Difference Between T1 and T2 Imaging in MRI?

T1 is a rate of longitudinal relaxation. When we tip the magnetization in tissue away from its alignment with the scanner’s magnetic field, it takes a little bit of time for it to go back to its equilibrium low energy. That rate of change is T1.

T2 is a rate of transverse relaxation. I think “spin-spin” is a confusing term, though it is commonly used. After we tip magnetization away from its alignment with the field axis, it precesses (rotates) around that axis, kinda like a gyroscope or a precessing spinning top. Neighboring ensembles don’t have the exact same precession frequency. There is a spread in these frequencies. Therefore, neighboring ensembles accumulate a phase relative to each other resulting in their signals gradually cancelling each other out, until the signal disappears. This rate of change is T2 (actually, it’s T2* – “Tee two star”, which is strongly related to T2).

T1 is different in different tissue types, as is T2, and T2*. These values also change with some pathology. relaxation rates are one form of tissue contrast. We can get an image that’s T1-weighted, or we can actually do a fitting and get a quantitative T1 map. The same is true for T2 or T2*. We can get a qualitative T2-weighted image, or a quantitative T2 map. I think radiologists need to get used to the quantitative maps, as the qualitative data may not be as reliable, and doesn’t represent a precise measurement. It can vary substantially based on measurement conditions and the setup. Yet, change apparently is tough – radiologists still rely heavily on qualitative data instead of the alternative, which actually can be used to make statistical inferences.

Image contrast is the goal in all imaging procedures. The imaging technique will emphasize certain contrast characteristics of anatomical structures and allow us to differentiate the structures and determine which structures are abnormal.

MRI structural image contrast is natively (i.e. without using contrast enhancing agents) superior than CT and other imaging techniques. In both CT and MRI system, image contrast is a function of tissue density. For MRI in which the source of signal are the protons (especially hydrogen protons), the type of density that matters the most is proton density. In addition to tissue density, tissue relaxation properties contribute to image contrast in MRI (but not CT). There are two types of relaxation properties: T1 relaxation and T2 relaxation. Both types have been correctly described by the other responders but let me state it in a slightly different way. During the process of T1 relaxation, protons reorient resulting in recovery of longitudinal magnetization. During the process of T2 relaxation, protons dephase (spin becomes desynchronized) resulting in decay of transverse magnetization.

 

MRI Contrast Agents: From Molecules to Particles

This book describes the multiple aspects of (i) preparation of the magnetic core, (ii) the stabilization with different coatings, (iii) the physico-chemical characterization and (iv) the vectorization to obtain specific nanosystems. Several bio-applications are also presented in this book. In the early days of Magnetic Resonance Imaging (MRI), paramagnetic ions were proposed as contrast agents to enhance the diagnostic quality of MR images. Since then, academic and industrial efforts have been devoted to the development of new and more efficient molecular, supramolecular and nanoparticular systems. Old concepts and theories, like paramagnetic relaxation, were revisited and exploited, leading to new scientific tracks. With their high relaxivity payload, the superparamagnetic nanoparticles are very appealing in the context of molecular imaging but challenges are still numerous: absence of toxicity, specificity, ability to cross the biological barriers, etc.

Dr. Sophie Laurent was born in 1967. Her studies were performed at the University of Mons-Hainaut (Belgium) where she received her PhD in Chemistry in 1993. She joined then Prof R.N. Muller’s team and was involved in the development (synthesis and physicochemical characterization) of paramagnetic Gd complexes and superparamagnetic iron oxide nanoparticles as contrast agents for MRI. She is currently working on the vectorization of contrast agents for molecular imaging. She is associate professor and co-author around 170 publications and more than 250 communications in international meetings.
Dr. Dimitri Stanicki did his graduate work at the University of Mons (Ph.D. degree in 2010), where he achieved the synthesis of organic compounds for the treatment of parasitic diseases. In 2011, he joined R. Muller’s research group (MRI) where he started to develop new nanosystems for molecular imaging applications. He is the co-author of approximatively 10 publications, including a patent and a chapter book in the field of superparamagnetic contrast agents.

Dr. Robert N. Muller, PhD in chemistry 1974 from the University of Mons-Hainaut where he was successively appointed Assistant, Lecturer and full Professor. Post-doctoral studies in Magnetic Resonance Imaging in Paul C. Lauterbur’s (2003 Nobel Prize in Medicine or Physiology) research group (MRI) at the State University of New York at Stony Brook in 1981-82 and sabbatical leave at the Center for Magnetic Resonance (CERM), Florence, Italy, in 2002-2003. He produced around 280 publications and 6 books. Currently Scientific Director of the Center for Microscopy and Molecular Imaging, Gosselies, Belgium.

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NMI20 MRI Contrast Agent Imager & Analyzer is a classic MRI instrument,which has a wide range of applications in life sciences research.it integrates industrial design, analysis, and imaging in one easy to use instrument. Its performance and quality are generally recognized by domestic and foreign expert users. The system has received a numb…

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The PQ001 MRI Contrast Agent Analyzer was launched in 2008. After years of upgrade, PQ001 has many advantages such as small size, high precision, good repeatability, good stability and excellent cost/benefit performance. PQ001 has been widely used in MRI Contrast Agent Research

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Rad Tech’s Guide to MRI

This handy reference will give the practicing and training technologist a solid understanding of basic MRI contrast agent principles on which further learning can be built. Beginning with a hardware overview and moving through tissue characteristics, image quality and flow imaging, Rad Tech’s Guide to Small Animals MRI: Basic Physics, Instrumenation, and Qaulity Control should be used as both an introduction and an examination preparation tool.
Each book in the Rad Tech’s Guide Series covers the essential basics for those preparing for their certifying examinations and those already in practice.

This handy reference will give the practicing and training technologist a solid understanding of basic MRI principles on which further learning can be built. Beginning with a hardware overview and moving through tissue characteristics, image quality and flow imaging, Rad Tech’s Guide to MRI: Basic Physics, Instrumenation, and Qaulity Control should be used as both an introduction and an examination preparation tool.
Each book in the Rad Tech’s Guide Series covers the essential basics for those preparing for their certifying examinations and those already in practice.
Special Features include:

Materal based on the ARRT educational requirements
Quick-reference bullet format
Concise presentation

Of all the books and materials I’ve read on MRI, Mr. Faulkner’s small book is the best written on understanding the key components to MRI. It is invaluable to someone who desires to understand the basic physics and is the single best foundation for a technologist to build on. It also seemed to dovetail with ARRT’s perspective in my Board Exam. If a tech had only one book to reference as he/she trains clinically, this would be it, in my opinion. I also attended Mr. Faulkner’s MRI class in Chattanooga, TN where he gives monthly seminar and a week’s review and it is the best 5 day seminar on MRI possible. If you read this book first and prepare questions for the seminar, you are 99% likely to come away with a highly expert understanding. If you have been out of MRI for a long time and need to review to get back up to speed, this book is the answer to that need. He wrote it for the ages. The basic physics will always apply as the technology advances. It is a tribute to love and understanding of MRI. Absolute Kudos.

This book is written with bullet points and highlights the main information needed in easy to understand language.

Atlas of Small Animal CT and MRI

This atlas represents a comprehensive compilation of cross-sectional (computed tomography, CT, and magnetic resonance, MR) images of normal anatomy and a wide range of pathologic conditions in dogs and cats. The book is logically structured into 6 sections (head and neck, brain, spine, thorax, abdomen and musculoskeletal system). A brief introduction and literature review at the beginning of each chapter provides an excellent and concise overview over relevant normal findings, anatomic variations, and pathologic lesions to be covered in the following imaging part. Multiple images are provided for each topic, often including both CT and MRI contrast agent images in various window settings and sequences, multiplanar reconstructions and 3-D volume rendered images of the same animal. Additionally, in many instances endoscopic, intra-operative or gross pathology images are provided along with CT and MR images of a given case, allowing clinical correlation. This is certainly the most comprehensive collection of normal and abnormal CT and MR images in small animal veterinary patients available to date. It does not only include examples of common diseases (e.g., nasal carcinoma or pituitary carcinoma) but also uncommon conditions cross sectional images of which are not easily found in the existing literature (e.g., effects of radiation on the brain or renal secondary parathyroidism). The book is beautifully produced, easy to follow, and the image quality is simply outstanding. Another review mentioned problems with the spine/binding – My copy is flawless, so I did not have the same experience. This atlas is a most valuable resource not only for veterinary radiologists and radiology residents but also for other specialists utilizing cross-sectional imaging (neurologist, internists, surgeons, (radiation) oncologists etc.), for private practitioners with access to CT or Small Animals MRI, and for veterinary students seeking correlation between diagnostic imaging and pathologic findings. I very much enjoyed reading this book, and I would give it my highest recommendations. It is an absolute must-have for anybody interested in cross-sectional imaging in dogs and cats.

This is a must have for anyone using cross-sectional imaging, and definitely for all residents and diplomates using CT/MR. The book is very well organized, to the point, and has an abundance of pertinent information on most major and minor disease processes. This includes a wealth of CT/MR images, common imaging findings, anatomy (including some line drawings), common differentials, some pathophysiology, and even some supplemental images (3D reconstructions, radiographs, ultrasound, gross pathology, endoscopy including virtual colonoscopy). References at the end of the chapters make great supplemental readings for those of you taking boards.
As far as quality goes – the images came out really sharp with excellent contrast and the paper feels very nice and glossy. The binding in my copy isn’t perfect, but that is A ok with me. All I really care about is the quality of the images and information and I am loving this awesome book!

I received the book as a gift after requesting it. This book is well organized into six an anatomical sections and several subsections within each of the main sections. Each subsection includes brief review (narrative and images) of the appearance of normal and abnormal structures and disorders, respectively, within that subsection. CT images (with and without contrast), MR images (multiple sequences), and some gross and 3-D reconstructed images are included. This book is very clinically applicable and is a must have for anyone studying or routinely using cross-sectional imaging in veterinary medicine!

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.