High-tech images open window into the skull

Both women had trouble speaking and moving their right sides when they showed up recently at Massachusetts General Hospital's emergency room. The patients, who didn't know each other, were roughly the same age and had similar symptoms, but imaging technologies quickly changed the arcs of their stories.

One woman's brain scans showed an incurable, malignant tumor that left her with a life expectancy of eight months. The other was sent home with a prescription for blood thinners after a bright spot on her scan indicated that she had had a minor stroke.

"We were able to diagnose them within an hour in the emergency room," said Dr. Gilberto Gonzalez, chief of neuroradiology at the hospital. "In the old days, it could have taken a week or more to sort [their diagnoses] out."

It's just one example of how the ability to see inside the brain without cutting it open has revolutionized doctors' abilities to understand and treat one of the body's most complex organs. By superimposing images of the blood flow, chemistry, and electricity that keep the brain alive, doctors can create a multidimensional map that can help them find, treat, and monitor neurological diseases that were once visible only through autopsies or surgery.

Better imaging also has pushed the limits of treatment, as new therapies spring up for stages of disease that were never previously seen.

Before scanners began to proliferate as clinical and research tools, Gonzalez said, "we didn't treat [patients], essentially; we'd watch them." New treatments were often tested "the hard way," by giving brain tumor patients a proposed drug therapy and then waiting to see who lived and who died. Many stroke victims faced paralysis or death, even if they got to the hospital quickly. When surgeons opened up the brain to look for a problem, they were handicapped by the lack of information about what was wrong and where they needed to look.

The window into the brain began opening in the mid-1970s with the introduction of a more sophisticated X-ray called computerized tomography, or CT, which shows both bone and some tissue. In the 1980s, the window inched open a bit more with the introduction of magnetic resonance imaging, or MRI, which reveals structure, tissue, and blood flow, a sign of activity in different areas of the brain.

"If we look at those images now, we're shocked; they look so crummy," said Alexandra Golby, a neurosurgeon at Brigham and Women's Hospital.

Over the past decade, variants of MRI and CT have expanded the kinds of topographical features that brain mappers can find to blood vessels, tissues, physical structure, and nerve fibers that connect different areas.

In a darkened room off Mass. General's emergency ward, Gonzalez called up pictures last week that told the story of a potential tragedy: a 38-year-old woman with two children who collapsed on her kitchen floor and was rushed to the hospital from her home in the North End.

A variant of MRI showed that a small region of her brain was dead from a stroke and that a large portion was still at great risk. A medical team used a CT scan taken just after she was admitted to hunt down the blood clot that caused her stroke.

Doctors then threaded a catheter through an artery to reach the clot and injected a drug to break it up. A later scan showed that a whole network of spidery blood vessels cut off by the clot had basically come back to life.

"After this procedure, she could talk, and she could move, and she literally walked home three days later," Gonzalez said.

Brain images have also provided doctors with better choices and more information, transforming long-existing treatments from a crapshoot to an informed choice.

Now, when surgeons decide to remove tumors, they have a better, though still not perfect idea of what they are slicing through and can steer around regions responsible for thought, talking, or movement.

Golby, a neurosurgeon since the infancy of combined imaging and surgery in 1996, worked with her team to develop what they describe as a global positioning, or GPS, navigation system for the brain. During surgery, she can point a wand to any portion of the patient's brain and see where she is on a computer image of the brain, which also incorporates information from other scans.

Understanding the meaning of these images remains a huge problem. "When you speak to me on the telephone, you may be using 58 different parts of the brain, but maybe only 20 of those are essential for you to speak to me," Golby said during a phone interview.

Her scans show her the 58 crucial areas, but don't tell her which 38 are not essential and could therefore be cut during surgery.

So, Golby looks for ways to relate her images to the current "gold standard" in brain mapping. In that system, surgeons, working with patients who are awake during surgery, identify crucial areas by zapping them with tiny electric currents and seeing what happens to the patients.

Golby looks forward to the day when the scans alone will give her a seamless map of the brain under her scalpel. "It would be great," he said, "if we'd have a definitive answer to the question: Someone's got something in their brain; what is it?"

Carolyn Johnson can be reached at cjohnson@globe.com.