Joel Garbow^1
1Washington University in St. Louis

Magnetic resonance imaging (MRI) is a powerful and versatile modality for preclinical studies. A particular strength of MRI is the wide variety of different image “contrasts”, many of which do not involve use of external contrast agents, that are available in imaging studies. These contrasts derive from the rich physics associated with the interaction of nuclear spins with external magnetic fields. This talk will provide an introduction to these physical principles. The presentation will be didactic in nature, with an emphasis on principles and insights, rather than equations and mathematics.

Jiangyang Zhang^1
1New York University

Among the imaging modalities commonly encountered in small animal imaging, MRI is arguably the most versatile imaging modality because of the rich tissue contrasts it provides. In designing and implementing small animal MRI studies, there are several technical aspects, mainly related to the unique anatomy and physiology of small animals, that need to be considered, including but not limited to: pros and cons of in vivo and ex vivo MRI; imaging resolution and speed; and image contrasts. Instead of providing a one-size-fit-all solution, this course tries to provide a general guide for people interested in this topic.

René in 't Zandt^1
1Lund Bioimaging Center, Lund University, Lund, Sweden

Neurochemical profiling of rat or mouse brain by MRS and MRSI requires optimization of many steps. Despite a strong magnetic field and the latest RF coil technology available, the spectral quality obtained might not be as expected. This presentation will give an overview of other factors that could be considered to achieve a consistent high quality spectroscopic dataset. 

Vera Zhang¹ and Mathew Hass^2
1MR Solutions, Inc., Boston, MA, United States, ²Boston MRI, Inc., Boston, MA, United States

MRI imaging provides very high spatial resolution and is very adept at morphological imaging and functional imaging (Molecular imaging, 2016). MRI imaging is non-invasive, making it possible for repetitive observations. Field strength is an important factor in selecting an MRI system for Animal Molecular imaging. The purpose of this talk is to explicate the important role of MRI for animal molecular imaging, the characterization of MRI imaging field strength, advantages and disadvantages of low field MRI for animal molecular imaging, the types of magnet technologies for low field preclinical MRI, and the strength and weakness of MRI systems using different magnet technologies. An understanding of both the advantages and disadvantages of different field strength choices and different magnet technologies is beneficial in determining a threshold of performance where going higher in field strength yields diminishing results for animal molecular imaging. Going through this exercise and determining that threshold will result in an optimum choice of MRI field strength for animal molecular imaging. Although High Field MRI (above 4.7T) has advantages for neurobiology applications, Low Field MRI for animal molecular imaging (1.5T to 4.7T) can provide more than adequate performance for most applications and can offer the benefits of lower cost, significantly easier siting, and remarkably low maintenance. 

Sheng-Kwei Song

MRI of small rodents requires a longer data acquisition than human subjects due to the small anatomic structures requiring high image resolution with high SNR. Thus, maintenance of animal physiology throughout the study plays a crucial role in a successful small animal MRI study. Among all physiological parameters, core temperature and physiological respiration is the most critically important. Avoiding non-physiological respiration due to hypothermia and inappropriate physical restraints will reduce animal stress and mortality. Examples of how this can be achieved in a typical small animal scanner will be described.

James Bankson^1
1Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX

Experimental magnetic resonance imaging is a powerful tool in biomedical research that can provide unique insight into the structure, function, and composition of tissue in vivo.  MRI data and associated analyses range in complexity and may be comprised of multiple sets of software tools and processes.   In this lecture, we will survey common approaches to processing MRI data, and tools and practices that facilitate the integration and use of experimental MRI in routine biomedical research.

Arvind Pathak^1
1Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

Over the past few decades, the use of ex vivo MRI has become widespread. This phenomenon was largely driven by the early development of various mammalian ‘brain atlases’ for neuroscientific applications as well as the need to characterize metabolism and other pathways in cells, isolated organs and cancer models. These early studies set the stage for more unconventional applications of ex vivo MRI. Recent advances in MRI hardware, RF coil design, pulse sequence design, image processing and visualization software, the availability of complementary modalities such as optical and micro-CT imaging, and affordable computational power have driven a slew of new applications of ex vivo MRI.  Therefore, recent applications of ex vivo MRI that are ‘off the beaten path’, or ‘beyond rodents’ are the focus of this lecture.

Dara Kraitchman^1,2,3
1Center for Image-Guided Animal Therapy, Johns Hopkins University, Baltimore, MD, United States, ²Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States, ³Department of Molecular and Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, United States

Large animal models are frequently used to develop new MRI pulse sequences, devices, or drug therapies.  In addition, MRI and MRS studies in large animals can aid with the mechanistic understanding of many diseases.  Recently, the use of spontaneous disease models in pets has been gaining traction for rapid translation from bench to bedside.  Tricks and tips for both MRI in both  traditional laboratory large animal and pets will be discussed.

Andrew Janke¹ and Jeremy Ullmann^1
1The University of Queensland, Brisbane, Australia

Exciting and relaxing fish. A detailed session on the methods and pitfalls of MRI of fish. The session covers, preparation, imaging and post-processing of fish MRI.

Henrik Lauridsen^1
1Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark

Preclinical research relies heavily on the use of traditional research animals which are well-characterized and share our mammalian ancestry. However, in some cases there exist untraditional research animals that are more suited to study specific preclinical questions. This is formulated in the August Krogh Principle: “For a large number of problems there will be some animal of choice or a few such animals on which it can be most conveniently studied”. This applies to a number of MRI experiments in which the use of unusual animal models is justified because of certain capabilities that cannot be mimicked in traditional models.