Mascott Christopher R, Summers Lori E
Beacon Department of Neurosciences, Beacon Hospital, Dublin 18, Ireland.
Surg Neurol. 2007 Jun;67(6):589-603; discussion 603. doi: 10.1016/j.surneu.2006.12.064.
Nonenhancing brain lesions can be relatively poorly defined on volumetric data sets routinely used for surgical guidance. Fluid-attenuated inversion recovery MRI sequences can provide better margin visualization of nonenhancing or poorly enhancing lesions.
Using image fusion programs, we combined data sets of SPGR imaging pulse sequence or volumetric CT with volumetrically acquired FLAIR sequences and subsequently used the fused data set for image-guided surgery. This technique was used in 50 surgical cases. Of these, 9 were nonenhancing intrinsic brain tumors, 13 were partially enhancing tumors, and 11 were enhancing tumors. In addition, FLAIR fusion was selectively used for 6 nontumoral lesions and in 11 nonlesional epilepsy surgery cases.
Image guidance using the fused data set was accurate in all 50 cases. Despite the lack of enhancement, 3 of the 9 nonenhancing tumors were found to be high grade. One of the low-grade tumors was associated with considerable areas of gliotic change not considered to represent tumor on permanent histology. In all other cases, the FLAIR-bright resected margins were consistent with tumor, not gliosis. Radical resection (>95% volume) was achieved in 21 of 23 tumor cases in which this had been the preoperative intent.
Nonenhancing lesions are often poorly demarcated not only on imaging studies, but also during surgery. Fluid-attenuated inversion recovery fusion allows resection of such lesions using intraoperative computer image guidance. Complementary FLAIR information can also occasionally be useful during surgical approaches to enhancing lesions or in nontumor cases. It must be kept in mind that FLAIR has high sensitivity but low specificity. Fluid-attenuated inversion recovery abnormalities do not obviate the need for mapping in potentially functional areas.
在常用于手术导航的容积数据集上，未强化的脑病变可能相对难以清晰界定。液体衰减反转恢复（FLAIR）磁共振成像序列能够更好地显示未强化或强化不佳病变的边界。
我们使用图像融合程序，将扰相梯度回波（SPGR）成像脉冲序列或容积CT的数据集与容积采集的FLAIR序列相结合，随后将融合后的数据集用于图像引导手术。该技术应用于50例手术病例。其中，9例为未强化的脑内肿瘤，13例为部分强化肿瘤，11例为强化肿瘤。此外，FLAIR融合还选择性地用于6例非肿瘤性病变以及11例非病变性癫痫手术病例。
在所有50例病例中，使用融合数据集进行的图像引导均准确无误。尽管缺乏强化，但9例未强化肿瘤中有3例被发现为高级别肿瘤。1例低级别肿瘤伴有相当大面积的胶质增生改变，在永久组织学检查中不被视为肿瘤。在所有其他病例中，FLAIR高信号的切除边缘与肿瘤相符，而非胶质增生。在23例术前计划进行根治性切除（>95%体积）的肿瘤病例中，有21例实现了根治性切除。
未强化病变不仅在影像学检查中常常边界不清，在手术过程中也是如此。液体衰减反转恢复融合技术能够在术中计算机图像引导下切除此类病变。在处理强化病变或非肿瘤病例的手术过程中，补充的FLAIR信息偶尔也会有用。必须牢记，FLAIR具有高敏感性但低特异性。液体衰减反转恢复异常并不能排除在潜在功能区进行定位的必要性。
