When a doctor looks at a patient's brain scan, some problems are immediately clear. Tumors, for instance, aren't easily hidden. Other subtle abnormalities are harder to detect, however. So for years, doctors have relied on brain atlases – compendiums of scans of normal brains in book form – to make comparisons and spot differences.
But book atlases are far from infallible. "The traditional atlas is an extrapolation of the general population," explains Jo Hajnal, a physicist at the MRC Clinical Services Centre at London's Imperial College. "They contain only whatever the preparer thought was useful," he adds. Now computer technology is giving physicians a much more powerful diagnostic tool: brain atlas images customized to each patient.
Hajnal is part of a team of researchers at Imperial College and King's College London that has devised a Dynamic Brain Atlas, which runs from a networked laptop. The current prototype can access hundreds of images stored in databases around the world and create a composite image that closely approximates each patient's brain. That image and the patient's scan can then be compared and contrasted. The images can be overlaid or placed side by side. And subtle differences that are otherwise hard to detect become more readily apparent to a trained observer: whether a brain is too thin, if there is lack of symmetry or if atrophy has set in. "We can see precisely if any part of the brain is abnormal," Hajnal says.
To create a customized atlas, information particular to that individual is made part of the search: for example, gender, age, handedness and medical history. It then works not unlike an Internet search engine, like Google. The Dynamic Brain Atlas should help doctors better diagnose such psychiatric ailments as chronic fatigue syndrome, autism, attention deficient disorder and dementia. It may also help spot other problems – like liver disease – which often cause brain abnormalities. Individualized brain atlases became possible only in the last year, thanks to a breakthrough in e-science called the Grid.
The Grid is a new type of distributive computing that links computers worldwide in what Hajnal calls a kind of "turbocharged Internet." At any given time, around the world, there are a lot of very powerful and large computers sitting idle. The Grid takes a job order then finds computers to do the work quickly. If 20 databases need to be searched, then it finds 20 computers to do the work, which is completed 20 times faster than it would take one PC to do the job. In a recent test of the Dynamic Brain Atlas, preprocessing that would take one computer a month to do was completed in a weekend. The final processing took just seconds. And as computerized searches become more available, and countless more databases are added, not only will processing time speed up, but the efforts "will yield highly specific, customized atlases," Hajnal says. Widespread use could still be a few years off because the technology is so new. But clearly the days of generalized brain atlases in book form are numbered.
(c) 2002 Time. Source: Co-Cure