Figure 9 - uploaded by Barbara Anne K. Kreilkamp
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Patient 65: FCD / gliosis in right superior frontal gyrus. Diagnosis was made based on the 3D T2-FLAIR image of 2015 (green image borders). The abnormality was not reported on the previous 2D axial T2-w image (red image borders) where only one slice showed the small abnormality. R ¼ right.
Source publication
Aim:
To evaluate whether a dedicated epilepsy research protocol with expert image re-evaluation can increase identification of patients with lesions and to attempt to ascertain the potential reasons why lesions were not identified previously on earlier clinical magnetic resonance imaging (MRI).
Materials and methods:
Forty-three patients (26 fem...
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Citations
... Despite prominent progress in neuroimaging techniques, particularly MRI, delicate alterations of brain tissue in epileptogenic lesion is hard to detect with conventional approaches. It has been shown recently that in part of originally diagnosed "non-lesional" epilepsies was a "lesion" identified later with more advanced imaging approaches [8]. Dysplastic tissue can be detected by MRI only in situations where it possesses distinct properties from surrounding tissue. ...
Magnetic Resonance Imaging (MRI) has revolutionized our ability to non-invasively study the brain's structural and functional properties. However, detecting myelin, a crucial component of white matter, remains challenging due to its indirect visibility on conventional MRI scans. Myelin plays a vital role in neural signal transmission and is associated with various neurological conditions. Understanding myelin distribution and content is crucial for insights into brain development, aging, and neurological disorders. Although specialized MRI sequences can estimate myelin content, these are time-consuming. Also, many patients sent to specialized neurological centers have an MRI of the brain already scanned. In this study, we focused on techniques utilizing standard MRI T1-weighted (T1w) and T2 weighted (T2w) sequences commonly used in brain imaging protocols. We evaluated the applicability of the T1w/T2w ratio in assessing myelin content by comparing it to quantitative T1 mapping (qT1). Our study included 1 healthy adult control and 7 neurologic patients (comprising both pediatric and adult populations) with epilepsy originating from focal epileptogenic lesions visible on MRI structural scans. Following image acquisition on a 3T Siemens Vida scanner, datasets were co registered, and segmented into anatomical regions using the Fastsurfer toolbox, and T1w/T2w ratio maps were calculated in Matlab software. We further assessed interhemispheric differences in volumes of individual structures, their signal intensity, and the correlation of the T1w/T2w ratio to qT1. Our data demonstrate that in situations where a dedicated myelin-sensing sequence such as qT1 is not available, the T1w/T2w ratio provides significantly better information than T1w alone. By providing indirect information about myelin content, this technique offers a valuable tool for understanding the neurobiology of myelin-related conditions using basic brain scans.
... The study ended with 230 PWE with three lesion evaluations using conventional and HARNESS-MRI protocol followed by HARNESS plus multidisciplinary meeting. The median age at the time of scanning was 20 and IQR (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29).75) years, and gender distribution was 146 (62%) male and 91 (38%) female patients. According to the 2017 ILAE classification, 186 (80.9%) patients had focal onset seizures, while 44 (19.1%) were unknown, lateralized to the right in 57 (31%) and the left in 58 (31%). ...
... The primary associated factors explaining the newly identified lesions were the choice of dedicated imaging sequences, optimized imaging parameters, maximum data quality, lesion not reported (human factor), and loss of information through incomplete documentation. All clinicians must proceed meticulously in the detailed assessment of epilepsy-dedicated in-vivo MRI and discuss challenging cases in multidisciplinary team meetings [15,16]. Neuropathological diagnoses were predicted accurately in 90% of epilepsy-dedicated imaging when correlating radiological findings with histopathology. ...
... Several studies demonstrated a critical reason why some lesions had previously escaped the attention of the reporting neuroradiologist. This may be due to the choice of sequence, with lesions being more conspicuous on dedicated epilepsy protocols [15]. The human factor might also play a role in omitting some lesions, which explains why the two neuroradiological experts examined the previous conventional MR in our study. ...
Objectives:
The international league against epilepsy (ILAE) recommended the harmonized neuroimaging of epilepsy structural sequences (HARNESS-MRI) to improve the detection of epileptogenic lesions in patients with focal drug-resistant epilepsy (DRE). The application of this protocol is still limited in low-resource countries, mainly due to apparent high costs. We aimed to evaluate the cost-effectiveness of the HARNESS-MRI protocol in Egypt and highlighted our experience.
Methods:
Patients diagnosed with focal DRE at Cairo University epilepsy clinic underwent both conventional MRI (c-MRI) and HARNESS-MRI. Electro-clinical data were collected and analyzed. After the radiologists' initial diagnosis, a multidisciplinary team re-evaluated the MRI. Lesion detection rate and cost for detecting an extra lesion by HARNESS-MRI protocol were calculated.
Results:
The study included 230 patients with focal DRE (146, 62% males and 91, 38% females), with a mean age of 20.5 years. Epileptogenic lesions detected by c-MRI and HARNESS-MRI before and after the board meeting were 40, 106, and 131 lesions, respectively (P < 0.001). Sixty-nine percent of the lesions detected by HARNESS-MRI were missed on c-MRI; most commonly were mesial temporal sclerosis (MTS) and Malformations of cortical development (MCDs). Thirty-seven MTS and 32 MCDs were detected with HARNESS-MRI, compared to only 6 and 3, respectively, detected on c-MRI (P < 0.001). HARNESS-MR protocol is more cost-effective than c-MRI in detecting MRI lesions; it can save about 42$ for detecting an extra lesion in MRI.
Conclusion:
The HARNESS-MRI protocol was cost-effective and highly recommended even in limited-resource countries for patients with focal DRE.
... Hippocampal sclerosis (HS) is the most frequently observed pathology in treatment-refractory mesial temporal lobe epilepsy [1]. For detecting such structural epileptogenic lesions, magnetic resonance imaging (MRI) with appropriate protocols is pivotal [2][3][4][5]. Radiological signs of HS include volume loss and T2/FLAIR signal alterations [6], whereas a loss of the hippocampal internal architecture is difficult to demarcate on 3T imaging [7]. The radiological interpretation from MRI is predominantly a visual task by qualitatively assessing the images, although quantitative volumetry has been generally recommended [8]. ...
Objective:
To evaluate the influence of quantitative reports (QReports) on the radiological assessment of hippocampal sclerosis (HS) from MRI of patients with epilepsy in a setting mimicking clinical reality.
Methods:
The study included 40 patients with epilepsy, among them 20 with structural abnormalities in the mesial temporal lobe (13 with HS). Six raters blinded to the diagnosis assessed the 3T MRI in two rounds, first using MRI only and later with both MRI and the QReport. Results were evaluated using inter-rater agreement (Fleiss' kappa [Formula: see text]) and comparison with a consensus of two radiological experts derived from clinical and imaging data, including 7T MRI.
Results:
For the primary outcome, diagnosis of HS, the mean accuracy of the raters improved from 77.5% with MRI only to 86.3% with the additional QReport (effect size [Formula: see text]). Inter-rater agreement increased from [Formula: see text] to [Formula: see text]. Five of the six raters reached higher accuracies, and all reported higher confidence when using the QReports.
Conclusion:
In this pre-use clinical evaluation study, we demonstrated clinical feasibility and usefulness as well as the potential impact of a previously suggested imaging biomarker for radiological assessment of HS.
... Designation as MRI-negative epilepsy is highly dependent on the quality of MR imaging as well as on the experience of the evaluating neuroradiologists. Previous studies have demonstrated that significantly higher percentage of MR images were rated as lesion-negative when evaluated by general radiologists vs radiologists at specialized epilepsy centers and when general MRI protocols were applied as opposed to specialized epilepsy protocols (Kreilkamp et al., 2019;von Oertzen et al., 2002). Improvements in MR-imaging technology are increasingly unmasking formerly undetected lesions, leading to a corresponding decrease in the number of MRIL101_-negative patients (Bernasconi et al., 2011). ...
Objective:
MRI-negative drug-resistant epilepsy presents a challenge when it comes to surgical planning, and surgical outcome is worse than in cases with an identified lesion. Although increasing implementation of more powerful MRI scanners and artificial intelligence has led to the detection of previously unrecognizable lesions, in some cases even postoperative pathological evaluation of electrographically epileptogenic zones shows no structural alterations. While in temporal lobe epilepsy a standardized resection approach can usually be performed, the surgical management of extra-temporal lesions is always individual. Here we present a strategy for treating patients with extra-temporal MRI-negative epilepsy focus and report our histological findings and patient outcome.
Methods:
Patients undergoing epilepsy surgery in the Department of Neurosurgery at the University Hospital Erlangen between 2012 and 2020 were included in the study. Inclusion criteria were: (1) failure to identify a structural lesion on preoperative high-resolution 3 Tesla MRI with a standardized epilepsy protocol and (2) preoperative intracranial EEG (iEEG) diagnostics.
Results:
We identified 8 patients corresponding to the inclusion criteria. Second look MRI analysis by an experienced neuroradiologist including the most recent analysis algorithm utilized in our clinic revealed a possible lesion in two patients. One of the patients with a clear focal cortical dysplasia (FCD) finding on a second look was excluded from further analysis. Of the other 7 patients, in one patient iEEG was performed with subdural electrodes, whereas the other 6 were evaluated with depth electrodes. MEG was performed preoperatively in all but one patient. An MEG focus was implemented in resection planning in 3 patients. FDG PET was performed in all, but only implemented in one patient. Histopathological evaluation revealed one non-lesional case, 4 cases of FCD and 2 cases with mild developmental malformation. All patients were free from permanent neurological deficits and presented with Engel 1A or 1B outcome on the last follow-up.
Conclusion:
We demonstrate that extra-temporal MRI-negative epilepsy can be treated successfully provided an extensive preoperative planning is performed. The most important diagnostic was stereo-EEG, whereas additional data from MEG was helpful and FDG PET was rarely useful in our cohort.
... [13][14][15][16] Existing literature on encephaloceles in epilepsy mostly comprises case reports, 12,15,[17][18][19] small case series, [20][21][22][23] and several retrospective studies. 1,[3][4][5]16,[24][25][26][27] No prospective trials have been reported. In recent reports, these lesions were identified on retrospective review of the imaging studies including computed tomography (CT) and different magnetic resonance imaging (MRI) sequences, suggesting that they are often missed during preoperative evaluation. ...
... In recent reports, these lesions were identified on retrospective review of the imaging studies including computed tomography (CT) and different magnetic resonance imaging (MRI) sequences, suggesting that they are often missed during preoperative evaluation. 2,4,24 There is no clear consensus on the management of these lesions with either lesionectomy (removing the encephalocele and repairing the defect) or partial/complete lobectomy. 16,25,28 In this article, we review the literature on encephaloceles and epilepsy, focusing on the location, type of epileptic activity, surgical procedure performed, and outcomes. ...
... Since then, high-resolution MRI has been described to successfully identify these lesions, usually by an experienced neuroradiologist because the abnormal findings may be subtle. 5,24,33 Wang et al. 30 described a case in which regular MRI sequences failed to detect the abnormality, but 3-T MRI with constructive interference in steady state confirmed the presence of an encephalocele. Furthermore, a study found that encephaloceles were significantly more likely to be identified if 3-T MRI was used compared with those patients imaged at a lower field strength. ...
Epileptogenic encephaloceles, most frequently located in the temporal lobe, are a known lesional cause of focal epilepsy. Data are limited regarding diagnosis, management, and outcomes of patients with epilepsy in the setting of an encephalocele, as the literature is mostly comprised of case reports, case series, and retrospective studies. We conducted a broad literature review for manuscripts related to encephaloceles and epilepsy regardless of level of evidence. Hence, this manuscript provides a summary of all available literature related to the topic. Thirty-six scientific reports that fulfilled our inclusion criteria were reviewed. The majority of reported cases presented with focal impaired awareness seizures and/or generalized tonic-clonic seizures. Although most of the encephaloceles were located in the temporal lobe, we found five cases of extra-temporal encephaloceles causing epilepsy. A greater proportion of cases that underwent either lesionectomy or lobectomy were seizure free at time of follow-up. In the temporal lobe, there is no clear consensus on the appropriate management for epileptic encephaloceles and further studies are warranted to understand the associated factors and long-term outcomes associated to epilepsy secondary to encephaloceles. Published data suggests that these cases could be potentially be manageable with surgical procedures including lesionectomy or lobectomy. Additionally, due to data suggesting similar results between procedures, a more conservative surgery with lesionectomy and defect repair rather than a lobectomy may potentially have lower surgical risks while having similar seizure freedom.
... This can be extremely challenging, in particular in those with small epileptogenic lesions such as focal cortical dysplasias (FCDs) which are often overlooked (e.g. 33% in [1]) or impossible to visualise on conventional magnetic resonance imaging (MRI) scans (e.g. 28% of patients in [2]). ...
Die Bedeutung der strukturellen Bildgebung hat durch stetige Verbesserungen der Auflösung mithilfe optimierter und neuer Sequenzen sowie durch verbesserte MRT-Scanner in den letzten Jahren deutlich zugenommen. Neben der Analyse der Anfallssemiologie und dem EEG ist das MRT des Kopfs, ambulant wie stationär, nunmehr die dritte essenzielle Säule der Epilepsiediagnostik. Sie hilft insbesondere bei der ätiologischen Zuordnung von Epilepsien und kann kausale Therapienotwendigkeiten und -optionen aufzeigen. Die zuverlässige Detektion epileptogener Läsionen erfordert die Verwendung epilepsiespezifischer MRT-Protokolle, die Kenntnis epileptogener Läsionen seitens der Befunder und das Vorhandensein einer klinischen Hypothese bezüglich der Zone des Anfallsursprungs.
Introduction
Malformation of cortical development (MCD) is strongly associated with drug-resistant epilepsies for which surgery to remove epileptogenic lesions is common. Two notable technological advances in this field are identification of the underlying genetic cause and techniques in neuroimaging. These now question how pre-surgical evaluation ought to be approached for ‘mTORpathies’.
Area covered
From review of published primary and secondary articles, the authors summarize evidence to consider focal cortical dysplasia (FCD), tuber sclerosis complex (TSC), and hemimegalencephaly (HME) collectively as MCD mTORpathies. The authors also consider the unique features of these related conditions with particular focus on the practicalities of using neuroimaging techniques currently available to define surgical targets and predict post-surgical outcome. Ultimately, the authors consider the surgical dilemmas faced for each condition.
Expert opinion
Considering FCD, TSC and HME collectively as mTORpathies has some merit; however, a unified approach to pre-surgical evaluation would seem unachievable. Nevertheless, the authors believe combining genetic-centered classification and morphologic findings using advanced imaging techniques will eventually form the basis of a paradigm when considering candidacy for early surgery.
[\({}^{18}\)F]fluorodeoxyglucose (FDG) positron emission tomography (PET) aids in the localisation of the epileptogenic zone in patients with focal epilepsy, especially when magnetic resonance imaging (MRI) is normal or non-contributory. We propose a two-stage deep learning framework to support the clinical evaluation of patients with focal epilepsy by identifying candidate regions of hypometabolism in [¹⁸F]FDG PET scans. In the first stage, we train a generative adversarial network (GAN) to learn the mapping between healthy [¹⁸F]FDG PET and T1-weighted (T1w) MRI data. In the second stage, we synthesise pseudo-normal PET images from T1w MRI scans of patients with epilepsy to compare to the real PET scans. Comparing the estimated pseudo-PET images to the true PET scans in healthy control data, our GAN produced whole-brain mean absolute errors of \(0.053 \pm 0.015\), outperforming a U-Net (\(0.058 \pm 0.021\)) and a high-resolution dilated convolutional neural network (\(0.060 \pm 0.024\); all images scaled 0–1). In a sample of 20 epilepsy patients, we created Z-statistic images (with thresholding at +2.33) by subtracting the patient’s true PET scans from their estimated pseudo-normal PET images to identify regions of hypometabolism. Excellent sensitivity for lobar location of abnormalities (\(92.9 \pm 13.1\%\)) was observed for the seven cases with MR-visible epileptogenic lesions. For the 13 cases with non-contributory MR, a lower sensitivity of \(74.8 \pm 32.3\%\) was observed. Our method performed better than a statistical parametric mapping analysis. Our results highlight the potential of deep learning-based pseudo-normal [¹⁸F]FDG PET synthesis to contribute to the management of epilepsy.
