Abstract An empirical equation for the magnetization transfer (MT) FLASH signal is derived by analogy to dual‐excitation FLASH, introducing a novel semiquantitative parameter MT, percentage saturation imposed one MT pulse during TR. This obtained linear transformation of inverse signal, using two reference experiments proton density and T 1 weighting. The influence sequence parameters on was studied. 8.5‐min protocol brain imaging at 3 based nonselective sagittal 3D‐FLASH 1.25 mm isotropic...

A pressing need exists to disentangle age-related changes from pathologic neurodegeneration. This study aims characterize the spatial pattern and differences of biologically relevant measures in vivo over course normal aging. Quantitative multiparameter maps that provide neuroimaging biomarkers for myelination iron levels, parameters sensitive aging, were acquired 138 healthy volunteers (age range: 19–75 years). Whole-brain voxel-wise analysis revealed a global degeneration. Significant...

Normal ageing is associated with characteristic changes in brain microstructure. Although vivo neuroimaging captures spatial and temporal patterns of age-related anatomy at the macroscopic scale, our knowledge underlying (patho)physiological processes cellular molecular levels still limited. The aim this study to explore tissue properties normal using quantitative magnetic resonance imaging (MRI) alongside conventional morphological assessment. Using a whole-brain approach cohort 26 adults,...

Neuroscience and clinical researchers are increasingly interested in quantitative magnetic resonance imaging (qMRI) due to its sensitivity micro-structural properties of brain tissue such as axon, myelin, iron water concentration. We introduce the hMRI-toolbox, an open-source, easy-to-use tool available on GitHub, for qMRI data handling processing, presented together with a tutorial example dataset. This toolbox allows estimation high-quality multi-parameter maps (longitudinal effective...

Abstract From the half‐angle substitution of trigonometric terms in Ernst equation, rational approximations flip angle dependence FLASH signal can be derived. Even function lowest order was good agreement with experiment for angles up to 20°. Three‐dimensional maps amplitude and longitudinal relaxation rates human brain were obtained from eight subjects by dual‐angle measurements at 3T (nonselective 3D‐FLASH, 7° 20° angle, TR = 30 ms, isotropic resolution 0.95 mm, each 7:09 min). The...

Abstract In vivo longitudinal relaxation times of N ‐acetyl compounds (NA), choline‐containing substances (Cho), creatine (Cr), myo ‐inositol (mI), and tissue water were measured at 1.5 3 T using a point‐resolved spectroscopy (PRESS) sequence with short echo time (TE). 1 values determined in six different brain regions: the occipital gray matter (GM), white (WM), motor cortex, frontoparietal WM, thalamus, cerebellum. The protons 26–38% longer than T. Significantly metabolite (11–36%) found...

Quantitative mapping of the longitudinal relaxation rate (R1 = 1/T1) in human brain enables investigation tissue microstructure and macroscopic morphology which are becoming increasingly important for clinical neuroimaging applications. R1 maps now commonly estimated from two fast high-resolution 3D FLASH acquisitions with variable excitation flip angles, because this approach is does not rely on special acquisition techniques. However, these need to be corrected bias due RF transmit field...

Basal ganglia and brain stem nuclei are involved in the pathophysiology of various neurological neuropsychiatric disorders. Currently available structural T1-weighted (T1w) magnetic resonance images do not provide sufficient contrast for reliable automated segmentation subcortical grey matter structures. We use a novel, semi-quantitative magnetization transfer (MT) imaging protocol that overcomes limitations T1w images, which mainly due to their sensitivity high iron content matter....

MRI techniques such as quantitative imaging and parallel transmit require precise knowledge of the radio-frequency field (B(1) (+)). Three published methods were optimized for robust B(1) (+) mapping at 3T in human brain: three-dimensional (3D) actual flip angle (AFI), 3D echo-planar (EPI), two-dimensional (2D) stimulated echo acquisition mode (STEAM). We performed a comprehensive comparison methods, focusing on artifacts, reproducibility, accuracy compared to reference 2D double method. For...

Voxel-based morphometry (VBM) shows a differentiated pattern in patients with atypical Parkinson syndrome but so far has had little impact individual cases. It is desirable to translate VBM findings into clinical practice and classification. To this end, we examined whether support vector machine (SVM) can provide useful accuracies for the differential diagnosis. We acquired volumetric 3D T1-weighted MRI of 21 idiopathic (IPS), 11 multiple systems atrophy (MSA-P) 10 progressive supranuclear...

Despite the constant improvement of algorithms for automated brain tissue classification, accurate delineation subcortical structures using magnetic resonance images (MRI) data remains challenging. The main difficulties arise from low gray-white matter contrast iron rich areas in T1-weighted (T1w) MRI and lack adequate priors basal ganglia thalamus. most recent attempts to obtain such were based on cohorts with limited size that included subjects a narrow age range, failing account...

Rationale Disruptions of brain anatomical connectivity are believed to play a central role in several neurological and psychiatric illnesses. The structural connectome is typically derived from diffusion tensor imaging (DTI), which may be influenced by methodological factors related signal processing, MRI scanners biophysical properties neuroanatomical regions. In this study, we evaluated how these variables affect the reproducibility connectome. Methods Twenty healthy adults underwent 3...

Abstract The high gray‐white matter contrast and spatial resolution provided by T1‐weighted magnetic resonance imaging (MRI) has made it a widely used protocol for computational anatomy studies of the brain. While image intensity in images is predominantly driven T1, other MRI parameters affect contrast, hence brain morphological measures derived from data. Because are correlates different histological properties tissue, this mixed contribution hampers neurobiological interpretation...

The longitudinal relaxation rate (R1 ) measured in vivo depends on the local microstructural properties of tissue, such as macromolecular, iron, and water content. Here, we use whole brain multiparametric data a general linear relaxometry model to describe dependence R1 these components. We explore a) validity having single fixed set coefficients for b) stability large cohort.Maps magnetization transfer (MT) effective transverse (R2 *) were used surrogates macromolecular iron content,...

Abstract Multicenter clinical and quantitative magnetic resonance imaging (qMRI) studies require a high degree of reproducibility across different sites scanner manufacturers, as well time points. We therefore implemented multiparameter mapping (MPM) protocol based on vendor's product sequences demonstrate its repeatability for whole‐brain coverage. Within ~20 min, four MPM metrics (magnetization transfer saturation [MT], proton density [PD], longitudinal [R1], effective transverse [R2*]...

Summary: Purpose : Neuropsychological studies suggest frontal lobe dysfunctions in patients with juvenile myoclonic epilepsy (JME). In this study we investigated whether an underlying mechanism could be a regional neuronal damage not visible structural magnetic resonance (MR), but detectable spectroscopy (MRS). Methods The included 15 JME and 10 matched healthy controls. Quantitative single voxel MRS was conducted at 1.5 Tesla by using STEAM sequence (TR/TE/TM = 6,000/30/13.7 ms). voxels...

Lichens from the genus Umbilicaria were collected across a 5,000-km transect through Antarctica and investigated for DNA sequence polymorphism in region of 480–660 bp nuclear internal transcribed spacer ribosomal DNA. Sequences both fungal (16 ascomycetes) photosynthetic partners (22 chlorophytes Trebouxia) determined compared with homologs lichens inhabiting more temperate, continental climates. The phylogenetic analyses reveal that Antarctic have colonized their current habitats multiple...

Despite advances in understanding basic organizational principles of the human basal ganglia, accurate vivo assessment their anatomical properties is essential to improve early diagnosis disorders with corticosubcortical pathology and optimize target planning deep brain stimulation. Main goal this study was detailed topological characterization limbic, associative, motor subdivisions subthalamic nucleus (STN) relation corresponding circuits. To aim, we used magnetic resonance imaging...

Background and objectives : The thalamus exerts a pivotal role in pain processing cortical excitability control, migraine is characterized by repeated attacks abnormal habituation to excitatory stimuli. This work aimed at studying the microstructure of patients using an innovative multiparametric approach high‐field magnetic resonance imaging (MRI). Design We examined 37 migraineurs (22 without aura, MWoA, 15 with MWA) as well 20 healthy controls (HC) 3‐T MRI equipped 32‐channel coil....

Cerebral dopamine neurotrophic factor (CDNF) belongs to a newly discovered family of evolutionarily conserved factors. We demonstrate for the first time therapeutic effect CDNF in unilateral 6-hydroxydopamine (6-OHDA) lesion model Parkinson's disease marmoset monkeys. Furthermore, we tested impact high chronic doses human recombinant on unlesioned monkeys and analyzed amino acid sequence CDNF. The severity 6-OHDA lesions treatment effects were monitored vivo using 123I-FP-CIT (DaTSCAN)...

Evidence from magnetic resonance imaging (MRI) studies shows that healthy aging is associated with profound changes in cortical and subcortical brain structures. The reliable delineation of cortex basal ganglia using automated computational anatomy methods based on T1-weighted images remains challenging, which results controversies the literature. In this study we use quantitative MRI (qMRI) to gain an insight into microstructural mechanisms underlying tissue ageing look for potential...