Application of MRI Post-processing in Presurgical Evaluation of Non-lesional Cingulate Epilepsy

Abstract

Background and Purpose: Surgical management of patients with cingulate epilepsy (CE) is highly challenging, especially when the MRI is non-lesional. We aimed to use a voxel-based MRI post-processing technique, implemented in a morphometric analysis program (MAP), to facilitate detection of subtle epileptogenic lesions in CE, thereby improving surgical evaluation of patients with CE with non-lesional MRI by visual inspection.Methods: Included in this retrospective study were 9 patients with CE (6 with negative 3T MRI and 3 with subtly lesional 3T MRI) who underwent surgery and became seizure-free or had marked seizure improvement with at least 1-year follow-up. MRI post-processing was applied to pre-surgical T1-weighted volumetric sequence using MAP. The MAP finding was then coregistered and compared with other non-invasive imaging tests (FDG-PET, SPECT and MEG), intracranial EEG ictal onset, surgery location and histopathology.Results: Single MAP+ abnormalities were found in 6 patients, including 3 patients with negative MRI, and 3 patients with subtly lesional MRI. Out of these 6 MAP+ patients, 4 patients became seizure-free after complete resection of the MAP+ abnormalities; 2 patients didn't become seizure-free following laser ablation that only partially overlapped with the MAP+ abnormalities. All MAP+ foci were concordant with intracranial EEG ictal onset (when performed). The localization value of FDG-PET, SPECT and MEG was limited in this cohort. FCD was identified in all patients' surgical pathology except for two cases of laser ablation with no tissue available.Conclusion: MAP provided helpful information for identifying subtle epileptogenic abnormalities in patients with non-lesional cingulate epilepsy. MRI postprocessing should be considered to add to the presurgical evaluation test battery of non-lesional cingulate epilepsy.

Morphometric MRI Analysis: Improved Detection of Focal Cortical Dysplasia Using the MP2RAGE Sequence

“…Morphometric MR imaging analysis was performed on MPRAGE and MP2RAGE images using a fully automated script, MAP, running in Matlab, Version R2014b (MathWorks). The current version of the program (MAP18) corresponds to previous implementations known as MAP07 6,11,12 but now uses algorithms of SPM12, eg, the algorithm for normalization into Montreal Neurological Institute space known as "unified segmentation" (with small modifications in SPM12 compared with SPM5; see SPM12 Manual, page 51f, www.fil.ion.ucl.ac.uk) and the recently improved segmentation into 5 tissue classes instead of 3 as in SPM5. The creation of the morphometric maps has been described in detail in previous publications.…”

Application of combined multimodal neuroimaging and video-electroencephalography in intractable epilepsy patients for improved post-surgical outcome prediction

“…It has been reported that the seizure-free rate among MAP-positive patients was significantly higher than among MAP-negative, as was found in the present study. This depended on the high sensitivity of junction images in FCD detection 27,28 (Fig 3a) and the high sensitivity of extension images in heterotopia detection. 12 MRI quantitative methods could provide complementary information for the PET/MRI results; however, according to the analysis reported in previous studies, the overall MAP detection rate ranged between 43% and 50% in MRI-negative epilepsy 15,29 (Fig 3b), which would affect the total value of MAP use for prognostic evaluation.…”

Preoperative evaluation of dynamic contrast‑enhanced MRI‑guided lesion identification using morphometric and textural analysis for patients with epilepsy

“…The pathophysiology of epilepsy includes the simultaneous presence of hippocampal sclerosis and its comorbidities associated with psychiatric and cognitive complications ( 28 ). Clinically, MRI is routinely performed to diagnose and assess non-lesional cingulate epilepsy ( 19 , 29 , 30 ). Dce-MRI examination has previously demonstrated considerable accuracy in the preoperative localization of epileptic foci, suggesting that Dce-MRI is suitable for use as a basic reference for the diagnosis of patients with epilepsy ( 20 ).…”