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4. Interictal blood–brain barrier dysfunction in piriform cortex of people with epilepsy.

Author

Schulte, Freya, Reiter, Johannes T., Bauer, Tobias, Taube, Julia, Bitzer, Felix, Witt, Juri‐Alexander, Piper, Rory, Thanabalasingam, Anoja, von Wrede, Randi, Racz, Attila, Baumgartner, Tobias, Borger, Valeri, Specht‐Riemenschneider, Louisa, Vatter, Hartmut, Hattingen, Elke, Deichmann, Ralf, Helmstaedter, Christoph, Radbruch, Alexander, Friedman, Alon, and Surges, Rainer

Subjects
TEMPORAL lobe epilepsy, PEOPLE with epilepsy, EPILEPSY surgery, VERBAL memory, CONTRAST media, TEMPORAL lobectomy
Abstract

Objective: The piriform cortex is considered to be highly epileptogenic. Its resection during epilepsy surgery is a predictor for postoperative seizure freedom in temporal lobe epilepsy. Epilepsy is associated with a dysfunction of the blood–brain barrier. We investigated blood–brain barrier dysfunction in the piriform cortex of people with temporal lobe epilepsy using quantitative T1‐relaxometry. Methods: Gadolinium‐based contrast agent was administered ictally and interictally in 37 individuals before undergoing quantitative T1‐relaxometry. Postictal and interictal images were co‐registered, and subtraction maps were created as biomarkers for peri‐ictal (∆qT1interictal‐postictal) and interictal (∆qT1noncontrast‐interictal) blood–brain barrier dysfunction. Values were extracted for the piriform cortex, hippocampus, amygdala, and the whole cortex. Results: In temporal lobe epilepsy (n = 14), ∆qT1noncontrast‐interictal was significantly higher in the piriform cortex than in the whole cortex (p = 0.02). In extratemporal lobe epilepsy (n = 23), ∆qT1noncontrast‐interictal was higher in the hippocampus than in the whole cortex (p = 0.05). Across all individuals (n = 37), duration of epilepsy was correlated with ∆qT1noncontrast‐interictal (ß = 0.001, p < 0.001) in all regions, while the association was strongest in the piriform cortex. Impaired verbal memory was associated with ∆qT1noncontrast‐interictal only in the piriform cortex (p = 0.04). ∆qT1interictal‐postictal did not show differences in any region. Interpretation: Interictal blood–brain barrier dysfunction occurs in the piriform cortex in temporal lobe epilepsy. This dysfunction is linked to longer disease duration and worse cognitive deficits, emphasizing the central role of the piriform cortex in the epileptogenic network of temporal lobe epilepsy. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Evidence for interictal blood–brain barrier dysfunction in people with epilepsy

Author

Reiter, Johannes T., primary, Schulte, Freya, additional, Bauer, Tobias, additional, David, Bastian, additional, Endler, Christoph, additional, Isaak, Alexander, additional, Schuch, Fabiane, additional, Bitzer, Felix, additional, Witt, Juri‐Alexander, additional, Hattingen, Elke, additional, Deichmann, Ralf, additional, Attenberger, Ulrike, additional, Becker, Albert J., additional, Helmstaedter, Christoph, additional, Radbruch, Alexander, additional, Surges, Rainer, additional, Friedman, Alon, additional, and Rüber, Theodor, additional

Published
2024
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19. Leptomeningeal Collateral Status by Signal Variance in Perfusion Magnetic Resonance Imaging: Association With Initial Stroke Severity and Early Functional Outcome After Thrombectomy

Author

Helwig, Niklas, primary, Seker, Fatih, additional, Möhlenbruch, Markus A., additional, Deichmann, Ralf, additional, Nöth, Ulrike, additional, Gracien, René‐Maxime, additional, Hattingen, Elke, additional, Wagner, Marlies, additional, and Seiler, Alexander, additional

Published
2023
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21. HiHi fMRI: a data-reordering method for measuring the hemodynamic response of the brain with high temporal resolution and high SNR

Author

Nagy, Zoltan; https://orcid.org/0000-0001-6611-6362, Hutton, Chloe; https://orcid.org/0000-0002-8897-0719, David, Gergely; https://orcid.org/0000-0002-9379-5193, Hinterholzer, Natalie; https://orcid.org/0000-0002-3530-0615, Deichmann, Ralf; https://orcid.org/0000-0002-4110-1225, Weiskopf, Nikolaus; https://orcid.org/0000-0001-5239-1881, Vannesjo, S Johanna; https://orcid.org/0000-0003-2432-4192, Nagy, Zoltan; https://orcid.org/0000-0001-6611-6362, Hutton, Chloe; https://orcid.org/0000-0002-8897-0719, David, Gergely; https://orcid.org/0000-0002-9379-5193, Hinterholzer, Natalie; https://orcid.org/0000-0002-3530-0615, Deichmann, Ralf; https://orcid.org/0000-0002-4110-1225, Weiskopf, Nikolaus; https://orcid.org/0000-0001-5239-1881, and Vannesjo, S Johanna; https://orcid.org/0000-0003-2432-4192

Abstract

There is emerging evidence that sampling the blood-oxygen-level-dependent (BOLD) response with high temporal resolution opens up new avenues to study the in vivo functioning of the human brain with functional magnetic resonance imaging. Because the speed of sampling and the signal level are intrinsically connected in magnetic resonance imaging via the T1 relaxation time, optimization efforts usually must make a trade-off to increase the temporal sampling rate at the cost of the signal level. We present a method, which combines a sparse event-related stimulus paradigm with subsequent data reshuffling to achieve high temporal resolution while maintaining high signal levels (HiHi). The proof-of-principle is presented by separately measuring the single-voxel time course of the BOLD response in both the primary visual and primary motor cortices with 100-ms temporal resolution.

Published
2023

22. Focal epilepsy without overt epileptogenic lesions: no evidence of microstructural brain tissue damage in multi-parametric quantitative MRI

Author

Hamid, Celona, Maiworm, Michelle, Wagner, Marlies, Knake, Susanne, Nöth, Ulrike, Deichmann, Ralf, Gracien, René-Maxime, Seiler, Alexander, Hamid, Celona, Maiworm, Michelle, Wagner, Marlies, Knake, Susanne, Nöth, Ulrike, Deichmann, Ralf, Gracien, René-Maxime, and Seiler, Alexander

Abstract

Background and purpose: In patients with epilepsies of structural origin, brain atrophy and pathological alterations of the tissue microstructure extending beyond the putative epileptogenic lesion have been reported. However, in patients without any evidence of epileptogenic lesions on diagnostic magnetic resonance imaging (MRI), impairment of the brain microstructure has been scarcely elucidated. Using multiparametric quantitative (q) magnetic resonance imaging MRI, we aimed to investigate diffuse impairment of the microstructural tissue integrity in MRI-negative focal epilepsy patients. Methods: 27 MRI-negative patients with focal epilepsy (mean age 33.1 ± 14.2 years) and 27 matched healthy control subjects underwent multiparametric qMRI including T1, T2, and PD mapping at 3 T. After tissue segmentation based on synthetic anatomies, mean qMRI parameter values were extracted from the cerebral cortex, the white matter (WM) and the deep gray matter (GM) and compared between patients and control subjects. Apart from calculating mean values for the qMRI parameters across the respective compartments, voxel-wise analyses were performed for each tissue class. Results: There were no significant differences for mean values of quantitative T1, T2, and PD obtained from the cortex, the WM and the deep GM between the groups. Furthermore, the voxel-wise analyses did not reveal any clusters indicating significant differences between patients and control subjects for the qMRI parameters in the respective compartments. Conclusions: Based on the employed methodology, no indication for an impairment of the cerebral microstructural tissue integrity in MRI-negative patients with focal epilepsy was found in this study. Further research will be necessary to identify relevant factors and mechanisms contributing to microstructural brain tissue damage in various subgroups of patients with epilepsy.

Published
2023

34. B1 mapping using an EPI‐based double angle approach: A practical guide for correcting slice profile and B0 distortion effects.

Author

Nöth, Ulrike, Shrestha, Manoj, and Deichmann, Ralf

Subjects
ECHO-planar imaging, POLYNOMIAL approximation, BRAIN mapping, ANGLES, CORRECTION factors
Abstract

Purpose: Aim of this study was to develop a reliable B1 mapping method for brain imaging based on vendor MR sequences available on clinical scanners. Correction procedures for B0 distortions and slice profile imperfections are proposed, together with a phantom experiment for deriving the approximate time‐bandwidth‐product (TBP) of the excitation pulse, which is usually not known for vendor sequences. Methods: The double angle method was used, acquiring two gradient echo echo‐planar imaging data sets with different excitation angles. A correction factor C (B1, TBP, B0) was derived from simulations for converting double angle method signal quotients into bias‐free B1 maps. In vitro and in vivo tests compare results with reference B1 maps based on an established in‐house sequence. Results: The simulation shows that C has a negligible B1 dependence, allowing for a polynomial approximation of C (TBP, B0). Signal quotients measured in a phantom experiment with known TBP reconfirm the simulation results. In vitro and in vivo B1 maps based on the proposed method, assuming TBP = 5.8 as derived from a phantom experiment, match closely the reference B1 maps. Analysis without B0 correction shows marked deviations in areas of distorted B0, highlighting the importance of this correction. Conclusion: Double angle method‐based B1 mapping was set up for vendor gradient echo‐echo‐planar imaging sequences, using a correction procedure for slice profile imperfections and B0 distortions. This will help to set up quantitative MRI studies on clinical scanners with release sequences, as the method does not require knowledge of the exact RF‐pulse profiles or the use of in‐house sequences. [ABSTRACT FROM AUTHOR]

Published
2023
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47. Brain responses to social cues of attachment in mid-childhood.

Author

Schoett, Margerete J.S., Basten, Ulrike, Deichmann, Ralf, Fiebach, Christian J., and Fischmann, Tamara

Subjects
BRAIN physiology, CONFIDENCE intervals, MAGNETIC resonance imaging, TASK performance, PSYCHOLOGICAL tests, T-test (Statistics), QUESTIONNAIRES, DESCRIPTIVE statistics, RESEARCH funding, SOCIAL skills, ANXIETY, STATISTICAL correlation, DATA analysis software, PROMPTS (Psychology), ATTACHMENT behavior in children, CHILD development deviations
Abstract

Physical separation from caregivers activates attachment-related behaviors. However, neural underpinnings of this biological mechanism in humans and their development are poorly understood. We examined via functional MRI brain responses to pictorial representations of separation as a function of attachment-security, attachment-avoidance, and attachment-anxiety measured using the Child-Attachment-Interview, in 30 typically developing children (9-11 years). Attachment-related stimuli elicited enhanced activation in the precuneus, temporoparietal junction area, and medial superior frontal gyrus (described as mentalization network). More negatively rated attachment stimuli yielded increased activity in the inferior frontal gyrus/anterior insula and dorsal anterior cingulate cortex/ACC. Furthermore, ACC responses to attachment-related as compared to control stimuli were positively correlated with attachment-security and negatively correlated with attachment-avoidance. Our findings suggest that processing of separation cues elicits increased mentalization-related processing in children and activation of the salience network with increased negative valence of stimuli. Avoidant vs. securely attached children differentially activate ACC-dependent processes of affective evaluation. [ABSTRACT FROM AUTHOR]

Published
2023
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