The Digital Fish Library
About the Digital Fish Library
The DFL Curator selects and transports specimens for scanning from the Marine Vertebrate Collection at SIO, a collection of more than 2 million specimens from around the world, including over 5,700 deep sea, pelagic, and marine shore species. These are taken to the Center for Functional MRI (CFMRI) on main campus at UCSD where they are processed for MRI scanning. This typically involves rinsing all of the alcohol from specimen tissues - a common storage media used by museum collections to preserve species long term, but a hindrance to MRI quality - followed by use of an MRI image contrast agent. Once they are ready for imaging, specimens are mounted inside a radio frequency (RF) coil which is then placed inside the bore of the MRI scanner.
Via the RF coil that houses the specimen, MRI scanners read magnetic resonance signals from the protons in
hydrogen atoms which are present in the water of an organism's soft tissue. These atoms have magnetic
properties that cause the protons to spin. When placed in a MRI scanner, the hydrogen
protons spin in line with the direction of the external magnetic field produced by the scanner's magnet. This magnetic
movement of the protons can be manipulated, recorded, and translated into a series of high-resolution
image slices depicting grey-scale contrasted details of tissue structure.
MRI signals differ depending on the type of soft tissue and the shape of the scanned specimen. Since fishes are not typically used for MRI study, we have developed customized imaging protocols for a host of different fish species in order to optimize our ability to detect high contrast signals from their soft tissues.
Click on the slideshow below to view the DFL curator scanning a specimen at the Center for Functional MRI, UCSD.