Reconstruction and Visualization of Fiber and Laminar Structure in the Normal Human Heart from Ex Vivo Diffusion Tensor Magnetic Resonance Imaging (DTMRI) Data

2007 ◽  
Vol 42 (11) ◽  
pp. 777-789 ◽  
Author(s):  
Damien Rohmer ◽  
Arkadiusz Sitek ◽  
Grant T. Gullberg
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Human Heart ◽  
Diffusion Tensor ◽  
Ex Vivo ◽  
Resonance Imaging ◽  
Laminar Structure ◽  
Normal Human

scholarly journals Diffusion Tensor Tractrography Visualizes Partial Nerve Laceration Severity as Early as 1 Week After Surgical Repair in a Rat Model Ex Vivo

2020 ◽  
Vol 185 (Supplement_1) ◽  
pp. 35-41 ◽  
Author(s):  
Angel F Farinas ◽  
Isaac V Manzanera Esteve ◽  
Alonda C Pollins ◽  
Nancy L Cardwell ◽  
Mark D Does ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Rat Model ◽  
Surgical Repair ◽  
Diffusion Tensor ◽  
Ex Vivo ◽  
Visual Representation ◽  
7 Tesla ◽  
Blue Staining ◽  
Resonance Imaging

Abstract Background: Previous studies in our laboratory have demonstrated that a magnetic resonance imaging method called diffusion tensor imaging (DTI) can differentiate between crush and complete transection peripheral nerve injuries in a rat model ex vivo. DTI measures the directionally dependent effect of tissue barriers on the random diffusion of water molecules. In ordered tissues such as nerves, this information can be used to reconstruct the primary direction of diffusion along fiber tracts, which may provide information on fiber tract continuity after nerve injury and surgical repair. Methods: Sprague-Dawley rats were treated with different degrees of partial transection of the sciatic nerve followed by immediate repair and euthanized after 1 week of recovery. Nerves were then harvested, fixed, and scanned with a 7 Tesla magnetic resonance imaging to obtain DTIand fiber tractography in each sample. Additional behavioral (sciatic function index, foot fault asymmetry) and histological (Toluidine blue staining) assessments were performed for validation. Results: Tractography yielded a visual representation of the degree of injury that correlated with behavioral and histological evaluations. Conclusions: DTI tractography is a noninvasive tool that can yield a visual representation of a partial nerve transection as early as 1 week after surgical repair.

scholarly journals Diffusion Magnetic Resonance Imaging with Applications to Cardiac Muscle: Short Review

2020 ◽  
Vol 62 (1) ◽  
pp. 108-119
Author(s):  
Mihaela Pop ◽  
Nicoleta Stefu
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cardiac Muscle ◽  
Diffusion Tensor ◽  
Ex Vivo ◽  
Pulse Sequences ◽  
Short Review ◽  
Fiber Tractography ◽  
Resonance Imaging ◽  
Parametric Maps

AbstractThis review describes in brief recent magnetic resonance imaging (MRI) methods for assessing cardiac structure in healthy and pathologic state using diffusion-weighted (DW) and diffusion tensor imaging (DTI) approaches. A background on the theory and MR pulse sequences employed in DW/DT imaging is given, along with the calculation of diffusion tensor (D), apparent diffusion coefficient (ADC) and fractional anisotropy (FA). Parametric maps derived from DW/DT images can quantify microstructure alterations due to fibrotic collagen deposition, along with associated changes in cardiac muscle anisotropy. Representative examples of ADC and FA parametric maps are shown from ex vivo high-resolution DT images of explanted healthy and scarred hearts obtained from pre-clinical investigations. Furthermore, examples of fiber tractography demonstrating DTI-based 3D (three-dimensional) reconstruction of fiber directions within the heart are illustrated using advanced open-source software. Lastly, future developments and potential translation of DW/DT methods into routine clinical evaluation for cardiac MR imaging protocols are highlighted.

scholarly journals Diffusion tensor magnetic resonance imaging of optic pathway in cases of suprasellar masses

2020 ◽  
Vol 51 (1) ◽  
Author(s):  
Nada Ashraf Abd El-Hady ◽  
Mohammad Mahmoud Alhousini Alashwah ◽  
Haitham Haroun Emam ◽  
Ashraf Mohamed Farid Rahil
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Diffusion Tensor ◽  
Optic Pathway ◽  
Resonance Imaging

scholarly journals Demyelination and remyelination detected in an alternative cuprizone mouse model of multiple sclerosis with 7.0 T multiparameter magnetic resonance imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuang Ding ◽  
Yu Guo ◽  
Xiaoya Chen ◽  
Silin Du ◽  
Yongliang Han ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Multiple Sclerosis ◽  
Magnetic Resonance ◽  
Mouse Model ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Blue Staining ◽  
Resonance Imaging ◽  
The Mean ◽  
Underlying Mechanisms

AbstractThe aim of this study was to investigate the mechanisms underlying demyelination and remyelination with 7.0 T multiparameter magnetic resonance imaging (MRI) in an alternative cuprizone (CPZ) mouse model of multiple sclerosis (MS). Sixty mice were divided into six groups (n = 10, each), and these groups were imaged with 7.0 T multiparameter MRI and treated with an alternative CPZ administration schedule. T2-weighted imaging (T2WI), susceptibility-weighted imaging (SWI), and diffusion tensor imaging (DTI) were used to compare the splenium of the corpus callosum (sCC) among the groups. Prussian blue and Luxol fast blue staining were performed to assess pathology. The correlations of the mean grayscale value (mGSV) of the pathology results and the MRI metrics were analyzed to evaluate the multiparameter MRI results. One-way ANOVA and post hoc comparison showed that the normalized T2WI (T2-nor), fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) values were significantly different among the six groups, while the mean phase (Φ) value of SWI was not significantly different among the groups. Correlation analysis showed that the correlation between the T2-nor and mGSV was higher than that among the other values. The correlations among the FA, RD, MD, and mGSV remained instructive. In conclusion, ultrahigh-field multiparameter MRI can reflect the pathological changes associated with and the underlying mechanisms of demyelination and remyelination in MS after the successful establishment of an acute CPZ-induced model.

scholarly journals Numerical Analysis of a Flexible Dual Loop Coil and its Experimental Validation for pre-Clinical Magnetic Resonance Imaging of Rodents at 7 T

2016 ◽  
Vol 16 (6) ◽  
pp. 294-299 ◽  
Author(s):  
S. Solis-Najera ◽  
F. Vazquez ◽  
R. Hernandez ◽  
O. Marrufo ◽  
A.O. Rodriguez
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Imaging System ◽  
Ex Vivo ◽  
Small Animal ◽  
Magnetic Resonance Imaging System ◽  
External Diameter ◽  
Rf Coil ◽  
Resonance Imaging ◽  
Clinical Magnetic Resonance Imaging

Abstract A surface radio frequency coil was developed for small animal image acquisition in a pre-clinical magnetic resonance imaging system at 7 T. A flexible coil composed of two circular loops was developed to closely cover the object to be imaged. Electromagnetic numerical simulations were performed to evaluate its performance before the coil construction. An analytical expression of the mutual inductance for the two circular loops as a function of the separation between them was derived and used to validate the simulations. The RF coil is composed of two circular loops with a 5 cm external diameter and was tuned to 300 MHz and 50 Ohms matched. The angle between the loops was varied and the Q factor was obtained from the S11 simulations for each angle. B1 homogeneity was also evaluated using the electromagnetic simulations. The coil prototype was designed and built considering the numerical simulation results. To show the feasibility of the coil and its performance, saline-solution phantom images were acquired. A correlation of the simulations and imaging experimental results was conducted showing a concordance of 0.88 for the B1 field. The best coil performance was obtained at the 90° aperture angle. A more realistic phantom was also built using a formaldehyde-fixed rat phantom for ex vivo imaging experiments. All images showed a good image quality revealing clearly defined anatomical details of an ex vivo rat.

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