A Novel Method of Seizure Onset Zone Localization by Serial Tc-99m ECD Brain Perfusion SPECT Clearance Patterns

2021 ◽  
Author(s):  
Chanan Sukprakun ◽  
Chusak Limotai ◽  
Kitiwat Khamwan ◽  
Panya Pasawang ◽  
Supatporn Tepmongkol
Keyword(s):  
Brain Perfusion ◽  
Brain Regions ◽  
Diagnostic Tools ◽  
Seizure Onset ◽  
Visual Grading ◽  
Seizure Onset Zone ◽  
Significant Difference ◽  
Perfusion Spect ◽  
Novel Method ◽  
Drug Resistant Epilepsy

Abstract In this prospective study, we postulate that there is a difference between clearance of [99mTc]Tc- ethyl cysteinate dimer (ECD) in the seizure onset zone (SOZ) and other brain areas and thus SOZ localization by clearance patterns might become a potential novel method for SOZ localization in epilepsy. The parametric images of brain ECD clearance were generated by linear regression model analysis from serial brain SPECT scans from 30 minutes to 240 minutes after ECD injection (7-times point) in 7 patients with drug-resistant epilepsy and 3 normal volunteers. Clearance patterns of the SOZ confirmed by good surgical outcome or consensus with other investigations were analyzed quantitatively and semi-quantitatively by visual grading (slower or faster washout than contralateral brain regions). The average [99mTc]Tc-ECD clearance rates of SOZs were + 1.08 % ± 2.57 %/hr (wash in), -7.02 % ± 2.56 %/hr (washout), and − 5.37% ± 1.71 %/hr (washout) in ictal, aura and interictal states, respectively. Paired t-tests between the SOZ and contralateral regions showed statistically significant difference (p = 0.039 in interictal state). Clearance patterns that can define the SOZs were 1) wash in and slow washout on ictal slope, 2) fast washout on aura slope and interictal slope with 100% (6/6), 100% (2/2) and 75% (6/8) localization using ictal, aura, and interictal slope maps, respectively. Our study provided the evidence that clearance pattern methods are potential additive diagnostic tools for SOZ localization when routine one-time point SPECT are unable to define the SOZ.

scholarly journals Comparison of Ictal Brain Perfusion SPECT With 99mTc-HMPAO Versus 99mTc-ECD for Identification of The Epileptic Seizure Onset Zone

2020 ◽  
Author(s):  
Mariam Jaber ◽  
Jila Taherpour ◽  
Berthold Voges ◽  
Ivayla Apostolova ◽  
Thomas Sauvigny ◽  
...  
Keyword(s):  
Brain Perfusion ◽  
Drug Resistant ◽  
Seizure Onset ◽  
Tracer Injection ◽  
Brain Perfusion Spect ◽  
Temporal Epilepsy ◽  
Large Patient ◽  
Seizure Onset Zone ◽  
Perfusion Spect ◽  
Drug Resistant Epilepsy

Abstract Background: The chemical microspheres 99mTc-HMPAO and 99mTc-ECD are widely used as tracers in ictal brain perfusion SPECT for identification of the seizure onset zone (SOZ) in presurgical evaluation of patients with drug-resistant epilepsy and uncertainty of SOZ localization after standard diagnostic workup. For both tracers there are theoretical arguments to favor it over the other for this task. The aim of this study was to compare the performance of ictal brain perfusion SPECT between 99mTc-HMPAO and 99mTc-ECD in a rather large patient sample.Methods: The study retrospectively included 196 patients from clinical routine in whom ictal perfusion SPECT had been performed with stabilized 99mTc-HMPAO (n = 110) or 99mTc-ECD (n = 86). Lateralization and localization of the SOZ was obtained by the consensus of two independent readers who visually inspected the SPECT images retrospectively. Results: The 99mTc-HMPAO group and the 99mTc-ECD group were well matched with respect to age, sex, age at first seizure, duration of disease, seizure frequency, history of previous brain surgery, and findings of presurgical MRI. The tracer groups differed significantly with respect to the latency of tracer injection (median latency 4 s longer in the 99mTc-HMPAO group), duration of the seizure after tracer injection (25 s shorter in the 99mTc-HMPAO group), tracer dose (70 MBq higher in the 99mTc-HMPAO group), and delay of the SPECT acquisition after tracer injection (63 min longer in the 99mTc-HMPAO group). The fraction of lateralising ictal SPECT did not differ significantly between the 99mTc-HMPAO and the 99mTc-ECD group (65.5% versus 72.1%, p = 0.355). Sensitivity of ictal perfusion SPECT (independent of the tracer) for correct localization of the SOZ in 62 patients with temporal lobe epilepsy and at least worthwhile improvement (Engel scale ≤ III) 12 months after temporal epilepsy surgery was 63%.Conclusions: This study does not provide evidence to favor 99mTc-HMPAO or 99mTc-ECD for identification of the SOZ by ictal perfusion SPECT in patients with drug resistant epilepsy.

No Evidence to Favor 99mTc-HMPAO or 99mTc-ECD for Ictal Brain Perfusion SPECT for Identification of the Seizure Onset Zone

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Mariam Jaber ◽  
Jila Taherpour ◽  
Berthold Voges ◽  
Ivayla Apostolova ◽  
Thomas Sauvigny ◽  
...  
Keyword(s):  
Brain Perfusion ◽  
Seizure Onset ◽  
Brain Perfusion Spect ◽  
Seizure Onset Zone ◽  
Perfusion Spect ◽  
99Mtc Hmpao

scholarly journals The Connectivity Index: An Effective Metric for Grading Epileptogenicity

2019 ◽  
Author(s):  
Qi Yan ◽  
Nicolas Gaspard ◽  
Hitten P Zaveri ◽  
Hal Blumenfeld ◽  
Lawrence J. Hirsch ◽  
...  
Keyword(s):  
Average Distance ◽  
Single Pulse ◽  
Brain Regions ◽  
Control Site ◽  
Connectivity Index ◽  
Evoked Responses ◽  
Seizure Onset ◽  
Seizure Onset Zone ◽  
Site Of Stimulation ◽  
Stimulation Of

AbstractObjectiveTo investigate the performance of a metric of functional connectivity to classify and grade the excitability of brain regions based on evoked potentials to single pulse electrical stimulation (SPES).MethodsPatients who received 1-Hz frequency stimulation between 2003 and 2014 at Yale at prospectively selected contacts were included. The stimulated contacts were classified as seizure onset zone (SOZ), highly irritative zone (IZp) or control. Response contacts were classified as seizure onset zone (SOZ), active interictal (IZp), quiet or other. The normalized number of responses was defined as the number of contacts with any evoked responses divided by the total number of recorded contacts, and the normalized distance is the ratio of the average distance between the site of stimulation and sites of evoked responses to the average distances between the site of stimulation and all other recording contacts. A new metric we labeled the connectivity index (CI) is defined as the product of the two values.Results57 stimulation-sessions in 22-patients were analyzed. The connectivity index (CI) of the SOZ was higher than control (median CI of 0.74 vs. 0.16, p = 0.0002). The evoked responses after stimulation of SOZ were seen at further distance compared to control (median normalized distance 0.96 vs. 0.62, p = 0.0005). It was 1.8 times more likely to record a response at SOZ than in non-epileptic contacts after stimulation of a control site. Habitual seizures were triggered in 27% of patients and 35 % of SOZ contacts (median stimulation intensity 4 mA) but in none of the control or IZp contacts. Non-SOZ contacts in multifocal or poor surgical outcome cases had a higher CI than non-SOZ contacts in those with localizable onsets (medians CI of 0.5 vs. 0.12, p = 0.04). There was a correlation between the stimulation current intensity and the normalized number of evoked responses (r = + 0.49, p 0.01) but not with distance (r = + 0.1, p 0.64)ConclusionsWe found enhanced connectivity when stimulating the SOZ compared to stimulating control contacts; responses were more distant as well. Habitual auras and seizures provoked by SPES were highly predictive of brain sites involved in seizure generation.

scholarly journals Spatial variation in high-frequency oscillation rates and amplitudes in intracranial EEG

Neurology ◽  
2018 ◽  
Vol 90 (8) ◽  
pp. e639-e646 ◽  
Author(s):  
Hari Guragain ◽  
Jan Cimbalnik ◽  
Matt Stead ◽  
David M. Groppe ◽  
Brent M. Berry ◽  
...  
Keyword(s):  
High Frequency ◽  
Anatomic Variation ◽  
Brain Regions ◽  
Brain Atlas ◽  
Reproducible Research ◽  
High Frequency Oscillation ◽  
Seizure Onset ◽  
Frequency Oscillation ◽  
Intracranial Eeg ◽  
Seizure Onset Zone

ObjectiveTo assess the variation in baseline and seizure onset zone interictal high-frequency oscillation (HFO) rates and amplitudes across different anatomic brain regions in a large cohort of patients.MethodsSeventy patients who had wide-bandwidth (5 kHz) intracranial EEG (iEEG) recordings during surgical evaluation for drug-resistant epilepsy between 2005 and 2014 who had high-resolution MRI and CT imaging were identified. Discrete HFOs were identified in 2-hour segments of high-quality interictal iEEG data with an automated detector. Electrode locations were determined by coregistering the patient's preoperative MRI with an X-ray CT scan acquired immediately after electrode implantation and correcting electrode locations for postimplant brain shift. The anatomic locations of electrodes were determined using the Desikan-Killiany brain atlas via FreeSurfer. HFO rates and mean amplitudes were measured in seizure onset zone (SOZ) and non-SOZ electrodes, as determined by the clinical iEEG seizure recordings. To promote reproducible research, imaging and iEEG data are made freely available (msel.mayo.edu).ResultsBaseline (non-SOZ) HFO rates and amplitudes vary significantly in different brain structures, and between homologous structures in left and right hemispheres. While HFO rates and amplitudes were significantly higher in SOZ than non-SOZ electrodes when analyzed regardless of contact location, SOZ and non-SOZ HFO rates and amplitudes were not separable in some lobes and structures (e.g., frontal and temporal neocortex).ConclusionsThe anatomic variation in SOZ and non-SOZ HFO rates and amplitudes suggests the need to assess interictal HFO activity relative to anatomically accurate normative standards when using HFOs for presurgical planning.

scholarly journals Weighted and directed interactions in evolving large-scale epileptic brain networks

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Henning Dickten ◽  
Stephan Porz ◽  
Christian E. Elger ◽  
Klaus Lehnertz
Keyword(s):  
Large Scale ◽  
Complex Dynamics ◽  
Brain Networks ◽  
Population Sample ◽  
Brain Regions ◽  
Seizure Onset ◽  
Dynamical Disease ◽  
Seizure Onset Zone ◽  
Promising Line ◽  
And Function

Abstract Epilepsy can be regarded as a network phenomenon with functionally and/or structurally aberrant connections in the brain. Over the past years, concepts and methods from network theory substantially contributed to improve the characterization of structure and function of these epileptic networks and thus to advance understanding of the dynamical disease epilepsy. We extend this promising line of research and assess—with high spatial and temporal resolution and using complementary analysis approaches that capture different characteristics of the complex dynamics—both strength and direction of interactions in evolving large-scale epileptic brain networks of 35 patients that suffered from drug-resistant focal seizures with different anatomical onset locations. Despite this heterogeneity, we find that even during the seizure-free interval the seizure onset zone is a brain region that, when averaged over time, exerts strongest directed influences over other brain regions being part of a large-scale network. This crucial role, however, manifested by averaging on the population-sample level only – in more than one third of patients, strongest directed interactions can be observed between brain regions far off the seizure onset zone. This may guide new developments for individualized diagnosis, treatment and control.

scholarly journals The seizure onset zone drives state-dependent epileptiform activity in susceptible brain regions

2019 ◽  
Vol 130 (9) ◽  
pp. 1628-1641 ◽  
Author(s):  
Joshua M. Diamond ◽  
Julio I. Chapeton ◽  
William H. Theodore ◽  
Sara K. Inati ◽  
Kareem A. Zaghloul
Keyword(s):  
Epileptiform Activity ◽  
Brain Regions ◽  
Seizure Onset ◽  
State Dependent ◽  
Seizure Onset Zone

scholarly journals Stable high frequency background EEG activity distinguishes epileptic from healthy brain regions

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Annika Minthe ◽  
Wibke G Janzarik ◽  
Daniel Lachner-Piza ◽  
Peter Reinacher ◽  
Andreas Schulze-Bonhage ◽  
...  
Keyword(s):  
High Frequency ◽  
Background Activity ◽  
Sleep Stage ◽  
Strong Association ◽  
Brain Regions ◽  
High Frequency Oscillation ◽  
Seizure Onset ◽  
High Frequency Oscillations ◽  
Seizure Onset Zone ◽  
Low Entropy

Abstract High-frequency oscillations are markers of epileptic tissue. Recently, different patterns of EEG background activity were described from which high-frequency oscillations occur: high-frequency oscillations with continuously oscillating background were found to be primarily physiological, those from quiet background were linked to epileptic tissue. It is unclear, whether these interactions remain stable over several days and during different sleep-wake stages. High-frequency oscillation patterns (oscillatory vs. quiet background) were analysed in 23 patients implanted with depth and subdural grid electrodes. Pattern scoring was performed on every channel in 10 s intervals in three separate day- and night-time EEG segments. An entropy value, measuring variability of patterns per channel, was calculated. A low entropy value indicated a stable occurrence of the same pattern in one channel, whereas a high value indicated pattern instability. Differences in pattern distribution and entropy were analysed for 143 280 10 s intervals with allocated patterns from inside and outside the seizure onset zone, different electrode types and brain regions. We found a strong association between high-frequency oscillations out of quiet background activity, and channels of the seizure onset zone (35.2% inside versus 9.7% outside the seizure onset zone, P < 0.001), no association was found for high-frequency oscillations from continuous oscillatory background (P = 0.563). The type of background activity remained stable over the same brain region over several days and was independent of sleep stage and recording technique. Stability of background activity was significantly higher in channels of the seizure onset zone (entropy mean value 0.56 ± 0.39 versus 0.64 ± 0.41; P < 0.001). This was especially true for the presumed epileptic high-frequency oscillations out of quiet background (0.57 ± 0.39 inside versus 0.72 ± 0.37 outside the seizure onset zone; P < 0.001). In contrast, presumed physiological high-frequency oscillations from continuous oscillatory backgrounds were significantly more stable outside the seizure onset zone (0.72 ± 0.45 versus 0.48 ± 0.53; P < 0.001). The overall low entropy values suggest that interactions between high-frequency oscillations and background activity are a stable phenomenon specific to the function of brain regions. High-frequency oscillations occurring from a quiet background are strongly linked to the seizure onset zone whereas high-frequency oscillations from an oscillatory background are not. Pattern stability suggests distinct underlying mechanisms. Analysing short time segments of high-frequency oscillations and background activity could help distinguishing epileptic from physiologically active brain regions.

A probabilistic approach for lateralization of seizure onset zone in drug-resistant epilepsy with bilateral cerebral pathology

2016 ◽  
Vol 277 ◽  
pp. 136-140
Author(s):  
Ravindra Arya ◽  
Siva Sivaganesan ◽  
Katherine D. Holland ◽  
Hansel M. Greiner ◽  
Francesco T. Mangano ◽  
...  
Keyword(s):  
Probabilistic Approach ◽  
Drug Resistant ◽  
Seizure Onset ◽  
Seizure Onset Zone ◽  
Cerebral Pathology ◽  
Drug Resistant Epilepsy
Sign in / Sign up

Export Citation Format

Share Document