PET of Serotonin 1A Receptors and Cerebral Glucose Metabolism for Temporal Lobectomy

Abstract

The objective of this study was to compare 5-hydroxytryptamine receptor 1A (5-HT1A) PET with cerebral metabolic rate of glucose (CMRglc) PET for temporal lobectomy planning. Methods We estimated 5-HT1A receptor binding preoperatively with 18F-trans-4-fluoro-N-2-[4-(2-methoxyphenyl) piperazin-1-yl]ethyl-N-(2-pyridyl) cyclohexane carboxamide (18F-FCWAY) PET and CMRglc measurement with 18F-FDG in regions drawn on coregistered MRI after partial-volume correction in 41 patients who had anterior temporal lobectomy with at least a 1-y follow-up. Surgery was tailored to individual preresection evaluations and intraoperative electrocorticography. Mean regional asymmetry values and the number of regions with asymmetry exceeding 2 SDs in 16 healthy volunteers were compared between seizure-free and non–seizure-free patients. 18F-FCWAY but not 18F-FDG and MRI data were masked for surgical decisions and outcome assessment. Results Twenty-six of 41 (63%) patients seizure-free since surgery had significantly different mesial temporal asymmetries, compared with 15 non-seizure-free patients for both 18F-FCWAY (F1,39 = 5.87; P = 0.02) and 18F-FDG PET (F1,38 = 5.79; P = 0.021). The probability of being seizure-free was explained by both 18F-FDG and 18F-FCWAY PET, but not MRI, with a significant additional 18F-FCWAY effect (χ22=9.8796; P = 0.0072) after the probability of being seizure-free was explained by 18F-FDG. Although MRI alone was not predictive, any combination of 2 lateralizing imaging studies was highly predictive of seizure freedom. Conclusion Our study provides class III evidence that both 5-HT1A receptor PET and CMRglc PET can contribute to temporal lobectomy planning. Additional studies should explore the potential for temporal lobectomy based on interictal elec-troencephalography and minimally invasive imaging studies.

Imaging biomarkers of behavioral impairments: A pilot micro–positron emission tomographic study in a rat electrical post–status epilepticus model

“…There is considerable interest in the application of 5HT 1A receptor imaging as a biomarker for psychiatric comorbidities . In patients with temporal lobe epilepsy, a negative correlation between 5HT 1A receptor binding and the severity of depression has been reported in mesial temporal structures and the insula . In the present study, a significant increase of septal [ 18 F]MPPF binding was evident in animals with epilepsy.…”

Neuroimaging of epilepsy

“…In combination with FDG-PET, 5HT-1A receptor imaging may help predict outcome after temporal lobectomy (Theodore et al, 2012a) (Fig. 51.23).…”

Monoaminergic Mechanisms in Epilepsy May Offer Innovative Therapeutic Opportunity for Monoaminergic Multi-Target Drugs

“…All of these studies point to the fact that diminished 5-HT 1A R expression and subsequent less activation by endogenous 5-HT may lead to the epileptic phenotype. PET imaging of brain 5-HT 1 A Rs has also helped in the correct identification of the epileptogenic zone during the preoperative evaluation of temporal lobe of PWE subjected to epilepsy surgery (Didelot et al, 2008; Theodore et al, 2012). …”