Search results for "MRI"
showing 10 items of 733 documents
Synthetic strategy for preparation of a folate corrole DOTA heterobimetallic Cu–Gd complex as a potential bimodal contrast agent in medical imaging
2015
Abstract An efficient sequential route to synthesize heterobimetallic complexes is reported herein. A folate, Cu corrole, Gd DOTA complex that addresses the requirements of a potential contrast agent (CA) for bimodal imaging (e.g., MRI/PET) is reported. The over-expression of the folate receptor in a variety of malignant tumors, along with its limited expression in healthy tissues, makes this an attractive tumor-specific molecular target. Synthesis of a bimetallic ligand potentially targeting the folate receptor, was easily achieved in only a few steps. Interestingly, preliminary studies showed that the relaxivity of the folic heterobimetallic derivative was higher in comparison to a clinic…
Design of Porphyrin-dota-Like Scaffolds as All-in-One Multimodal Heterometallic Complexes for Medical Imaging
2013
A series of four multimodal ligands incorporating one porphyrin moiety and one or more dota-like macrocycles all-in-one in the same molecular architecture have been synthesized and full characterized. The corresponding gadolinium(III) complexes were also synthesized and heterometallic complexes incorporating both gadolinium(III) and copper(II) ions were prepared as potential MRI/PET multimodal contrast agents. One ligand (L4) includes an amine moiety that can be activated for easy conversion into an isothiocyanate group for further anchoring to a biological vector. Preliminary relaxivity, cytotoxicity, and MRI studies showed that the complexes developed in this work are very promising medic…
An investigation of the neural circuits underlying reaching and reach-to-grasp movements: from planning to execution
2014
Experimental evidence suggests the existence of a sophisticated brain circuit specifically dedicated to reach-to-grasp planning and execution, both in human and non-human primates (Castiello, 2005). Studies accomplished by means of neuroimaging techniques suggest the hypothesis of a dichotomy between a "reach-to-grasp" circuit, involving the anterior intraparietal area, the dorsal and ventral premotor cortices (PMd and PMv - Castiello and Begliomini, 2008; Filimon, 2010) and a "reaching" circuit involving the medial intraparietal area and the superior parieto-occipital cortex (Culham et al., 2006). However, the time course characterizing the involvement of these regions during the planning …
Stochastic model of memristor based on the length of conductive region
2021
Abstract We propose a stochastic model of a voltage controlled bipolar memristive system, which includes the properties of widely used dynamic SPICE models and takes into account the fluctuations inherent in memristors. The proposed model is described by rather simple equations of Brownian diffusion, does not require significant computational resources for numerical modeling, and allows obtaining the exact analytical solutions in some cases. The noise-induced transient bimodality phenomenon, arising under resistive switching, was revealed and investigated theoretically and experimentally in a memristive system, by finding a quite good qualitatively agreement between theory and experiment. B…
Resting-State Functional Magnetic Resonance Imaging for Brain Tumor Surgical Planning: Feasibility in Clinical Setting.
2019
The aim of this study was to introduce resting-state functional magnetic resonance imaging (rest-fMRI) capability for brain tumor surgical planning. rest-fMRI is an emerging functional neuroimaging technique potentially able to provide new insights into brain physiology and to provide useful information regarding brain tumors in preoperative and postoperative settings. rest-fMRI evaluates low-frequency fluctuations in the blood oxygen level–dependent signal while the subject is at rest during magnetic resonance imaging examination. Multiple resting-state networks have been identified, including the somatosensory, language, and visual networks, which are of primary importance for surgical pl…
MR-guided focused ultrasound application for moving target tumor ablation in abdominal area: Coil selection
2020
PubMed: 32276552
Non-volatile memory characteristics of a Ti/HfO2/Pt synaptic device with a crossbar array structure
2022
The resistive switching and synaptic behavior of a fabricated Ti/HfO2/Pt crossbar array device are investigated. The results demonstrated that TiOx layers are created by the movement of oxygen ions during the positive SET process, thereby improving the endurance and multilevel switching behavior of the device. The random properties of SET process were described with the help of stochastic model of memristor based on the length of conductive filament. The analysis of the mean first passage time allows estimating the parameters of the dielectric switching layer such as the activation energy of the diffusive defects, its variation under the influence of the driving voltage and the value of the…
The importance of level stratification for quantitative MR studies of lumbar intervertebral discs : a cross-sectional analysis in 101 healthy adults
2019
Purpose: To investigate whether quantitative T2-times depend on lumbar intervertebral disc (IVD) level. Methods: The lumbar spine (Th12/L1–L5/S1) of 101 participants (53.5% female, 30.0[± 3.6]years, 173.5[± 9.6]cm and 69.9[± 13.4]kg), without history of back pain, was examined on a 3T scanner with sagittal T2-mapping. All IVDs were stratified according to Pfirrmann grade and lumbar level, with mean T2-time determined for the entire IVD volume and in five subregions of interests. Results: Significant level-dependent T2-time differences were detected, both for the entire IVD volume and its subregions. For the entire IVD volume, Pfirrmann grade 2 IVDs displayed 9–18% higher T2-times in Th12/L1…
Functional connectivity modulation induced by transcranial direct current stimulation of the motor network investigated by resting state fMRI
2015
This study is aimed at measuring the variation of functional connectivity between cortical brain regions after tDCS along time. For this purpose we enrolled 20 healthy right-handed subjects.
A Guide to Designing a Memory fMRI Paradigm for Pre-surgical Evaluation in Temporal Lobe Epilepsy
2020
There has been increasing interest in the clinical and experimental use of memory functional Magnetic Resonance Imaging (fMRI). The 2017 American Academy of Neurology practice guidelines on the use of pre-surgical cognitive fMRI suggests that verbal memory fMRI could be used to lateralize memory functions in people with Temporal Lobe Epilepsy (TLE) and should be used to predict post-operative verbal memory outcome. There are however technical and methodological considerations, to optimize both the sensitivity and specificity of this imaging modality. Below we discuss these constraints and suggest recommendations to consider when designing a memory fMRI paradigm.