Mri Definition and 94 Threads

Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not know whether this is a fair price, which I find suspicious. The same procedure in France costs $300. As I am unsure what to do, I would appreciate...

Hello all, I know that MRI is focuse on Hydrogen proton, but I don't understand if it focuse just in the Hydrogen proton that in water (Liquids) of the body or in all the Hydrogen proton that are within the molecules in the body. In relation to this, how the MRI could distinguish...

I am trying to understand MRI scanners. I know that MRIs work by aligning the protons in the direction of the large magnetic field and the radio frequency sets the frequency of the oscillations to the lamour frequency - also raising its energy level. Then when the RF is switched off, the...

I saw a House episode where a person had internal bleeding because they had metal inside their body and they went into an MRI machine. I'm learning about NMR now and I want to try and understand it more.

I just want to gain a ballpark estimate for how much force an MRI machine can generate on a small object such as a nail.. let's say the magnet is 1-2 Tesla. Very rough estimates are ok.

In the case of detecting muscle damage, would there be any reason to choose a CT scan over MRI? I know MRI takes longer and can be more expensive, but the CT scan radiation seems to be high enough to try and avoid it if possible. fyi, I am in communication with a doctor, but he's taking ages to...

I'm a little confused regarding MRI scans. So you add a strong magnetic field and the protons spin. However, some websites are saying the protons allign with or against the magnetic field. Other websites are saying the protons precess (not even sure what that is) and something about Larmor...

An N45 Grade Neodymium Rare Earth magnet has a remnance (Br) of 1320 mT and Coercive force (Hcj) of 923 kA/m. I am a little confused with the units of Coercive Force, how does A/m relate to Gauss/Tesla? Also, if an N45 magnet was placed inside a 2T MRI, would that be strong enough to...

So I want to know if MRI scan can be performed from a distance away. As far as I know MRI consists of a magnetic field to realign the hydrogen atoms in our body. After this the radio frequency pulse is applied and this energy is absorbed by some of the protons. When the radio frequency pulse is...

There are (at least) two issues regarding the presence of ferromagnetic materials around an MRI scanner (of strength e.g. 3 Tesla). (i) that something (e.g. scissors in a health worker's pocket) becomes a projectile, and (ii) that an implant may experience a twisting force (e.g. ferromagnetic...

MRI imaging uses primarily the magnetic fields of spinning hydrogen protons to generate images. I read somewhere that the magnetic fields generated by spinning electrons are stronger then those created by spinning protons. Why then are electrons not used in MRI imaging? Thanks

There is a hugh amount of magnetic field during MRI scanning, I would like to know whether our heart beat rhythm will be affected by this magnetic field or not if the magnetic field is too strong. Does anyone have any suggestions? Thanks in advance for any suggestions

What kind of advances have been made in this field (since I don't stay on top of it)? If I wanted to image, say, where my fluorinated drug is going within a rat, is it possible? NMR is inherently not a sensitive modality. Hydrogen is vastly more abundant in a living organism than fluorine...

Hi experts please explain energy levels of nucleus in emitting radiation in MRI

Hi, Which frequencies does an MRI machine use? Is it microwaves? Would prolonged exposure to it be damaging to the body?

http://www.smh.com.au/technology/sci-tech/mindreading-technology-reconstructs-videos-from-brain-20110923-1ko5s.html ::I can't locate the primary source:: Didn't want to put this in skepticism or another sub section.. too interesting. Move if wrong thanks.

Hi, MRI safety manual says that whenever you are scanning a patient with a certain surface coil you should remove all unplugged coils from the bore during the scan. For example, if you have a head/neck + spine coil matrix with two coil ports and you are scanning only the spine part then you...

I want to understand MRI and what exactly is T2. I have read the November issue of Sci-am and I'm still confused what exactly is T2 as it has different descriptions. The article "The Incredible Shrinking Scanner" by Bernhard Blumich: "The system can also monitor the precessing spins as they...

Homework Statement One possible concern with MRI (magnetic resonance imaging) is turning the magnetic field on or off too quickly. Bodily fluids are conductors, and a changing magnetic field could cause electric currents to flow through the patient. Suppose a typical patient has a maximum...

I've heard again and again that time is more or less the same as any other spatial dimension. I'll refer to them as X, Y, Z, and W, where you can pick any three to be space and a fourth to be time, since they're the same. W will be time for ease of reference. Except, if that's the case, and...

Hi i am new here so, please take it easy with me lol i have afew Q and i relly need help with them 1) compare and evaluate the appearance of bone and soft tissue in an MRI scan compared with a conventional X-ray. 2) Explainthe factors influencing the signal intensity in MRI. Thank...

dears I study nuclear engineering (medical radiation ,MS) , my proposal for graduation is (Modeling of Acoustical Noise in MRI and It Is Validation Through Measurements). I want to make and deliver a mathematical model for reducing noise in mri,would you please tell me what should i do? and...

Hello all, experts and otherwise. I'm looking for some links to software and documentation for selecting Regions of Interest (ROI) in MRI data of the human brain. Saving ROIs is a must. Any tips also appreciated. Thank you!

What is the point of repeating the TR 90 degree pulse in MRI? I understand you must modify the TR time to get different T1 times, but since the echo signal is read, would'nt all the echo signals be read to the same intensity after a 90 degree pulse?

hi there i was wondering if you could help me: • explain the factors influencing signal intensity in MRI this is one of the questions in my assignment i was wondering if you could please help me ASAP as I am completely confused!

1. MRI (magnetic resonance imaging) is a medical technique that produces detailed "pictures" of the interior of the body. The patient is placed into a solenoid that is 40 cm in diameter and 1.0 m long. A 100 A current creates a 5.0 T magnetic field inside the solenoid. To carry such a large...

Hi, I have been trying to figure out how MRI scanners work but am getting a bit confused and wondered if someone could put me straight on this ? I am just interested as they strike me as being amazing machines (possibly one of human kinds greatest inventions?) and the way they work is...

Hi, know where I can find "Journal of Magnetic Resonance article [18]" public domain version? I scan google and did not find. It is part of article title "Direct 3D Imaging of Molecular Structure:Quantum Sensing and Control" PDF...

This suddenly came up in a MRI class. I kinda understand IQ modulation (both amplitude and phase are modulated). But how does IQ demodulating a signal help, specially MRI signal. In case you don't know a MRI signal, its just a exponentially decaying sine.

What is the source of noises we hear during MRI imaging? Thanks!

Hi,I study protection of superconducting coils.I adopt heaters to protect coils.The circuit is in attachment. There are 6 coils,so I use 6 quench heaters.I want to know how I choose the heaters? It must do the Quench Heater Simulation for protection of superconducting coils before...

This is for a sci-fi novel I’m writing, and I actually posted this at another site but the answers given were a little vague. What would occur, either on a computer monitor (or other monitoring device, depending on the machine) or on a photo film, if an: a. X-ray b. CT scan c. ultrasound...

Does anyone know of any resources, textbooks etc that are suitable for high school students, A-levels, to learn about MRI?

About a year and a half ago, I had an MRI. During the scan something very strange kept happening. The procedure was actually a series of many scans - it took over an hour to get them all done. Before each one, the tech would go through a procedure he called tuning. The machine would hum...

Homework Statement Magnetic resonance imaging (MRI) is a medical technique for producing "pictures" of the interior of the body. The patient is placed within a strong magnetic field. One safety concern is what would happen to the positively and negatively charged particles in the body fluids...

Homework Statement We will make a Spin-Echo experiment, and we know \rho_{w}, T1_{w},T2_{w}, \rho_{g},T1_{g},T2_{g}, where T1 and T2 are relaxation time,\rho is a proton density, and g mean gray matter, w mean white matter. We search TR and TE, TR is a repetition time, TE is an echo time. We...

Hello, I don't know a lot on this subject, but at a last nights weekly philosophical discussion a friend mentioned that they could use MRI machines to scan and see electrical impulses light up parts of the mind during electrical impulse testing to the brain. I guess like showing images to...

hi budy i need a book ar sites for MRI and if possible a lectures ... hope find any help thanks

NMR and MRI -- questions! I'm currently doing an experiment on nuclear magnetic resonance for an undergrad physics lab. Our experiment was based around determining the effects of proton concentration on spin-lattice and spin-spin relaxation times. We used two separate sets of ionic solutions...

Hey , Actually I need someone to recommend some useful web sites that would contians animations about Nuclear well logging and Nuclear Magnetic Resonance Imaging to help me in my presentations . :cool:

I only have a vague idea of how the brain and MRI work but from my understanding the brain uses electric impusles and an MRI uses a huge magnet. Since a magnetic force redirects a moving charge, why doesn't someone go crazy when they are in an MRI because the neurons don't go where they are...

In reading about magnetic resonance imaging, I was surprised to learn that the coil/antenna used to send a radiofrequency pulse into the person being scanned is not a coil/antenna at one end of the person, but a large coil actually wrapped around the person. I know how alternating current...

Our MRI literature states that 98% of the hydrogen atoms in our body are lined up in the same direction while we aere in the magnet. The other 2% are in counter-allignment to the field. Why is this so?

In all situations (that I can think of) of particles relaxing from an excited state to their ground state, the direction of the resultant photons is isotropic. In magnetic resonance imaging (MRI) the excited protons are all in the -Z direction (+ some thermal motion). Will this have any bearing...