MRI for Africa
For eight years in a former life, Steve Schiff was a children’s neurosurgeon at the Children’s National Medical Center in Washington, D.C. Much of his time there he spent treating a potentially fatal condition called hydrocephalus—a buildup of cerebrospinal fluid in the brain—which is the most common reason for an infant or young child to need neurosurgery. “In the United States,” he says, “typically about half of our practice in general children’s neurosurgery is taking care of children with hydrocephalus.”
In industrialized nations, like the United States, the most common reason for a child to get hydrocephalus is a congenital disorder compounded by premature birth and ensuing complications. “Even though we’ve gotten very good at salvaging low-weight premature infants,” Schiff explains, “we’ve never solved the problem that their blood vessels are fragile in their brains and they tend to bleed very early in their premature life; that tends to ‘plug up the works,’ and they get hydrocephalus.”
In the developing world, far fewer low-birth-weight premature infants survive. Many infants who are carried to term will contract a serious infection—neonatal sepsis—in their first month of life, and of those who survive, many will then get hydrocephalus. “In East Africa, where I’ve been working for over 10 years,” Schiff says, “we’ve attacked this from a number of standpoints: First, how do you treat a child with hydrocephalus in an impoverished country?” In the United States, the standard treatment is to put in a plastic shunt with a valve; but, Schiff says, these are expensive and tend to malfunction, necessitating emergency care. In poorer countries, such care is often infeasible, and so infants may not survive post-surgery complications.
For these reasons, Schiff and his colleagues have studied the efficacy of shunt-less surgery where, using a small endoscope, the doctor makes a diversion inside the brain so the fluid can begin circulating properly again. “That seems to do quite well,” he says, “and we have shown not just that we can do it safely but that the development of the brain was equivalent whether we did the shunt-less or the shunt-based surgery. So we’re very much shifting to try to take that approach in treating patients.” Along the way, Schiff also made an unexpected discovery: Although high intracranial pressure in hydrocephalic infants causes their brains to stop growing, after treatment about a quarter of those infants’ brains begin growing again at an accelerated pace and actually catch up to what their normal growth should be. So if hydrocephalus can be diagnosed early and treated effectively, these children can potentially be spared the long-term effects of this often-devastating condition.
The most crucial component of diagnosis, Schiff says, is first being able to detect the buildup of fluid in the brain, which can be done with magnetic resonance imaging, or MRI. The barrier in Africa, he explains, is cost; and commercial MRI instruments like those used in the United States all cost well over a million dollars. Another option is to use X-ray–based computed tomography (CT), commonly known as a CAT scan. But, Schiff says, “The infants we’re looking at are the most vulnerable to the radiation from CT scans.” And these instruments are also expensive; one that Schiff used in Africa cost roughly three-quarters of a million dollars. Furthermore, maintaining and repairing a commercial CT scanner or MRI machine in a remote location, far from parts suppliers and technicians, is prohibitively difficult.
Consequently, Schiff says, “We’ve been very interested in how to rethink a very old style of MRI— one that’s never found a place in clinical practice—that uses old-fashioned coils of wire. Really, an MRI is a magnet, a radio transmitter, and a radio receiver; the rest is commentary.” One of his former Ph.D. students, Johnes Obungoloch—“a really brilliant student who came to us from Uganda,” he says, with a master’s degree in biomedical engineering and an undergraduate degree in electronics—decided that for his thesis he would redesign such an instrument, a low-power MRI, to accommodate an adult head. “That really hadn’t been done,” Schiff says, “and it’s important because these babies with hydrocephalus have very large heads.” He and Obungoloch consulted with several other scientists at the Los Alamos National Laboratory and Penn State, and together they managed to build a working device.
Although the images his device produces are much lower in resolution than those made by a commercial high-field MRI machine, Schiff says, “We don’t really care about the details. We need to know where the brain is and where the water is. So the imaging challenge is not at all unreasonable.” The question now, he says, is how to improve the technology while keeping the cost low. “No one’s ever tried to optimize these very-low-field units,” he explains. “If you ask a scientist ‘What’s the limit of resolution and tissue contrast you can get out of such a unit?’, they don’t have a firm answer. So we’re trying to push those limits through both hardware and software engineering.”
A clinical trial of the device is currently underway at the CURE Children’s Hospital of Uganda, with support from the National Institutes of Health (NIH) and the government of the Netherlands, and Schiff has high hopes. “There’s a real need to demonstrate that this type of technology could be diagnostically and therapeutically useful,” he says “We’re going to meet the requirements for the United States Food and Drug Administration device trials as well as the NIH regulations, and in the next few years, with that under our belt, we’re interested in tackling the next one or two major advances needed for introducing this technology into clinical practice.”
Schiff’s device is bound to make waves in the medical community; but he emphasizes that, although it is likely to be disruptive, it won’t supplant the instruments currently being used in industrialized nations. “It’s a little bit like when personal computers came around with mainframes,” he says. “The idea wasn’t to compete with the mainframes and what they did well; nor are we going to compete with beautiful, high-field, commercial cryogenic MRI machines. But the majority of problems don’t need high resolution, so if you can align the technology with the actual clinical needs and measure the outcomes per dollar invested, we think that this is one example of how technology can be made less expensive and still be very efficacious in medical care.”
Steve Schiff is the Brush Chair Professor of Engineering, a professor of engineering science and mechanics, professor of neurosurgery, and professor of physics, and the director of the Center for Neural Engineering at Penn State.