A new brain-scanning technique may help clinicians better diagnose attention deficit hyperactivity disorder (ADHD) by measuring levels of iron.
The use of magnetic resonance imaging (MRI) technology provides an indirect but noninvasive way of measuring iron levels indicative of the condition, potentially helping doctors and parents make wiser decisions about medication. Today, 3-7 percent of American schoolchildren are believed to suffer from ADHD, for which doctors commonly prescribe psychostimulants, such as Ritalin.
Vitria Adisetiyo, an investigator at the Medical University of South Carolina, used the brain-scanning technology to measure levels of brain iron in 22 children and adolescents with the condition, in addition to 27 others used as a comparison.
"Studies show that psychostimulant drugs increase dopamine levels and help the kids that we suspect have lower dopamine levels," Adisetiyo told reporters in a statement. "As brain iron is required for dopamine synthesis, assessment of iron levels with MRI may provide a noninvasive, indirect measure of dopamine."
The investigators used a relatively new “magnetic field correlation” (MFC) imaging technique, first introduced in 2006. "MRI relaxation rates are the more conventional way to measure brain iron, but they are not very specific," Adisetiyo said. "We added MFC because it offers more refined specificity."
In the experiments, a dozen of the study subjects who’d never received medication showed significantly lower levels of brain iron than others in the study diagnosed with the condition. The method worked better than other attempts to measure iron in the brain, the investigators said. "This method enables us to exploit inherent biomarkers in the body and indirectly measure dopamine levels without needing any contrast agent,” Adisetiyo said.
The new method might help clinicians better assess whether a child may benefit from ADHD medications, psychoactive medications sometimes disruptive with a risk of encouraging abuse of similar drugs, such as cocaine. In practice, such a tool would eliminate much of the guesswork from decisions about treatment in children diagnosed with the condition.
"It would be beneficial, when the psychiatrist is less confident of a diagnosis, if you could put a patient in a scanner for 15 minutes and confirm that brain iron is low,” Adisetiyo said. "And we could possibly identify kids with normal iron levels who could potentially become addicts."
Aside from looking to replicate the study on a larger scale, the Canadian team hopes to investigate the relationship between cocaine addiction and brain iron, too. The team presented their findings in Chicago at the annual meeting of the Radiological Society of North America.