Magnetic resonance tractography of the lumbosacral plexus: Step-by-step.

MR tractography of the lumbosacral plexus (LSP) is challenging due to the difficulty of acquiring high quality data and accurately estimating the neuronal tracts. We proposed an algorithm for an accurate visualization and assessment of the major LSP bundles using the segmentation of the cauda equina as seed points for the initial starting area for the fiber tracking algorithm.Twenty-six healthy volunteers underwent MRI examinations on a 3T MR scanner using the phased array coils with optimized measurement protocols for diffusion-weighted images and coronal T2 weighted 3D short-term inversion recovery sampling perfection with application optimized contrast using varying flip angle evaluation sequences used for LSP fiber reconstruction and MR neurography (MRN).

Multiparametric Quantitative Brain MRI in Neurological and Hepatic Forms of Wilson's Disease.

Background: In Wilson's disease (WD), demyelination, rarefaction, gliosis, and iron accumulation in the deep gray matter cause opposing effects on T -weighted MR signal. However, the degree and interplay of these changes in chronically treated WD patients has not been quantitatively studied.

Purpose: To compare differences in brain multiparametric mapping between controls and chronically treated WD patients with neurological (neuro-WD) and hepatic (hep-WD) forms to infer the nature of residual WD neuropathology.

The aging effect on prostate metabolite concentrations measured by H MR spectroscopy.

Objective: The effects of aging, magnetic field and the voxel localization on measured concentrations of citrate (Cit), creatine (Cr), cholines (Cho) and polyamines (PA) in a healthy prostate were evaluated.

Materials And Methods: 36 examinations at both 1.5T and 3T imagers of 52 healthy subjects aged 19-71 years were performed with PRESS 3D-CSI sequences (TE = 120 and 145 ms).

Flip-angle mapping of 31P coils by steady-state MR spectroscopic imaging.

Purpose: Phosphorus ((31)P) MR spectroscopic imaging (MRSI) is primarily applied with sensitive, surface radiofrequency (RF) coils that provide inhomogeneous excitation RF field (B1(+)) and rough localization due to their B1(+) and sensitivity (B1(-)) profiles. A careful and time-consuming pulse adjustment and an accurate knowledge of flip angle (FA) are mandatory for quantification corrections.

Materials And Methods: In this study, a simple, fast, and universal (31)P B1(+) mapping method is proposed, which requires fast steady-state MRSI (typically one sixth of normal measurement time) in addition to the typical MRSI acquired within the examination protocol.

Recognition of anaplastic foci within low-grade gliomas using MR spectroscopy.

Background: The recognition of anaplastic foci within low-grade gliomas is of extreme importance in patients under follow-up for Grade II gliomas. We present the algorithm of MR spectroscopy (MRS)-guided brain biopsy and its correlation with tumour histology.

Methods: Twenty-seven patients harbouring suspected Grade II/III glioma were examined on our 3T MR.

jSIPRO - analysis tool for magnetic resonance spectroscopic imaging.

Magnetic resonance spectroscopic imaging (MRSI) involves a huge number of spectra to be processed and analyzed. Several tools enabling MRSI data processing have been developed and widely used. However, the processing programs primarily focus on sophisticated spectra processing and offer limited support for the analysis of the calculated spectroscopic maps.

Multimodal elucidation of choline metabolism in a murine glioma model using magnetic resonance spectroscopy and 11C-choline positron emission tomography.

The metabolites, transporters, and enzymes involved in choline metabolism are regarded as biomarkers for disease progression in a variety of cancers, but their in vivo detection is not ideal. Both magnetic resonance spectroscopy [MRS using chemical shift imaging (CSI) total choline (tCho)] and C-choline positron emission tomography (PET) can probe this pathway, but they have not been compared side by side. In this study, we used the spontaneous murine astrocytoma model SMA560 injected intracranially into syngeneic VM/Dk mice, analyzing animals at various postimplantation time points using dynamic microPET imaging and CSI MRS.

Quantitative MR imaging and spectroscopy of brain tumours: a step forward?

Objectives: A prospective quantitative MR study of brain tumours was performed to show the potential of combining different MR techniques to distinguish various disease processes in routine clinical practice.

Methods: Twenty-three patients with various intracranial tumours before treatment (diagnosis confirmed by a biopsy) and 59 healthy subjects were examined on a 3-T system by conventional MR imaging, 1H spectroscopic imaging, diffusion tensor imaging and T2 relaxometry. Metabolic concentrations and their ratios, T2 relaxation times and mean diffusivities were calculated and correlated on a pixel-by-pixel basis and compared to control data.

Fractional anisotropy and mean diffusivity in the corpus callosum of patients with multiple sclerosis: the effect of physiotherapy.

Introduction: Modulation of neurodegeneration by physical activity is an active topic in contemporary research. The purpose of this study was to investigate changes in the brain's microstructure in multiple sclerosis (MS) after facilitation physiotherapy.

Methods: Eleven patients with MS were examined using motor and neuropsychological testing and multimodal MRI at the beginning of the study, with second baseline measurement after 1 month without any therapy, and after a 2-month period of facilitation physiotherapy.

The correlation between 1H MRS choline concentrations and MR diffusion trace values in human brain tumors.

Objective: The aim of this study was to develop a method for evaluating the spatial distribution of human brain gliomas in individual subjects by evaluating the correlation between the Choline (Cho) signal intensity and the diffusion trace (Tr(ADC)) values.

Materials And Methods: Eleven patients with different histopathologic diagnoses and five healthy subjects were examined with diffusion-weighted EPI-trace sequence and (1)H MR spectroscopic imaging. The calculation of the correlation between choline and Tr(ADC) values on a pixel-by-pixel basis and simulations estimating the influence of partial volume effects on the result were performed.

1H MR spectroscopy as a diagnostic tool for cerebral creatine deficiency.

Objective: Total creatine (tCr) constitutes one of the most prominent signals in human brain MR spectra. A significant decrease in the tCr signal indicates a severe disorder of creatine metabolism. We describe the potential of 1H MR spectroscopy in differential diagnosis of creatine transporter (SLC6A8) deficiency syndrome.

Introduction to post-processing techniques.

The quality of data measured in in vivo MR spectroscopy is often insufficient due to a number of limitations such as low concentrations of observed metabolites and restricted measurement time resulting in a low signal-to-noise ratio. However, there are a variety of methods called post-processing techniques which allow the enhancement of the measured signal after measurement. In this review an introduction to the most important post-processing techniques for (1)H MR spectroscopy is given and practical examples are shown.

Spectroscopic imaging: basic principles.

Spectroscopic imaging (SI) is a method that enables the measurement of the spatial distribution of metabolite concentrations in tissue. In this paper, an overview of measurement and processing techniques for SI is given. First, the basic structure of SI pulse sequences is introduced and the concepts of k-space, point spread function and spatial resolution are described.

Magnetic resonance spectroscopy of the thalamus in patients with mesial temporal lobe epilepsy and hippocampal sclerosis.

Purpose: to investigate potential neuronal dysfunction within the thalamus in patients suffering from mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE/HS).

Methods: we examined twenty epileptic patients suffering from mesial temporal lobe epilepsy with hippocampal sclerosis (17 females, 3 males) and twenty sex- and age-matched healthy controls. H MR spectroscopic imaging (SI) was performed over the right and left thalamus in all patients and controls.

(1)H MR spectroscopic imaging in patients with MRI-negative extratemporal epilepsy: correlation with ictal onset zone and histopathology.

Proton magnetic resonance spectroscopy ((1)H MRS) is beneficial in the lateralization of the epileptogenic zone in temporal lobe epilepsy; however, its role in extratemporal and, especially, MRI-negative epilepsy has not been established. This study seeks to verify how (1)H MRS could help in localizing the epileptogenic zone in patients with MRI-negative extratemporal epilepsy. Seven patients (8-23 years) with MRI-negative refractory focal epilepsy were studied using (1)H MRS on a 1.

Intramyocellular lipid quantification from 1H long echo time spectra at 1.5 and 3 T by means of the LCModel technique.

Purpose: To introduce a method of independent determination of CH2 and CH3 components of intramyocellular lipids (IMCLs) by using long TE for spectra measurement and LCModel for spectra evaluation, to test this technique in controls and insulin-resistant subjects, and to compare results at 1.5 and 3 T.

Materials And Methods: Eight healthy volunteers and 11 patients with type 2 diabetes mellitus underwent measurement using a 1.

MR relaxometry and 1H MR spectroscopy for the determination of iron and metabolite concentrations in PKAN patients.

The influence of iron deposits on T2 values and the content of metabolites in the brain of three patients with DNA proved pantothenate kinase-associated neurodegeneration (PKAN, formerly Hallervorden-Spatz syndrome) was studied. An eye-of-the-tiger sign, a typical MR finding for PKAN, was observed in two patients with the same mutation. A hypointensive lesion in a whole globus pallidus was observed in the third patient with the additional mutation.

The role of relaxation time corrections for the evaluation of long and short echo time 1H MR spectra of the hippocampus by NUMARIS and LCModel techniques.

1H MR spectroscopy is routinely used for lateralization of epileptogenic lesions. The present study deals with the role of relaxation time corrections for the quantitative evaluation of long (TE=135 ms) and short echo time (TE=10 ms) 1H MR spectra of the hippocampus using two methods (operator-guided NUMARIS and LCModel programs). Spectra of left and right hippocampi of 14 volunteers and 14 patients with epilepsy were obtained by PRESS (TR/TE=5000/135 ms) and STEAM (TR/TE=5000/10 ms) sequences with a 1.