Loubeyre P, Canet E, Zhao S, Benderbous S, Amiel M, Revel D
Laboratoire de Radiologie Expérimentale (CNRS URA 1216), Lyon, France.
Invest Radiol. 1996 May;31(5):288-93. doi: 10.1097/00004424-199605000-00008.
The authors evaluate the efficiency of various doses of a paramagnetic macromolecular contrast agent, a gadolinium (Gd)-DTPA-dextran conjugate, as a blood-pool contrast media, in a transverse three-dimensional time-of-flight (TOF) magnetic resonance (MR) angiography sequence of the abdominal aorta in rabbits.
Imaging experiments were performed on a 1.5-T magnet, using a transverse three-dimensional TOF tilted optimized nonsaturating excitation (TONE) sequence. The macromolecular contrast media used was a carboxymethyl-dextran-Gd-DTPA (CMD-Gd-DTPA). Different concentrations of CMD-Gd-DTPA (0.005, 0.01, 0.03, 0.05 mmol Gd/kg) were evaluated. A comparative study using Gd-DOTA (0.01 and 0.1 mmol/kg) was performed. A visual analysis based on the gain in the visualized length of small arteries (renal arteries), and a quantitative analysis based on the percent contrast enhancement of the aorta plotted against distance in the slab from the top edge of the acquisition volume were obtained.
A signal-to-noise ratio enhancement of the distal part of the aorta and an improvement in the visualized length of the renal arteries were noted for concentrations of CMD-Gd-DTPA ranging form 0.01 to 0.05 mmol Gd/kg. Venous enhancement was noted for concentrations greater than 0.01 mmol Gd/kg when using CMD-Gd-DTPA or Gd-DOTA.
Carboxymethyl-dextran-Gd-DTPA reduced, in part, the saturation effect in a three-dimensional transverse TOF TONE MR angiography in rabbits. To prevent venous enhancement, observed with the higher concentrations used in this study, a decrease in the polydispersity of the polymer should be a goal in the future. Rapid extravasation of the low-molecular weight fraction of the polymer could explain the venous enhancement.
作者评估了不同剂量的顺磁性大分子造影剂钆（Gd）-二乙三胺五乙酸-葡聚糖共轭物作为血池造影剂，在兔腹主动脉横向三维时间飞跃（TOF）磁共振（MR）血管造影序列中的效能。
在1.5-T磁体上进行成像实验，采用横向三维TOF倾斜优化非饱和激发（TONE）序列。使用的大分子造影剂为羧甲基葡聚糖-Gd-二乙三胺五乙酸（CMD-Gd-二乙三胺五乙酸）。评估了不同浓度的CMD-Gd-二乙三胺五乙酸（0.005、0.01、0.03、0.05 mmol Gd/kg）。进行了使用钆-多胺大环配合物（Gd-DOTA）（0.01和0.1 mmol/kg）的对比研究。获得了基于小动脉（肾动脉）可视化长度增加的视觉分析，以及基于主动脉对比增强百分比相对于采集容积顶部边缘层面距离绘制的定量分析。
对于浓度范围为0.01至0.05 mmol Gd/kg的CMD-Gd-二乙三胺五乙酸，观察到主动脉远端的信噪比增强以及肾动脉可视化长度的改善。使用CMD-Gd-二乙三胺五乙酸或Gd-DOTA时，浓度大于0.01 mmol Gd/kg会出现静脉强化。
羧甲基葡聚糖-Gd-二乙三胺五乙酸在兔三维横向TOF TONE MR血管造影中部分降低了饱和效应。为防止本研究中使用较高浓度时观察到的静脉强化，降低聚合物的多分散性应是未来的目标。聚合物低分子量部分的快速外渗可能解释了静脉强化现象。
