1Department of Neurosurgery, Johns Hopkins School of Medicine.
2Department of Neurology, Johns Hopkins School of Medicine.
J Neurosurg. 2022 Apr 29;137(6):1601-1609. doi: 10.3171/2022.3.JNS212490. Print 2022 Dec 1.
Piriform cortex (PC) is one of the critical structures in the epileptogenesis of mesial temporal lobe epilepsy (mTLE), but its role is poorly understood. The authors examined the utility of apparent diffusion coefficient (ADC; an MR-based marker of tissue pathology) of the PC as a predictor of seizure outcome in patients with mTLE undergoing MR-guided laser interstitial thermal therapy (MRgLITT).
A total of 33 patients diagnosed with mTLE who underwent MRgLITT at the authors' institution were included in the study. The 6-month postoperative seizure outcomes were classified using the International League Against Epilepsy (ILAE) system as good (complete seizure freedom, ILAE class I) and poor (seizure present, ILAE classes II-VI). The PC and ablation volumes were manually segmented from both the preoperative and intraoperative MRI sequences, respectively. The mean ADC intensities of 1) preablation PC; 2) total ablation volume; 3) ablated portion of PC; and 4) postablation residual PC were calculated and compared between good and poor outcome groups. Additionally, the preoperative PC volumes and proportion of PC volume ablated were examined and compared between the subjects in the two outcome groups.
The mean age at surgery was 36.5 ± 3.0 years, and the mean follow-up duration was 1.9 ± 0.2 years. Thirteen patients (39.4%) had a good outcome. The proportion of PC ablated was significantly associated with seizure outcome (10.16 vs 3.30, p < 0.05). After accounting for the variability in diffusion tensor imaging acquisition parameters, patients with good outcome had a significantly higher mean ADC of the preablation PC (0.3770 vs -0.0108, p < 0.05) and the postoperative residual PC (0.4197 vs 0.0309, p < 0.05) regions compared to those with poor outcomes. No significant differences in ADC of the ablated portion of PC were observed (0.2758 vs -0.4628, p = 0.12) after performing multivariate analysis.
A higher proportion of PC ablated was associated with complete seizure freedom. Preoperative and postoperative residual ADC measures of PC were significantly higher in the good seizure outcome group in patients with mTLE who underwent MRgLITT, suggesting that ADC analysis can assist with postablation outcome prediction and patient stratification.
梨状皮层（PC）是内侧颞叶癫痫（mTLE）致痫形成的关键结构之一，但作用机制尚不清楚。作者研究了 PC 的表观扩散系数（ADC；组织病理学的一种基于磁共振的标志物）作为接受磁共振引导激光间质热疗（MRgLITT）的 mTLE 患者术后癫痫发作结果预测因子的效用。
共纳入 33 例在作者单位接受 MRgLITT 的 mTLE 患者，使用国际抗癫痫联盟（ILAE）系统对术后 6 个月的癫痫发作结果进行分类，结果为良好（完全无癫痫发作，ILAE Ⅰ级）和不良（有癫痫发作，ILAE Ⅱ-Ⅵ级）。分别从术前和术中 MRI 序列手动分割 PC 和消融体积。比较两组间 1）术前 PC 的平均 ADC 强度；2）总消融体积；3）PC 消融部分；4）术后残留 PC 的平均 ADC 强度。另外，比较两组间患者的术前 PC 体积和 PC 消融比例。
手术时的平均年龄为 36.5±3.0 岁，平均随访时间为 1.9±0.2 年。13 例（39.4%）患者术后结果良好。PC 消融比例与癫痫发作结果显著相关（10.16 比 3.30，p<0.05）。在考虑扩散张量成像采集参数的变异性后，术后结果良好的患者术前 PC（0.3770 比-0.0108，p<0.05）和术后残留 PC（0.4197 比 0.0309，p<0.05）的 ADC 均值显著更高。多变量分析后，PC 消融部分的 ADC 无显著差异（0.2758 比-0.4628，p=0.12）。
更高的 PC 消融比例与完全无癫痫发作有关。接受 MRgLITT 的 mTLE 患者中，术后良好的癫痫发作结果与术前和术后残留 PC 的 ADC 测量值显著较高有关，提示 ADC 分析可辅助术后结果预测和患者分层。
