Practical Small Animal MRI

Practical Small Animal MRI is the seminal reference for clinicians using Magnetic Resonance Imaging in the diagnosis and treatment of veterinary patients. Although MRI is used most frequently in the diagnosis of neurologic disorders, it also has significant application to other body systems. This book covers normal anatomy and specific clinical conditions of the nervous system, musculoskeletal system, abdomen, thorax, and head and neck. It also contains several chapters on disease of the brain and spine, including inflammatory, infectious, neoplastic, and vascular diseases, alongside congenital and degenerative disorders.

The two authors, a radiologist and a neurologist, supported by two other contributors, each have over 20 years’ experience in MRI, and this is borne out by the huge amount of information and images presented.

A fascinating insight into the field; the text is well-written and extremely detailed…. invaluable as an introduction to principles of the physics of MRI and the challenges of producing diagnostic images without artifacts, and as a reference for use in clinical situations.

The extensive experience of the authors combined with a comprehensive review of the literature published on small animals MRI imaging make this the most comprehensive text on this subject…. the image quality is excellent.

I purchased the book for my boyfriend as a gift. He’s an MRI tech/Vet tech for a veterinary neurology practice. He really enjoys the book and says that it is exactly what he needed. He thinks the content is well written and has helped him with MRI scanning. His only complaint is that in three months the book is falling apart. This isn’t a book that gets throw around or misused. Half of the neurology chapter has fallen out of the book along with some other pages. Considering the cost of the book this is very surprising. At this rate this book may not last a year. Not sure if it’s just his copy or if others have had the same experience. Unfortunately, because of this experience I can not recommend getting the hardcover version of this book.


Why do I need to have gadolinium contrast medium?

Gadolinium MRI contrast agent is used in about 1 in 3 of MRI scans to improve the clarity of the images or pictures of your body’s internal structures. This improves the diagnostic accuracy of the MRI scan. For example, it improves the visibility of inflammation, tumours, blood vessels and, for some organs, blood supply.

Before the scan begins, the radiologist (specialist doctor supervising the scan) will decide, on the basis of the notes sent by your referring doctor, whether gadolinium injection is likely to be helpful and should be recommended for your MRI.

Before any MRI scan, you will be asked a number of questions about your medical history, and any implants you might have, to make sure that you will not be at risk from the strong magnetic fields of the scanner. You will also be asked about conditions that might mean a gadolinium injection would not be recommended (e.g. pregnancy, previous allergic reaction, severe kidney disease). If you have any of these conditions, then you will not be given gadolinium, but if there is no condition preventing injection, you might be asked to sign a consent form in case gadolinium is required.

Usually, you will be advised by the technologist or nurse before you have the MRI scan that it is recommended that gadolinium contrast medium be injected during the examination. As with any medical procedure, you have the right to seek further advice and/or to decline a gadolinium injection. The technologist who carries out the MRI scan, a nurse or a radiologist will give you the injection.

Sometimes, even though gadolinium initially would not have been required based on the referral notes provided by your doctor, the radiologist might decide during your scan that gadolinium would help make the images clearer. If you are told part of the way through your scan that gadolinium will be needed, you should not be concerned that this indicates something serious is wrong. Most often, this is being done to make the images clearer and of a higher quality, so the radiologist can provide your doctor with a more accurate diagnosis of your symptom or condition. If the gadolinium is not given after such a recommendation, another scan may be required later.

Q & A about NMR and MRI

What is the marginal cost of an MRI, CT, and X-ray scan?
Preferably with all the components of cost (depreciation, power, staff, maintenance, etc) and with a source?

Source: Taiwan’s NHI (National health insurance) payment (in Chinese)
33070B CT without contrast: 3800 points
33071B CT with contrast:4560 points
33072B CT with and without contrast: 5035 points
33084B MRI without contrast: 6500 points
33085B MRI with contrast: 11500 points
32001C Chest X-ray: 200 points
1 points = 0.8~0.9 NTD, 1 NTD = 0.03 USD

It includes imaging and reading. If the film is not read by a bordered radiologist, the NHI will not pay.

I assume that by marginal cost you mean something like the average cost per study, factoring in amortization of the machine, materials, salaries for technical personal AND cost of interpretation by a radialogist (I am not an accountant so I am not sure what the proper term for all of this is). The cost vary depending on the precise type of study done (some studies involve injecting a contrast agent, MRI of the spine take longer than the brain, etc), and the volume of studies done.
The best info I could find was at Healthcare Bluebook. They suggest a “fair price” (in a competitive market I think this would be close to the price you are looking for) is $408 for a CT of the brain, $731 for an MRI of the brain, both non-contrast. The numbers quoted by another respondent (Mr. Kalariya) are probably the “chargemaster” charges for the studies. Such numbers are essentially made up out of thin air by hospitals. Almost nobody pays that much.

How are NMR spectra acquired?
Answering your clarification in the comment, which was “What exactly happens between the time you pulse the sample with a magnetic field to when you have the final spectrum?”

First of all, it’s a radio frequency pulse, the field is held constant. There are usually many pulses in an NMR experiment, especially if you’re after 2D or 3D spectra. In any case, after the last pulse, the spin system is still “ringing” for a little while (a few seconds), emitting exponentially decaying radio frequency signal. It is recorded by RF coils in the probe (same coils that generate the pulses. They are often cryogenically cooled for sensitivity). That signal is digitized and stored as files which you can download from the spectrometer. There are several mathematical operations that can be done to these time domain spectra (multiplying by differently shaped functions, etc), but sooner or later it goes through digital Fourier transform, which produces the frequency-domain spectrum you know.

Planning and Positioning in MRI

Positioning in MRI contrast agent is a clinical manual about the creation of magnetic resonance images. This manual focuses upon patient positioning and image planning.

The manual is organised by body region and provides valuable insight into –

Patient pathology on MRI.
Considerations when positioning both the patient and coil.
Imaging planes.
Anatomical image alignment.
This manual is a comprehensive highly visual reference to the planning and positioning of patients and coils in MR imaging. High quality imaging specific to patient pathology is encouraged through the focus on ‘considerations’ specific to coil and patient placement and imaging plane selection.

Over 200 MR images
Formulaic internal design assist use as clinical manual to small animals MRI planning
Evidence base provided where appropriate (cranial neurology)
Image selection – assist learning principles that underpin good positioning and anatomical coverage
Explores positioning of patient and coils specific to individual treatment requirements
Evolve website – image collection (over 200 MR images) and additional case studies

This is a gem of a book that I refer to often for positioning of those rarely done or difficult to position exams. This book is nearly complete from head to toe in MRI positioning and is easy to read with great photos showing slice selections. It includes pituitary, orbits, cranial nerves, TMJ’s, brachial plexus, elbow/FABS view, pancreas, fetal, pelvic arteries, femur/quads/hamstring, foot and other more and less common exams.

Each chapter begins with an anatomy drawing with labels to the important/obscure parts. Every section in the chapter clearly states what the different series demonstrate in the anatomy which I find very helpful when a patients diagnosis is already known and certain sequences can provide greater detail for the radiologist. Using this reference has helped build my confidence and made me look really smart to my peers too.

What are the best MRI constrast agents?

The answer to this as it is in most questions that start with “what is the best …” is that it definitely depends.

It really depends what you’re looking for and what you’re looking to highlight. For instance, Richard Tabassi mentioned above that targeting is important. Most targeting is done using chemistry at the surface of ultra-small superparamagnetic iron-oxides (USPIO), which are not approved for human use by the FDA.

These are T2-shortening agents. It means it decreases the signal at the site of the contrast agent. There are methods to increase the signal to get positive contrast (i.e. making the image brighter at the site of the agent), such as this: Generating positive contrast from off-resonant spins with steady-state free precession magnetic resonance imaging: theory and proof-of-principle experiments – Abstract – Physics in Medicine and Biology – IOPscience

The Gadolinium-based agents are typically used more as blood-pool agents for angiography (looking at blood vessel structure) and blood-flow measurements. They are a better blood-pool agent because they have a strong effect on blood T1, resulting in bright blood in images, while USPIO effect on T1 is minimal.

Gd-based contrast agents have been discouraged / contraindicated in some cases of people with kidney conditions because of their strongly suspected side effects on the kidney, likely causing or accelerating nephrogenic systemic fibrosis (NSF): Nephrogenic systemic fibrosis: a serious late adverse reaction to gadodiamide. However, they are still widely used for many applications.

I doubt the long-term side effects of Gd or USPIO are all well-known. It’s very difficult to know the long-term effects of such agents (or of almost of anything foreign to the body). It’s easy for scientists simply to dismiss these concerns and assume something to be harmless using arguments like “it is entirely secreted through this or that system”, etc., but this is what we thought about Gd and it turned out to be wrong.

MRI has some organ specific contrast agents, and also some you can drink that don’t use Gd, but the only injectable general MRI contrast agent used in the US are chelated gadolinium (Gd) compounds.

For reasons discussed by Sherif Fahmy, these may cause nephrogenic sclerosis, but the odds are low if you have no renal disease (and they will do a blood test to check). Still, the Gd agents that are less-well chelated are more highly correlated with this problem (which is no doubt caused by free Gd+3 ion, which is toxic), so it would make sense to get the second generation macrocyclic ionic Gd agents that are better chelated. In the US, this presently means only Dotarem (gadoterate):

FDA Approves Dotarem® (gadoterate meglumine), first macrocyclic and ionic gadolinium-based contrast agent in USA

This, rather than older first-generation agents like OptiMARK, Omniscan, and Magnevist, which have all been associated with nephrogenic sclerosis. Unfortunately, you probably won’t get a choice, and certainly won’t if you’re not the payor. In an HMO you get what they have, and there are something like eight other (cheaper) agents besides Dotarem that you may, and probably will, get instead. If you pay for the MRI out of pocket, on the other hand, you can call around and find what the clinic uses, and perhaps even make a deal for what they’re going to use. They may be willing to order Dotarem for you.

I’m not a salesman for Dotarem and have nothing to do with the stuff. But if I had to pick a general Gd agent to be injected with for an affordable mri system, I would try to get this one. It just makes better sense.

Good for basic knowlege for MRI

It’s perhaps more in-depth than one needs to pass the MRI registry, but once you read it (er, over and over), the book does a good job of making sense of highly complex material.

What disappoints me is the lack of practical information that a tech absolutely requires to excel, e.g., in-depth discussions on how to resolve wrap, artifact, etc. by considering the differing phase directions of all three imaging planes, FOV, application of sat bands, etc. These are the concepts I’ve had to work out in my head and discover completely on my own as a new tech–concepts far more valuable to my job than abstract discussions on k space and precessing photons.

I have a PhD specializing in MRI contrast agent. I would say this is a great book at the beginner to maybe intermediate level. Should be enough for a Masters’ degree. Its a great first step to understanding intricate complicated MR Physics. A lot of complex stuff is simplified here. Many advanced books explain even basic simple concepts using huge equations which can be intimidating for a lot of people – certainly was for me. This books does the exact opposite. It introduces you in a friendly way and keeps you engaged.
I highly recommend this book. Also its at a very economic price.

Cons: Has some minor typos, has some answers wrong – but you will figure it out easily.

The book, bought new, is in perfect condition aside from the slight fraying and peeling of the pages abd cover of the top left corner. The access code was not touched, which is why I bought new rather than used. The shipping was super quick and Im very satisfied with my purchase!

Hey this book is really helpful I’m still in the process of learning things but I know with time it will become clearer to understanding the benchtop nmr book. You guys have really made this book very detailed to where we could understand the material. The data, pictures, and videos are all a big help to many students out here who are taking upon themselves to become an MRI tech and this book is a plus. Thank you, you have Done a Good Deed!

Basic Principles and Applications MRI

I highly recommend this book to anyone who is currently doing breast MRI or interesting in starting. The first several chapters are directed toward understanding the physics behind breast MR and are easy to understand even by a non-physicist. The second half of the book turns toward protocols, safety and optimizing breast MRI techniques. The book is clearly written and has changed my clinical practice. I am now performing studies that use magnet time more efficiently and with improved image quality. This book is valuable to both the beginner and the experienced breast imager. It is particularly helpful to radiologists who want to improve their breast MRI protocols. I also recommend this book to any technologist who wants to know more about breast MRI contrast agent .

Magnetic Resonance Imaging (MRI) is an integral component of medical imaging. Whilst new measurement techniques and applications continue to be developed nearly thirty years after the initial clinical scanners were installed the basic principles behind the measurement techniques remain as true today as then. This fifth edition of MRI Basic Principles and Applications presents the fundamental concepts of MRI in a clear and concise manner, minimizing the mathematical formalism yet providing a foundation to understand the results that are obtained with today’s clinical scanners. This book:

Accessible introductory guide from renowned teachers in the benchtop nmr field
Provides a concise yet thorough introduction for MRI focusing on fundamental physics, pulse sequences, and clinical applications without presenting advanced math
Takes a practical approach, including up-to-date protocols, and supports technical concepts with thorough explanations and illustrations
Highlights sections that are directly relevant to radiology board exams
Presents new information on the latest scan techniques and applications including 3 Tesla whole body scanners, safety issues, and the nephrotoxic effects of gadolinium-based contrast media
This is an ideal resource to help radiologists prepare for their exams and understand the underlying MR physics principles as efficiently as possible.