Dear Dr. SerVaas: Do you have information on whether MRI or CT scans of the brain during depression help identify the best manner of treatment?Can MRI or CT scanning help doctors differentiate manic depression from other types of depression?

Penny Andrews
Minneapolis, Minnesota

Dear Reader: Dr. John Nurnberger, director of the Indiana University Institute of Psychiatric Research, provides the following comments:

"The question refers to the potential value of MRI (magnetic resonance imaging) or CT (computerized tomography) scans in the diagnosis and treatment of depression. The short answer is that the major use of MRI or CT scans in depression at this time is to identify specific neurologic problems that might be confused with depression (such as a brain tumor or multiple sclerosis). A scan would not be a standard part of the medical workup for depression, but would be indicated if the history or physical examination suggested a neurologic problem.

"It's certainly possible that an MRI or CT scan (or other brain evaluation measures such as a positron emission tomographic (PET) scan or magnetic-resonance spectroscopy (MRS) or electroencephalography (EEG) might be part of an evaluation for depression in the future. For instance, it has been observed that some patients with depression or bipolar disorder (manic-depression) have abnormalities in the brain white matter (long nerve fiber areas). Recently it has been found that bipolar patients have a reduced size of the amygdala, a part of the brain very involved with emotion and affect. Also, CT scans sometimes show enlarged fluid spaces (the ventricles) in patients with bipolar illness. These are all research findings that are not yet ready for clinical use, and they only apply to some patients and not others. As yet, they do not give us clues to treatment response. But certainly brain imaging techniques are very promising for our understanding of the causes and treatments for depression in the future."