Houkin K, Kamiyama H, Iwasaki Y, Abe H, Miyasaka K, Koiwa M, Kashiwaba T
Department of Neurosurgery, Hokkaido University School of Medicine.
No Shinkei Geka. 1992 Nov;20(11):1155-60.
In its initial stage of development, poor time resolution was supposed to be inevitable for magnetic resonance imaging (MRI). The development of the gradient echo technique, however, has made an opening for a breakthrough to a fast MRI technique. However, conventional gradient echo technique is not fast enough to disclose the cerebral blood circulation. A new technique (turbo-FLASH), which combines gradient echo and preparation pulse, has opened the door to a true dynamic (high time resolution) MRI. The authors performed a basic study of this new fast imaging technique (Turbo-FLASH) for the evaluation of cerebral blood circulation. Using this dynamic MRI, the conventional Gd-DTPA administration (0.1mmol/kg, intravenous manual administration) has produced sufficient contrast to reveal a difference of the extent of enhancement between normal gray matter and white matter. In patients of cerebral infarction, the infarcted brain does not show any significant increase of signal intensity after the administration of contrast medium, whereas the normal brain shows a sharp increase of signal intensity after the administration of contrast medium. Indeed, many puzzling questions remain to be solved for clinical application of this new dynamic MRI. For example, the optimal quantity of contrast medium and optimal parameters for this sequence (T1 weighted or T2 weighted?) are still unknown. But, in any case, this dynamic MRI is expected to be a clinically powerful tool for the evaluation of cerebral blood flow.
在其发展的初始阶段，人们认为磁共振成像（MRI）的时间分辨率较差是不可避免的。然而，梯度回波技术的发展为快速MRI技术的突破开辟了道路。然而，传统的梯度回波技术速度不够快，无法揭示脑血液循环情况。一种将梯度回波和准备脉冲相结合的新技术（快速低角度激发序列，Turbo-FLASH）为真正的动态（高时间分辨率）MRI打开了大门。作者对这种用于评估脑血液循环的新型快速成像技术（快速低角度激发序列，Turbo-FLASH）进行了基础研究。使用这种动态MRI，传统的钆喷酸葡胺给药（0.1mmol/kg，静脉手动给药）产生了足够的对比度，以揭示正常灰质和白质之间强化程度的差异。在脑梗死患者中，梗死的脑组织在给予造影剂后信号强度没有任何显著增加，而正常脑组织在给予造影剂后信号强度急剧增加。事实上，这种新型动态MRI的临床应用仍有许多令人困惑的问题有待解决。例如，造影剂的最佳用量以及该序列的最佳参数（T1加权还是T2加权？）仍然未知。但是，无论如何，这种动态MRI有望成为评估脑血流的一种强大的临床工具。
