We use cookies to create the best experience for you. Keep on browsing if you are OK with that, or find out how to manage cookies.
Nobody downloaded yet

Echo-planar Imaging in Magnetic Resonance Imaging - Essay Example

Comments (0) Cite this document
Summary
EPI in MRI Introduction MRI, or magnetic resonance imaging, fabricates information for a picture from a sequence of separate samples of signals. Echo planar imaging, or EPI, is a method that can form an absolute image from a single data sample. This provides significant advantages, as far as the speed factor is concerned (Cohen, 2000, p.2)…
Download full paperFile format: .doc, available for editing
Polish This Essay96.5% of users find it useful
Echo-planar Imaging in Magnetic Resonance Imaging
Read TextPreview

Extract of sample
"Echo-planar Imaging in Magnetic Resonance Imaging"

Download file to see previous pages However, EPI can be very intolerant and the system needs careful selection of parameters. Echo-planar imaging is the fastest and most supple means of MR imaging nowadays. It offers substantial autonomy in the assortment of the parameters needed for contrast and resolution. However, according to the process, the system of formation of the images works close to its confines of performance depending on amplitude of the gradients and the number of times it rises, the stability in the structure and general stature of the noise formed and, thus, proves to be a difficult method. Even so, the advantages of EPI in “functional neuroimaging” have increased its demand and provide technological development (Cohen, 2000, p.15). The present study focuses on the concept of EPI in MRI and discusses the method, its working, the issues of image ghosting, its disadvantages, its sensitivity, as well as clinical benefits. BLIP EPI Method Echo-planar imaging (EPI) is skilled to considerably cut down the times of magnetic resonance (MR) imaging. It allows getting hold of representations within a timeframe of only 20–100 msec. This particular resolution of time enables successful elimination of motion-related relics. Consequently, it becomes possible to achieve imaging of rapidly changing physiologic processes. In order to understand the basic principles and working of the method, the understanding of k space theory is necessary. K space is a realistic medium of data where the MR imaging is in a digitized form and represents the picture before “Fourier transform analysis”. All points in k space contain data from all locations within an MR image. The Fourier transform of k space is the image” (Poustchi-Amin et al, 2001, pp.767-779). While studying the working of echo-planar imaging, it is helpful to put the usual spin-echo (SE) imaging side by side. In pulse progression of a SE, a single line of the data of representation, which is actually a single line in k space or a single stride of encoding a phase, is composed in every time of repetition (TR) period. Then the series of the pulse is continued for numerous times of TR in anticipation of all the steps of encoding the phase, collection and filling the k space. As a result, the time of imaging becomes equal to the creation of the TR, as well as the number of phase-encoding steps (Poustchi-Amin et al, 2001, pp.767-779). As compared to Fast Spin Echo (FSE), the gradient refocused echo in EPI adds a single line in the area of k-space. The direction in which line is read is altered by the positive and negative read gradients. A shift in k-space occurs through the presence of the phase blip that occurs between the echoes. This is the method known as blip EPI. The spins are excited once in the process of EPI and the pulses between the echoes do not involve any 180 degrees RF. If there is a spin echo EPI sequence, a large positive phase may be used that encodes the gradient if it does not reach the 180° degree pulse. Gradients are used by EPI, having both a negative and positive polarity, such that both odd and even echoes may be produced. The contrast in EPI can be restricted by varying the preliminary preparation of the echo from a spin echo to a gradient echo, or by the use of inversion recovery (Module 1, pp.7-16). In the process of echo-planar imaging, several lines of information related to the picture are achieved following a ...Download file to see next pagesRead More
Cite this document
  • APA
  • MLA
  • CHICAGO
(“Echo-planar Imaging in Magnetic Resonance Imaging Essay”, n.d.)
Echo-planar Imaging in Magnetic Resonance Imaging Essay. Retrieved from https://studentshare.org/physics/1456467-epi-in-mri
(Echo-Planar Imaging in Magnetic Resonance Imaging Essay)
Echo-Planar Imaging in Magnetic Resonance Imaging Essay. https://studentshare.org/physics/1456467-epi-in-mri.
“Echo-Planar Imaging in Magnetic Resonance Imaging Essay”, n.d. https://studentshare.org/physics/1456467-epi-in-mri.
  • Cited: 0 times
Comments (0)
Click to create a comment or rate a document
CHECK THESE SAMPLES - THEY ALSO FIT YOUR TOPIC
Functional magnetic resonance imaging
Functional magnetic resonance imaging or fMRI is a process of mapping brain activities by analysing the modifications in blood flow and oxygenation levels that vary according to neural activities taking place within the brain (Huettel, Song and McCarthy, 2009).
11 Pages(2750 words)Essay
Echo Planar Imaging, or EPI, Fast Imaging Techniques (MRI)
EPI is a fast, flexible imaging method, with good contrast and resolution, and with many potential applications in clinical imaging, such as functional MRI and rapid entire brain imaging. Though, EPI can be very unforgiving and requires careful parameter selection (Weishaupt, Koechli and Marincek, 2008).
15 Pages(3750 words)Essay
Echo Planar Imaging, or EPI, Fast Imaging Techniques (MRI)
Introduction Magnetic susceptibility refers to the process y issue tissue affects magnetic field. The existing boundaries between fat and compact bone are normally affected by the transverse magnetic field de-phasing and signal distortion. The consequent of the above is that frequency positions in the wrong location in the phase direction.
10 Pages(2500 words)Essay
BLIP Echo Planar Imaging Method
This method of imaging is used in functional MRI and rapid whole brain imaging. The time required to acquire an image is dependent on Tacq = Nacq x Ny x TR Where Nacq is the no. of acquisitions, Ny is the no. of phase encoding steps and TR is the repetition time.
10 Pages(2500 words)Essay
Fast Imaging Techniques (MRI)
Receiver bandwidth is generally used to fasten the digitalisation of the MR signals. In this regard, the receiver bandwidth 1 can determine the frequency ranges that will eventually be sampled using the frequency encoding gradient. During the optimization through an increase of receiver bandwidth, the amount of time at the flat top of the gradient is significantly reduced.
6 Pages(1500 words)Essay
Perfusion-weighted imaging (PW) MRI (magnetic resonance imaging)
The amalgamation of both practices is tremendously encouraging for the primary recognition and valuation of stroke, for tumour description and for the estimation of neurodegenerative illnesses (Nelson, et al., 1995). Perfusion applications are intended to evaluate the distribution of blood to a vascular bed.
12 Pages(3000 words)Essay
The aim of this research project is to critically review the literature on best practice Magnetic Resonance Imaging ('MRI')
Since its implementation into health care settings in the late 1980s, the focus on MRI safety has dramatically increased. This project provides a critical review on best practice MRI safety protocol. The project presents results of a review of peer review literature which is pertinent to MRI safety.
20 Pages(5000 words)Essay
Functional Magnetic Resonance Imaging
Such changes in neuronal activity correlate strongly with changes in blood properties; this is called hemodynamic effect. The oxygen content of the blood increases in a region of the brain with induced activity. Physiologically, oxyhemoglobin concentration increases in an activated region, whereas local deoxhemoglobin concentration decreases.
12 Pages(3000 words)Essay
Magnetic Resonance Imaging (MRI)
When in use, the machine takes images of the target organ in various angles which are then processed using a computer to yield a picture of high detail of the area selected for observation. Basically therefore, the technique makes use of a computer, an
6 Pages(1500 words)Essay
Let us find you another Essay on topic Echo-planar Imaging in Magnetic Resonance Imaging for FREE!
Contact us:
+16312120006
Contact Us Now
FREE Mobile Apps:
  • About StudentShare
  • Testimonials
  • FAQ
  • Blog
  • Free Essays
  • New Essays
  • Essays
  • The Newest Essay Topics
  • Index samples by all dates
Join us:
Contact Us