Nakaguchi H, Sasaki T, Kirino T, Okubo T, Hayashi N
Department of Neurosurgery, Faculty of Medicine, University of Tokyo.
No Shinkei Geka. 1997 Jul;25(7):599-606.
Whenever the extirpation of intracranial tumors is planned, neurosurgeons always keep their eyes on the cerebrospinal fluid (CSF) space around intracranial tumors. If enough space exists in the neighborhood of the tumors, the damage to adjacent parenchyma may be reduced by the procedure through the CSF space. A newly advanced MRI pulse sequence: the FLAIR (fluid attenuated inversion recovery) imaging, in which a long TE spin echo sequence is used with suppression of the CSF with an inversion pulse, displays the CSF space as a no-signal intensity area. There have been only a few reports, however, on the FLAIR pulse sequence of brain tumors as yet. We examined 34 cases of intracranial tumors by FLAIR images and analyzed the advantages and disadvantages of the FLAIR pulse sequence for decision making on tumor removal. Making use of the FLAIR pulse sequence, the CSF space is depicted as a no-signal intensity area and much more information about perifocal edema and the invasion area around the tumors can be provided than that provided by the other ordinary pulse sequences (T1 weighted images, T2 weighted images and Proton weighted images). Therefore, operative strategies can be more easily worked out on the FLAIR images. Furthermore, the difference between arachnoid and epidermoid is able to be detected on the FLAIR images. Nevertheless, on FLAIR images, the tumors without perifocal edema or invasion to adjacent parenchyma were not apparent and the difference between tumoral dissemination into multi-ventricular space and the periventricular artifact of FLAIR images could not be distinguished. The FLAIR pulse sequence has other artifacts like intraventricular flow related enhancement and so on. If the images are carefully checked up on the above-mentioned points, the FLAIR pulse sequence of MRI can not fail to be useful in making plans for operations on intracranial neoplasms.
每当计划切除颅内肿瘤时，神经外科医生总会密切关注颅内肿瘤周围的脑脊液（CSF）间隙。如果肿瘤周围有足够的间隙，通过脑脊液间隙进行手术可减少对相邻实质的损伤。一种新的先进MRI脉冲序列：液体衰减反转恢复（FLAIR）成像，它使用长TE自旋回波序列并通过反转脉冲抑制脑脊液，将脑脊液间隙显示为无信号强度区域。然而，关于脑肿瘤的FLAIR脉冲序列的报道迄今仍很少。我们通过FLAIR图像检查了34例颅内肿瘤，并分析了FLAIR脉冲序列在决定肿瘤切除方面的优缺点。利用FLAIR脉冲序列，脑脊液间隙被描绘为无信号强度区域，与其他普通脉冲序列（T1加权图像、T2加权图像和质子加权图像）相比，它能提供更多关于肿瘤周围水肿和肿瘤侵袭区域的信息。因此，在FLAIR图像上更容易制定手术策略。此外，在FLAIR图像上能够检测到蛛网膜囊肿和表皮样囊肿之间的差异。然而，在FLAIR图像上，没有肿瘤周围水肿或未侵袭相邻实质的肿瘤并不明显，并且无法区分肿瘤播散到多个脑室间隙与FLAIR图像的脑室周围伪影之间的差异。FLAIR脉冲序列还有其他伪影，如与脑室内血流相关的强化等。如果仔细检查上述各点，MRI的FLAIR脉冲序列在制定颅内肿瘤手术计划时肯定会有用。
