Dunn Receives NIH Funding for New Neurosurgery Imaging Technique

The National Institutes of Health has awarded Professor Andrew Dunn with a four-year, $1.8 million grant to develop a new technique for imaging blood flow across the surface of the brain.

The technique, called multi-exposure speckle imaging (MESI), can be used to measure blood flow in patients undergoing neurosurgery and to provide quantitative information on blood flow changes after a stroke.

When patients undergo surgery for an aneurysm, they are first injected with a fluorescent dye that lights up perfused vessels and darkens blocked vessels in the brain. Neurosurgeons use this imaging as a guide to determine where to clip an artery. But often vessels have varying degrees of blood flow, and current imaging methods do not quantitatively measure blood flow. Current methods also have limitations because patients may be allergic to dyes, and a surgeon is only able to use this dye method once during a surgery.

microscopic view of blood vessels

Using multi-exposure speckle imaging shows higher blood flow in red areas and less in yellow areas, giving neurosurgeons more accurate information in real-time.

MESI is able to give a surgeon an exact measurement of how much blood is flowing where, without the use of a dye. The technique will provide neurosurgeons with accurate information in real-time, with no disruption to the surgical process. Professor Dunn and his lab are collaborating with Dr. Douglas Fox, a neurosurgeon at St. David's Hospital, to translate the technology to the clinic.


MESI is also a tool that can provide quantitative imaging of blood flow after stroke. In the days and weeks after a stroke, the brain undergoes changes, growing new vessels to repair itself. Little is known about this remodeling process, but MESI will be able to provide measurements that could be helpful to drug developers in the design of drugs to restore blood flow to the brain. MESI may also be used as a tool to better inform stroke rehabilitation strategies by giving a better understanding of how the brain is remodeling itself.