Magnetic resonance imaging of water ascent in embolized xylem vessels of grapevine stem segments

2013 ◽  
Vol 93 (5) ◽  
pp. 879-893 ◽  
Author(s):  
Mingtao Wang ◽  
Melvin T. Tyree ◽  
Roderick E. Wasylishen
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Spatial Information ◽  
Ambient Pressure ◽  
Vessel Diameter ◽  
Resonance Imaging ◽  
Model Calculations ◽  
Ascent Velocity ◽  
Water Ascent ◽  
Stem Segments

Wang, M., Tyree, M. T. and Wasylishen, R. E. 2013. Magnetic resonance imaging of water ascent in embolized xylem vessels of grapevine stem segments. Can. J. Plant Sci. 93: 879–893. Temporal and spatial information about water refilling of embolized xylem vessels and the rate of water ascent in these vessels is critical for understanding embolism repair in intact living vascular plants. High-resolution 1H magnetic resonance imaging (MRI) experiments have been performed on embolized grapevine stem segments while they were subjected to refilling at two different applied water pressures in order to investigate these important aspects of embolism repair. Magnetic resonance imaging difference images show that vessels located near the bark tend to refill faster than do inner ones, suggesting that vessel position within the cross section of the stem may affect the refilling process within the vessel. An MRI method for determining the water ascent velocity in each individual embolized xylem vessel is presented. At ambient pressure, the water ascent velocity ranges from 0.0090 to 0.60 mm min−1, but increases to a range of 0.016 to 0.70 mm min−1 at 9.8 kPa above ambient pressure. A steady-state bubble model that offers analytical solutions of the water ascent velocity in embolized xylem vessels is presented; model calculations show that if other parameters are held constant, water ascent velocity is influenced by vessel diameter and position.

Visualization of morphological details in congenitally malformed hearts: virtual three-dimensional reconstruction from magnetic resonance imaging

2003 ◽  
Vol 13 (5) ◽  
pp. 451-460 ◽  
Author(s):  
Thomas Sangild Sørensen ◽  
Erik Morre Pedersen ◽  
Ole Kromann Hansen ◽  
Keld Sørensen
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Real Time ◽  
Clinical Experience ◽  
Spatial Information ◽  
Three Dimensional ◽  
Three Dimensional Reconstruction ◽  
Resonance Imaging ◽  
Cardiac Malformations ◽  
Dimensional Reconstruction

In recent years, three-dimensional imaging has provided new opportunities for visualizing congenital cardiac malformations. We present the initial clinical experience using a recently implemented system, which employs some of new interactive, real-time, techniques. We show how three-dimensional rendering based on magnetic resonance imaging can provide detailed spatial information on both intrinsic and extrinsic cardiac relations, and hence how a virtual examination can potentially provide new means to a better understanding of complex congenital cardiac malformations.

Large Pituitary Gland Adenomas Evaluated with Magnetic Resonance Imaging

Neurosurgery ◽  
1987 ◽  
Vol 21 (4) ◽  
pp. 540-546 ◽  
Author(s):  
Benjamin Kaufman ◽  
Bruce A. Kaufman ◽  
Baha'Uddin M. Arafah ◽  
Uros Roessmann ◽  
Warren R. Selman
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pituitary Gland ◽  
Cavernous Sinus ◽  
Spatial Information ◽  
Bone Destruction ◽  
Ct Scanning ◽  
Resonance Imaging ◽  
Cavernous Sinus Invasion ◽  
Contrast Enhanced Ct

Abstract Magnetic resonance imaging (MRI), computed tomographic (CT) scanning, and angiography or digital subtraction angiography (DSA) were used preoperatively to evaluate 16 surgically proven cases of sellar tumor with extrasellar extension. There were 15 pituitary tumors and 1 schwannoma. The capabilities of MRI in evaluating these tumors were compared with CT scanning and angiography. Bone destruction and tumor calcification were better detected by CT scanning than by MRI. MRI was as effective as CT scanning in detecting a cyst or variation in tumor consistency. Neither MRI nor CT scanning was capable of distinguishing specific tumor types. In every case, MRI was superior to CT scanning for delineating spatial relationships of the tumor to the 3rd ventricle, the optic apparatus, adjacent brain, and parasellar vasculature. Vessel encasement by tumor was clearly seen on MRI when there was no direct indication of this on other studies. Cavernous sinus invasion was not demonstrated by CT scanning, but was indicated by MRI in 5 cases and was surgically confirmed in 3. MRI can provide more precise spatial information on extrasellar tumor extension. Vascular encasement and cavernous sinus invasion may be determined preoperatively. Treatment expectations and operative approaches can be guided by this information. When MRI is available, it is the test of choice for the preoperative evaluation of patients with suspected large pituitary gland (sellar region) tumors. Contrast-enhanced CT scanning and angiography can be used as supplementary studies to add information inherently unique to these techniques. (Neurosurgery 21:540-546, 1987)

scholarly journals Insights into Automotive Particulate Filters using Magnetic Resonance Imaging : Understanding filter drying in the manufacturing process and the effect of particulate matter on filter operation and fluid dynamics

2020 ◽  
Vol 64 (2) ◽  
pp. 165-179
Author(s):  
J. D. Cooper ◽  
N. P. Ramskill ◽  
A. J. Sederman ◽  
L. F. Gladden ◽  
A. Tsolakis ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Fluid Dynamics ◽  
Particulate Matter ◽  
Magnetic Resonance ◽  
Spatial Information ◽  
Particulate Filter ◽  
Drying Process ◽  
Resonance Imaging ◽  
Emissions Control ◽  
Particulate Filters

Understanding the manufacture and operation of automotive emissions control particulate filters is important in the optimised design of these emissions control systems. Here we show how magnetic resonance imaging (MRI) can be used to understand the drying process, which is part of the manufacture of catalysed particulate filters. Comparison between a wall-flow particulate filter substrate and a flow-through monolith (FTM) has been performed, with MRI giving spatial information on the drying process. We have also used MRI to study the fluid dynamics of a gasoline particulate filter (GPF). Inlet and outlet channel gas velocities have been measured for a clean GPF and two GPF samples loaded with particulate matter (PM) to understand the effect of PM on the filter flow profiles and porous wall permeability as soot is deposited.

Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

2014 ◽  
Vol 83 (2) ◽  
pp. 378-383 ◽  
Author(s):  
Masoud Shariat ◽  
Daryl Schantz ◽  
Shi-Joon Yoo ◽  
Bernd J. Wintersperger ◽  
Mike Seed ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pulmonary Artery ◽  
Vessel Diameter ◽  
Resonance Imaging

Functional information from magnetic resonance imaging

1995 ◽  
Vol 53 ◽  
pp. 84-85
Author(s):  
Alan P. Koretsky ◽  
Afonso Costa e Silva ◽  
Yi-Jen Lin
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Cancer Biology ◽  
Imaging Modality ◽  
Magnetic Resonance Images ◽  
Great Success ◽  
Functional Information ◽  
Resonance Imaging ◽  
High Resolution Mri

Magnetic resonance imaging (MRI) has become established as an important imaging modality for the clinical management of disease. This is primarily due to the great tissue contrast inherent in magnetic resonance images of normal and diseased organs. Due to the wide availability of high field magnets and the ability to generate large and rapidly switched magnetic field gradients there is growing interest in applying high resolution MRI to obtain microscopic information. This symposium on MRI microscopy highlights new developments that are leading to increased resolution. The application of high resolution MRI to significant problems in developmental biology and cancer biology will illustrate the potential of these techniques.In combination with a growing interest in obtaining high resolution MRI there is also a growing interest in obtaining functional information from MRI. The great success of MRI in clinical applications is due to the inherent contrast obtained from different tissues leading to anatomical information.

Functional Magnetic Resonance Imaging Measures of Blood Flow Patterns in the Human Auditory Cortex in Response to Sound

1998 ◽  
Vol 41 (3) ◽  
pp. 538-548 ◽  
Author(s):  
Sean C. Huckins ◽  
Christopher W. Turner ◽  
Karen A. Doherty ◽  
Michael M. Fonte ◽  
Nikolaus M. Szeverenyi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Speech Stimuli ◽  
Complex Stimuli ◽  
Scanning Session ◽  
Auditory Research

Functional Magnetic Resonance Imaging (fMRI) holds exciting potential as a research and clinical tool for exploring the human auditory system. This noninvasive technique allows the measurement of discrete changes in cerebral cortical blood flow in response to sensory stimuli, allowing determination of precise neuroanatomical locations of the underlying brain parenchymal activity. Application of fMRI in auditory research, however, has been limited. One problem is that fMRI utilizing echo-planar imaging technology (EPI) generates intense noise that could potentially affect the results of auditory experiments. Also, issues relating to the reliability of fMRI for listeners with normal hearing need to be resolved before this technique can be used to study listeners with hearing loss. This preliminary study examines the feasibility of using fMRI in auditory research by performing a simple set of experiments to test the reliability of scanning parameters that use a high resolution and high signal-to-noise ratio unlike that presently reported in the literature. We used consonant-vowel (CV) speech stimuli to investigate whether or not we could observe reproducible and consistent changes in cortical blood flow in listeners during a single scanning session, across more than one scanning session, and in more than one listener. In addition, we wanted to determine if there were differences between CV speech and nonspeech complex stimuli across listeners. Our study shows reproducibility within and across listeners for CV speech stimuli. Results were reproducible for CV speech stimuli within fMRI scanning sessions for 5 out of 9 listeners and were reproducible for 6 out of 8 listeners across fMRI scanning sessions. Results of nonspeech complex stimuli across listeners showed activity in 4 out of 9 individuals tested.

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