Dynamic fluctuations in brain iron content during migraine attacks: insights from relaxometry and diffusion tensor imaging.

Background: There is evidence that iron metabolism may play a role in the underlying pathophysiological mechanism of migraine. Studies using (=1/ ) relaxometry, a common MRI-based iron mapping technique, have reported increased values in various brain structures of migraineurs, indicating iron accumulation compared to healthy controls.

Purpose: To investigate whether there are short-term changes in during a migraine attack.

Multimodal analytical tools for the molecular and elemental characterisation of lesions in brain tissue of multiple sclerosis patients.

Multiple sclerosis (MS) is a prevalent immune-mediated inflammatory disease of the central nervous system inducing a widespread degradation of myelin and resulting in neurological deficits. Recent advances in molecular and atomic imaging provide the means to probe the microenvironment in affected brain tissues at an unprecedented level of detail and may provide new insights. This study showcases state-of-the-art spectroscopic and mass spectrometric techniques to compare distributions of molecular and atomic entities in MS lesions and surrounding brain tissues.

Extracellular Matrix Changes in Subcellular Brain Fractions and Cerebrospinal Fluid of Alzheimer's Disease Patients.

The brain's extracellular matrix (ECM) is assumed to undergo rearrangements in Alzheimer's disease (AD). Here, we investigated changes of key components of the hyaluronan-based ECM in independent samples of post-mortem brains (N = 19), cerebrospinal fluids (CSF; N = 70), and RNAseq data (N = 107; from The Aging, Dementia and TBI Study) of AD patients and non-demented controls. Group comparisons and correlation analyses of major ECM components in soluble and synaptosomal fractions from frontal, temporal cortex, and hippocampus of control, low-grade, and high-grade AD brains revealed a reduction in brevican in temporal cortex soluble and frontal cortex synaptosomal fractions in AD.

Autolysis Affects the Iron Cargo of Ferritins in Neurons and Glial Cells at Different Rates in the Human Brain.

Iron is known to accumulate in neurological disorders, so a careful balance of the iron concentration is essential for healthy brain functioning. An imbalance in iron homeostasis could arise due to the dysfunction of proteins involved in iron homeostasis. Here, we focus on ferritin-the primary iron storage protein of the brain.

Orientation dependence of R relaxation in the newborn brain.

In MRI the transverse relaxation rate, R = 1/T shows dependence on the orientation of ordered tissue relative to the main magnetic field. In previous studies, orientation effects of R relaxation in the mature brain's white matter have been found to be described by a susceptibility-based model of diffusion through local magnetic field inhomogeneities created by the diamagnetic myelin sheaths. Orientation effects in human newborn white matter have not yet been investigated.

Technical note: Quantitative optimization of the FLAIR sequence in post mortem magnetic resonance imaging.

The fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) sequence aims at suppressing the signal of the cerebrospinal fluid (CSF) by acquiring images at the time point at which the longitudinal magnetization and therefore the signal of CSF is zero. This time point is also called the null point inversion time (TI). However, the FLAIR sequence is impaired by the temperature dependency of TI in post mortem MRI due to the lower body temperature of the deceased subject.

The Effects of Wearing a 3-Ply or KN95 Face Mask on Cerebral Blood Flow and Oxygenation.

Background: The SARS-CoV-2 virus has impacted life in many ways, one change being the use of face masks. Their effect on MRI-based measurements of cerebral oxygen levels with quantitative susceptibility mapping (QSM) and cerebral blood flow (CBF) is not known.

Purpose: This study investigated whether wearing a face mask leads to changes in CBF and cerebral venous oxygen saturation measured with MRI.

Revisiting brain iron deficiency in restless legs syndrome using magnetic resonance imaging.

Study Objectives: Studies on brain iron content in restless legs syndrome (RLS) using magnetic resonance imaging (MRI) are heterogeneous. In this study, we sought to leverage the availability of a large dataset including a range of iron-sensitive MRI techniques to reassess the association between brain iron content and RLS with added statistical power and to compare these results to previous studies.

Methods: The relaxation rates R, R', and R* and quantitative susceptibility are MRI parameters strongly correlated to iron content.

HFP-QSMGAN: QSM from homodyne-filtered phase images.

Purpose: Homodyne filtering is a standard preprocessing step in the estimation of SWI. Unfortunately, SWI is not quantitative, and QSM cannot be accurately estimated from filtered phase images. Compared with gradient-echo sequences suitable for computing QSM, SWI is more readily available and is often the only susceptibility-sensitive sequence acquired in the clinical setting.

High-resolution neural network-driven mapping of multiple diffusion metrics leveraging asymmetries in the balanced steady-state free precession frequency profile.

We propose to utilize the rich information content about microstructural tissue properties entangled in asymmetric balanced steady-state free precession (bSSFP) profiles to estimate multiple diffusion metrics simultaneously by neural network (NN) parameter quantification. A 12-point bSSFP phase-cycling scheme with high-resolution whole-brain coverage is employed at 3 and 9.4 T for NN input.

Recovering SWI-filtered phase data using deep learning.

Purpose: To develop a deep neural network to recover filtered phase from clinical MR phase images to enable the computation of QSMs.

Methods: Eighteen deep learning networks were trained to recover combinations of 13 SWI phase-filtering pipelines. SWI-filtered data were computed offline from five multiorientation, multiecho MRI scans yielding 132 3D volumes (118/7/7 training/validation/testing).

Automated segmentation of deep brain nuclei using convolutional neural networks and susceptibility weighted imaging.

The advent of susceptibility-sensitive MRI techniques, such as susceptibility weighted imaging (SWI), has enabled accurate in vivo visualization and quantification of iron deposition within the human brain. Although previous approaches have been introduced to segment iron-rich brain regions, such as the substantia nigra, subthalamic nucleus, red nucleus, and dentate nucleus, these methods are largely unavailable and manual annotation remains the most used approach to label these regions. Furthermore, given their recent success in outperforming other segmentation approaches, convolutional neural networks (CNN) promise better performances.

Phosphorous Magnetic Resonance Spectroscopy and Molecular Markers in IDH1 Wild Type Glioblastoma.

The World Health Organisation's (WHO) classification of brain tumors requires consideration of both histological appearance and molecular characteristics. Possible differences in brain energy metabolism could be important in designing future therapeutic strategies. Forty-three patients with primary, isocitrate dehydrogenase 1 (IDH1) wild type glioblastomas (GBMs) were included in this study.

Sensitivity of fiber orientation dependent to temperature and post mortem interval.

Purpose: imaging of brain white matter is well known for being sensitive to the orientation of nerve fibers with respect to the B field of the MRI scanner. The goal of this study was to evaluate whether and to which extent fiber orientation dependent differs between in vivo and post mortem in situ examinations, and to investigate the influence of varying temperatures and post mortem intervals (PMI).

Methods: Post mortem in situ and in vivo MRI scans were conducted at 3T.

Myelin water imaging depends on white matter fiber orientation in the human brain.

Purpose: The multi-exponential T decay of the MRI signal from cerebral white matter can be separated into short T components related to myelin water and long T components related to intracellular and extracellular water. In this study, we investigated to what degree the apparent myelin water fraction (MWF) depends on the angle between white matter fibers and the main magnetic field.

Methods: Maps of the apparent MWF were acquired using multi-echo Carr-Purcell-Meiboom-Gill and gradient-echo spin-echo sequences.

The influence of iron oxidation state on quantitative MRI parameters in post mortem human brain.

A variety of Magnetic Resonance Imaging (MRI) techniques are known to be sensitive to brain iron content. In principle, iron sensitive MRI techniques are based on local magnetic field variations caused by iron particles in tissue. The purpose of this study was to investigate the sensitivity of MR relaxation and magnetization transfer parameters to changes in iron oxidation state compared to changes in iron concentration.

Correction: Hepatic gene expression explains primary drug toxicity in bipolar disorder.

The original Article had an incomplete acknowledgements list. The following sentence has now been added to the HTML and PDF versions of this Article: "This study was performed within the framework of the PhD program Molecular Medicine of the Medical University of Graz. This work was supported by the Medical University of Graz within the Open Access Publishing Funding Program.

Hepatic gene expression explains primary drug toxicity in bipolar disorder.

In bipolar disorder (BPD), long-term psychotropic drug treatment is often necessary to prevent relapse or recurrence. Nevertheless, adverse drug effects including disturbances in hepatic metabolism are observed and still poorly understood. Here, the association between hepatic gene expression and histopathological changes of the liver was investigated.

The influence of brain iron on myelin water imaging.

With myelin playing a vital role in normal brain integrity and function and thus in various neurological disorders, myelin sensitive magnetic resonance imaging (MRI) techniques are of great importance. In particular, multi-exponential T relaxation was shown to be highly sensitive to myelin. The myelin water imaging (MWI) technique allows to separate the T decay into short components, specific to myelin water, and long components reflecting the intra- and extracellular water.

The role of iron and myelin in orientation dependent R of white matter.

Brain myelin and iron content are important parameters in neurodegenerative diseases such as multiple sclerosis (MS). Both myelin and iron content influence the brain's R relaxation rate. However, their quantification based on R maps requires a realistic tissue model that can be fitted to the measured data.

An Unbiased Approach of Sampling TEM Sections in Neuroscience.

Investigations of the ultrastructural features of neurons and their synapses are only possible with electron microscopy. Especially for comparative studies of the changes in densities and distributions of such features, an unbiased sampling protocol is vital for reliable results. Here, we present a workflow for the image acquisition of brain samples.

Quantitative Susceptibility Mapping to Assess Cerebral Vascular Compliance.

This study explored whether autoregulatory shifts in cerebral blood volume induce susceptibility changes large enough to be depicted by quantitative susceptibility mapping. Eight healthy subjects underwent fast quantitative susceptibility mapping at 3T while lying down to slowly decrease mean arterial pressure. A linear relationship between mean arterial pressure and susceptibility was observed in cortical and subcortical structures, likely representing vessels involved in autoregulation.

Month-of-birth-effect in multiple sclerosis in Austria.

Background: The month-of-birth-effect (MoBE) describes the finding that multiple sclerosis (MS) patients seem to have been born significantly more frequently in spring, with a rise in May, and significantly less often in autumn and winter with the fewest births in November.

Objectives: To analyse if the MoBE can also be found in the Austrian MS population, and if so, whether the pattern is similar to the reported pattern in Canada, United Kingdom, and some Scandinavian countries.

Methods: The data of 7886 MS patients in Austria were compared to all live births in Austria from 1940 to 2010, that is, 7.

Assessment of ferritin content in multiple sclerosis brains using temperature-induced R* changes.

Purpose: Current MRI techniques cannot reliably assess iron content in white matter due to the confounding diamagnetic effect of myelin. The purpose of this study was to validate with histology a novel iron mapping technique that uses the temperature dependency of the paramagnetic susceptibility in multiple sclerosis (MS) brains, where white matter has been reported to show significant variations in iron content.

Methods: We investigated post mortem brain tissue from three MS patients and one control subject.