高于增强前,但没有统计学意义(t=1.885,P=0.074),图像的CNR(21.20±7.65)明显高于增强前.注射对比剂后5和15 min图像的SNR和CNR没有明显的区别.结论 快速注射结合缓慢融入Gd-DTPA,可以获得延长短T1效应的采样时间,以适应冠状动脉MRA多期扫描的需求.     

Gadolinium DTPA in a MR study of expansive lesions of the cranial base

Twenty-five patients were investigated by MR imaging in order to evaluate the diagnostic value of Gadolinium (Gd)-DTPA in skull-base tumors. The patients were studied with standard acquisition techniques (T1, mixed and T2-weighted images) without contrast medium. The images obtained were then compared with the T1-weighted images obtained after intravenous injection of Gd-DTPA. The contrastographic results in the different types of acquisition were evaluated. Thanks to the extraordinary increase in contrast resolution it provides, Gd-DTPA allowed the precise evaluation of the lesion and of its perfect spatial definition in all cases. Our experience demonstrated that Gd-DTPA considerably increases the sensitivity of the technique in this anatomical region. On the contrary, as regards the nature of the lesion, the signal did not significantly vary after the iv injection of Gd-DTPA in the various kinds of lesion. In addition to the important diagnostic advantages of Gd-DTPA, its excellent tolerability and the absence of side-effects must be stressed.     

Hip dGEMRIC in asymptomatic volunteers and patients with early osteoarthritis: the influence of timing after contrast injection.

Eight asymptomatic volunteers and 10 patients with early hip osteoarthritis (OA) were investigated with hip delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) at 30, 65, 100, and 135 min after IV injection with Gd-DTPA(2-). In asymptomatic volunteers there was a decrease in the dGEMRIC index (T(1)(Gd)) between 30 and 100 min. In patients the wash-in of Gd-DTPA(2-) was faster, with a low T(1)(Gd) at 30 min that did not change significantly over time. Therefore, earlier time points showed a larger separation in T(1)(Gd) between asymptomatic and OA hips, with more convenient timing logistics. However, T(1)(Gd) at 30 min had a larger standard deviation (SD) in the OA group, possibly due to variability of the steep slope of wash-in. This sensitivity to the imaging window may be less desirable for longitudinal studies in which reproducibility is a concern. At all time points, T(1)(Gd) was 20-30% lower in patients than in asymptomatic volunteers (P < 0.003), which demonstrates the sensitivity of dGEMRIC to early hip OA.