Kopka L, Vosshenrich R, Rodenwaldt J, Grabbe E
Department of Radiology, Hospital of Georg-August-University, Goettingen, Germany.
AJR Am J Roentgenol. 1998 Feb;170(2):345-8. doi: 10.2214/ajr.170.2.9456943.
The aim of the study was to evaluate the optimization of injection rates with an automatic power injector versus manual injection for contrast-enhanced breath-hold three-dimensional (3D) MR angiography of the abdominal aorta and its branches.
In a prospective study, 50 patients underwent breath-hold 3D MR angiography (5/2 [TR/TE]; flip angle, 30 degrees) of the abdominal vessels on a 1.5-T system. Each patient received 0.15 mmol/kg of gadopentetate dimeglumine. All patients were randomly assigned to one of five equally sized groups. The contrast bolus was injected manually in group 1, always by the same investigator, who tried to perform a steady injection rate of 2 ml/sec. An automatic injector was used in groups 2-5 with injection flow rates of 0.5 ml/sec, 2 ml/sec, 4 ml/sec, and 6 ml/sec. The start of the MR sequence was tailored individually to the applied volume of contrast material after determination of circulation times by a test bolus. We measured the signal-to-noise and contrast-to-noise ratios as well as the relative vascular enhancement. The visualization of different abdominal vessel segments was independently ranked on a scale of 1-5 (1 = not visible; 5 = excellent visualization) by three reviewers who were unaware of the applied contrast material injection rate.
The signal-to-noise and contrast-to-noise ratios of groups 3 and 4 (2 ml/sec and 4 ml/sec, respectively) were significantly (p < .05) higher than the ratios of groups 1, 2, and 5. The average relative vascular enhancement of groups 3 and 4 was significantly higher (p < .05) than the enhancement of all other groups. The contrast bolus applied with a faster injection rate (group 5) did not cover large parts of the K-space, resulting in increased blurring of the vessel contours. The subjective evaluation of large and small diameter vessels showed significantly better results in groups 3 and 4 than in groups 1, 2, and 5.
The use of an automatic MR power injector proved superior to manual injection of contrast material. The optimal injection rate was 2 ml/sec for 3D breath-hold MR angiography of the abdominal vessels.
本研究旨在评估在腹部主动脉及其分支的对比增强屏气三维（3D）磁共振血管造影中，使用自动高压注射器与手动注射相比时注射速率的优化情况。
在一项前瞻性研究中，50例患者在1.5-T系统上接受腹部血管的屏气3D磁共振血管造影（5/2 [TR/TE]；翻转角，30度）。每位患者接受0.15 mmol/kg的钆喷酸葡胺。所有患者被随机分配到五个大小相等的组中的一组。第1组采用手动注射造影剂团注，始终由同一位研究者进行，其试图以2 ml/秒的稳定注射速率注射。第2 - 5组使用自动注射器，注射流速分别为0.5 ml/秒、2 ml/秒、4 ml/秒和6 ml/秒。在通过试验团注确定循环时间后，磁共振序列的启动根据所注射造影剂的体积进行个体化调整。我们测量了信噪比和对比噪声比以及相对血管强化程度。由三位不知道所应用造影剂注射速率的观察者，对不同腹部血管段的可视化情况独立地按照1 - 5级进行评分（1 = 不可见；5 = 极佳的可视化）。
第3组和第4组（分别为2 ml/秒和4 ml/秒）的信噪比和对比噪声比显著高于（p < 0.05）第1组、第2组和第5组。第3组和第4组的平均相对血管强化程度显著高于（p < 0.05）所有其他组。以更快注射速率（第5组）注射的造影剂团注未覆盖大部分K空间，导致血管轮廓的模糊度增加。对大直径和小直径血管的主观评估显示，第3组和第4组的结果明显优于第1组、第2组和第5组。
使用自动磁共振高压注射器证明优于手动注射造影剂。对于腹部血管的3D屏气磁共振血管造影，最佳注射速率为每秒2毫升。
