Online Issues

Journal Vol 49 (1)

Small Animal Imaging with Magnetic Resonance Microscopy

Bastiaan Driehuys, John Nouls, Alexandra Badea, Elizabeth Bucholz, Ketan Ghaghada, Alexandra Petiet, and Laurence W. Hedlund

Bastiaan Driehuys, PhD, is an assistant professor; Alexandra Badea, PhD, and Ketan Ghaghada, PhD, are research associates; and Laurence W. Hedlund, PhD, is a professor, all in the Department of Radiology at Duke University Medical Center in Durham, North Carolina. John Nouls, MS, Elizabeth Bucholz, BS, and Alexandra Petiet, MS, are PhD candidates in the Department of Biomedical Engineering at Duke University. All work was performed at the Duke University Center for In Vivo Microscopy.

Address correspondence and reprint requests to Dr. Bastiaan Driehuys, Center for In Vivo Microscopy, Box 3302, Duke University Medical Center, Durham, NC 27710 or email driehuys@orion.duhs.duke.edu.

Abstract

Small animal magnetic resonance microscopy (MRM) has evolved significantly from testing the boundaries of imaging physics to its expanding use today as a tool in noninvasive biomedical investigations. MRM now increasingly provides functional information about living animals, with images of the beating heart, breathing lung, and functioning brain. Unlike clinical MRI, where the focus is on diagnosis, MRM is used to reveal fundamental biology or to noninvasively measure subtle changes in the structure or function of organs during disease progression or in response to experimental therapies. High-resolution anatomical imaging reveals increasingly exquisite detail in healthy animals and subtle architectural aberrations that occur in genetically altered models. Resolution of 100 μm in all dimensions is now routinely attained in living animals, and (10 μm)³ is feasible in fixed specimens. Such images almost rival conventional histology while allowing the object to be viewed interactively in any plane. In this review we describe the state of the art in MRM for scientists who may be unfamiliar with this modality but who want to apply its capabilities to their research. We include a brief review of MR concepts and methods of animal handling and support, before covering a range of MRM applications—including the heart, lung, and brain—and the emerging field of MR histology. The ability of MRM to provide a detailed functional and anatomical picture in rats and mice, and to track this picture over time, makes it a promising platform with broad applications in biomedical research.

Key Words: disease model; magnetic resonance imaging; microscopy; mouse; rat; rodent