不同粒径脂质体包裹顺磁性对比剂的体外R1弛豫率及MR增强成像研究

目的 通过制备不同粒径脂质体包裹顺磁性Gd-DTPA,观察其理化特性及对大鼠肝脏的强化作用.材料与方法 采用薄膜蒸发法制备不同粒径脂质体包裹顺磁性Gd-DTPA,观察其理化特性.动物实验选择雄性健康SD大鼠18只(平均分为3组),静脉注射不同粒径的顺磁性对比剂脂质体,于注射对比剂前、15 min后对实验动物进行MRI.测定增强扫描前后肝脏、背景组织的信号强度,计算强化率、对比噪声比(CNR).结果 制备出粒径分别为400 nm、200 nm、78 nm以下的顺磁性脂质体,其平均R1弛豫率分别为0.64、1.05、1.60 min-1·s-1,随着脂质体粒径减小,其包封率下降,体外R1弛豫率增高.静脉注射3种粒径的顺磁性脂质体后,肝脏的强化存在差异,表现为400 nm粒径的脂质体对肝脏的强化作用高于其他2种粒径脂质体,测量肝脏的强化率和CNR较200 nm、78nm脂质体差异有显著统计学意义(P<0.001).结论 脂质体包裹Gd-DTPA对肝脏具有强化作用,粒径大小对其弛豫率和强化作用有影响.     

顺磁性对比剂增强MR脑灌注成像

随着MR快速成像技术的发展、顺磁性对比剂的应用，顺磁性对比剂增强MR脑灌注成像已应用于颅脑检查的许多方面，并且在部分疾病（如急性脑卒中和脑肿瘤等）检查中已成为常规，并逐渐延伸至脑变性疾病等更为广泛的领域。对疾病除早期显示病变外，且可指导疾病的治疗及判断预后。就其成像原理、检查方法以及临床应用进行介绍。     

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.     

超顺磁性氧化铁（SPIO）对比剂肝脾MR成像的比较研究

目的 比较两种超顺磁性氧化铁（superparamagnetic iron oxide,SPIO)对比剂,Ferumoxides及SHU－555A在肝脾MR成像中的效应。材料与方法 36例已知为肝转移癌患者于SPIO造影前后进行T2WI快速自旋回波成像（T2WI TSE）及T1WI梯度回波快去速相位成像（T1WI FLASH）。扫描伪为1．0T MR机。18例患者行Ferumoxides增强后90分钟进行MR成像;另18例行SHU－55A快速团柱增强,注药后即刻、30秒及480秒行T1WI FLASH成像,10分钟行T2WI TSE成像。测量肝脾、肝转移癌SPIO增强前后的信号强度（signal intensity,SI),计算两种SPIO对比剂在肝脾、肝转移癌增强前后SI变化的百分比（percentage signal intensity change,PSIC)及病灶肝脏对比噪声比（lesion-to-liver contrast-to-noise ratio,CNR)及其变化（ΔCNR）。结果 在T2WI TSE图像上,两种SPIO对比剂造成的肝实质SI下降无显著性差异（P＞0．05）。Ferumoxides引的脾信号下降显著大于SHU－555A（P＜0．05）。两种SPIO对比剂均导致肝实转移癌SNR显著增高。T1WI FLASH图像上,两种对比剂均可导致延迟像上肝脏SI的轻度下降及肝转移癌CNR下降,两者肝脏SIC之间无显著性差异。T1WI上两种对比剂均可导致脾脏SI显著升高,两者脾脏PSIC之间无显著性差异（P＞0．05）。结论 两种SPIO在肝脏的TI及T2增强效应相似,而脾脏的T2增强效应,Ferumoxides强于SHU－555A。     

顺磁性对比剂动态增强MR脑灌注成像

随着MR快速成像技术的发展,顺磁性对比剂的应用,基本平面回波技术的顺磁性对比剂动态增强MR脑灌注成像已应用于颅脑检查的许多方面,并且在急性脑卒中、脑肿瘤等部分疾病检查中已成为常规,并逐渐延伸至脑变性疾病、烟雾病及吸毒者及功能评估等更为广泛的领域。对疾病除早期显示病变外,还可指导疾病的治疗及判断预后。就其成像原理、计算参数、检查方法入临床应用进行介绍。     

MR淋巴成像研究现状

准确地榆出和评判淋巴结的良恶性是进行肿瘤分期和制定治疗计划的关键,影响肿瘤病人的预后.常规CT、MRI和超声依靠淋巴结的大小、形态区分良恶性,诊断准确率有限.MR淋巴成像作为一种新型的微创性的方法,对比分辨力和空间分辨力均较高,可同时提供淋巴结、淋巴管的解剖和功能两方面的信息,对肿瘤转移性淋巴结的检出和良恶性淋巴结的鉴别有非常大的帮助.     

MR淋巴成像研究现状

准确地检出和评判淋巴结的良恶性是进行肿瘤分期和制定治疗计划的关键,影响肿瘤病人的预后。常规CT、MRI和超声依靠淋巴结的大小、形态区分良恶性,诊断准确率有限。MR淋巴成像作为一种新型的微创性的方法,对比分辨力和空间分辨力均较高,可同时提供淋巴结、淋巴管的解剖和功能两方面的信息,对肿瘤转移性淋巴结的检出和良恶性淋巴结的鉴别有非常大的帮助。     

脂质体MRI对比剂的研究进展

脂质体作为诊断和治疗靶向药物的载体,进入体内后具有被动靶向和主动靶向2种作用,近年来,随着脂质体制备技术的进展和各种新型脂质体的出现,使其在MR靶向成像中的应用有了较快的发展,介绍了MR脂质体对比剂的特性及其制备的基本原理,总结了不同脂质体对比剂在MRI靶向成像中的应用价值.     

脂质体MRI对比剂的研究进展

脂质体作为诊断和治疗靶向药物的载体,进入体内后具有被动靶向和主动靶向2种作用,近年来,随着脂质体制备技术的进展和各种新型脂质体的出现,使其在MR靶向成像中的应用有了较快的发展,介绍了MR脂质体对比剂的特性及其制备的基本原理,总结了不同脂质体对比剂在MRI靶向成像中的应用价值.     

CD40突变体靶向MR分子成像探针制备及体外卵巢癌成像的实验研究

目的 探讨超微超顺磁氧化铁(USPIO)粒子负载的,CD40突变体抗体分子探针的构建方法和其生物、理化性状,以及在体外对卵巢癌的靶向作用.方法 采用化学交联法将单克隆抗体交联于二巯基丁二酸(DMSA)修饰的USPIO,形成具有免疫活性的分子探针,进行磁学性能鉴定.USPIO标记的抗人CD40突变体单克隆抗体5H6(5H6-USPIO)作为实验组,USPIO标记的抗人CD40单克隆抗体5C11(5C11-USPIO)及USPIO为对照组.通过流式细胞术、共聚焦显微镜及普鲁士蓝染色分析其体外生物学特性,采用3.0T MR对探针与高表达CD40突变体卵巢癌(HO8910)进行体外细胞成像.信号变化数据组间比较采用单因素方差分析和LSD检验.采用Cell Counting Kit-8试剂盒检测探针对HO8910细胞的增殖影响.结果 携带USPIO的抗CD40突变体分子探针被成功构建并分离纯化.合成的探针同USPIO相比具有相似的磁学特性和良好的稳定性.流式细胞术、共聚焦显微镜及普鲁士蓝染色证实抗体分子探针能够特异性识别HO8910细胞表面的CD40突变体,对细胞HO8910的增殖无影响.体外MRI显示探针同HO8910细胞结合后T2、T2*值明显缩短,T2图像较对照组明显变暗.5H6-USPIO组的T2、T2*弛豫时间分别为(40.05±1.62)、(3.08±0.11)ms,短于5C11-USPIO[分别为(85.38±4.74)和(11.82±1.00)ms]和USPIO组[分别为(91.62±3.35)和(13.60±1.92)ms],差异均有统计学意义(F值分别为196.29、60.73,P值均＜0.01),而5C11-USPIO、USPIO两组T2、T2*弛豫时间差异无统计学意义(P值均＞0.05).结论 化学交联法可制备出CD40突变体单克隆抗体超顺磁氧化铁粒子探针,该探针具有良好磁学特性及较高生物活性,能够特异性识别卵巢癌细胞HO8910.     

Detection of liver metastases: Gadoxetic acid-enhanced three-dimensional MR imaging versus ferucarbotran-enhanced MR imaging

Purpose

To compare the diagnostic performance of gadoxetic acid-enhanced MRI with ferucarbotran-enhanced MRI for the detection of liver metastases.

Materials and methods

Thirty-six patients with 80 liver metastases who underwent gadoxetic acid-enhanced MRI using a three-dimensional volumetric interpolated technique and ferucarbotran-enhanced MRI with a mean interval of 7 days (range, 5-10 days) were included in this study. Two observers independently interpreted the two sets of images - the gadoxetic acid set (unenhanced, early dynamic and 20 min delayed phase images) and the ferucarbotran set (unenhanced and ferucarbotran-enhanced T2*-weighted-gradient echo and T2-weighted turbo spin echo images). Diagnostic accuracy was evaluated using the alternative-free response receiver operator characteristic (ROC) method. Sensitivity and positive predictive value were also evaluated.

Results

There was a trend toward increased areas under the ROC curve (Az values) for the gadoxetic acid set (0.950, 0.948) as compared with the ferucarbotran set (0.941 and 0.939) of images, but no significant difference was found for both observers (p < 0.05). Sensitivities of the gadoxetic acid set (93.8% and 92.5%) were also slightly better than those of the ferucarbotran set (88.8% and 87.5%) with no significant difference (p = 0.13). The two image sets showed similar positive predictive values (98.7% and 98.6%, respectively).

Conclusions

Gadoxetic acid-enhanced MRI showed comparable diagnostic performance to ferucarbotran-enhanced MRI for the detection of liver metastases.     

应用MRI评估肾功能的研究进展

MRI提供丰富的肾脏实质及大血管的形态学诊断信息及肾脏各项功能参数,近年来得到较大发展.就肾功能相关的各种MRI技术包括传统序列成像、血氧饱和依赖成像、弥散加权成像、动脉自旋标记等非定量分析方法;对比剂增强首次通过法、MR肾图等定量分析法进行了综述.     

Characterization of time-enhancement curves of benign and malignant prostate tissue at dynamic MR imaging

Our objectives were to determine time-enhancement curves of prostate cancer, peripheral zone, and adenoma at gadolinium-enhanced MR imaging, and to determine if a high-spatial/low-temporal dynamic imaging could be accurate in depicting prostate cancer, or if a higher temporal resolution (and a lower spatial resolution) should be favored. Thirty-nine patients with prostate cancer underwent MR imaging before radical prostatectomy by using T1- and T2-weighted axial images and a single-slice dynamic gadolinium-enhanced sequence (40 images; one image per 6 s; injection of 20 ml at 2 ml/s). After analysis of the pathologic specimens, four region-of-interest (ROI) cursors (cancer, peripheral zone, adenoma, and muscle) were retrospectively placed on dynamic images. Time-enhancement curves of the ROIs were obtained. The theoretical accuracy of a 30-s dynamic multislice MR sequence in depicting cancer within peripheral zone and adenoma (ROC curves) was calculated from these curves. On average, prostate cancer enhanced more and earlier than peripheral zone and adenoma, but there were great interindividual variations. For start delays ranging from 12 to 84 s, the areas under the ROC curves ranged from 0.602 to 0.698 for the depiction of cancer within adenoma and from 0.614 to 0.827 for the depiction of cancer within peripheral zone. The best results were obtained with a 36-s start delay. In conclusion, we found a 30-s scanning window which seems to allow a good depiction of cancer within peripheral zone. Because of largely overlapping enhancement patterns, cancer will probably not be depicted within adenoma by dynamic imaging, at least by using low temporal resolution. Electronic Publication     

Detection of liver metastases: gadobenate dimeglumine-enhanced three-dimensional dynamic phases and one-hour delayed phase MR imaging versus superparamagnetic iron oxide-enhanced MR imaging

The aim of this study was to compare the diagnostic performance of gadobenate dimeglumine (Gd-BOPTA)-enhanced MR imaging, including dynamic phases and one-hour delayed phase, versus superparamagnetic iron oxide (SPIO)-enhanced imaging for detection of liver metastases. Twenty-three patients with 59 liver metastases underwent Gd-BOPTA-enhanced MR imaging (unenhanced, arterial, portal, equilibrium and one-hour delayed phase) using three-dimensional volumetric interpolated imaging and SPIO-enhanced T2-weighted turbo spin–echo and T2*-weighted gradient-echo sequences on a 1.5-T unit. Three observers independently interpreted the three sets of images, i.e. Gd-BOPTA-enhanced dynamic MRI (set 1), delayed phase imaging (set 2) and SPIO-enhanced MRI (set 3). Diagnostic accuracy was evaluated using the alternative-free response receiver operating chracteristic (ROC) analysis. Sensitivity and positive predictive value were also evaluated. The mean accuracy (Az values) and sensitivity of Gd-BOPTA-enhanced delayed phase imaging (0.982, 95.5%) were comparable to those of SPIO-enhanced imaging (0.984, 97.2%). In addition, Az values and sensitivities of both imaging sets were significantly higher than those of Gd-BOPTA-enhanced dynamic images (0.826, 77.4%: p<0.05). There was no significant difference in the positive predictive value among the three image sets. Gd-BOPTA-enhanced delayed phase imaging showed comparable diagnostic performance to SPIO-enhanced imaging for the detection of liver metastases, and had a better diagnostic performance than Gd-BOPTA-enhanced dynamic images.     

Added diagnostic value of T2-weighted MR imaging to gadolinium-enhanced three-dimensional dynamic MR imaging for the detection of small hepatocellular carcinomas

Purpose

To assess the added value of T2-weighted MRI to gadolinium-enhanced dynamic MRI for detection of HCCs.

Materials and methods

Two readers retrospectively analyzed MRIs of 115 patients with 131 HCCs (size; 0.6–2.0 cm) that had been diagnosed by histology (n = 41) or imaging findings (n = 90). Two separate blind image analyses of the gadolinium set and the combined T2-weighted imaging and gadolinium sets were performed. Diagnostic accuracy was evaluated using the alternative-free response receiver operating characteristic method with four-point scale. Sensitivity and positive predictive value were also calculated.

Results

For both observers, the Az values and sensitivities with the combined T2-weighed imaging and gadolinium set (mean Az 0.806, sensitivity 84.7) were significantly higher than those with the gadolinium set (mean Az 0.660, sensitivity 59.9) (p < 0.05). The addition of T2-weighted imaging led to a change in diagnosis for 27 lesions by both observers, which at gadolinium set were assigned a confidence level of 1 or 2 but at additional reading of T2-weighted imaging were assigned a confidence level of 3 or 4. For the positive predictive values, each image set showed a similar value for each observer.

Conclusion

The addition of T2-weighted imaging to gadolinium-enhanced 3D dynamic imaging could be helpful in the detection of HCC by increasing reader confidence for HCCs with equivocal findings on gadolinium-enhanced MRIs.     

腹部磁共振成像应用口服造影剂枸橼酸铁铵的研究

缺乏一种理想的口服造影剂已成为腹部ＭＲＩ发展中的一大障碍。笔者选用枸橼酸铁铵（ＦＡＣ）作为ＭＲ口服造影剂，对其作用机理、增强规律、最佳浓度、造影方法、临床效果等问题进行了试管、动物实验和临床对照研究。ＦＡＣ具有较强的弛豫增强作用，低浓度时，以缩短Ｔ＿１为主，信号强度随浓度升高而增高；高浓度时，以缩短Ｔ＿２为主，信号强度随浓度升高而降低。当ＦＡＣ浓度为２．１ｍｍｏｌ／Ｌ时，Ｔ＿１Ｗ和Ｔ＿２Ｗ像均得到满意的对比增强，故为最佳浓度。ＦＡＣ口服造影可以标记胃肠道、提高邻近正常结构和病灶的解剖分辨率。造影时配合应用胃肠道松弛剂效果更好，低张造影组肝左叶、胰腺各段及胆总管下端的分辨效果明显优于平扫组。ＦＡＣ具有价格低廉、无毒副作用、造影效果良好等优点，是较理想的ＭＲ口服造影剂。     

周围型肝内胆管细胞癌的磁共振诊断

目的 :评价磁共振 (MRI)平扫及联合动态增强MRI对周围型肝内胆管细胞癌 (PCC)的诊断价值。方法 :回顾性分析 15例经手术病理证实的周围型肝内胆管细胞癌的MRI平扫及动态增强表现。结果 :全部病灶显示满意。参考平扫胆管扩张情况定性诊断符合率为 3 3 .3 % ,联合动态增强定性符合率提高至 86.7%。结论 :MRI平扫能较好显示病灶和胆管扩张情况 ,平扫联合动态增强检查可提高对PCC的定性符合率。     

Gd-DTPA标记单克隆抗体对荷人肝癌裸鼠的MR成像研究

目的评价特异性MR对比剂Gd-DTPA-单克隆抗体HAb18对肿瘤的强化效果.材料与方法制备Gd-DTPA标记的单克隆抗体,并测定每分子抗体所结合的Gd 3数目及其免疫活性.12只荷人肝癌裸鼠分为两组,分别给予Gd-DTPA-McAb和Gd-DTPA后进行MR扫描,测量SE T1WI平扫及增强后10 min、30 min、1 h、3 h、6 h、12 h、24 h、48 h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.结果 Gd-DTPA-单克隆抗体组在注射MR对比剂后的早期,肿瘤表现为缓慢轻度的强化,在注射对比剂24 h后,肿瘤强化达25%,与其他各时间点有统计学差异.Gd-DTPA对照组内,肿瘤表现为快进快出的强化特点.结论使用Gd-DTPA-单克隆抗体进行靶向显像具有特异性作用,有助于肿瘤的定性诊断.     

钆喷酸葡甲胺脂质体的制备及对大鼠肝癌灶的诊断作用

目的 :探讨Gd DTPA脂质体造影剂对大鼠肝癌灶的诊断价值。方法 :采用冻融超声法制备出粒径 0 .61±0 .3 4 μm的装载Gd DTPA的脂质体 ,二乙基亚硝胺法建立大鼠肝癌灶模型 ( 5例 ) ;观察静注 0 .1mmol/10 0 g体重Gd DT PA脂质体后大鼠肝癌灶显示情况 ,并与尸检对照。结果 :脂质体造影剂包裹率为 2 0 .1% ,能有效、持续地造成肝脏选择性靶向强化 ,从而衬托出肝癌病灶 ,使癌灶检出率由平扫 17.6%上升至增强后的 76.5 % ( 0 .0 1

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