MR快速序列动态增强扫描对前列腺癌的诊断

磁共振是前列腺癌的最佳影像学检查方法，但磁共振常规扫描对早期前列腺癌的诊断率及术前分期准确率尚较低，而磁共振快速序列动态增强扫描可使两提高并能提供肿瘤的血供信息。综述了磁共振快速序列动态增强扫描的基本原理、检查方法、前列腺癌的诊断及与增生等良性病变鉴别诊断方面的临床应用价值及限度。     

Gd-DTPA增强对于肝脏及肝脏疾病31P-MRS代谢参数的影响

目的 探讨Gd-DTPA增强对于肝脏及肝脏疾病31P-MRS代谢参数的影响.方法 分别对肝内良、恶性病变(分别为31例和54例)及肝硬化和正常肝脏(分别为34例和21例)进行单体素31P-MRS扫描.计算肝细胞内pH值(pHi)、磷酸单脂(PME)、磷酸双脂(PDE)、无机磷(Pi)、γ-ATP、β-ATP、α-ATP、PME/ATP、Pi/ATP、PME/PDE、PME/Pi、PDE/Pi、PDE/ATP和低能磷酸盐(LEP)等参数.分析Gd-DTPA增强前、后肝内病变的显示情况,以及以上代谢物参数的差异.结果 Gd-DTPA增强前在体线圈定位图像上,肝癌、转移瘤和胆管癌显示欠佳或其边界欠清者分别占该病总数的47.8%(11/23)、13.6%(3/22)和66.7%(6/9);增强后则分别为13.0%(3/23)、4.5%(1/22)和22.2%(2/9);增强前肝脓肿、海绵状血管瘤、局灶性结节增生及腺瘤显示欠佳或其边界欠清的分别占该病总数的11.1%(1/9)、29.4%(5/17)、80%(4/5),增强后分别为0%(0/9)、5.9%(1/17)、0%(0/5).在增强前和增强后,正常肝脏,肝硬化,肝脏良、恶性病变的31P-MRS各代谢物参数均未见统计学差异(P>0.05).结论 Gd-DTPA增强技术可增加31P-MRS定位的准确性,钆对比剂不影响肝脏及其疾病代谢物检测的准确性.     

Gd-EOB-DTPA与Gd-DTPA增强MR对肝硬化患者肝血管和肝实质增强效果的自身对照研究

【摘要】目的：自身对照比较Gd-EOB-DTPA与Gd-DTPA增强MR对肝硬化患者的肝动脉、门静脉和肝实质强化效果的差异。方法：回顾性分析35例肝硬化患者的Gd-EOB-DTPA与Gd-DTPA增强MR图像,计算肝总动脉、门静脉和肝实质的强化比率（PE）和肝总动脉、门静脉与肝实质的相对对比度（RC）,并统计是否存在差异。结果：Gd-EOB-DTPA增强MR肝总动脉、门静脉的平均PE明显低于Gd-DTPA（P<0.05）。Gd-EOB-DTPA的门脉期肝实质的平均PE明显低于Gd DTPA（P<0.05）而动脉期肝实质的PE值无明显差异（P=0.1010）。肝总动脉、门静脉与肝实质的RC值Gd-DTPA增强MR略高于Gd-EOB-DTPA,但是无明显统计学差异（P分别为0.3421和0.2389）。结论：肝硬化患者Gd-EOB-DTPA增强MR的肝血管和肝实质效果低于Gd-DTPA, Gd-EOB-DTPA的剂量需要进一步调整。     

动态增强容积内插序列在肝脏占位性病变的临床应用价值

目的:评价MRI三维动态增强容积内插序列在肝脏局灶性病变的临床应用价值.方法:91例肝脏占位性病变患者进行常规MR T1WI和T2WI扫描后,采用三维扰相梯度序列行屏气全肝3期动态增强扫描并进行图像重组,观察病灶的增强特点,并对肝动脉的显示程度进行分级.结果:91例中原发性肝癌17例,肝血管瘤24例,肝转移性肿瘤16例,局灶性结节增生2例,肝脓肿11例,肝囊肿21例.肝动脉显示为2级86例94.5%,1级3例3.3%,0级2例2.2%.结论:MR 动态增强容积内插技术可以获得高质量的图像(尤其是动脉期),有利于肝脏局灶性病变的定性、定位诊断和指导临床治疗.     

肝脏MR扫描体会

MR是多参数多序列成像，较传统X线、CT有较大区别，增加了操作者的操作难度。肝内病灶较为复杂，鉴别难度大，但如果熟悉各序列特点，了解扫描病灶部位及病灶的要点，在常规扫描基础上，选用适当的扫描方法，可取得事半功倍的效果，下面结合我院使用0．23T低场机扫描肝脏多例谈谈心得体会。     

肾脏肿瘤的MR动态增强扫描研究

目的:探讨MR动态增强扫描在肾脏肿瘤诊断和鉴别诊断中的价值。方法:对21例肾细胞癌、11例肾错构瘤和6例肾囊肿行MR常规检查及动态增强和延迟增强扫描,测量病灶的信号强度,绘制时间-对比增强率曲线并对动态增强的类型及血液动力学改变进行分析。结果:肾脏肿瘤动态增强后的时间-对比增强率曲线不同,富血供肾癌在早期强化并逐渐上升,但其时间-对比增强率曲线无明显峰值;乏血供肾癌早期轻度强化,缓慢上升至60s后趋于稳定;肾错构瘤早期即明显强化,于30s达到强化高峰后快速下降;肾囊肿则无明显强化。结论:通过定量分析肾脏肿瘤的信号强度,动态增强MRI可以提供肿瘤的血供信息,有助于肾脏肿瘤的诊断和鉴别诊断。     

人工注射法动态增强扫描在肝脏病变MRI中的应用价值

目的:探讨人工注射法动态增强扫描在肝脏病变MRI中的应用价值。方法:对临床疑有肝脏病变和/或经CT及超声检查后诊断为肝脏病变的94例患者进行人工注射法MRI动态增强扫描检查,分析人工注射法动态增强扫描的特点。结果:94例中,肝硬化7例,肝血管瘤16例,肝脏囊肿4例,肝脓肿3例,肝炎性假瘤2例,肝转移瘤10例,原发性肝癌5 2例。结论:肝脏病变MRI动态增强扫描中使用人工注射法可以较好满足临床的诊断需要     

兔动脉粥样硬化斑块:USPIO增强MR与Gd-DTPA增强MR对比实验研究

目的 在MR连续观察下,采用自制超小超顺磁性氧化铁(ultrasmall superparamagnetic iron oxide,US-PIO),与钆喷酸葡胺(Gd-DTPA)对比,分别对动脉粥样硬化(AS)兔行增强MR检查,旨在探讨USPIO增强MR对AS兔的价值.材料与方法35只雄性新西兰大白兔随机分为两组,25只给予高脂饮食诱导动脉粥样硬化,10只给予正常饮食作为对照组.所有扫描均在1.5 T磁共振扫描仪上进行,采用Cardiac线圈.扫描序列包括:T1WISE,T1WI SE脂肪抑制,T2WI FSE,T2*WI GRE.所有动物于喂养10周时测血清总胆固醇量,并进行平扫及USPIO增强24 h扫描,1周后行Gd-DTPA增强扫描,完成Gd-DTPA增强扫描当天处死不同喂养阶段模型兔及同期对照组正常兔,整个过程每2周重复一次.USPIO使用剂量为0.05 mmolFe/kg体重,Gd-DTPA使用剂量为0.25 mmol/kg体重.MR所见与病理相对照.结果 喂养10周时模型兔血清总胆固醇值明显高于正常组(P＜0.05),且所有模型兔大体标本均发生肉眼可见动脉粥样硬化样改变,除5只模型兔喂养中途死亡,其余兔均完成全程扫描.病理证实斑块内巨噬细胞吞噬USPIO.USPIO增强MR较Gd-DTPA增强能更好识别斑块内各种成分.结论 US-PIO增强MR对识别斑块成分具有独特价值,并能反映斑块内炎性浸润,因此对判断斑块易损性优于Gd-DTPA增强MR.     

肝脏肿瘤手推团注动态MR增强扫描方法及2种对比剂效果比较

目的介绍肝脏病变手推团注动态MR增强扫描方法,对比离子型钆喷酸葡胺和非离子型钆双胺MR对比剂在肝脏肿瘤性病变动态增强的效果。方法185例肝脏肿瘤患者分2组:第1组91例(男52例,女39例),采用非离子型钆双胺MR对比剂(Gd-DTPA-BMA);第2组94例(男55例,女39例),采用离子型钆喷酸葡胺MR对比剂(Gd-DTPA)。行手推团注动态MR增强扫描。结果①手推团注动态强化效果总满意率75.14%,一般率24.32%,差0.54%。②2组间动态强化效果t检验无显著性差异,P>0.05。③各类肝脏肿瘤动态强化表现组间t检验无显著性差异,P>0.05。结论肝肿瘤手推团注动态MR增强扫描,Gd-DTPA-BMA和Gd-DTPA均可达到满意的增强效果。完全可满足临床诊断要求。     

MR动态增强扫描在肝硬化中的应用

目的研究肝硬化动态增强扫描的特点。资料与方法对20例正常人和34例肝硬化患者行肝脏MR动态增强扫描,比较两组肝脏强化比、门静脉灌注分数。结果肝硬化组动脉期、门静脉期和延迟期强化比分别为0.255±0.155、0.64±0.268、0.55±0.245,均高于正常组,差异具有统计学意义。两组门静脉期的强化比均高于动脉期、延迟期的强化比。肝硬化组和正常组的门静脉灌注分数分别为2.90±2.74、3.88±2.62,肝硬化组门静脉灌注分数低于正常组,二者差异具有统计学意义。结论MR动态增强扫描可以观察肝硬化者肝脏血液灌注情况。     

Interstitial MR lymphography in mice with gadopentetate dimeglumine and gadoxetate disodium

Purpose

To investigate the utility of interstitial MR lymphography with gadopentetate dimeglumine (Gd‐DTPA) or gadoxetate disodium (Gd‐EOB‐DTPA) in mice.

Materials and Methods

We performed MR lymphography after the subcutaneous injection of Gd‐DTPA or Gd‐EOB‐DTPA (0.1, 0.5, or 2.0 μmol per mouse) into the right footpad in six healthy mice, and the time courses of contrast enhancement were assessed. Additionally, the lymphatic pathways from two distinct sites were assessed in tandem by interstitial MR lymphography studies.

Results

Subcutaneous injection of Gd‐DTPA or Gd‐EOB‐DTPA caused lymph node enhancement immediately after injection, followed by a rapid decline. Dose dependency was shown for the lymph node enhancement, and a high‐dose injection caused prominent visualization of the veins. Lymph node enhancement did not differ significantly between Gd‐DTPA and Gd‐EOB‐DTPA or between Gd‐EOB‐DTPA premixed and not premixed with bovine serum albumin. The tandem assessment of two lymphatic pathways was feasible, and image fusion aided detailed comparison.

Conclusion

Interstitial MR lymphography with Gd‐DTPA or Gd‐EOB‐DTPA allowed clear visualization of the lymphatic pathway in healthy mice, and no significant difference was found between the two agents. Their rapid kinetics limits the imaging timing window, however, facilitates repeated assessment in a single imaging session. J. Magn. Reson. Imaging 2011;33:490–497. © 2011 Wiley‐Liss, Inc.     

MRI特异性对比剂铁羧葡胺对肝脏局灶性病变检出的比较研究

目的 通过比较MR平扫、应用对比剂钆喷替酸葡甲胺（Gd—DTPA）增强MRI及MRI特异性对比剂铁羧葡胺增强MRI对肝脏局灶性病变的检出，验证铁羧葡胺在病灶检出方面的优势。方法 2003年12月至2004年7月，选择怀疑为肝脏局灶性病变的病例59例，根据相对金标准判定共133个病灶。所有病例均先行梯度回波（GRE）T1WI、去脂快速自旋回波（FSE）序列T2WI、动态梯度回波Gd—DTPA增强MRI，48h后行铁羧葡胺动态GRE增强扫描及去脂FSE T2WI与GRE TW^＊W延迟扫描。统计各序列对局灶性病变检出的敏感性。结果 铁羧葡胺延迟增强去脂FSE T2W序列、动态GRE增强扫描、GRE T2^＊W延迟增强扫描检出病灶数分别为130、115、127个；平扫GRE T1WI序列、去脂FSE T2WI检出病灶分别为84和106个；Gd—DTPA动态GRE增强检出123个病灶。对于其中44个的微小病灶（〈1cm），铁羧葡胺延迟增强去脂FSE T2WI检出率达到932％（41/44），铁羧葡胺动态增强检出率为727％（32/44），铁羧葡胺延迟增强GRE T2^＊WI检出率为886％（39/44），Gd—DTPA动态增强检出率为795％（35/44），平扫去脂FSE T2WI检出率为545％（24/44），平扫GRE T1WI检出率为34.1％（15/44）。铁羧葡胺延迟增强去脂FSE T2WI及GRE T2WI显著提高了对于微小病灶（〈1cm）的检出率，与平扫MR（包括去脂FSE T2WI和GRE T1WI）及Gd—DTPA动态增强MR相比差异有统计学意义（P〈005）。结论 铁羧葡胺延迟增强去脂FSE T2WI及GRE T2^＊WI序列优势主要为提高肝微小病灶（〈10cm）的检出率。     

口服静脉用钆喷替酸葡甲胺对MR胰胆管成像质量影响的研究

目的 选择出静脉用钆喷替酸葡甲胺(Gd-DTPA)作为MR胰胆管成像(MRCP)口服胃肠道阴性对比剂的最佳浓度及容量;评价口服Gd-DTPA对比剂在抑制胃肠道高信号、改善MRCP图像质量中的作用.方法 (1)体外实验:对不同浓度Gd-DTPA稀释液及温开水空白对照组行T1WI、T2WI、二维单层快速自旋回波(FSE)序列及三维半傅立叶单次激发快速自旋回波(HASTE)序列扫描,测量不同成像序列上的信号强度并计算增强率,选择出最佳浓度;(2)临床实验:分别配制不同容量的最佳浓度Gd-DTPA稀释液作为MRCP口服胃肠道阴性对比剂,选择出最佳容量;以最佳浓度和容量Gd-DTPA对比剂对24例临床疑有胰胆管病变的患者行口服前及口服后5～10、10～15 minMRCP扫描,分析图像质量.统计方法采用计算机软件包SPSS 10.0版,对实验结果进行方差分析.结果 T1WI上对照组均为低信号,Gd-DTPA浓度≤0.01 mol/L时为完全高信号;T2WI上对照组为明亮高信号,Gd-DTPA浓度≥0.015 mol/L为完全低信号;2D FSE单层MRCP图像上对照组为明亮高信号,Gd-DTPA浓度在0.0025～0.0300 mol/L之间均为低信号;3D HASTE MRCP图像上对照组为明亮高信号,Gd-DTPA浓度≥0.01 mol/L时为完全低信号;容量≥100 ml浓度为0.01 mol/L的Gd-DTPA对比剂对胃及十二指肠内液体高信号的抑制效果完全;24例患者口服100 ml浓度为0.01 mol/LGd-DTPA对比剂10～15 min后MRCP图像上肝内1、2、3级胆管、肝总管、胆囊、胆总管、胰管头、体、尾的平均等级分数(分别为3.63、3.46、3.08、3.71、3.87、3.88、3.79、3.71、3.50)略高于5～10 min的图像(分别为3.54、3.46、3.00、3.79、3.96、3.87、3.71、3.67、3.54),差异无统计学意义(P值均>0.05),而口服对比剂后肝内3级胆管、胆总管、胰管的等级分数明显高于口服对比剂前(分别为2.79、3.71、3.50、3.42、3.25),差异有统计学意义(F值分别为4.36、4.75、7.86、8.05、7.55,P值均<0.05).结论 100 ml浓度0.01 mol/L的Gd-DTPA对比剂能使胃及十二指肠内潴留液高信号抑制完全,可作为MRCP理想的胃肠道阴性对比剂;口服对比剂后5～10 min行MRCP扫描,图像质量效果最佳.     

A double-blind,comparative study of gadodiamide injection and gadopentetate dimeglumine in MRI of the central nervous system

Summary Seventy-nine patients with known or suspected central nervous system lesions were studied with MRI in a phase III double-blind study. Forty were given gadopentetate dimeglumine (Gd-DTPA) and 39 gadodiamide injection (Gd-DTPA BMA), a new low-osmolar nonionic contrast enhancing medium. The dosage was 0.1 mmol/kg body weight, corresponding to 0.2 ml/kg. Spin-echo sequences were performed before and immediately after injection. The safety and efficacy of the two contrast media were assessed. No changes were observed in blood pressure, heart rate or neurological status. Five adverse effects (two episodes of headaches, two of nausea and one of dizziness) were reported by 2 patients who received gadodiamide injection and 1 who received gadopentetate dimeglumine. All events were mild and their relationship to the contrast media was uncertain. For both contrast media statistically significant changes in serum iron were observed 24 h after injection. More than 70% of the patients had abnormal findings on MRI, and in 56% of these contrast enhancement of the abnormal structure or lesion was seen. Contrast enhancement provided the diagnosis in about 50%, changed it in 40% and increased diagnostic confidence in 95%.     

MR胆管水成像和钆贝葡胺增强胆管成像对肝移植供体胆管显示的对照研究

目的 探讨MR胆管水成像(T2WI-MRC)和钆贝葡胺增强后胆管成像(CE-MRC)对肝移植供体胆管显示的差别.方法 32名肝移植供体术前均行T2WI-MRC和CE-MRC检查,以术中胆管造影结果为金标准,对比2种成像方法对肝内外胆管的显示情况,并对胃肠内液体影、呼吸引起的运动伪影进行比较.结果 胆管变异9名,2种检查方法均正确诊断.2种方法均可清楚显示3级肝内胆管,T2WI-MRC有28名(87.5%)能显示肝内3级以上胆管,CE-MRC只有14名(43.8%)可以显示.2名受检者T2WI-MRC显示胆总管不连续,CE-MRC及术中胆管造影显示胆总管正常.T2WI-MRC有6名(18.8%)受检者肠道内液体影响胆管显示,CE-MRC则无一名受检者肠道液体影响胆管显示.呼吸引起的运动伪影2种检查方法均不明显.结论 T2WI-MRC和CE-MRC均可用来评估术前肝移植供体胆管解剖,但CE-MRC受肠道液体影响少,较T2WI-MRC对于肝内3级以上胆管显示具有优势.     

Double-dose 1.0-M gadobutrol versus standard-dose 0.5-M gadopentetate dimeglumine in revealing small hypervascular hepatocellular carcinomas

The purpose of this study was to compare the diagnostic efficacy of double-dose 1.0-M gadobutrol with that of standard-dose 0.5-M gadopentetate dimeglumine for revealing small hypervascular hepatocellular carcinomas (HCCs). Twenty-three patients with 37 HCCs (mean size: 1.2 cm) that were diagnosed by histology (n = 13) or imaging findings (n = 10) underwent two separate 3D dynamic MRIs with 0.2 mmol/kg of gadobutrol and 0.1 mmol/kg of gadopentetate dimeglumine. Three observers interpreted both MRIs in terms of lesion detection using the alternative-free response receiver operating characteristic method and lesion-to-liver contrast using matched pairs analysis. The two MRIs were also compared quantitatively by measuring the signal-to-noise ratio (SNR) of the liver and lesion as well as the lesion-liver contrast-to-noise ratio (CNR). The SNR of the liver and lesion and lesion-liver CNR with gadobutrol were better than those with gadopentetate dimeglumine (p < 0.01). However, in terms of the diagnostic accuracy (mean Az for gadobutrol: 0.878, and mean Az for gadopentate dimeglumine: 0.873), the sensitivity (92.8%), positive predictive value (92.8% vs. 93.7%) and lesion-liver contrast, the two dynamic MRIs were equivalent. Gadobutrol showed a superior degree of enhancement for hypervascular HCC than did gadopentetate dimeglumine, but the diagnostic capabilities of the two agents for revealing HCCs were equivalent.     

Magnetic resonance enhancement pattern and diagnostic accuracy of gadofluorine M in a rabbit VX2 tumor model: Comparison with gadopentetate dimeglumine

Objective

The purpose of this study was to evaluate the enhancement pattern and the diagnostic accuracy of gadofluorine M in comparison with gadopentetate dimeglumine in a rabbit VX2 tumor model.

Materials and methods

Thirteen rabbits with experimentally induced VX2 carcinomas in the thighs underwent sequential T1-weighted enhancement MR imaging using a 3.0 T MR imager, first with gadopentetate dimeglumine, and then 24 (n = 4) or 4 h (n = 9) later with gadofluorine M. In 4 rabbits with 13 tumors, the time-percentage enhancement (PE; i.e., percentage of signal intensity increase) curve was obtained for up to 24 h for each contrast agent. In 9 rabbits with 49 tumors (random numbers of VX2 tumors were inoculated at random sites in the thigh), 3 readers unaware of the histopathologic results interpreted the MR images and determined the number and conspicuity level of the detected tumors. The reference standard was the histopathology of the specimen.

Results

The time-to-peak PE for gadopentetate dimeglumine was 1 min and gadopentetate dimeglumine showed a rapid washout pattern. The time-to-peak PE for gadofluorine M was 30 min and gadofluorine M showed a plateau enhancement pattern for up to 24 h. The peak PE of gadofluorine M was approximately twice that of the same dose of gadopentetate dimeglumine (108.2 ± 14.8 vs. 51.5 ± 24.0). The sensitivities for detecting VX2 tumors by 3 readers were 89.8% (44/49), 85.7% (42/49), and 95.9% (47/49) for gadopentetate dimeglumine-enhanced MR imaging, and 87.8% (43/49), 89.8% (44/49), and 89.8% (44/49) for gadofluorine M-enhanced MR imaging. No significant differences in the sensitivities existed between the two contrast agents for any reader. However, the conspicuity level of tumors was superior with gadofluorine M-enhanced MR imaging for two readers and similar for the other reader.

Conclusion

Gadofluorine M showed strong and plateau enhancement of tumors for up to 24 h. In the reader study, gadofluorine M showed better conspicuity for VX2 tumors than gadopentetate dimeglumine, but had a similar sensitivity.     

静脉注射对比剂钆喷替酸葡甲胺对肾功能正常及轻、中度异常者近期血清肌酐值的影响

目的 探讨静脉注射对比剂Gd-DTPA对常规MR增强扫描人群肾功能的影响.方法 连续收集门诊住院病例623例,均注射Gd-DTPA行MR增强扫描检查的病例进行研究,检测患者增强扫描前2周内的基础血清肌酐值以及增强扫描后24～72 h内的血清肌酐值,并计算其肾小球滤过率估算值(eGFR)进行分组及统计分析.根据注射对比剂剂量将患者分为常规剂量组和双倍剂量组,各组根据注射前eGFR值再各分为肾功能正常、轻度异常及中度异常组.对各组注射前后血清肌酐值的比较均使用配对样本的t检验,eGFR均值的比较均使用成组配对样本秩和检验.结果 无患者出现严重不良反应及严重肾功能衰竭.注射对比剂后,总体血清肌酐值从(74.0±17.2)μmol/L降至(71.5±19.0)μmoL/L(t=5.39,P＜0.05);除双倍剂量下肾功能轻度组的血清肌酐值从(89.6±12.2)μmoL/L升至(92.1±14.6)μmol/L(t=0.68,P＞0.05),肾功能中度异常组从(118.3±15.3)μmol/L升至(135.7±8.5)μmol/L(t=2.02,P＜0.05)之外,肾功能正常组以及常规剂量下各组的血清肌酐值均降低.结论 Gd-DTPA在常规剂量下经静脉注射对肾功能正常及轻、中度异常者的近期血清肌酐值影响不大,是一种比较安全的MR对比剂.但对于肾功能异常者行双倍剂量注射时需密切观察并随访.     

A comparison of Gd-BOPTA and Gd-DOTA for contrast-enhanced MRI of intracranial tumours

A two-centre intra-individual crossover study was performed in 23 patients with suspected high-grade glioma or metastases to assess and compare the safety and enhancement characteristics of two different MRI contrast media (gadobenate dimeglumine, Gd-BOPTA and gadoterate meglumine, Gd-DOTA) at equivalent doses of 0.1 mmol/kg body weight. T1-weighted spin-echo (SE) and T2-weighted fast SE images were obtained before and T1-weighted images 0, 2, 4, 6, 8 and 15 min after injection. T1-weighted images with magnetisation transfer contrast were acquired 12 min after injection. Qualitative assessment by blinded, off-site readers (reader 1: 19 patients; reader 2: 21) and on-site investigators (23) revealed significant (P 0.005) overall preference for Gd-BOPTA over Gd-DOTA for contrast enhancement (Gd-BOPTA preferred in 18, 15 and 18 cases; Gd-DOTA in 0, 1 and 1 and no preference in 1, 5 and 4; off-site readers 1 and 2, and on-site investigators, respectively). A similar significant preference for Gd-BOPTA was expressed by off-site readers and on-site investigators for lesion-to-brain contrast, lesion delineation, internal lesion structure, and overall image preference. Quantitative assessment by off-site readers revealed significantly (p<0.05) greater lesion enhancement with Gd-BOPTA than with Gd-DOTA at all times from 2 min after injection.