1Department of Neurosurgery, Pasteur 2 Hospital, University Hospital of Nice, France.
2Clinical Research Unit UR2CA team PIN, French Riviera University, Nice, France.
J Neurosurg. 2024 Apr 19;141(3):684-694. doi: 10.3171/2024.1.JNS23568. Print 2024 Sep 1.
The free-water correction algorithm (Freewater Estimator Using Interpolated Initialization [FERNET]) can be applied to standard diffusion tensor imaging (DTI) tractography to improve visualization of subcortical bundles in the peritumoral area of highly edematous brain tumors. Interest in its use for presurgical planning in purely infiltrative gliomas without peritumoral edema has never been evaluated. Using subcortical maps obtained with direct electrostimulation (DES) in awake surgery as a reference standard, the authors sought to 1) assess the accuracy of preoperative DTI-based tractography with FERNET in a series of nonedematous glioma patients, and 2) determine its potential usefulness in presurgical planning.
Based on DES-induced functional disturbances and tumor topography, the authors retrospectively reconstructed the putatively stimulated bundles and the peritumoral tracts of interest (various associative and projection pathways) of 12 patients. The tractography data obtained with and without FERNET were compared.
The authors identified 21 putative tracts from 24 stimulation sites and reconstituted 49 tracts of interest. The number of streamlines of the putative tracts crossing the DES area was 26.8% higher (96.04 vs 75.75, p = 0.016) and their volume 20.4% higher (13.99 cm3 vs 11.62 cm3, p < 0.0001) with FERNET than with standard DTI. Additionally, the volume of the tracts of interest was 22.1% higher (9.69 cm3 vs 7.93 cm3, p < 0.0001).
Free-water correction significantly increased the anatomical plausibility of the stimulated fascicles and the volume of tracts of interest in the peritumoral area of purely infiltrative nonedematous gliomas. Because of the functional importance of the peritumoral zone, applying FERNET to DTI could have potential implications on surgical planning and the safety of glioma resection.
自由水校正算法（FERNET）可应用于标准弥散张量成像（DTI）示踪术，以改善高度水肿脑肿瘤瘤周区皮质下束的可视化效果。但从未评估其在无瘤周水肿的纯浸润性胶质瘤的术前规划中的应用。本研究使用清醒开颅术中直接电刺激（DES）获得的皮质下图谱作为参考标准，旨在：1）评估 FERNET 在一系列无水肿性胶质瘤患者中基于术前 DTI 示踪术的准确性；2）确定其在术前规划中的潜在作用。
基于 DES 诱导的功能障碍和肿瘤位置，作者回顾性重建了 12 例患者的推测受刺激束和瘤周感兴趣区（各种联合和投射通路）。比较了有无 FERNET 时的示踪数据。
作者从 24 个刺激部位确定了 21 个推测束，并重建了 49 个感兴趣束。穿过 DES 区域的推测束的流线数量增加了 26.8%（96.04 比 75.75，p = 0.016），体积增加了 20.4%（13.99cm3 比 11.62cm3，p < 0.0001）。此外，感兴趣区的束体积增加了 22.1%（9.69cm3 比 7.93cm3，p < 0.0001）。
自由水校正显著提高了单纯浸润性无水肿性胶质瘤瘤周区受刺激束和感兴趣区束的解剖学可信度。由于瘤周区的功能重要性，FERNET 应用于 DTI 可能对手术规划和胶质瘤切除的安全性产生潜在影响。
