Heverhagen Johannes T, Bourekas Eric, Sammet Steffen, Knopp Michael V, Schmalbrock Petra
Department of Radiology, The Ohio State University, Columbus, Ohio 43210-1250, USA.
Invest Radiol. 2008 Aug;43(8):568-73. doi: 10.1097/RLI.0b013e31817e9b2c.
Magnetic resonance angiography (MRA) is noninvasive and does not require the application of high doses of contrast agents, and thus is used in the clinical routine for evaluation of cerebrovascular diseases, eg, aneurysm and arteriovenous malformations. However, more subtle microvascular disease usually cannot be seen with the resolution capabilities of standard field strength MRA. The purpose of this study was to evaluate the ability of 7-T time-of-flight (ToF) MRA to depict the arterial brain vasculature and to compare the results to data from 1.5 T and 3 T.
The study was IRB approved and complied with The Health Insurance Portability and Accountability Act. All subjects gave written informed consent. Eight healthy volunteers (age: 36 +/- 10 years; 3 female, 5 male) were investigated using ToF MRA at 7 T, 3 T, and 1.5 T. Signal intensities of the large, primary vessels of the Circle of Willis were measured and signal-to-noise ratios were calculated. Visibility of smaller arteries was evaluated.
The results show that ultrahigh field allows depiction of the large vessels of the Circle of Willis. Although it provides only small increases in signal-to-noise ratios for these vessels, compared with 1.5 T and 3 T, it additionally demonstrates considerably more first- and second-order branches.
Because of its considerably enhanced potential to depict vessels of the Circle of Willis and its first- and second-order branches, ToF MRA at 7 T may become an important tool in future neuroradiology research and clinical care.
磁共振血管造影（MRA）是非侵入性的，不需要使用高剂量的造影剂，因此用于临床常规评估脑血管疾病，如动脉瘤和动静脉畸形。然而，标准场强MRA的分辨率通常无法显示更细微的微血管疾病。本研究的目的是评估7T时间飞跃（ToF）MRA描绘脑动脉血管系统的能力，并将结果与1.5T和3T的数据进行比较。
本研究经机构审查委员会批准，并符合《健康保险流通与责任法案》。所有受试者均签署了书面知情同意书。8名健康志愿者（年龄：36±10岁；3名女性，5名男性）接受了7T、3T和1.5T的ToF MRA检查。测量了 Willis 环主要大血管的信号强度，并计算了信噪比。评估了较小动脉的可视性。
结果表明，超高场能够描绘 Willis 环的大血管。虽然与1.5T和3T相比，它只为这些血管提供了小幅的信噪比提升，但它还能显示出更多的一级和二级分支。
由于7T的ToF MRA描绘 Willis 环血管及其一级和二级分支的能力显著增强，它可能成为未来神经放射学研究和临床护理的重要工具。
