Case Studies
Dr. G. Allan Johnson, Duke University
Cardiac Gated Imaging of the Heart with Fenestra VC
Heart and Lung Imaging in the Mouse -- Challenges
Dr. Allan Johnson
“The heart and lung represent a rich and challenging area for image based phenotyping,” according to Dr. Johnson. “The area is rich because there are so many excellent mouse models of cardiopulmonary disease already available and many new models being created every day. Imaging the heart and lung of the mouse is, however, no easy task. One cannot simply scale the human imaging systems to support the mouse. One must be cognizant of both the spatial and temporal resolution required. The mouse at 25 gm is nearly 3000X smaller than the man, requiring a commensurate increase in resolution. One must also be aware of the temporal resolution. The R-R interval of the mouse @ 100 ms is easily 10X shorter than that of the man.”
Type of Imaging Study or Application of Fenestra
Eight volumetric images are acquired in a single scanning session with isotropic 100 micron resolution. Each volume is synchronized to a different 10 ms interval of the cardiac cycle. All images are acquired at end expiration. Contrast in the blood is attained through the use of Fenestra VC. The scan time is ~ 60 minutes during which Fenestra VC provides a very constant and high level of image contrast.
Representative Images
The figure below shows representative images from a recent study in mice. Each image in the figure is a single frame from a 4 dimensional study in a C57BL/6J mouse. Fenestra VC filled and opacified the cardiac chambers after peripheral injection for several hours after administration. Visualization of the heart throughout the cardiac cycle is possible, especially the aspects of endocardial border delineation, cardiac wall thickening and relative changes in chamber volume. Vasculature in the thoracic cavity was also enhanced throughout the study by the agent.
Cardiac gated microCT imaging of a live mouse following injection of Fenestra VC.
Badea C et al, 4D micro-CT of the mouse heart. Molecular Imaging, 2005. 4(2): p. 110-116.
Testimonial
“Previous efforts in our imaging studies using more conventional iodinated contrast agents were less successful because of the rapid clearance of the contrast agent and the resulting variation in contrast levels over the course of the study. Because of the long-lasting, stable contrast enhancement afforded by Fenestra VC, our image quality and ease of image interpretation have improved substantially. We look forward to using Fenestra VC to extend the utility of our imaging equipment into new areas of cardiovascular imaging and image-based phenotyping of small animals.” - G. Allan Johnson, PhD.
Dr. Johnson is Professor of Radiology, Physics and Biomedical Engineering and is the Charles E. Putman University Professor of Radiology at Duke University. After completing undergraduate studies in physics and mathematics (magna cum laude) at St. Olaf College, he earned his doctorate degree in Physics from Duke University. Since completing his doctoral work, Dr. Johnson has held numerous faculty positions of increasing responsibility at Duke University and has also served as Vice Consul General of the Division of Spatially Resolved NMR in the Société Ampiere. In addition to being an author on more than 200 peer-reviewed publications, Dr. Johnson has served on the editorial boards of several respected scientific journals including Magnetic Resonance in Medicine and the Journal of Molecular Imaging.