Knollmann F D, Böck J C, Teltenkötter S, Wlodarczyk W, Mühler A, Vogl T J, Felix R
Forschungslaboratoden Schering AG, Berlin, Germany.
J Magn Reson Imaging. 1997 Jan-Feb;7(1):191-6. doi: 10.1002/jmri.1880070129.
The purpose of our research was to determine the effects of superparamagnetic iron oxide on MR imaging of the portal venous system. Eight piglets were examined in deep anaesthesia and respiratory arrest using a time-of-flight magnetic resonance fast low angle shot, two-dimensional angiography sequence at 1.5T, MR angiograms were acquired precontrast and after intravenous administration of a cumulative dose of 10, 20 and 40 mumol/kg SHU 555A, a superparamagnetic iron oxide contrast agent for MR imaging with a particle size of 60 nm. For each dose, two subsequent sets of scans were obtained and reconstructed by a maximum-intensity-projection algorithm. Hepatic parenchymal and portal venous signal intensities were measured, and portal vein contrast calculated for each set of scans. All examinations were visually rated as to portal vein contrast and homogeneity by two blinded observers. Receiver operating characteristics of both observers were analyzed. The contrast agent reduced hepatic parenchymal signal in a dose-dependent way. After a cumulative dose of 10 mumol iron oxide, hepatic parenchymal signal intensity decreased to 63 +/- 6% (average of measurements at 4 and 14 minutes, mean +/- standard error of the mean), after 20 mumol to 24 +/- 3%, and after 40 mumol to 12 +/- 1% of control. Intravascular signal in the left main portal vein branch increased to 117 +/- 6%, 127 +/- 10%, and 133 +/- 9% of control, respectively. The contrast-to-noise ratio of the portal vein improved (521 +/- 90%, 891 +/- 178%, and 995 +/- 201% of control in the left portal vein main branch). Intravascular signal intensities increased slightly. The combined effect improved contrast of the portal vein stem and its branches. Receiver operating characteristics analysis documented dose-dependency of contrast medium effects on portal venous contrast and intravascular homogeneity. Visual rating also indicated a positive effect on portal venous contrast. The superparamagnetic iron oxide agent improved portal venous contrast with surrounding hepatic parenchyma in this normal animal model, and could potentially result in more accurate diagnosis of portal venous pathology.
我们研究的目的是确定超顺磁性氧化铁对门静脉系统磁共振成像的影响。使用飞行时间磁共振快速低角度激发二维血管造影序列，在1.5T磁场下对8只处于深度麻醉和呼吸停止状态的仔猪进行检查。在静脉注射累积剂量分别为10、20和40 μmol/kg的SHU 555A（一种粒径为60 nm的用于磁共振成像的超顺磁性氧化铁造影剂）之前和之后采集磁共振血管造影图像。对于每个剂量，进行两组连续扫描，并通过最大强度投影算法重建图像。测量肝实质和门静脉的信号强度，并计算每组扫描的门静脉对比度。由两名不知情的观察者对所有检查的门静脉对比度和均匀性进行视觉评分。分析两名观察者的受试者操作特征。造影剂以剂量依赖的方式降低肝实质信号。累积剂量为10 μmol氧化铁后，肝实质信号强度降至对照值的63±6%（4分钟和14分钟测量值的平均值，均值±均值标准误差），20 μmol后降至24±3%，40 μmol后降至12±1%。左主门静脉分支的血管内信号分别增加至对照值的117±6%、127±10%和133±9%。门静脉的对比噪声比得到改善（左门静脉主分支中分别为对照值的521±90%、891±178%和995±201%）。血管内信号强度略有增加。综合效应改善了门静脉主干及其分支的对比度。受试者操作特征分析证明了造影剂对门静脉对比度和血管内均匀性影响的剂量依赖性。视觉评分也表明对门静脉对比度有积极影响。在这个正常动物模型中，超顺磁性氧化铁制剂改善了门静脉与周围肝实质的对比度，并可能有助于更准确地诊断门静脉病变。
