Correlations of interictal FDG-PET metabolism and ictal SPECT perfusion changes in human temporal lobe epilepsy with hippocampal sclerosis

Nelissen, Natalie; Paesschen, Wim Van; Baete, Kristof; Laere, Koen Van; Palmini, André; Billoen, H. Van; Dupont, Patrick

doi:10.1016/j.neuroimage.2006.04.185

Cited by 133 publications

(104 citation statements)

References 48 publications

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“…The spatial pattern of this network was similar to that of the temporal epileptic network reported in other studies using different imaging modalities [Bernhardt et al, 2008;Blumenfeld et al, 2004;Spencer, 2002;Tae et al, 2005]. Although a general consensus has been reached that the hippocampus is the key of the epileptogenic focus, increasing evidence has shown that widespread brain structures, including the bilateral mesial temporal structures [Bernhardt et al, 2008;Seidenberg et al, 2005;Spencer, 2002], neocortices such as the lateral temporal [Blumenfeld et al, 2004;Tae et al, 2005] and parietal lobes [Englot et al, 2008;Nelissen et al, 2006;Tae et al, 2005], subcortical structures such as the thalamus [Labate et al, 2008;Schwarcz et al, 2002;Yune et al, 1998], basal ganglia and pontine nuclei [Bouilleret et al, 2005] etc., compose a reciprocal mesial temporal epileptic network contributing to the process of mTLE [Blumenfeld et al, 2004;Sakamoto et al, 2003;Spencer, 2002]. The largely overlapped results might implicate that the widespread increased ALFF is underpinned by the mesial temporal epileptic network proposed by Spencer [2002].…”

Section: Regions Showing Increased Alff and The Temporal Epileptic Nesupporting

confidence: 82%

fMRI study of mesial temporal lobe epilepsy using amplitude of low‐frequency fluctuation analysis

Zhang

Zhong

et al. 2010

Human Brain Mapping

180

163

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Various functional imaging tools have been used to detect epileptic activity in the neural network underlying mesial temporal lobe epilepsy (mTLE). In the present fMRI study, a data-driven approach was employed to map interictal epileptic activity in mTLE patients by measuring the amplitude of low-frequency fluctuation (ALFF) of the blood oxygen level-dependent (BOLD) signal. Twenty-four left mTLE patients and 26 right mTLE patients were investigated by comparing with 25 healthy subjects. In the patients, the regions showing increased ALFF were consistently distributed in the mesial temporal lobe, thalamus, and a few of other cortical and subcortical structures composing a mesial temporal epilepsy network proposed previously, while the regions showing decreased ALFF were mostly located in the areas of so-called default-mode network. Data of simultaneous EEG-fMRI from a portion of the patients suggested that the increases in ALFF might be associated with the interictal epileptic activity. Individual analyses based on statistic parametric mapping revealed a moderate sensitivity and a fairly high specificity for the lateralization of unilateral mTLE. We conclude that the ALFF analysis may provide a useful tool in fMRI study of epilepsy.

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Section: Regions Showing Increased Alff and The Temporal Epileptic Nesupporting

confidence: 82%

fMRI study of mesial temporal lobe epilepsy using amplitude of low‐frequency fluctuation analysis

Zhang

Zhong

et al. 2010

Human Brain Mapping

180

163

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“…F-FDG PET and a high-resolution 3D T1-weighted Magnetization Prepared Rapid Acquisition Gradient Echo (3D-MPRAGE) MR scan of twenty neurologically normal volunteers (9 male/11 female, median age: 29 (range 21-49)) were available from a previous study approved by the Local Ethics Committee (30). Informed consent had been obtained from all participants before the investigations.…”

Section: Healthy Volunteersmentioning

confidence: 99%

“…The reconstructed images of the patient data were first flipped if needed to make sure the epileptogenic focus was always at the left side. All reconstructions of the measured human data were then first normalized to cancel out differences in average WM activity, as proposed in (30). Next, these images were spatially normalized to the stereotactic Montreal Neurological Institute (MNI) space using the non-linear warping obtained during MR segmentation.…”

Section: Spm Analysismentioning

confidence: 99%

Voxel-based comparison of state-of-the-art reconstruction algorithms for 18F-FDG PET brain imaging using simulated and clinical data

et al. 2014

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The resolution of a PET scanner (2.5-4.5 mm for brain imaging) is similar to the thickness of the cortex in the (human) brain (2.5 mm on average), hampering accurate activity distribution reconstruction. Many techniques to compensate for the limited resolution during or postreconstruction have been proposed in the past and have been shown to improve the quantitative accuracy. In this study, state-of-the-art reconstruction techniques are compared on a voxel-basis for quantification accuracy and group analysis using both simulated and measured data of healthy volunteers and patients with epilepsy. Methods: Maximum a posteriori (MAP) reconstructions using either a segmentation-based or a segmentation-less anatomical prior were compared to maximum likelihood expectation maximization (MLEM) reconstruction with resolution recovery. As anatomical information, a spatially aligned 3-D T1-weighted magnetic resonance image was used. Firstly, the algorithms were compared using normal brain images to detect systematic bias with respect to the true activity distribution, as well as systematic differences between two methods. Secondly, it was verified whether the algorithms yielded similar results in a group comparison study. Results: Significant differences were observed between the reconstructed and the true activity, with the largest errors when using (postsmoothed) MLEM. Only 5-10 % underestimation in cortical gray matter voxel activity was found for both MAP reconstructions. Higher errors were observed at GM edges. MAP with the segmentation-based prior also resulted in a significant bias in the subcortical regions due to segmentation inaccuracies, while MAP with the anatomical prior which does not need segmentation did not. Significant differences in reconstructed activity were also found between the algorithms at similar locations (mainly in gray matter edge voxels and in cerebrospinal fluid voxels) in the simulated as well as in the clinical data sets. Nevertheless, when comparing two groups, very similar regions of significant hypometabolism were detected by all algorithms. Conclusion: Including anatomical a priori information during reconstruction in combination with resolution modeling yielded accurate gray matter activity estimates, and a significant improvement in quantification accuracy was found when compared to post-smoothed MLEM reconstruction with resolution modeling. AsymBowsher provided more accurate subcortical GM activity estimates. It is also reassuring that the differences found between the algorithms did not hamper the detection of hypometabolic regions in the gray matter when performing a voxel-based group comparison. Nevertheless, the size of the detected clusters differed. More elaborated and application-specific studies are required to decide which algorithm is best for a group analysis.

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“…8,9 If scalp interictal and ictal EEG do not adequately localise the area of seizure onset, it may be necessary to undertake intracranial EEG recordings, with intracerebral depth electrodes and/or subdural strips and grids of electrodes (Fig 3). These are a major undertaking with a risk of significant morbidity.…”

Section: The Evaluationmentioning

confidence: 99%

Epilepsy surgery

Duncan

2007

Clinical Medicine

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-If the first two or three antiepileptic drugs used do not control epilepsy, there is little chance that subsequent medications will be effective. In individuals with refractory focal epilepsy, neurosurgery can have a 60-70% chance of bringing long-term remission and these cases should be referred to a specialised centre for evaluation. The standard evaluation includes clinical review, brain imaging with magnetic resonance imaging, recording of seizures with prolonged scalp electroencephalography (EEG) and video, neuropsychological and psychiatric assessments. The aim is to establish converging evidence that there is a single epileptic focus and that the rest of the brain is functioning normally. In some individuals further evaluation with functional imaging and intracranial EEG recordings may be necessary. The most commonly performed resective operation is an anterior temporal lobe resection to remove a sclerotic hippocampus, followed by lesionectomies and neocortical resections. Palliative manoeuvres, to reduce seizure frequency and severity include corpus callosotomy, subpial transection and vagal nerve stimulation.

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Correlations of interictal FDG-PET metabolism and ictal SPECT perfusion changes in human temporal lobe epilepsy with hippocampal sclerosis

Cited by 133 publications

References 48 publications

fMRI study of mesial temporal lobe epilepsy using amplitude of low‐frequency fluctuation analysis

fMRI study of mesial temporal lobe epilepsy using amplitude of low‐frequency fluctuation analysis

Voxel-based comparison of state-of-the-art reconstruction algorithms for 18F-FDG PET brain imaging using simulated and clinical data

Epilepsy surgery

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