Epilepsy Society Magnetic Resonance Imaging Unit, Department of Clinical and Experimental Epilepsy, University College London Institute of Neurology, and Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, United Kingdom.
Ann Neurol. 2012 Mar;71(3):334-41. doi: 10.1002/ana.22619.
Anterior temporal lobe resection (ATLR) is an effective treatment for refractory temporal lobe epilepsy but may result in a contralateral superior visual field deficit (VFD) that precludes driving in the seizure-free patient. Diffusion tensor imaging (DTI) tractography can delineate the optic radiation preoperatively and stratify risk. It would be advantageous to incorporate display of tracts into interventional magnetic resonance imaging (MRI) to guide surgery.
We studied 20 patients undergoing ATLR. Structural MRI scans, DTI, and visual fields were acquired before and 3 to 12 months following surgery. Tractography of the optic radiation was performed on preoperative images and propagated onto postoperative images. The anteroposterior extent of the damage to Meyer's loop was determined, and visual loss was quantified using Goldmann perimetry.
Twelve patients (60%) suffered a VFD (10-92% of upper quadrant; median, 39%). Image registration took <3 minutes and predicted that Meyer's loop was 4.4 to 18.7mm anterior to the resection margin in these patients, but 0.0 to 17.6mm behind the resection margin in the 8 patients without VFD. The extent of damage to Meyer's loop significantly correlated with the degree of VFD and explained 65% of the variance in this measure.
The optic radiation can be accurately delineated by tractography and propagated onto postoperative images. The technique is fast enough to propagate accurate preoperative tractography onto intraoperative scans acquired during neurosurgery, with the potential to reduce the risk of VFD.
前颞叶切除术（ATLR）是治疗耐药性颞叶癫痫的有效方法，但可能导致对侧上视野缺损（VFD），使无癫痫发作的患者无法驾驶。弥散张量成像（DTI）束追踪术可以在术前描绘视辐射并分层风险。将束显示纳入介入性磁共振成像（MRI）以指导手术将是有利的。
我们研究了 20 例接受 ATLR 的患者。在手术前和手术后 3 至 12 个月，采集了结构 MRI 扫描、DTI 和视野。在术前图像上进行视辐射的束追踪，并将其传播到术后图像上。确定 Meyer 环的前后损伤范围，并使用 Goldmann 视野计量化视力丧失。
12 名患者（60%）出现 VFD（上象限的 10-92%；中位数为 39%）。图像配准耗时不到 3 分钟，并预测在这些患者中，Meyer 环位于切除缘前 4.4 至 18.7mm，而在无 VFD 的 8 名患者中位于切除缘后 0.0 至 17.6mm。Meyer 环的损伤程度与 VFD 的程度显著相关，解释了该指标 65%的方差。
视辐射可以通过束追踪术准确描绘，并传播到术后图像上。该技术足够快，可以将准确的术前束追踪术传播到神经外科术中获得的术中扫描上，有降低 VFD 风险的潜力。
