Morphometric analysis program and quantitative positron emission tomography in presurgical localization in MRI-negative epilepsies: a simultaneous PET/MRI study.

Kun Guo,Guoguang Zhao,Yihe Wang,Jie Lu,Zhenming Wang,Bixiao Cui,Jingjuan Wang

doi:10.1007/s00259-021-05657-w

Abstract

To evaluate morphometric analysis program (MAP) and quantitative positron emission tomography (QPET) in epileptogenic zone (EZ) identification using a simultaneous positron emission tomography/magnetic resonance imaging (PET/MRI) system in MRI-negative epilepsies. Seventy-one localization-related MRI-negative epilepsies who underwent preoperative simultaneous PET/MRI examination and surgical resection were enrolled retrospectively. MAP was performed on a T1-weighted volumetric sequence, and QPET was analyzed using statistical parametric mapping (SPM) with comparison to age- and gender-matched normal controls. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MAP, QPET, MAP + QPET, and MAP/QPET in EZ localization were assessed. The correlations between surgical outcome and modalities concordant with cortical resection were analyzed. Forty-five (63.4%) patients had Engel I seizure outcomes. The sensitivity, specificity, PPV, and NPV of MAP were 64.4%, 69.2%, 78.3%, and 52.9%, respectively. The sensitivity, specificity, PPV, NPV of QPET were 73.3%, 65.4%, 78.6%, and 58.6%, respectively. MAP + QPET, defined as two tests concordant with cortical resection, had reduced sensitivity (53.3%) but increased specificity (88.5%) relative to individual tests. MAP/QPET, defined as one or both tests concordant with cortical resection, had increased sensitivity (86.7%) but reduced specificity (46.2%) relative to individual tests. The regions determined by MAP, QPET, MAP + QPET, or MAP/QPET concordant with cortical resection were significantly associated with the seizure-free outcome. QPET has a superior sensitivity than MAP, while the combined MAP + QPET obtained from a simultaneous PET/MRI scanner may improve the specificity of the diagnostic tests in EZ localization coupled with the preferable surgical outcome in MRI-negative epilepsies.

Highlights

For the magnetic resonance imaging (MRI)-negative intractable focal epilepsy patients, identifying a subtle abnormality that was previously undetected helps to provide an opportunity for surgical treatment
The focal hypometabolism foci shown on interictal 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) was associated with epileptogenic zone (EZ) [6, 7]. 18F-FDG PET has been widely used in preoperative localization of drug-resistant epilepsy with a negative MRI [8, 9]
Our study found that Morphometric analysis program (MAP) positive regions concordant with cortical resection associated with a favorable surgical outcome compared to the non-concordant ones

Summary

Introduction

For the magnetic resonance imaging (MRI)-negative intractable focal epilepsy patients, identifying a subtle abnormality that was previously undetected helps to provide an opportunity for surgical treatment. Longitudinal studies in MRI-negative focal epilepsy patients showed that resected surgery offers the potential for long-term seizure control [1, 2], which encouraged researchers using postprocessing imaging analysis to identify more potential epileptogenic zone (EZ). Morphometric analysis program (MAP), one of many MRI postprocessing imaging analysis, several researchers have demonstrated that MAP could be helped detect subtle abnormalities of focal cortical dysplasia (FCD) in MRI-negative surgical candidates [3,4,5]. 18F-FDG PET has been widely used in preoperative localization of drug-resistant epilepsy with a negative MRI [8, 9]. There are fewer data in the literature on the sensitivity and specificity of combined post-processing imaging with localization-related MRI-negative epilepsies

Methods

Results

Conclusion