Improved synthetic T1-weighted images for cerebral tissue segmentation in neurological diseases

Gracien, René‐Maxime; Wijnen, Alexandra van; Maiworm, Michelle; Petrov, Franca; Merkel, Nina; Paule, Esther; Steinmetz, Helmuth; Knake, Susanne; Rosenow, Felix; Wagner, Marlies; Deichmann, Ralf

doi:10.1016/j.mri.2019.05.013

Cited by 11 publications

(16 citation statements)

References 26 publications

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“…Accordingly, the group of patients and healthy control subjects and the acquired data overlap in part with those of previous studies with different aims, presenting novel methods for FCD detection or creating improved synthetic T 1 -weighted datasets. [19][20][21]…”

Section: Participantsmentioning

confidence: 99%

“…For tissue segmentation, synthetic T 1 -weighted magnetizationprepared rapid acquisition of gradient echoes (MP-RAGE) datasets were derived from quantitative T 1 maps using the same MR protocols (total duration = 16 minutes 43 seconds) and postprocessing algorithms as described previously 19 and assuming the following virtual acquisition parameters: matrix size = 256 × 224 × 160, isotropic resolution = 1 mm 3 , field of view = 256 × 224 × 160 mm 3 , TR = 1900 msec, TI = 900 msec, flip angle (α) = 9 , echo spacing = 8.1 msec.…”

Section: Mri Acquisition and T 2 Mappingmentioning

confidence: 99%

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Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T₂ Mapping

Ahmad

Maiworm

Nöth

et al. 2020

Magnetic Resonance Imaging

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Background: In epilepsy patients with focal cortical dysplasia (FCD) as the epileptogenic focus, global cortical signal changes are generally not visible on conventional MRI. However, epileptic seizures or antiepileptic medication might affect normal-appearing cerebral cortex and lead to subtle damage. Purpose: To investigate cortical properties outside FCD regions with T 2-relaxometry. Study Type: Prospective study. Subjects: Sixteen patients with epilepsy and FCD and 16 age-/sex-matched healthy controls. Field Strength/Sequence: 3T, fast spin-echo T 2-mapping, fluid-attenuated inversion recovery (FLAIR), and synthetic T 1weighted magnetization-prepared rapid acquisition of gradient-echoes (MP-RAGE) datasets derived from T 1-maps. Assessment: Reconstruction of the white matter and cortical surfaces based on MP-RAGE structural images was performed to extract cortical T 2 values, excluding lesion areas. Three independent raters confirmed that morphological cortical/juxtacortical changes in the conventional FLAIR datasets outside the FCD areas were definitely absent for all patients. Averaged global cortical T 2 values were compared between groups. Furthermore, group comparisons of regional cortical T 2 values were performed using a surface-based approach. Tests for correlations with clinical parameters were carried out. Statistical Tests: General linear model analysis, permutation simulations, paired and unpaired t-tests, and Pearson correlations. Results: Cortical T 2 values were increased outside FCD regions in patients (83.4 AE 2.1 msec, control group 81.4 AE 2.1 msec, P = 0.01). T 2 increases were widespread, affecting mainly frontal, but also parietal and temporal regions of both hemispheres. Significant correlations were not observed (P ≥ 0.55) between cortical T 2 values in the patient group and the number of seizures in the last 3 months or the number of anticonvulsive drugs in the medical history. Data Conclusion: Widespread increases in cortical T 2 in FCD-associated epilepsy patients were found, suggesting that structural epilepsy in patients with FCD is not only a symptom of a focal cerebral lesion, but also leads to global cortical damage not visible on conventional MRI. Evidence Level: 21 Technical efficacy Stage: 3

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Section: Participantsmentioning

confidence: 99%

Section: Mri Acquisition and T 2 Mappingmentioning

confidence: 99%

Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T₂ Mapping

Ahmad

Maiworm

Nöth

et al. 2020

Magnetic Resonance Imaging

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“…For segmentation purposes, optimized synthetic MP-RAGE anatomies which are intrinsically corrected for bias fields (Gracien et al, 2019) were derived from qMRI maps of T1, B0, and the transmitted field B1 as described previously in the literature (Gracien et al, 2019), assuming the following virtual MP-RAGE acquisition parameters: FoV = 256 × 224 × 160 mm 3 , isotropic resolution = 1 mm, TR = 1,900 ms, TI = 900 ms, α = 9 • . The total acquisition time for all underlying qMRI maps was 16:42 min.…”

Section: Data Acquisition and Processingmentioning

confidence: 99%

Distribution of Cortical Diffusion Tensor Imaging Changes in Multiple Sclerosis

et al. 2020

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Purpose: Diffuse cortical damage in relapsing-remitting multiple sclerosis (RRMS) is clinically relevant but cannot be directly assessed with conventional MRI. In this study, it was aimed to use diffusion tensor imaging (DTI) techniques with optimized intrinsic eddy current compensation to quantify and characterize cortical mean diffusivity (MD) and fractional anisotropy (FA) changes in RRMS and to analyze the distribution of these changes across the cortex. Materials and Methods: Three-Tesla MRI acquisition, mapping of the MD providing information about the integrity of microstructural barriers and of the FA reflecting axonal density and surface-based analysis with Freesurfer were performed for 24 RRMS patients and 25 control subjects. Results: Across the whole cortex, MD was increased in patients (p < 0.001), while surface-based analysis revealed focal cortical FA decreases. MD and FA changes were distributed inhomogeneously across the cortex, the MD increase being more widespread than the FA decrease. Cortical MD correlated with the Expanded Disability Status Scale (EDSS, r = 0.38, p = 0.03). Conclusion: Damage of microstructural barriers occurs inhomogeneously across the cortex in RRMS and might be spatially more widespread than axonal degeneration. The results and, in particular, the correlation with the clinical status indicate that DTI might be a promising technique for the monitoring of cortical damage under treatment in larger clinical studies.

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“…In the current study, a completely different approach is described which utilizes multiparametric qMRI data and a surface-based analysis. Furthermore, some data obtained on subjects with FCD overlap with previous studies with different aims evaluating improved synthetic T1weighted datasets for tissue-segmentation (Gracien et al, 2019) and assessing normal-appearing cortical tissue in patients with FCD via T2-relaxometry (Ahmad et al, 2020).…”

Section: Participantsmentioning

confidence: 89%

“…Synthetic T1-weighted magnetization-prepared rapid gradient-echo (MP-RAGE) anatomies were obtained as described previously (Gracien et al, 2019), using B0-corrected T1-maps and pseudo-PD-maps derived from T1-data via the Fatouros equation (Fatouros et al, 1991;Volz et al, 2012b). The virtual acquisition-parameters assumed for the synthetic data were: TR = 1900 ms, TI = 900 ms, α = 9 • , echo-spacing = 8.1 ms. All geometrical parameters (FoV, matrix size, spatial resolution, volume coverage) were identical to the respective parameters of the underlying T1-maps.…”

Section: Data Acquisition and Qmri-mappingmentioning

confidence: 99%

Improved Visualization of Focal Cortical Dysplasia With Surface-Based Multiparametric Quantitative MRI

et al. 2020

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Improved synthetic T1-weighted images for cerebral tissue segmentation in neurological diseases

Cited by 11 publications

References 26 publications

Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T₂ Mapping

Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T₂ Mapping

Distribution of Cortical Diffusion Tensor Imaging Changes in Multiple Sclerosis

Improved Visualization of Focal Cortical Dysplasia With Surface-Based Multiparametric Quantitative MRI

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Improved synthetic T1-weighted images for cerebral tissue segmentation in neurological diseases

Cited by 11 publications

References 26 publications

Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T2 Mapping

Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T2 Mapping

Distribution of Cortical Diffusion Tensor Imaging Changes in Multiple Sclerosis

Improved Visualization of Focal Cortical Dysplasia With Surface-Based Multiparametric Quantitative MRI

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Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T₂ Mapping

Cortical Changes in Epilepsy Patients With Focal Cortical Dysplasia: New Insights With T₂ Mapping