Questions related to Magnetic Resonance
I'm trying to acquire raw data from Philips MRI.
I followed the save raw data procedures and then I obtained a .idx and a .log file.
I'm not sure if I implemented the procedure correctly.
Are .idx and .log file the file format of Philips MRI raw data?
If so, how to open these files? Is it possible to open these files in matlab?
Could anyone recommend some good book or other references on learning the basics of ODMR? I am very new to this technique so would like to learn the basics on how this technique works and the type of materials studied.
When it comes to feeding the circuit with WPT, magnetic resonance method.
References voltages or the signal inside of the circuit keep fluctuate quite a lot when I wiggle or moves the circuit while it receiving the power from the TX antenna.
Differences of the H field might be the reason for that.
Is there anyone who knows how to handle this problem?
I am looking for a dataset including paired low and high quality MR images of brain (healthy subject).
It would be great if the dataset includes multi contrasts such as T2-weighted, flair, etc.
I will be thankful if you share any related datasets with me.
This machine is said to conduct comprehensive tests in humans but I am yet to see scientific articles using this machine.
This field being new to me, I have tried reading random research papers but it couldn't help me much.I want to know about entire setup starting from field generation in driver coil till power delivery to load.
I am working on characterization of Brain Tumors using T1 and T2 relaxation and implication for MR fingerprinting. Fortunately, I found an article here https://pdfs.semanticscholar.org/f1a0/8882c6616100abe3427ca306733211405bf1.pdf that is close to our research question. However, I have been wondering if there are similar studies in recent time and at higher teslas. Your kind suggestions and recommendations would be very appreciated. Thanks
We are analysing a fuel sample, we ish to conduct NMR on the Sample, we are thinking of seperating the fuel using fractional distillation before we conduct Nuclea Magnetic resonance test on each component. Kindly advise and share relevant materials
I would appreciate it if someone explains the basic physical principles underlying the differences in appearance (image content, and tissue differentiation) among T1, T2, and PD weighted images.
It is important as sometime this was treated as reference by the Magnetic resonance instrument by default as other reference like TMS etc were absent.... From 1 of the 3 papers i come to know about the temperature dependency of the HOD PEAK already!
Self-made RF receiver coil is hard to connect and match to clinical MR scanner due to many reasons.
Can I do the workaround? I use manufacturer`s coil,e.g. small disc-shape receiver coil and connect my self-made coil to it via inductive coupling, say by conducting loop (connected with my coil) pressed to the manufacturer coil windinds? How many losses (mismatch, inductive losses, etc) do I get? Are the similar articles, attemps? Thank you for nuts and bolts!
MR image brightness very depends on relaxation time value. Relaxation time hugely depends on temperature. So the way to improve the contrast is to heat up or down a human tissue investigated in MR scanner. Are there any works on it for clinical MRI?
There is the old IEEE article on MRI measurement of neuronal current by Dr. Ueno:
"Neuronal current distribution imaging using Magnetic Resonance" , IEEE Transactions on Magnetics, Vol. 5, No 35, 1999, p.4109
Now Bruker biospec resolution is about 30 micrometers in plane. Can we now make an image of neuronal currents in animal brain? Thank you for the articles.
I need to use blood signal intensity in T1 MRI as reference in my project about brain tumors.What I have, are slices of MRI for entire brain. Is it possible to define blood signal in T1 MRI of brain? Your help is deeply appreciated in advance.
(For the calculation, or at least rough approximation), of cerebral blood flow. Is there another way to estimate the signal intensity of fully relaxed blood spins? As per equation in Alsop DC et al., Magn Reson Med 2015.
We have a GE 3T 750w
I have a problem with the contrast-enhanced MR angio of the neck (see screenshot)
- we have a ring, like a "donut" around the vessels
Sometimes it is difficult to exclude e.g. a dissection, notably of smaller vessels such as the non-dominant vertebral artery
We use the standard CE MRA sequence
Do you see the same "donut" on your CE-MRA?
If not, which kind of sequence, and which rate of Gd injection do you use?
Thanks for your help - very much appreciated to improve the image quality !
Happy new year !
We wanted to change from manually segmentation to fully automated segmentation of MRI scans from the whole body. We like to measure the Volume of muscle mass (legs, arms, trunk) and fat mass (SAT, VAT) in adults and children. I found MIPAV as freeware, but is it really full automated and can segment whole body data? Does anyone now an easy tutorial for this software? Or is there another validated software?
I want to implement the magnetic field around a 3D dipole in z direction in MATLAB and look at it slice by slice in all three directions. I have got an expression from internet which is ((mu)/r^3)*(3(z^2/r^2)-1). But it looks like an expression in 2-D space,whereas I am looking for an expression in 3D space.
And as per my knowledge, the 2D contour plot should be similar in yz and zx plane and the plot in xy plane look like a circle.Or am I missing a point here?
Attached are the plots obtained from the above expression. Also, the origin of the dipole in k-space is another issue. Right now I have set it at the centre of the dipole. I am not sure if it is right. Please help if someone has more expertise in this.
I am wondering what are the ideal MRI scan parameters for both pre and postoperative DBS surgery for use with the software LEAD-DBS. I currently have postop scans that are not ideal and LEAD-DBS is having difficulty reading them.
Our center uses a 1.5T with low SAR, but we are not opposed to increasing SAR slightly.
Current set ups is 3T Verio, with 12 -ch and 32-ch coils. Population - life-span (children, young adults and up to the 9th decade of life). Advice pertinent to longitudinal studies will be particularly appreciated.
Sequences include but are not limited to MPRAGE, FLAIR, DTI, resting state BOLD, ASL and MRS (both 1H and 31P).
What are the differences and transition issues in acquisition and post-processing?
many thanks in advance.
In case of metallic antenna, we have electric resonance, while dielectric antenna have electric and magnetic resonance. Even, we can tune these resonance by changing the aspect ration of the dielectric disk. See page no 06 of the following article.
This is less a question, more a request for confirmation of my understanding of some reading I've done. Is the following true?
For asymptotically flat solitons (generalisations of Bartnik and McKinnon's su(2) solutions), it appears that the asymptotic values of the gauge fields (i.e. for r tending to infinity) are fixed to certain integer values, which means that the tangential pressure P vanishes at infinity. This in turn means the solutions carry no global magnetic charge, for if they did, the Einstein equations would be singular at infinity.
If anyone could either confirm this, or else point out my error(s), I'd much appreciate it.
I am currently dealing with functional connectivity at rest preprocessing (using DPARSFA v4). I've recently noticed that although most subjects have the same functional resting-state sequence (30 axial slices), some of them have a different sequence (29 axial slices). Both have been acquired in the same scanner, and they have same repetition time (2000ms), same echo time (30ms), same number of volumes, same matrix size (64x64) and same acquisition order (interleaved). They only differ between them in slice number (30 vs. 29) and in slice thickness (3.5mm vs. 4.5mm). The voxel size is equal in x and y axis (3.5mm), but they differ in z dimension. I was wondering if I can use both sets of images supposing I did different slice timing correction for each of them. After this can I follow the next steps (i.e: corregister, nuisance covariates regression, spatial normalization, smoothing and filter) as if they were comparable images? Anybody can help me? Thanks in advance.
PD: T1 structural 3d images have all equal parameters. The aim of this study is to explore seed-FC differences between groups.
Maximum likelihood estimation for denoising of MR images. Could anybody tell me about what is the value of "A" in Maximum likelihood formulation?
I am looking for a Mac OS alternative to the above mentioned program. Besides basic functionality including zero filling, filtering, and peak assignment I am also looking for a quantitation tool similar to AMARES. Any suggestions?
I want to study aneurysm growth (in volume) in a set of subjects, based on Time of Flight images (MR) images at two time points.
For each subject, I want to do a rigid registration between time of flight images as well as a segmentation of the cerebral vascular system. And then, I want to compare the two registered segmentation volumes in order to quantify the aneurysm growth.
For doing this, some teams used in-house registration tools (not distributed as far as I know, AnToNIA for ex) and the registration is performed using a volume of interest around the aneurysm sac (and not using the whole brain).
I currently know free registration tools not specific to aneurysms (FLIRT of FSL for exemple: http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/FLIRT). Additional question: Do you think these kind of methods is appropriate to do "aneurysms registration" ?
Thanks in advance,
I will be the US liaison-consultant for an Australia project to quantitate therapeutic Y90 implanted in the liver across imaging manufacturers. I have never seen a PET/MR image of Y90, although PET/CT imaging of implanted Y90 has progressed rapidly. If you have an image to share, it would be much appreciated and can be kept within a very limited circle of professionals if desired.
I've read the abstract. How do you explain that US is less sensitive but more specific than MRI in local staging of rectal cancer? I agree in full about the need of specific training (this rule is always true!), although the differences in MRI performances seem less understandable.
In childhood onset adrenoleukodystrophy, can white matter abnormalities be observed exclusively in the brainstem corticospinal tracts and internal capsule on MRI in absence of occipital or frontal white matter involvement?
Please also give me an idea about what type of oscillator we should use?
I am currently working on MR diffusion model to monitor defects in human heart. Meanwhile, I am able to assume that diffusion coefficient is related to the relaxation rates (R1=1/T1 and R2=1/T2), I need experts to advise on which substance whose T1 and T2, I will have to use.
I need these features because the substance which is diffusing is expected to carry molecular signatures of the heart. Thank you.
I started to analyze the EPR spectra of Fe+3 system but it is new to me, I don't have enough experience in analyzing epr data. so how can I get the zero field splitting parameters (D,E) and hyperfine coupling constant from experimental data, I just calculated the g factor? I have been trying to use easyspin for the simulations but have been unable to get any results do to the lack of knowledge of easyspin. Can someone please help me in understanding easyspin?
When you acquire an MRS spectra you must use the absortion mode to improve visualization and spectral analysis, before quantificate to obtain relieble metabolite estimates. But, why the phase (in some 400 MHz acquisition) is coiled? What is the reason for that? Is it for the many NSA used in T1?
UPDATE: I'm using non-parametric tests such as Wilcoxon signed-rank test for paired samples and Mann Whitney for independent samples. I've also looked into using MAD to exclude values but that is less preferable.
What are methods/decision rules to eliminate extreme beta values when standard deviation around the mean is not helpful?
Would it be a good idea to create a better fitting distribution (e.g. by bootstrapping?) of the output values and have a decision rule based on that? Any better ideas?
Thank you very much!
I came across the equation :
Lex (effective exchange rate) = 𝜋(Aeff/Keff)1/2
Lex= effective exchange rate
Aeff = effective exchange thickness
Keff = effective anisotropy constant
when trying to seek the relation between the magnetic properties of NiAl thin film vs its particle size.
The literature review states that, with refinement of the particles reduces the Keff. which increases the Lex, hence causing the particles to be exchange-coupled and increasing the remnant magnetization.
However, a more detailed explanation is not given. I was wondering if anyone can help me to understand this equation better.
And also, if this equation would also explain the effect of smaller particle size towards the domain wall pinning?
Nuisance covariate regression (head motion, CSF and WM signal, global signal) in local connectivity measures (like Regional Homogeneity (ReHo), Amplitude of Low Frequency Fluctuations (ALFF and fALFF), Degree Centrality and Voxel-Mirrored Homotopic Connectivity (VMHC)) is still a matter of debate. What is your opinion? Is nuisance regression more effective before or after bandpass filtering?
I'm trying to study a different filtering process (not as Gaussian FWHM usually used for fMRI), in a BOLD signal in a healthy control just to see if this new filter could provide a better activation segmented area. But I need some tips for making the more appropriate quality measurements for my research. What would be the best measurements for this purpose? Is it the root mean square error (RMSE) between the Gaussian filtering and my filtering approach in the activation segmented area a reasonable quality measurement?
I don't have much expertise in fMRI analysis, for this reason any suggestion from a specialist in the fMRI area will be a great help for me. I'm using FSL MELODIC tools to create the ICA for activation maps.
The solar system is characterised as a quantised lognormal distribution exhibiting spin-orbit coupling in my paper: “The Hum: log-normal distribution and planetary–solar resonance”. Does this indicate that the solar-magnetically braked proto-planetary disc of the early solar system was (and planetary spins and orbits still are) significantly affected by magnetism in addition to gravity?
I can't find any validation studies with MRI, so not entirely convinced yet, but opinions very much appreciated.
I perform whole-body DWI on GE Optima 450w 1.5T scanner using BODY coil and noticed that DWI signal at the shoulders region is very weak. All other body regions are of good quality. In patients with lymphoma, which is my primary interest, enlarged lymph nodes around clavicles are not visible on DWI at all or, if very large, they do have increased signal but are deformed a lot, looks like elongated stripes. Using 8 channel coil do not helps. Does anybody have experience with DWI on GE scanners or may suggest possible solution how to improve DWI quality at the shoulders region?
I am doing some experiment with chicken embryos. I need to keep them motionless as long as possible but not cause death. I went through some literatures which said "dropping" some anesthetics onto the CAM works. I tried to drop some anesthetics but it did not work. Is there some tricks? Or should I anesthetize them in different way?
To improve S/N and decrease distortions in deep small brain structures, which Siemens Skyra upgrade is the most crucial between TIMthx ZOOMit or channels upgrade and 64 channels coil?
i have been trying to relate the B field to the E-field in MRI for assessment of safety issues. I have only got the relationship for a close loop system as show in the ATTACHMENT. I like to know if B and E have a relationship in Cartesian, cylindrical and spherical coordinates.
For example, while working with selective unlabeling of Ubiquitin I used to add the selectively unlabeled amino acid at the time of transferring the culture to minimal media. But, scrambling effect (mis-incorporation of isotope labels at undesired sites) was the major problem. Then during induction-time (at the time of adding IPTG) I added the unlabeled amino acid, but the result was same.
Can anyone suggest what might be the proper time to add the unlabeled amino-acid to get the optimal labeling scheme of any protein without scrambling?
I need to normalize two MR brain volumes in order to match them on a voxel by voxel basis. That means that I need perfect matching between the two brains, i.e. each point of each structure of the first should coincide with the same point (or at least the nearest voxel) of the second. For example the point (x,y) of the thalamus of the first brain should match the same point of the second one.
I tried to use SPM to do this because in the last few years I used it to conduct VBM analyses but I did not obtain an exact correspondence (the reason for which I reflected a lot on this kind of analysis).
Could you please suggest the best way to reach my objective?
I am looking for a laboratory which has a 500 or 600 MHz Bruker NMR machine without digital filtering. I would like to send you one liquid sample in a NMR tube for a quick 1D NMR measurement which I would like to compare with my own measurement with digital filtering done on the same sample. After the measurement you can dispose the sample, no worries with mailing! I only need the data (zip-File by e-mail). The question is: how do hard-ware (Bessel-Type) and digital filters react on very high sample concentrations - which artifacts do the filters produce?
I'm currently comparing the DTI data of three groups of subjects using TBSS.
At first glance I found significant differences among them by performing unpaired t-tests.
After removing two outliers, due to their clinical condition, and using a multiple comparison correction strategy I didn’t find significant differences in two of the comparisons anymore. I therefore tried to compare them without corrections (using a standard threshold) and I found the expected differences again.
Does anyone has the same problem? Do you think it possible to publish uncorrected data if they are reasonable?
I have some Siemens MR spectroscopy data and no access to a Siemens console. I need to be able to view the data and import the values into Matlab, etc. Do you know of any tools or resources to help with this? It would be much appreciated and it is time-sensitive.
The particular signals that I want to explore are on the limit of MRI accuracy because they have too small a period. Because they can be detected either by EEG or by MEG type systems the idea of integrating an MRI accurate image with a MEG type detector which is what Magnetic Source Imaging is all about, seems almost overkill in comparison to standard fMRI. However the signals are within the parameters of this type of detection equipment. I am wondering what would be involved in putting together an MSI laboratory since I am unfamiliar with anything more than the general idea.