Normal volumetric and T1 relaxation time values at 1.5 T in segmented pediatric brain MRI using a MP2RAGE acquisition

Morel, Baptiste; Piredda, Gian Franco; Cottier, Jean‐Philippe; Tauber, Clovis; Destrieux, Christophe; Hilbert, Tom; Sirinelli, D.; Thiran, Jean‐Philippe; Maréchal, Bénédicte; Kober, Tobias

doi:10.1007/s00330-020-07194-w

Cited by 7 publications

(11 citation statements)

References 40 publications

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“…After written and informed consent, the patient underwent 7T MR scans (MAGNETOM 7T; Siemens Healthcare) for absolute volume and average T 1 values (3D MP2RAGE sequence, TR = 6 s, TE = 2.05 ms, TI1 = 0.8 s, TI2 = 2.7 s, α 1 = 4°, α 2 = 5°, 0.6 × 0.6 × 0.6 mm3 resolution, 320 × 320 × 256 matrix size, TA = 10 min) especially in the globus pallidus using the MorphoBox prototype, 23 while short echo time 1 H MR spectra were acquired in a voxel located in gray matter dominated prefrontal cortex (20 × 20 × 25 mm 3 ), as described previously. 24 Briefly, the semi‐adiabatic SPECIAL sequence at short echo‐time (16 ms) was used (TR = 6500 ms, 2 × 50 averages (i.e., acquisitions per spectrum), spectral width of 4000 Hz, 2048 points in FID).…”

Section: Methodsmentioning

confidence: 99%

Neurometabolism and brain morphometry in an adolescent female with an extra‐hepatic congenital portosystemic shunt

Chabbey,

Cudalbu,

Barras

et al. 2023

JPGN rep.

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BackgroundChronic hepatic encephalopathy (CHE) has been reported both in patients with congenital porto‐systemic shunts (CPSS) and chronic liver disease. CHE is difficult to recognize in children as there is no clear definition and its manifestations are highly variable. CHE is associated with variations in brain volumes and metabolites that have already been demonstrated using 1.5‐3T MRI systems. However, the in‐depth study of brain metabolism requires the high spectral resolution of high magnetic fields.Objectives and MethodsWe analyzed the neurometabolic profile, brain volumes and T1 relaxation times of a child with a CPSS using high field proton magnetic resonance spectroscopy (1H MRS, 7T) combined with MRI and compared it to an age‐matched control group. We also evaluated the impact of shunt closure on neurocognitive symptoms using adapted neuropsychological tests.Results7T MRS revealed a significant increase in glutamine compared to controls, a decrease in brain osmolytes, and a slight elevation in NAA concentrations. 7T MRI scans showed morphological abnormalities but no changes in the signal intensity of the globus pallidus. Neurocognitive testing revealed attention deficit disorder, language difficulties, and mild intellectual disability. Most of these areas improved after shunt closure.ConclusionsIn this paediatric case of type B HE with normal fasting ammonia, neurometabolic profile was compatible with what has been previously shown in chronic liver disease, while also demonstrating an isolated glutamine peak. In addition, neurocognitive function partially improved after shunt closure, arguing strongly for shunt closure in both presymptomatic and symptomatic patients.

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Section: Methodsmentioning

confidence: 99%

Neurometabolism and brain morphometry in an adolescent female with an extra‐hepatic congenital portosystemic shunt

Chabbey,

Cudalbu,

Barras

et al. 2023

JPGN rep.

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“…An automated brain segmentation was performed using a dedicated MP2RAGE processing pipeline based on the MorphoBox research application [ 23 ] with a previously reported adaptation of its templates [ 21 ]. A volumic segmentation of a total of 38 anatomical brain structures was obtained according to the standard anatomical nomenclature, including the CC [ 24 ].…”

Section: Methodsmentioning

confidence: 99%

“…To address this problem, an automated MRI-based segmentation of the midline brain structures relying on the magnetization prepared 2 rapid acquisition gradient echoes (MP2RAGE) sequence was previously developed [ 21 ] to provide CC volumetry and T1 mapping, the latter also giving an indication of the microstructural tissue status. In addition, the method incorporates a comparison with normative values of both volumes and T1 values including a spatial visualization of deviations from the norm using Z -score maps.…”

Section: Introductionmentioning

confidence: 99%

Corpus callosum in children with neurodevelopmental delay: MRI standard qualitative assessment versus automatic quantitative analysis

Mandine,

Tavernier,

Hülnhagen

et al. 2023

Eur Radiol Exp

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Background The corpus callosum (CC) is a key brain structure. In children with neurodevelopmental delay, we compared standard qualitative radiological assessments with an automatic quantitative tool. Methods We prospectively enrolled 73 children (46 males, 63.0%) with neurodevelopmental delay at single university hospital between September 2020 and September 2022. All of them underwent 1.5-T brain magnetic resonance imaging (MRI) including a magnetization-prepared 2 rapid acquisition gradient echoes − MP2RAGE sequence. Two radiologists blindly reviewed the images to classify qualitatively the CC into normal, hypoplasic, hyperplasic, and/or dysgenetic classes. An automatic tool (QuantiFIRE) was used to provide brain volumetry and T1 relaxometry automatically as well as deviations of those parameters compared with a healthy age-matched cohort. The MRI reference standard for CC volumetry was based on the Garel et al. study. Cohen κ statistics was used for interrater agreement. The radiologists and QuantiFIRE’s diagnostic accuracy were compared with the reference standard using the Delong test. Results The CC was normal in 42 cases (57.5%), hypoplastic in 20 cases (27.4%), and hypertrophic in 11 cases (15.1%). T1 relaxometry values were abnormal in 26 children (35.6%); either abnormally high (18 cases, 24.6%) or low (8 cases, 11.0%). The interrater Cohen κ coefficient was 0.91. The diagnostic accuracy of the QuantiFIRE prototype was higher than that of the radiologists for hypoplastic and normal CC (p = 0.003 for both subgroups, Delong test). Conclusions An automated volumetric and relaxometric assessment can assist the evaluation of brain structure such as the CC, particularly in the case of subtle abnormalities. Relevance statement Automated brain MRI segmentation combined with statistical comparison to normal volume and T1 relaxometry values can be a useful diagnostic support tool for radiologists. Key points • Corpus callosum abnormality detection is challenging but clinically relevant. • Automated quantitative volumetric analysis had a higher diagnostic accuracy than that of visual appreciation of radiologists. • Quantitative T1 relaxometric analysis might help characterizing corpus callosum better. Graphical Abstract

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“…13 T 1 measurements derived with the MP2RAGE were proved to be both reproducible 16,17 and sensitive to microstructural changes causes by brain pathologies. 11,18,19 This makes the MP2RAGE sequence a good candidate to quantitatively characterize T 1 changes associated with tissue structure alterations. However, automated processing pipelines used at 3T to perform single-subject comparisons 7,20 generally cannot be transferred to 7T without additional corrections due to differences in contrast and larger spatial signal variations caused by B 1 + and B 1 − inhomogeneities in the GRE 1 and GRE 2 images.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, as the sequence parameters can be tuned so that the UNI contrast depends almost exclusively on T 1 , a quantitative T 1 map can be directly derived from the UNI image using Bloch simulations 13 . T 1 measurements derived with the MP2RAGE were proved to be both reproducible 16,17 and sensitive to microstructural changes causes by brain pathologies 11,18,19 . This makes the MP2RAGE sequence a good candidate to quantitatively characterize T 1 changes associated with tissue structure alterations.…”

Section: Introductionmentioning

confidence: 99%

Submillimeter T₁ atlas for subject‐specific abnormality detection at 7T

Piredda

Caneschi

Hilbert

et al. 2022

Magnetic Resonance in Med

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Purpose: Studies at 3T have shown that T 1 relaxometry enables characterization of brain tissues at the single-subject level by comparing individual physical properties to a normative atlas. In this work, an atlas of normative T 1 values at 7T is introduced with 0.6 mm isotropic resolution and its clinical potential is explored in comparison to 3T. Methods: T 1 maps were acquired in two separate healthy cohorts scanned at 3T and 7T. Using transfer learning, a template-based brain segmentation algorithm was adapted to ultra-high field imaging data. After segmenting brain tissues, volumes were normalized into a common space, and an atlas of normative T 1 values was established by modeling the T 1 inter-subject variability. A method for single-subject comparisons restricted to white matter and subcortical structures was developed by computing Z-scores. The comparison was applied to eight patients scanned at both field strengths for proof of concept. Results: The proposed method for morphometry delivered segmentation masks without statistically significant differences from those derived with the original pipeline at 3T and achieved accurate segmentation at 7T. The established normative atlas allowed characterizing tissue alterations in single-subject comparisons at 7T, and showed greater anatomical details compared with 3T results. Conclusion:A high-resolution quantitative atlas with an adapted pipeline was introduced and validated. Several case studies on different clinical conditions showed the feasibility, potential and limitations of high-resolution single-subject comparisons based on quantitative MRI atlases. This method in conjunction with 7T higher resolution broadens the range of potential applications of quantitative MRI in clinical practice.

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Normal volumetric and T1 relaxation time values at 1.5 T in segmented pediatric brain MRI using a MP2RAGE acquisition

Cited by 7 publications

References 40 publications

Neurometabolism and brain morphometry in an adolescent female with an extra‐hepatic congenital portosystemic shunt

Neurometabolism and brain morphometry in an adolescent female with an extra‐hepatic congenital portosystemic shunt

Corpus callosum in children with neurodevelopmental delay: MRI standard qualitative assessment versus automatic quantitative analysis

Submillimeter T₁ atlas for subject‐specific abnormality detection at 7T

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Normal volumetric and T1 relaxation time values at 1.5 T in segmented pediatric brain MRI using a MP2RAGE acquisition

Cited by 7 publications

References 40 publications

Neurometabolism and brain morphometry in an adolescent female with an extra‐hepatic congenital portosystemic shunt

Neurometabolism and brain morphometry in an adolescent female with an extra‐hepatic congenital portosystemic shunt

Corpus callosum in children with neurodevelopmental delay: MRI standard qualitative assessment versus automatic quantitative analysis

Submillimeter T1 atlas for subject‐specific abnormality detection at 7T

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Submillimeter T₁ atlas for subject‐specific abnormality detection at 7T