Search results for " Magnetic resonance imaging"

Water Dynamics in Neural Tissue

2013

Water dynamics in post-mortem two-years old bovine cerebral right hemisphere has been investigated through Elastic and Quasi-elastic Neutron Scattering. Experimental parameters such as stability in time of the proton dynamics, data reproducibility and changes in the tissues dynamics upon the conservation protocol, cryogenic towards formalin addition, have been carefully investigated. Results are extremely encouraging and comparisons to magnetic resonance imaging findings are discussed.

Semiautomatic detection of myocardial contours in order to investigate normal values of the left ventricular trabeculated mass using MRI

2015

Purpose To propose, assess, and validate a semiautomatic method allowing rapid and reproducible measurement of trabeculated and compacted left ventricular (LV) masses from cardiac magnetic resonance imaging (MRI). Materials and Methods We developed a method to automatically detect noncompacted, endocardial, and epicardial contours. Papillary muscles were segmented using semiautomatic thresholding and were included in the compacted mass. Blood was removed from trabeculae using the same threshold tool. Trabeculated, compacted masses and ratio of noncompacted to compacted (NC:C) masses were computed. Preclinical validation was performed on four transgenic mice with hypertrabeculation of the LV…

Comparison of Functional Network Connectivity and Granger Causality for Resting State fMRI Data

2017

Functional network connectivity (FNC) and Granger causality have been widely used to identify functional and effective connectivity for resting functional magnetic resonance imaging (fMRI) data. However, the relationship between these two approaches is still unclear, making it difficult to compare results. In this study, we investigate the relationship by constraining the FNC lags and the causality coherences for analyzing resting state fMRI data. The two techniques were applied respectively to examine the connectivity within default mode network related components extracted by group independent component analysis. The results show that FNC and Granger causality provide complementary result…

Resting state functional magnetic resonance imaging analysis of the brain of pathological gamblers

2018

Purpose . Gambling disorder has been recently reclassified under the category ‘‘substance-related and addictive disorders”. Recent studies performed through functional MRI (fMRI) have shown that the perseverance of some behaviors can alter brain activation [1,2]. In this work we aim at investigating functional connectivity changes in pathological gamblers (PGs) in comparison to healthy controls (HCs) by means of resting state functional Magnetic Resonance Imaging (rs-fMRI). Methods and materials. Thirteen HCs and fourteen PGs were recruited (all right handed males; drugs free; mean age 36 ± 10 yrs). All acquisitions were performed through a 1,5 T MRI scanner using a 8-channels phased-array …

Transsacral rectocele following combined neurinoma resection: A case report

2015

Highlights • Case of a combined (transsacral and laparoscopic) resection of a presacral tumour. • First described case of a transsacral rectocele two years after this procedure. • Possibility of laparoscopic defect repair of transsacral defects.

Semi-blind Independent Component Analysis of functional MRI elicited by continuous listening to music

2013

This study presents a method to analyze blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (tMRI) signals associated with listening to continuous music. Semi-blind independent component analysis (ICA) was applied to decompose the tMRI data to source level activation maps and their respective temporal courses. The unmixing matrix in the source separation process of ICA was constrained by a variety of acoustic features derived from the piece of music used as the stimulus in the experiment. This allowed more stable estimation and extraction of more activation maps of interest compared to conventional ICA methods.

Snowball ICA: A Model Order Free Independent Component Analysis Strategy for Functional Magnetic Resonance Imaging Data

2020

In independent component analysis (ICA), the selection of model order (i.e., number of components to be extracted) has crucial effects on functional magnetic resonance imaging (fMRI) brain network analysis. Model order selection (MOS) algorithms have been used to determine the number of estimated components. However, simulations show that even when the model order equals the number of simulated signal sources, traditional ICA algorithms may misestimate the spatial maps of the signal sources. In principle, increasing model order will consider more potential information in the estimation, and should therefore produce more accurate results. However, this strategy may not work for fMRI because …

Chirurgia trans-cranica mediante ultrasuoni focalizzati ad alta intensità su guida RM: esperienza preliminare a 1,5T

2015

Da qualche anno la chirurgia mediante ultrasuoni focalizzati ad alta intensità guidati da Risonanza Magnetica (Magnetic Resonance guided Focused Ultrasound Surgery, MRgFUS) si sta diffondendo anche in Italia per la palliazione del dolore da metastasi ossee, per il trattamento di tumori ossei primitivi (benigni e non), dei fibromi e dell’adenomiosi uterina; sono già stati inoltre pubblicati i risultati preliminari del trattamento di alcuni tumori epatici, pancreatici, prostatici e della mammella mediante MRgFUS. Questa innovativa tecnica prevede l’utilizzo di un’apparecchiatura di Risonanza Magnetica per il monitoraggio della procedura e sfrutta le caratteristiche fisico- meccaniche degli …

Is there still a role for lesioning in functional neurosurgery: the Italian experience of delivering focused ultrasound high energy through a 1,5 tes…

2017

Microcephaly a clinical-genetic and neurologic approach

2013