arXiv:2508.13406cs.LGcs.AI2025-08

用啁啾信号异常检测辅助癫痫灶定位,提升手术成功患者定位精度。

Semi-Supervised Anomaly Detection Pipeline for SOZ Localization Using Ictal-Related Chirp

  • 基于啁啾信号的时频特征,用自适应邻域的局部异常因子检测异常电极。
  • 加权空间匹配比精确重合更能准确识别癫痫起始区,手术成功者平均精确率达86.5%。
  • 适合癫痫外科术前评估,尤其对术后效果好的患者有显著辅助价值。

本研究提出一种定量评估临床定义的癫痫发作起始区(SOZ)与通过啁啾事件时频分析识别的统计异常电极空间一致性框架。该流程采用两步法:(1) 无监督异常检测,利用自适应邻域选择的局部异常因子(LOF)分析,基于啁啾信号的起始频率、终止频率和持续时间等时频特征识别异常电极;(2) 空间相关性分析,计算精确共现指标与加权指数相似性,融合半球一致性与电极邻近性。结果显示,采用N=20、污染率=0.2的LOF方法有效检测异常点,加权相似性指标优于精确匹配。在无发作患者中,指数精确率均值达0.903;手术成功者为0.865;失败病例则仅0.460。结论表明,结合加权空间度量的啁啾异常检测可作为癫痫灶定位的补充方法,尤其适用于手术预后良好的患者。

原文摘要 · Abstract (English)

This study presents a quantitative framework for evaluating the spatial concordance between clinically defined seizure onset zones (SOZs) and statistically anomalous channels identified through time-frequency analysis of chirp events. The proposed pipeline employs a two-step methodology: (1) Unsupervised Outlier Detection, where Local Outlier Factor (LOF) analysis with adaptive neighborhood selection identifies anomalous channels based on spectro-temporal features of chirp (Onset frequency, offset frequency, and temporal duration); and (2) Spatial Correlation Analysis, which computes both exact co-occurrence metrics and weighted index similarity, incorporating hemispheric congruence and electrode proximity. Key findings demonstrate that the LOF-based approach (N neighbors=20, contamination=0.2) effectively detects outliers, with index matching (weighted by channel proximity) outperforming exact matching in SOZ localization. Performance metrics (precision, recall, F1) were highest for seizure-free patients (Index Precision mean: 0.903) and those with successful surgical outcomes (Index Precision mean: 0.865), whereas failure cases exhibited lower concordance (Index Precision mean: 0.460). The key takeaway is that chirp-based outlier detection, combined with weighted spatial metrics, provides a complementary method for SOZ localization, particularly in patients with successful surgical outcomes.

癫痫定位异常检测脑电分析手术辅助

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