An infant born ten weeks early is a fragile creature. Ever so small, not much longer than a hand, with skin as thin as tissue and internal organs not much stronger, a preemie is exquisitely vulnerable to any stress. Too much handling, or even a loud noise, can send the infant into life-threatening distress.

Which is why it is hard to find out what is happening inside such babies. Although premature infants in the Neonatal Intensive Care Unit (NICU) are constantly monitored for temperature, heartbeat and blood oxygen levels, doctors have had difficulties getting a more detailed physiological picture. The most powerful machine available for imaging subtle changes inside the body is the magnetic resonance imaging (MRI) scanner, a hulking, clanking machine not well suited for such vulnerable patients.

Now, UCSF and General Electric Company have designed and constructed a neonatal MRI-compatible incubator to make it safer and easier to get MRI scans of preemies. The new MRI table at UCSF, still the only one of its kind, has already vastly improved the screening of the smallest babies and paved the way for improvements in neonatal medicine, says A. James Barkovich, the UCSF physician whose inventiveness led to the incubator's construction.

Getting an MRI scan used to require exactly the type of handling that preemies don't tolerate well. "Even noise at the bedside can cause irregularities in heart rate and breathing patterns," says Nancy Newton, a research nurse in the Pediatric Clinical Research Center.

Prior to the development of the MRI incubator, an infant was moved in a nursery isolette from the 15th floor NICU to the MRI suite 12 floors below. "Once there, up to 30 minutes were required to prepare the baby for the MRI procedure," Newton says. "This involved moving the baby from the isolette to an MRI table, disconnecting monitor cables and hooking him up to the MRI monitoring cables and administering sedation."

Often this activity was rushed, both to avoid exposing the infant to the cold air in the MRI suite and because other patients were due to use the tightly scheduled machines. "It was stressful for the baby and trying for the staff," Newton says. As a result, many of the youngest, sickest babies could not be studied.

The new MRI incubator makes the whole process much easier, starting with the ability to do most of the preparation in the NICU, where there are many resources available if the infant destabilizes. In order to protect the highly sensitive babies, the nurses are able to ready the infant with the measured, deliberative pace that NASA takes when preparing an astronaut for liftoff. Each step of the process is "staged," done one step at a time, with time between each stage, allowing the baby to calm down before the next procedure begins.

Wires that connect the baby to the machines that monitor vital signs are exchanged with special leads that work in the scanner. Tiny earmuffs are slipped on to shield the infant from the clanking, banging noises of the MRI magnets. The head, perhaps no bigger than a tangerine, is cradled in a multilayered foam headrest that wraps around the ears and earmuffs, further blocking sounds.

Lastly, the baby slides into a capsule made of double-paned Plexiglas that muffles sound and holds in heat. Inside, he or she is able to breathe fresh, warmed air piped in from the outside. A video camera is built into the casing so that doctors and nurses can see how the baby is doing during the scan, and four sliding panels offer quick access to the preemie in case anything goes wrong. "Babies are often so relaxed and comfortable in the MRI incubator that they fall asleep while the incubator is being moved to the MRI suite," Newton says.

The fact that babies fall asleep naturally is important to more than their comfort. The MRI scanner works slowly and requires patients to be very still for up to an hour. If the baby is not able to fall asleep naturally, sedatives have to be used. Since the MRI incubator has been in use, about 50 percent of the scans have been successfully completed without sedation.

UCSF's Barkovich, in his work on neonatal brain injury in conjunction with UCSF chief of Child Neurology Donna Ferriero, was the first to see the need for the MRI incubator. About ten years ago he started experimenting with a removable Plexiglas cover that would offer babies some thermal and sonic insulation. While not fully successful, the idea had merit and showed what could be done.

With funding support obtained by chairman of the Department of Radiology Ronald Arenson from the Lucile Packard Foundation and GE Medical Systems, the project proceeded to the planning and development stage. GE sent teams of engineers out from its Corporate Research and Development center in Albany, NY to observe neonatal imaging procedures and ask questions. Barkovich, Newton, UCSF neonatologist Colin Partridge and UCSF professor of Radiology Daniel Vigneron in turn visited the GE engineers to work on the table's design and optimize patient comfort, safety and image quality. In addition to developing the new heating and monitoring systems, they developed a specialized, high-sensitivity MR detector that substantially improved the quality and scope of MR imaging information that can be obtained from the neonatal brain.

The result of years of effort was the prototype table that now sits just outside the neonatal intensive care unit on the 15th floor of the UCSF Medical Center. The MRI table is about the size of those used for adults, but is laden with monitors, oxygen bottles, overhead lights and the Plexiglas incubator perched on one end. Nothing on the table can be made of magnetic materials, which means no steel of any kind. Everything the baby needs is supplied by components made of plastic, aluminum or brass.

The new MRI incubator makes it possible to roll the baby right into the elevator and then straight into the MRI suite. Once there, the medical staff can dock the table directly to the MR magnet, advance the Plexiglas incubator into the scanner without further handling of the baby, and begin the scan immediately, Newton says. Barkovich credits the nursing staff with extreme dedication in making the scan possible. "I've seen nurses come in at 4 a.m. to prepare for a 7 a.m. scan," he says.

Barkovich hopes to use his improved window onto the brain to understand how brain damage occurs in preemies and newborns. One current project is to do an MR-based study of every baby that experiences a prolonged deprivation of oxygen (such as when the umbilical cord gets wrapped around the neck) during birth. The latest MRI techniques allow the researchers to get metabolic as well as structural information about the brain, which might enable researchers to solve standing mysteries about how brain damage occurs. "Sometimes we see brain damage from some previous event, and we don't know exactly how it happened," Barkovich says.

One goal of the current studies is to better understand how brain damage that shows up on the images is associated with outcomes years down the line. "If we know more about how a specific injury correlates with neurodevelopmental outcomes, we will be better able to counsel parents and offer early interventions that may lessen the impact of the brain injury," Newton says.

The ultimate goal would be to be able to step in when a scan shows an injury occurring and stop the damage. Barkovich is still working with Ferriero to find neuroprotective agents that could be administered in such cases. "The holy grail would be to block cell death after the initial injury and prevent permanent damage," Newton says.