Jamu K. Alford1, Christian T. Farrar1, Yan Yang1, William Bradfield Handler2, Blaine A. Chronik2, Timothy J. Scholl3, Gunjan Madan4, Peter Caravan1
1Radiology, A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; 2Physics & Astronomy, the University of Western Ontario, London, ON, Canada; 3Department of Medical Biophysics, the University of Western Ontario, London, ON, Canada; 4Siemens Medical Solutions Inc., Malvern, PA, USA
We present the first example of direct protein imaging in a living animal. Delta relaxation enhanced MR (dreMR) is a method that exploits the strong magnetic field dependence of slow-tumbling gadolinium-based contrast agents. A 1.5T, clinical MRI was outfitted with an actively shielded electromagnet to dynamically control the magnetic field in the imaging region. A nude mouse implanted with LS174T tumors was imaged within the electromagnetic insert using the albumin-bindin agent MS-325. Using the insert, the B0 field was varied from 1.4T to 1.6T to produce images of albumin distribution throughout the mouse.