Can dynamic contrast-enhanced magnetic resonance imaging combined with texture analysis differentiate malignant glioneuronal tumors from other glioblastoma?

An interesting approach has been proposed to differentiate malignant glioneuronal tumors (MGNTs) as a subclass of the WHO grade III and IV malignant gliomas. MGNT histologically resemble any WHO grade III or IV glioma but have a different biological behavior, presenting a survival twice longer as WHO glioblastomas and a lower occurrence of metastases. However, neurofilament protein immunostaining was required for identification of MGNT.

Preliminary MRI quality assessment and device acceptance guidelines for a multicenter bioclinical study: the GO Glioblastoma Project.

It is a major challenge to guarantee homogeneous acquisition during a prospective multicenter magnetic resonance imaging (MRI) study that makes use of different devices. The goal of the multicenter Grand Ouest Glioblastoma Project (GOGP) was to correlate MRI quantitative parameters with biological markers extracted from image-guided biopsies. Therefore, it was essential to ensure spatial coherence of the parameters as well as the signal intensity and homogeneity.

The impact of image dynamic range on texture classification of brain white matter.

Background: The Greylevel Cooccurrence Matrix method (COM) is one of the most promising methods used in Texture Analysis of Magnetic Resonance Images. This method provides statistical information about the spatial distribution of greylevels in the image which can be used for classification of different tissue regions. Optimizing the size and complexity of the COM has the potential to enhance the reliability of Texture Analysis results.

Magnetic resonance imaging measurements of vascular permeability and extracellular volume fraction of breast tumors by dynamic Gd-DTPA-enhanced relaxometry.

Vascular permeability (k(ep), min(-1)) and extracellular volume fraction (v(e)) are tissue parameters of great interest to characterize malignant tumor lesions. Indeed, it is well known that tumors with high blood supply better respond to therapy than poorly vascularized tumors, and tumors with large extracellular volume tend to be more malignant than tumors showing lower extracellular volume. Furthermore, the transport of therapeutic agents depends on both extracellular volume fraction and vessel permeability.

Texture analysis of magnetic resonance images of rat muscles during atrophy and regeneration.

Objectives: The goals of the current study were (i) to introduce texture analysis on magnetic resonance imaging (MRI-TA) as a noninvasive method of muscle investigation that can discriminate three muscle conditions in rats; these are normal, atrophy and regeneration; and (ii) to show consistency between MRI-TA results and histological results of muscle type 2 fibers' cross-sectional area.

Method: Twenty-three adult female Wistar rats were randomized into (i) control (C), (ii) immobilized (I) and (iii) recovering (R) groups. For the last two groups, the right hind limb calf muscles were immobilized against the abdomen for 14 days; then, the hind limb was remobilized only for the R group for 40 days.

Proton NMR visible mobile lipid signals in sensitive and multidrug-resistant K562 cells are modulated by rafts.

BACKGROUND: Most cancer cells are characterized by mobile lipids visible on proton NMR (1H-NMR), these being comprised mainly of methyl and methylene signals from lipid acyl chains. Erythroleukemia K562 cells show narrow signals at 1.3 and 0.

Magnetic resonance imaging contrast-enhanced relaxometry of breast tumors: an MRI multicenter investigation concerning 100 patients.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using extracellular contrast agents has proved to be useful for the characterization of breast tumors. DCE-MRI has demonstrated a high sensitivity (around 95%) but a rather poor and controversial specificity, varying, according to the different studies, from 45% to 90%. In order to increase (a) the specificity and (b) the robustness of this quantitative approach in multicenter evaluation (five MRI units), a quantitative approach called dynamic relaxometry has been developed.

Three dimensional texture analysis in MRI: a preliminary evaluation in gliomas.

The discrimination of tumor boundaries from normal tissue, as well as the evaluation of tissue heterogeneity and tumor grading often continue to pose a challenge in MRI. Although yielding promising results in various fields of medical imaging, two- dimensional (2D) texture analysis in MRI has, until now, demonstrated a lack of specificity in brain tumor classification. A new three-dimensional (3D) approach using Cooccurrence Matrix analysis is proposed to increase the sensitivity and specificity of brain tumor characterization.

Detection of acoustic waves by NMR using a radiofrequency field gradient.

A B(1) field gradient-based method previously described for the detection of mechanical vibrations has been applied to detect oscillatory motions in condensed matter originated from acoustic waves. A ladder-shaped coil generating a quasi-constant RF-field gradient was associated with a motion-encoding NMR sequence consisting in a repetitive binomial 13;31; RF pulse train (stroboscopic acquisition). The NMR response of a gel phantom subject to acoustic wave excitation in the 20-200 Hz range was investigated.

Follow-up by one- and two-dimensional NMR of plasma from pigs with ischemia-induced acute liver failure treated with a bioartificial liver.

Hepatic encephalopathy may occur following acute hepatic failure (AHF), which results in the release of toxic compounds from the injured liver. These compounds, which induce cerebral edema, are not well characterized, yet. The aim of this study was to evaluate the potential interest of NMR spectroscopy in the follow-up of different plasma compounds in pigs with ischemia-induced fulminant hepatic failure treated or not with a bioartificial liver (BAL), which has been previously shown to improve the neurological status of the animals.

MR detection of mechanical vibrations using a radiofrequency field gradient.

A new method for NMR characterization of mechanical waves, based upon radiofrequency field gradient for motion encoding, is proposed. A binomial B1 gradient excitation scheme was used to visualize the mobile spins undergoing a periodic transverse mechanical excitation. A simple model was designed to simulate the NMR signal as a function of the wave frequency excitation and the periodicity of the NMR pulse sequence.