Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, United Kingdom.
Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, United Kingdom.
Neuroimage Clin. 2018 Aug 13;20:458-465. doi: 10.1016/j.nicl.2018.08.021. eCollection 2018.
Surgical resection is an effective treatment for temporal lobe epilepsy but can result in visual field defects. This could be minimized if surgeons knew the exact location of the anterior part of the optic radiation (OR), the Meyer's loop. To this end, there is increasing prevalence of image-guided surgery using diffusion MRI tractography. Despite considerable effort in developing analysis methods, a wide discrepancy in Meyer's loop reconstructions is observed in the literature. Moreover, the impact of differences in image acquisition on Meyer's loop tractography remains unclear. Here, while employing the same state-of-the-art analysis protocol, we explored the extent to which variance in data acquisition leads to variance in OR reconstruction.
Diffusion MRI data were acquired for the same thirteen healthy subjects using standard and state-of-the-art protocols on three scanners with different maximum gradient amplitudes (MGA): Siemens Connectom (MGA = 300 mT/m); Siemens Prisma (MGA = 80 mT/m) and GE Excite-HD (MGA = 40 mT/m). Meyer's loop was reconstructed on all subjects and its distance to the temporal pole (ML-TP) was compared across protocols.
A significant effect of data acquisition on the ML-TP distance was observed between protocols ( < .01 to 0.0001). The biggest inter-acquisition discrepancy for the same subject across different protocols was 16.5 mm (mean: 9.4 mm, range: 3.7-16.5 mm).
We showed that variance in data acquisition leads to substantive variance in OR tractography. This has direct implications for neurosurgical planning, where part of the OR is at risk due to an under-estimation of its location using conventional acquisition protocols.
手术切除是治疗颞叶癫痫的有效方法，但会导致视野缺陷。如果外科医生知道视辐射（optic radiation，OR）前部即 Meyer 袢的确切位置，这种情况可以最小化。为此，越来越多的外科医生使用扩散磁共振成像束追踪术进行图像引导手术。尽管在开发分析方法方面付出了相当大的努力，但文献中观察到 Meyer 袢重建存在相当大的差异。此外，图像采集差异对 Meyer 袢追踪术的影响仍不清楚。在这里，我们在使用相同的最先进分析协议的同时，探讨了数据采集的差异在多大程度上导致 OR 重建的差异。
我们对 13 名健康受试者使用标准和最先进的协议，在 3 台具有不同最大梯度幅度（maximum gradient amplitude，MGA）的扫描仪上采集扩散磁共振成像数据：西门子 Connectom（MGA=300 mT/m）；西门子 Prisma（MGA=80 mT/m）和 GE Excite-HD（MGA=40 mT/m）。在所有受试者上重建 Meyer 袢，并比较其与颞极的距离（ML-TP）。
我们观察到协议之间数据采集对 ML-TP 距离有显著影响（<0.01 至 0.0001）。同一受试者在不同协议之间的最大采集差异为 16.5mm（平均值：9.4mm，范围：3.7-16.5mm）。
我们表明，数据采集的差异会导致 OR 追踪术的实质性差异。这对神经外科手术计划有直接影响，由于使用常规采集协议低估了其位置，OR 的一部分处于风险之中。
