Unique Type Of MRI Scan Shows Promise In Treating Bipolar Disorder

"This is a very unusual MRI exam used for the first time in this study. Wewere surprised at our good fortune in discovering this effect and we areexcited about the initial findings," says Michael Rohan, imaging physicistin McLean's Brain Imaging Center.

The study published in the January 1 issue of the American Journal ofPsychiatry had a surprising start. Rohan explains, "We were using MRI toinvestigate the effectiveness of certain medications in bipolar patients andnoticed that many came out of the MRI feeling much better than when theywent in. We decided to investigate further."

Researchers theorized that one type of magnetic pulse they were using washaving the positive effect. "This was purely accidental. We just happenedto use this set of magnetic gradients, which we think somehow matches thenatural firing rhythm of brain cells." Technically this kind of scan iscalled EP-MRSI, or Echo-Planar Magnetic Resonance Spectroscopic Imaging.

After realizing they may be observing a real effect, researchers expandedthe study to include sham EP-MRSI scans with bipolar subjects, normalEP-MRSI scans in healthy subjects, in addition to EP-MRSI scans in bipolarsubjects.

The results showed 23 out of 30 bipolar subjects who received the actualEP-MRSI tests reported mood improvement, indicating a 77 percent responserate. In addition, subjects who were not on medication showed even greaterresponse (100 percent) compared to the response rate of those on medication(63 percent). These results were not seen in the other two groups, thosewith bipolar disorder receiving sham EP-MRSI and healthy individualsreceiving EP-MRSI.

The authors note that one other test using electromagnetic energy haspreviously shown some positive effect in subjects with depression. ThisrTMS, or repetitive transcranial magnetic stimulation test, was originallydeveloped in the 1980s to test nerve function. It uses a magnetic devicethat is held next to the head. Studies using this treatment for depressiontypically result in a 40 percent to 50 percent response rate. However, theMcLean authors note that this test uses a much stronger magnetic field thatcan be painful to the patient.

The magnetic field the McLean researchers are using is approximately 200times weaker than rTMS and like a standard MRI, the patients feel nothing.Researchers are currently developing a tabletop device that delivers theprecise magnetic field originally used in this study with the MRI scanner.

Downsizing the machinery is expected to prove more efficient and costeffective in the long run.

"We are also planning a much larger clinical study using this smaller deviceto further test this effect," adds Rohan. Researchers believe one day sucha device may be used during perhaps a 20-minute nap at a doctor's office.

McLean Hospital is the largest psychiatric affiliate of Harvard MedicalSchool and maintains the largest research program of any private psychiatrichospital in the U.S.