The evidence seems to favor using brain imaging to help diagnose and treat adult ADHD, but medical experts remain divided about its current overall effectiveness. Although brain imaging tests can't provide a definite diagnosis, they do offer a wealth of data that can be compared to databases on thousands of other patients with adult ADHD.

MRI

Brain imaging, or MRI, produces a clear, detailed picture of brain structures. An MRI can show slight variations between the brains of people with ADHD and those without it.

A functional MRI, or an FMRI, is a more powerful type of MRI that analyzes brain activity. Unfortunately, it's so new that many radiologists haven't been trained to use it yet.

PET Scans

Positron emission topography (PET) scans measure the presence and motion of radioactive substances that are injected into a patient. As the radioactive material travels to the brain, the PET shows blood flow and glucose metabolism. As part of a growing field of high-tech medicine called nuclear medicine, PET scans provide very high-quality images of the brain that far surpass what older devices can do.

SPECT scans

SPECT scans are a lower-tech version of PET scans. It's still the same basic scenario: radioactive substances are injected into the arm and provide a record of what happens as the material travels to the brain. These scans are less detailed than those recorded by PET scans, but SPECT scans cost much less than PET scans, are easier to administer, and are more widely available.

EEG

Electroencephalogram technology, or EEG, measures the electrical activity in your brain, otherwise known as brain waves. Electrodes placed on the scalp transmit information about brain waves to an amplifying device, then on to a computer so a neurologist can view and analyze them. It's been useful in showing an increase in larger, slower brain waves, which some researchers believe is an indication of ADHD. The downside to EEG is that it only tracks brain waves on the surface of the brain and can't see into the organ like newer technology.

QEEG

Quantitative Electroencephalogram, or QEEG, measures brain wave activity against normal brain waves stored in a database.

ERP

Event-related potential (ERP) tests record changes in brain activity via electrodes placed on the scalp. Changes are measured against a repeated stimulus. People with ADHD often respond to the stimulus in a certain way that confirms or aids diagnosis.