Hypometabolism in the Posteromedial Temporal and Medial Occipital Cortex on Preoperative 2-Deoxy-2-(18F) Fluoro-D-Glucose Positron Emission Tomography Suggests Exacerbation of Visual Field Defects After Surgery for Temporal Lobe Epilepsy: A Retrospective Long-Term Follow-Up Study

• Published in: World neurosurgery Vol. 188; pp. e223 - e232
• Main Authors: Shanta, Thapa, Tomari, Yumi Kashida, Higashi, Takuichiro, Madan, Bajagain, Hosoyama, Hiroshi, Otsubo, Toshiaki, Yamahata, Hitoshi, Hanaya, Ryosuke
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2024
• Subjects: FDG-PET; Glucose hypometabolism; Optic radiation; Surgery; Temporal lobe epilepsy; Visual field defect; FDG-PET; HFA; MO; Optic radiation; MRI; EOS; FDG; Glucose hypometabolism; TLE; VFD; Surgery; PMT; Visual field defect; PDPPs; Temporal lobe epilepsy; ATL; SAH; PET; temporal lobe epilepsy; optic radiation; glucose hypometabolism; visual field defect; surgery
• ISSN: 1878-8750; 1878-8769; 1878-8769
• DOI: 10.1016/j.wneu.2024.05.089

Surgery is a good treatment option for drug-resistant temporal lobe epilepsy (TLE). 2-deoxy-2-(18F) fluoro-D-glucose (FDG) positron emission tomography (PET) is used to detect epileptic foci as hypometabolic lesions in presurgical evaluation. Visual field defects (VFDs) in the contralateral homonymous upper quadrant are common postoperative complications in TLE. This study aimed to quantify VFDs using pattern deviation probability plots (PDPPs) and examine the effect of hypometabolism in FDG-PET on VFDs. This study included 40 patients. Both visual fields were assessed using the Humphrey field analyzer preoperatively and 3 months and 2 years postoperatively. PDPPs with <0.5% confidence level counted in the contralateral homonymous upper quadrant. FDG-PET results were compared between groups with (15 patients) and without (24 patients) hypometabolism in the optic radiation. All 40 patients were evaluated by Humphrey field analyzer at 3 months postoperatively and 39 at 2 years postoperatively. The incidence of VFDs 3 months postoperatively was 35/40 (87.5%), and 17/40 (42.5%) patients had severe VFDs. In cases of surgery on the left temporal lobe, ipsilateral eyes appeared to be more significantly affected than contralateral eyes. VFDs were more severe in patients with FDG hypometabolism than in those without hypometabolism in posteromedial temporal and medial occipital cortex (P < 0.01); however, 85% of patients with FDG hypometabolism had a reduced VFD 2 years postoperatively. PDPP counting is useful for quantifying VFDs. Preoperative dysfunction indicated by preoperative FDG-PET in the posteromedial temporal and medial occipital cortex could enhance VFDs early after TLE surgery.