Gd-DTPA在MRI中的诊断作用

目的:探讨Gd-DTPA在MRI中的诊断作用。材料与方法:总结分析了被确诊的378例(402人次)患者应用Gd-DTPA增强检查后的效果。对肿瘤、感染、梗塞等病变的强化特点进行了讨论。结果:使用Gd-DTPA后,有23例平扫时误诊的病例得到了纠正,并发现了MRI平扫时未能发现的一些病变,诸如管内型听神经瘤、脑膜炎、脑(脊)膜的转移性病变等。但是,作者还同时发现即使在用了Gd-DTPA之后,仍有多种病变存在鉴别诊断上的困难。结论:合理使用增强检查,将有助于提高诊断的符合率。     

椎管内肿瘤磁共振成像增强扫描初步观察

对１１例手术病理证实的椎管内肿瘤进行磁共振成像（ＭＲＩ）增强扫描的前、后分析，并对肿瘤定位、定性和鉴别诊断作了初步探讨。根据肿瘤形态、边界、强化程度，及与脊髓、硬脊膜、神经根等关系，ＭＲＩ的增强扫描对提高其定位、定性诊断均有较大的帮助。     

Cystic lumbar meningioma presenting as a ring enhancing lesion on MRI

We report a cystic lumbar meningioma which presented as a ring enhancing lesion on MRI.     

Multimodal imaging for a theranostic approach in a murine model of B-cell lymphoma with engineered nanoparticles

Nanoparticles (NPs) are a promising tool for in vivo multimodality imaging and theranostic applications. Hyaluronic acid (HA)-based NPs have numerous active groups that make them ideal as tumor-targeted carriers. The B-lymphoma neoplastic cells express on their surfaces a clone-specific immunoglobulin receptor (Ig-BCR). The peptide A20-36 (pA20-36) selectively binds to the Ig-BCR of A20 lymphoma cells. In this work, we demonstrated the ability of core-shell chitosan-HA-NPs decorated with pA20-36 to specifically target A20 cells and reduce the tumor burden in a murine xenograft model. We monitored tumor growth using high-frequency ultrasonography and demonstrated targeting specificity and kinetics of the NPs via in vivo fluorescent reflectance imaging. This result was also confirmed by ex vivo magnetic resonance imaging and confocal microscopy. In conclusion, we demonstrated the ability of NPs loaded with fluorescent and paramagnetic tracers to act as multimodal imaging contrast agents and hence as a non-toxic, highly specific theranostic system.     

对比剂Gd-DTPA对肝外胆管癌磁共振扩散加权成像的影响

目的:探讨对比剂钆喷替酸葡甲胺(Gd-DTPA)对肝外胆管癌磁共振扩散加权成像(DWI)图像质量及表观扩散系数(ADC)的影响。方法:回顾性分析经病理证实并被DWI检出的57例肝外胆管癌患者的DWI图像资料,比较静脉注射对比剂Gd-DTPA增强前后及不同b值条件下肝外胆管癌病灶信噪比(SNR)、病灶与正常肝脏间对比信噪比(CNR)及ADC值的差异。结果:同一b值条件下,增强前后病灶SNR、CNR、ADC值的差异均无统计学意义(P>0.05);增强前后肝外胆管癌病灶SNR、CNR及ADC值均随着b值的增大而降低,其差异均有统计学意义(P<0.05)。结论:肝外胆管癌病灶的DWI图像质量及ADC值不受Gd-DTPA影响,所以选择合适b值的增强后DWI序列是可行的。     

椎管内神经瘤的增强磁共振成像研究

目的：评估增强后磁共振成像诊断椎管内神经瘤的特异性。材料和方法：对经外科手术的２０例椎管内神经瘤患者，回顾性比较分析病理和ＭＲＩ（包括Ｔ１加权成像、Ｔ２加权成像和静脉注射Ｇｄ－ＤＴＰＡ后Ｔ１加权成像）。结果：在Ｔ１加权像，与脊髓相比，呈均质低信号９例，不均质低信号１０例，不均质高信号１例；在Ｔ２加权像，２０例均示明显高信号（均质１３例，不均质７例）；静脉注射Ｇｄ－ＤＴＰＡ后Ｔ１加权成像，２０例均示明显强化，据其强化形态不同分为①均质强化８例；②明显不均质强化５例，病理上存在坏死囊变和陈旧性出血；③“煤渣状”不均质强化７例，病理上可能由不同量的ＡｎｔｏｎｉＡ和ＡｎｔｏｎｉＢ组织交互存在所造成或部分代表显微镜下见的微囊改变。结论：Ｔ１加权像呈低信号，Ｔ２加权呈明显的高信号，注射造影剂后出现明显的不均质强化和“煤渣状”不均质强化，是椎管内神经瘤的特征性ＭＲＩ征象。     

Quantitative Analysis of Dynamic Gd-DTPA Enhancement in Breast Tumors Using a Permeability Model

The MRI signal enhancement in a breast tumor, measured as a function of time after a bolus injection of Gd-DTPA, may contain enough information to differentiate malignant from benign tissue. We find a physiological model for measuring capillary permeability and leakage space (P. S. Tofts, A. G. Kermode, measurement of the blood-brain barrier permeability and leakage space using dynamic MR imaging. 1. Fundamental concepts. Magn. Reson. Med. 17, 357–367 (1991)) fits the data well. The enhancement curve is particularly sensitive to the preinjection T₁, of the tumor, the dose, and the time of injection. This model may provide a means of characterizing the pathophysiology of breast tumors from the Gd-DTPA enhancement curve.     

脊髓Gd-DTPA增强磁共振血管造影检查方法研究

笔者应用常规剂量Ｇｄ－ＤＴＰＡ增强进行ＴＯＦ法ＭＩＰ重建脊髓磁共振血管造影（ＭＲＡ）研究，检查了１１例正常人和３５例椎管内疾病患者。结果显示３Ｄ－ＴＯＦ明显优于２Ｄ－ＴＯＦ法，增强脊髓ＭＲＡ图像能清楚显示正常脊髓的动、静脉，并显示肿瘤染色，血管移位等占位征象和动静脉畸形的畸形血管团。本研究证明：增强ＭＲＡ是一种简便易行、无创伤、无射线、行之有效的检查方法     

Gd-DTPA作为肾脏CT血流灌注对比剂的动物实验研究

目的探讨Gd-DTPA作为肾脏CT增强对比剂用于肾脏血流灌注研究的可行性.方法 12只新西兰白兔,分组注射Gd-DTPA或碘对比剂,CT动态扫描获得主动脉和肾脏的时间-密度曲线,计算血流灌注数值.结果静脉注射0.5 mmol/(kg*ml) Gd-DTPA后,肾皮质增强(33.2±11.9) Hu.Gd-DTPA和碘对比剂获得的肾脏皮质、髓质血流灌注数值无明显差异.结论 Gd-DTPA能够作为X线对比剂用于肾脏增强CT检查,并用于研究肾脏血流灌注.     

In vivo imaging of extraction fraction of low molecular weight mr contrast agents and perfusion rate in rodent tumors

Tissue uptake of a fully extractable MR detectable tracer, deuterated water (D₂O), was compared with that of a less extractable contrast agent, Gadolinium-DTPA-dimeglumine (Gd-DTPA), in rodent tumor and muscle tissue. This dual tracer method allowed calculation of relative (to muscle) tissue perfusion and extraction fraction of Gd-DTPA in each image pixel in vivo. Solutions of Gd-DTPA and D₂O were injected intravenously into Fisher female rats (n = 9) with R3230 mammary adenocarcinomas implanted in the hind limb. Perfusion rate was approximately two times greater (P < 0.005 by paired t test) in tumor than in muscle. Gd-DTPA extraction fraction at the interface between tumor and muscle was 2.0 times the extraction fraction in normal muscle (P <0.005 by paired t test). Extraction fraction at the tumor center was 1.6 times the extraction fraction in muscle (P <0.01 by paired t test). High extraction fraction of Gd-DTPA correlated with high capillary permeability determined from Evans Blue staining. Low molecular weight Gd-DTPA derivatives are widely used in clinical practice, and their extraction fractions are crucial determinants of image contrast during the first few passes of the contrast agent bolus. Therefore spatially resolved measurements of contrast agent extraction fractions obtained in vivo have significant clinical utility. The data demonstrate that extraction of low molecular weight tracers is sensitive to increased permeability in tumor vasculature and that this increased permeability can be imaged.