Tuesday, March 29, 2005

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The Use of Brain SPECT Imaging in ADHD

The Use of Brain SPECT Imaging in ADHD

by Anthony Kane, MD

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The use of brain SPECT imaging as a diagnostic tool in Psychiatry is extremely controversial. The pioneer of the field and its main proponent, Dr. Daniel Amen, has been fighting mainstream psychiatry for fifteen years, trying to gain acceptance for this diagnostic technique. There are still only a handful of clinics in the country that do use brain SPECT imaging for psychiatric diagnosis and the only person with any significant experience with this technique is Dr. Amen.


The Problem

When a person has a broken leg the orthopedic surgeon takes an x-ray. This tells him the exact nature of the brake and how best to treat it. When a patient has a heart problem the cardiologist performs a cardiac catheterization study. The doctor sees the exact area of the obstruction and knows how best to treat it. When a patient needs a tumor removed the surgeon will order a CT scan or an MRI scan so he has an exact image of the disease before he takes the person to surgery. Almost every medical specialty relies on some type of imaging test so that the physician can visualize the problem and plan the best course of action for his patient.

The brain is the most complex structure in the known universe. Yet even more perplexing than its physical intricacy is the complexity with which it functions. CT scans and MRI scans can give the physician a clear picture of the physical structure of the brain. EEG can give a crude picture of the electrical activity of the brain. Yet unlike most other areas of medicine, psychiatry has no real way to visualize its specialty’s focus, brain function. When it comes to treating disorders of brain function, such as Bipolar disorder or Oppositional Defiant Disorder, psychiatrists are working in the dark. They are dealing with the most complex aspect of the most complicated structure in the universe, but they have no way to visualize the problems.


What is Brain SPECT Imaging

SPECT, which is an acronym for Single Photon Emission Computerized Tomography, is a sophisticated nuclear medicine study that examines blood flow in the brain. This in turn gives the physician a picture of brain activity. When an area of the brain is active, it demands more from the blood supply. When an area is inactive it requires much less blood. With this in mind it is easy to understand how a SPECT imaging can be used to evaluate brain function.

SPECT can identify specifically which areas of the patient’s brain are overactive, which are functioning normally, and which areas are not working well. This information, combined with what we know about the function the specific areas of the brain, can give the clinician a very clear picture of exactly what is going on. This information along with a detailed clinical history, can give the psychiatrist a detailed picture of the physiological cause of the problem he is treating. This in turn can help him to pinpoint the best treatment to balance brain function.


The Procedure

In a SPECT study, a radioactive isotope is chemically bound to a substance that is readily taken up by the cells in the brain. This compound is injected into the patient's blood stream and eventually makes its way to the brain. Since active areas of the brain receive more blood flow, they absorb more of this chemical. The radioactive material emits pulses of energy, which makes the active areas of the brain light up. These pulses are photographed by a camera and sent to a computer, which reconstructs a 3-dimentional image of the brain. Thus you have a photographic image of brain activity, depicting the parts of the brain where the activity is high, where it is normal, and where it is low. With this 3-D image of brain function, the psychiatrist can identify certain patterns of brain activity that correlate with psychiatric and neurological illnesses.

Generally, the procedure for ADHD is run twice in a four-day period. The first study images the patient at rest. This gives the clinician a baseline view of the patient’s brain function. For the second scan, the patient is given a concentration task. This gives an image of the brain when it is actively working and helps to identify areas of dysfunction during performance.


Advantages

Brain SPECT scans give an accurate picture brain activity. When combined with our knowledge of what function various areas of the brain serve, this information can lead to a much more accurate diagnosis.

In addition SPECT can help guide treatment. The current state of the art method in psychiatric treatment is guessing. Now these guesses are educated guesses, so they are usually pretty good, but they are still guesses.

For example, when a psychiatrist sees a child who is hyperactive, inattentive, and impulsive, he gets a “clinical impression” that this child has ADHD. He knows that more than 90% of ADHD children will improve with drugs like Ritalin. For this patient Ritalin is a very good guess, so the psychiatrist prescribes Ritalin. So what does the doctor do when Ritalin doesn’t work? He makes another guess. However, this usually won’t happen in children who have the classic ADHD symptoms.

However, say the psychiatrist sees a second child, who is very hyperactive and aggressive, but he doesn’t seem to have an attention problem. This is not the typical ADD ADHD child. The psychiatrist may still feel that Ritalin is the best guess, but this choice is not quite as good as it is for the first child. It is much more likely to fail and the psychiatrist will need to spend months or years trying different things until he hits upon a combination that helps this child. Often he will settle for only a partial relief of symptoms.

Now let’s say the physician had done brain SPECT imaging on this second child and he identifies a defect in temporal lobe function. He knows that this area of the brain responds well to Valproic acid, a drug that is seldom used for ADHD, and that is what he prescribes. Without the brain SPECT imaging, the psychiatrist may never have made the proper guess and found the optimal treatment to help this child to function normally. However, with the brain SPECT scan he would know exactly how to treat this child.


Disadvantages

The main problem with SPECT imaging is the cost is very high. A complete evaluation is about $3000 and is usually not covered by most insurance plans.

Also, there is limited access to this test. Brain SPECT imaging for psychiatric diagnosis has not been embraced by mainstream medicine. Unless you live in one of the few areas in the country where this test is done, you are going to have to take a small vacation.

Finally, we still only have a minimal amount of information to connect specific brain function defects to clinical behavior. We still need a lot more research before this will become a really useful technique, and considering the degree of opposition this is going to take a while.

What’s Holding Things Back To say that Brain SPEC imaging is in its infancy would be an exaggeration. It is more like it is in its fetal stage; and there are numbers of physicians who have been trying to abort this baby.

Most psychiatrists balk at the idea of using an imaging study to make what they feel is purely a clinical diagnosis. They feel that Dr. Amen has greatly overstressed the value of this technique. As one well known psychiatrist puts it, “If it were really worth it, don’t you think that Harvard and Yale would be using it?”

With this type of attitude it is amazing that the field has gotten anywhere. However, Dr. Amen has slowly made progress over the last decade and now many former opponents are entertaining the idea that brain SPECT imaging may have some value.


Conclusion

We are still a long way from realizing the full benefit of brain SPECT imaging. It is not yet a refined diagnostic tool for psychiatric disorders. It is also expensive and inconvenient.

Although there are a few places in the United States that do this test, Dr. Amen is still the only practitioner with any significant experience. Probably you are going to eventually have to go to him and pay the price in time and money. However, for children who do not respond to conventional treatment, I feel that brain SPECT imaging may have a lot to offer.


Anthony Kane, MD

ADD ADHD Advances



Anthony Kane, MD is a physician and international lecturer. Get ADD ADHD Child Behavior and Treatment Help for your child, including child behavior advice and information on the latest ADHD treatment, and help with Oppositional Defiant Disorder (ODD). Share your views at the ADD ADHD Blog. Sign up for the free ADD ADHD Advances online journal

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