Fluid and white matter suppression with the MP2RAGE sequence

Tanner, Mark; Gambarota, Giulio; Kober, Tobias; Krueger, Gunnar; Erritzoe, David; Marques, José P.; Newbould, Rexford D.

doi:10.1002/jmri.23532

Cited by 61 publications

(106 citation statements)

References 17 publications

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“…Other T1-weighted methods such as inversion-recovery turbo spin echo (IR-TSE) could be considered but are often associated with SAR above regulatory limits at 7T. Tuning the MP2RAGE sequence to get WM null contrast close to our optimization could be possible (Tanner et al, 2012) and could be of benefit in making quantitative T1 maps possible (Marques et al, 2010). The SNR efficiency of this strategy would need to be evaluated compared to MPRAGE optimization shown here.…”

Section: Discussionmentioning

confidence: 99%

Visualization of intra-thalamic nuclei with optimized white-matter-nulled MPRAGE at 7T

et al. 2014

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Novel MR image acquisition strategies have been investigated to elicit contrast within the thalamus, but direct visualization of individual thalamic nuclei remains a challenge because of their small size and the low intrinsic contrast between adjacent nuclei. We present a step-by-step specific optimization of the 3D MPRAGE pulse sequence at 7T to visualize the intra-thalamic nuclei. We first measured T1 values within different sub-regions of the thalamus at 7T in 5 individuals. We used these to perform simulations and sequential experimental measurements (n=17) to tune the parameters of the MPRAGE sequence. The optimal set of parameters was used to collect high-quality data in 6 additional volunteers. Delineation of thalamic nuclei was performed twice by one rater and MR-defined nuclei were compared to the classic Morel histological atlas. T1 values within the thalamus ranged from 1400ms to 1800ms for adjacent nuclei. Using these values for theoretical evaluations combined with in vivo measurements, we showed that a short inversion time (TI) close to the white matter null regime (TI=670ms) enhanced the contrast between the thalamus and the surrounding tissues, and best revealed intra-thalamic contrast. At this particular nulling regime, lengthening the time between successive inversion pulses (TS=6000ms) increased the thalamic signal and contrast and lengthening the α pulse train time (N*TR) further increased the thalamic signal. Finally, a low flip angle during the gradient echo acquisition (α=4°) was observed to mitigate the blur induced by the evolution of the magnetization along the α pulse train. This optimized set of parameters enabled the 3D delineation of 15 substructures in all 6 individuals; these substructures corresponded well with the known anatomical structures of the thalamus based on the classical Morel atlas. The mean Euclidean distance between the centers of mass of MR- and Morel atlas-defined nuclei was 2.67mm (±1.02mm). The reproducibility of the MR-defined nuclei was excellent with intraclass correlation coefficient measured at 0.997 and a mean Euclidean distance between corresponding centers of mass found at first versus second readings of 0.69mm (±0.38mm). This 7T strategy paves the way to better identification of thalamic nuclei for neurosurgical planning and investigation of regional changes in neurological disorders.

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Section: Discussionmentioning

confidence: 99%

Visualization of intra-thalamic nuclei with optimized white-matter-nulled MPRAGE at 7T

et al. 2014

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“…A 3D T1-weighted spoiled gradient echo volume of isotropic 1 × 1 × 1 mm resolution was acquired at six echo times: 6.29, 13, 21, 29, 37, and 49 ms in each TR of 56 ms. A 240 × 256 × 160 mm sagittal FOV and flip angle of 35° was used, with a parallel imaging factor of 2, requiring 10 m:14 s. A double-echo inversion recovery sequence (MP2RAGE) 22 was also acquired with identical resolution and coverage at inversion times of 409 ms and 1100 ms in a 5 s TR with a parallel imaging factor of 2, requiring 10 m:57 s. This sequence gives two co-registered volumes: one with fluid nulled similar to the ADNI MPRAGE 23 and one with white matter nulled for subcortical visualization. The signal decay in each voxel across the six echo acquisition was fit to the non-linear signal equation:where S 0 represents the effective proton density, including partial T1 recovery, and the C term captures a rectified noise floor from magnitude imaging with possible low SNR in the final echo volume.…”

Section: Methodsmentioning

confidence: 99%

Brain iron chelation by deferiprone in a phase 2 randomised double-blinded placebo controlled clinical trial in Parkinson’s disease

Martín-Bastida

Ward

Newbould

et al. 2017

Sci Rep

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295

232

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Parkinson’s disease (PD) is associated with increased iron levels in the substantia nigra (SNc). This study evaluated whether the iron chelator, deferiprone, is well tolerated, able to chelate iron from various brain regions and improve PD symptomology. In a randomised double-blind, placebo controlled trial, 22 early onset PD patients, were administered deferiprone, 10 or 15 mg/kg BID or placebo, for 6 months. Patients were evaluated for PD severity, cognitive function, depression rating and quality of life. Iron concentrations were assessed in the substantia nigra (SNc), dentate and caudate nucleus, red nucleus, putamen and globus pallidus by T2* MRI at baseline and after 3 and 6 months of treatment. Deferiprone therapy was well tolerated and was associated with a reduced dentate and caudate nucleus iron content compared to placebo. Reductions in iron content of the SNc occurred in only 3 patients, with no changes being detected in the putamen or globus pallidus. Although 30 mg/kg deferiprone treated patients showed a trend for improvement in motor-UPDRS scores and quality of life, this did not reach significance. Cognitive function and mood were not adversely affected by deferiprone therapy. Such data supports more extensive clinical trials into the potential benefits of iron chelation in PD.

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“…To aid the definition of the regions of interest (ROIs), high resolution structural MRIs and two components of the FLAWS sequence (Tanner et al, 2012) were acquired on 3-Tesla MR scanner (Magnetom Trio Syngo MR B13 Siemens 3T; Siemens AG, Medical Solutions) to provide a T1-weighted contrast and WM nulled image in a single scan. T1-weighted 3D MPRAGE volumes were acquired using the ADNI-GO recommended parameters: 256 Â 192mm field of view, 1mm 3 isotropic resolution.…”

Section: Imagingmentioning

confidence: 99%

In Vivo Imaging of Cerebral Dopamine D3 Receptors in Alcoholism

Erritzoe

Tziortzi

Bargiela

et al. 2014

Neuropsychopharmacol

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Animal studies support the role of the dopamine D3 receptor (DRD3) in alcohol reinforcement or liking. Sustained voluntary alcohol drinking in rats has been associated with an upregulation of striatal DRD3 gene expression and selective blockade of DRD3 reduces ethanol preference, consumption, and cue-induced reinstatement. In vivo measurement of DRD3 in the living human brain has not been possible until recently owing to a lack of suitable tools. In this study, DRD3 status was assessed for the first time in human alcohol addiction. Brain DRD3 availability was compared between 16 male abstinent alcohol-dependent patients and 13 healthy non-dependent age-matched males using the DRD3-preferring agonist positron emission tomography (PET) radioligand [ 11 C]PHNO with and without blockade with a selective DRD3 antagonist (GSK598809 60 mg p.o.). In striatal regions of interest, where the [ 11 C]PHNO PET signal represents primarily DRD2 binding, no differences were seen in [ 11 C]PHNO binding between the groups at baseline. However, baseline [ 11 C]PHNO binding was higher in alcohol-dependent patients in hypothalamus (V T : 16.5±4 vs 13.7±2.9, p ¼ 0.040), a region in which the [ 11 C]PHNO signal almost entirely reflects DRD3 availability. The reductions in regional receptor binding (V T ) following a single oral dose of GSK598809 (60 mg) were consistent with those observed in previous studies across all regions. There were no differences in regional changes in V T following DRD3 blockade between the two groups, indicating that the regional fractions of DRD3 are similar in the two groups, and the increased [ 11 C]PHNO binding in the hypothalamus in alcohol-dependent patients is explained by elevated DRD3 in this group. Although we found no difference between alcohol-dependent patients and controls in striatal DRD3 levels, increased DRD3 binding in the hypothalamus of alcohol-dependent patients was observed. This may be relevant to the development of future therapeutic strategies to treat alcohol abuse.

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Fluid and white matter suppression with the MP2RAGE sequence

Cited by 61 publications

References 17 publications

Visualization of intra-thalamic nuclei with optimized white-matter-nulled MPRAGE at 7T

Visualization of intra-thalamic nuclei with optimized white-matter-nulled MPRAGE at 7T

Brain iron chelation by deferiprone in a phase 2 randomised double-blinded placebo controlled clinical trial in Parkinson’s disease

In Vivo Imaging of Cerebral Dopamine D3 Receptors in Alcoholism

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