- The author of the article: Ofer Ben Horin, who has about 20 years of experience in applications, research and training in the field ofMRI. Author of the bookMRI The complete guide - medicine and physics meet".
News has recently been published in the media that gadolinium, the contrast agent injected in MRI, accumulates in the brain. In this article, I will try to shed more light on the essence of the matter while providing a comprehensive explanation of what gadolinium is, what are the types of contrast agents based on it (GBCA) and on what recent studies the news is based on, and which caused the "uproar" in the matter. It is important to note, this article is not intended to reassure or scare, but to present the facts as they are. Scientific research is a world in the making, new things are constantly being discovered and this is a photographic source of what is currently happening in the field. Also there is some kind of technical section in a few paragraphs that may not be understood by those who are not from the field, you are welcome to skip it straight to the actual research part.
Let's start with the question why do we inject gadolinium at all?
Before I begin, I would just like to point out that gadolinium is not only injected in brain MRI scans (as implied by certain articles in the Israeli media), but also in MRI scans of other body organs to enhance surgical scars, tumor findings, etc. In most institutes it is customary to inject in all brain tests, but this is not always necessary. Also, studies indicate that gadolinium does not accumulate only in the brain, but also in bones, skin and other body organs.
The proton signal in MRI is a weak signal and there are all kinds of ways to strengthen it. One of the ways is with the help of gadolinium which allows to see better mainly pathologies, but also differentiates between similar tissues, and then makes it easier for the radiologists in decoding.
Gadolinium is a rare element that exists in nature. Its atomic number in the periodic table is 64 and its symbol is Gd. It is never found in its free form but in minerals such as gadolinite, monazite and stanzaite. It is important to note that gadolinium in its natural form is a toxic substance, therefore if it is used during the MRI scan, it is bound to other substances such as DTPA - Diethylene Triamine Pentaacetic Acid, thus eliminating its toxicity. Gadolinium was then called Gadolinium-DTPA. In general, gadolinium-based contrast agents are called GBCA -gadolinium-based contrast agent.
What does the gadolinium actually do?
Gadolinium is a paramagnetic material. Paramagnetism is a form of magnetism that only appears in the presence of an external magnetic field; The paramagnetic materials fail to maintain their magnetism without an external magnetic field. After its injection, gadolinium is absorbed in certain tissues and due to local magnetic fields it induces, it shortens their T1 and T2 times. As a result, during the same TR that we used before the injection, a higher signal will be generated. However, during the same time TE a lower signal will be generated. The effect on the images will be an enhanced signal in the T1 image and a loss of signal, or reduced signal, in the T2 image. This effect is called enhancement, and more precisely the enhancement of the return of the protons to the initial state (proton relaxation enhancement) since it improves the speed of the restoration of the longitudinal magnetization and the decay of the transverse magnetization. Since it is easier to assess signal gain than signal loss, T1 scans are performed after gadolinium injection. The tissues that absorbed the gadolinium in a better way are enhanced and the contrast in the image is better.
How does gadolinium help us locate the pathologies?
The gadolinium does not penetrate into all tissues equally. There are tissues that absorb it better, and those are the ones it magnifies. For example, it accumulates more within the blood vessels of tumors and thus makes it possible to differentiate between a tumor, which appears lighter, and the edematous area (edema) around it, which is almost unaffected by it and appears darker. Gadolinium is also able to cross the Blood-Brain Barrier (BBB), a feature that makes it effective in brain scans as well.
In conclusion, the gadolinium helps, due to its glimmering property, to shorten the TR time and therefore, besides improving the ability to clearly diagnose pathologies, after the injection, the scans are conducted faster than the scans before it.
Is gadolinium dangerous to humans?
By and large no. In a review published in July 2015 The FDA has announced that gadolinium-based contrast agents (GBCA) are safe to use. In the latest update to this review (May 22.5.2017, XNUMX), the FDA stated that there were no changes to their recommendations at that time.
In the review, approximately 17 scientific publications and adverse event reports related to GBCA injected into humans and animals were examined, some of them for over a year, and it became clear that gadolinium is retained in organs such as the brain, bones and skin. Publications Evidence suggests that certain types of GBCA with a linear structure (linear GBCA) tend to be retained in the brain more than GBCA with a macrocyclic structure (macrocyclic GBCA). It is important to note that the FDA stressed even then that they did not identify widespread negative health effects related to the retention of the substance in the brain but recommended limiting the use of GBCA when it is not necessary to use it.
The only known health effect associated with gadolinium's tendency to persist in the brain and body is a rare condition called NSF - Nephrogenic Systemic Fibrosis. In Hebrew, this pathological process is called systemic renal fibrosis, where fibrosis is fibrosis (a pathological process of creating connective tissue in an organ or tissue, essentially a scar, as the body's attempt to repair itself from damage caused by trauma, inflammation, etc.; this connective tissue impairs the function of the organ).
Systemic nephropathy, according to the 2015 FDA review, can occur in a small group of kidney failure patients. It is a skin disease characterized by thickening of the skin and then pain and limitation of joint movement within weeks to months. Recent publications, who are currently being tested, report cases of skin hardening (fibrosis) similar to NSF also in patients with normal kidney function, who received GBCA during an MRI scan. In these publications it became clear that in some of these patients there is retention of gadolinium in the body.
Following these recent studies, the FDA has not changed its recommendations from 2015 to use GBCA only when there is a real need to use it, but intends to review the latest publications and conduct a comprehensive discussion on the matter. He emphasized the importance of this instruction especially when it comes to MRI scans for children, pregnant women and patients with renal failure. He also ordered a number of linear GBCA suppliers to update the product label with the very fact that it tends to be retained in body tissues such as the brain, skin, etc. The competent authorities in Canada, Australia and New Zealand followed the same path, and so did the Israeli Ministry of Health guide the MRI institutes in Israel's hospitals. In this context, it is important to note that in Israel no side effects of the type mentioned in recent publications have been encountered in response to GBCA injection.
The European Medicines Agency (EMA) also did not identify negative health effects with the mere retention of gadolinium in the body, but unlike the FDA, issued a recommendation on the suspension of the marketing authorizations of several linear GBCAs, due to the very fact that they cause increased retention of gadolinium in the body compared to macrocyclic GBCA . This decision is currently under appeal and further review.
The field is currently being studied in large-scale experiments on animals in order to see the effects of gadolinium retention in the brain and body, and also to understand how gadolinium is retained and not excreted from the body - but in any case, at the moment, given the small number of cases, there is no cause for concern. Nevertheless, if you or your patients have encountered noteworthy side effects in response to the GBCA injection, you can contact the FDA at the email address druginfo@fda.hhs.gov Or send to us, to the Israeli MRI portal to the email address info@mriportal.co.il And we will transfer to them.
- The author of the article: Ofer Ben Horin, who has about 20 years of experience in applications, research and training in the field ofMRI. Author of the bookMRI The complete guide - medicine and physics meet".
bibliography
FDA's 2015 Review Update (May 2017)
European EMA notification and suspension of several linear GBCA contrast agents (April 2017)
A 2017 study found that linear GBCA tends to accumulate more than macrocyclic GBCA
Studies which found that gadolinium accumulates in the body
Studies that found a connection between people with normal kidney function and high levels of gadolinium in the skin and toxic effects
Information about Nephrogenic Systemic Fibrosis (emedicine website)
http://emedicine.medscape.com/article/1097889-overview
19 תגובות
I too would love to know with what type of compound of goldinium is used in Asuta.
Thanks. You are mixing up two different sites, of which I am the editor.
In any case, you should contact an expert in the field. .
Try Ziv Tsekh, he is the operator of a Facebook page on the subject.
Send me an email to editor@hayadan.org.il
And I'll give you his phone number
Peace,
I tried to send an email to the address you provided info@mriportal.co.il, but I got an error message.
I would be very happy to get in touch with you, in order to find out what type of gadolinium compound is used in Asuta Hospital, Ramat Ha'ayil, and in Israel in general, as well as the dose, as I undergo about three scans every year which is a regular procedure.
I would appreciate it if you could give me an email address or contact phone number,
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Nissim did give a good basic explanation. As written, it is difficult to explain all the physics of the MRI on one leg and the article is not intended for that but a book I wrote in the field that is over 300 pages long. The purpose of this article was to present the latest research in the field of gadolinium (and therefore it is also written for those who are not from the field to skip the technical paragraph, its presence is important for those involved in the field). For those interested in knowing more about the physics of the MRI, there is another article of mine in the science which describes the physics of the MRI (search under my name) and of course you can go to the book's website http://www.mriguide.co.il.
Those who wish to ask additional questions in the field or in any field related to MRI, including receiving further clarifications, can visit the Israeli MRI portal- http://www.mriportal.co.il, write to me through the email that appears there and I will be happy to help.
I did two MRIs with the linear Israeli substance - Magnetol, which is produced in Sorek. There isn't even an FDA approval should I worry?
It is clear to everyone that there are metals in the body and they are necessary for functioning. The thing is, there is a difference between a large amount that is forcibly introduced to paint a brain and a natural amount. There is no claim to a conspiracy theory here either. MRI is a first rate tool to see symptoms that no other way can and is safer than CT to use. And more effective than ultrasound in some cases. The point is to say that gadolinium is safe to use. It is more correct to say: we thought that the brain was cleared, therefore we thought that it was safe now that we found out
that does not drain and is required to investigate toxicity. I write the article as an expert, but there is no knowledge of the effects in the world, therefore: a. The amount of largesse has been reduced to a minimum. B. Obviously, there is now a follow-up of patients who have been injected and a statistical study will be carried out by (artificial intelligence) for the link between the Hadolinum and the number of cases above the average. This is the way of medicine that you find bad effects when you look for them and if there are any.
Regarding radiation, it was brought up as an analogy where non-ionizing radiation is sharpened to the public. According to studies, at least a thousand of the public is sensitive to cellular radiation and electrical cables. Also sensitive to industrialized food and the pressures of modern life.
This is a topic that doctors know exists and there is a lot of high-quality research
But the presentation to the public that there is no radiation and damage.
And of course there is radiation from broadcast antennas and people with a genetic predisposition to cancer.
Of course I meant a strong magnetic field...
I have been doing MRI for several years. You are absolutely right to explain the concepts a bit again.
Nissim, thanks for the explanation! The knowledge you have on the subject is certainly impressive, I imagine you are in the field?
In any case, I would expect the author of the article to bother and explain the professional concepts he uses, and not let the readers break their heads and try to understand what he is talking about.
The scan is performed in a very strong electric field, by pulses of radiation radiation. After each pulse they wait and then measure a certain type of radiation created by the hydrogen nuclei in the tissues. The time between pulses is called TR and the time between pulses to measurement is called TE.
If we get a little into physics then we see that there are basically two types of magnetic decay that are measured. One of them is longitudinal and happens after a short time. Such a scan is called T1. In this scan you see fat in white and water in black.
Another decay mode is transverse and happens after a longer time, and this is called a T2 scan. In this scan, the water looks clear (in the ventricles of the brain and lice, for example).
There are other mods like FLAIR and DTI. Each mode is suitable for detecting different pathologies.
Gadolinium gallium garnet of Einav Gand Galili
https://m.youtube.com/watch?v=AA9D68TK-xE&feature=youtu.be
The MRI machine provides volumetric information about tissues. The machine gives (not always though) one number for each volume unit. Let's say - a number between 0 and 5000 per cubic millimeter. The number is the result of the decay of a magnetic property after a certain time. There are several different times, called T1, T2 and so on.
The scan is good for soft tissues, and there is a contrast problem - many values are concentrated in a small range. The gadolinium attaches to certain tissues only and thus increases the contrast.
Some people are allergic to contrast-enhancing substances. But in most cases, the danger in these materials is probably negligible compared to the benefit of a good scan.
Yosef
There are at least 9 metals we need. Do you give up, for example, calcium and iron?
Avi Blizovsky
Why is this message blocked???
Yosef:
Calcium and iron are metals without which there is no life. Strontium, molybdenum and selenium are heavy metals that are found in the body without a problem. Wait, I forgot sodium, potassium, magnesium...
It is clear that the Minister of Health Litzman thinks differently because he does not order the addition of magnesium to desalinated water, it only remains to investigate how many deaths are caused by this.
Yosef
How about calcium, iron, sodium and potassium? And how about manganese, cobalt, magnesium, zinc and copper?
Yosef
Although your intention is quite clear, however, it should be precise: at the very least, the human body is partly composed of metal... iron, for example. As strange as it sounds... this is a natural element... and in nature as in nature - it's all a matter of dosage...
It is true that gadolinium has some people who require periodic MRI. No choice. It's a disease surveillance tool. The worst is less.
But gadolinium is a metal. And I don't know a metal whose presence in the body is not harmful. Therefore it is likely that it is harmful and more years are needed to research how much and how. like a cell phone The fact that they allegedly did not find a connection stems from a strong lobby in my opinion. A more scientific review of the studies shows that at least one thousand of the population is sensitive with a genetic connection and the medical community that treats them knows it. I don't want to detail what the damage is here. he is great. By the way, I started the journey believing that the damage is minimal.
Although it is difficult to put the finger exactly on the radiation, the statistics are clear. In any other medical research, the connection between radiation and damage would be treated as significant.
"The gadolinium is absorbed in certain tissues and due to the local magnetic fields it induces, it shortens their T1 and T2 times. As a result, during the same TR that we used before the injection, a higher signal will be generated. However, for the same TE time a lower signal will be generated. The effect on the images will be an enhanced signal in the T1 image and a loss of signal, or a reduced signal, in the T2 image"
What is the average reader supposed to understand from this illegible wording? Doesn't it make sense for the writer to explain in a few words the concepts he uses? T1, T2, TR, TE…. What is??? Where is the explanation??
"The gadolinium is absorbed in certain tissues and due to the local magnetic fields it induces, it shortens their T1 and T2 times. As a result, during the same TR that we used before the injection, a higher signal will be generated. However, for the same TE time a lower signal will be generated. The effect on the images will be an enhanced signal in the T1 image and a loss of signal, or a reduced signal, in the T2 image"
I don't understand, what is Chinese? What is the average reader supposed to understand from this? T1, T2, TR, TE... It doesn't seem reasonable to the writer to explain in a few words the meaning of these incomprehensible concepts? Is this an article intended for MRI specialists?