Here are some of the factors that need to be considered in SPECT scans.
Variability-of-Technique Issues Processing protocols need to be standardized and optimized. Motion can ruin a scan, so it is important that there be no motion on the scan. The professionals need to know how to identify and deal with image artifacts and other sophisticated technical issues.
Variability of cameras. Multiheaded cameras are clearly superior, as they can scan much faster. It takes an hour to do a scan on a single-headed camera, thirty minutes on a dual-headed camera, and fifteen minutes on a triple-headed camera.
Experience of readers. At the Amen Clinics, we have developed a standardized reading technique for which we have doc.u.mented high inter- and intrarater reliability.
Image display. Scans must be clear, understandable, easily ill.u.s.trative of brain function, and available to the patient on a timely basis. We believe our 3-D rendering software makes the scans easy for professionals, patients, and families to understand.
Drugs. Scans can be affected by a number of substances that need to be controlled, including medications, street drugs, and caffeine.
All of the above issues have been addressed at the Amen Clinics by carefully standardized procedures for all our SPECT scans.
Common Concerns CONCERN: Low resolution-it is commonly said that a SPECT scan is a "poor man"s PET study."
RESPONSE: With multiheaded cameras, SPECT has the same resolution as PET with considerably lower cost, better insurance coverage, greater availability, and fewer image artifacts.4 Also, it is an easier procedure to do. SPECT provides more-than-adequate resolution for our applications.
CONCERN: Radiation exposure, especially in children.
RESPONSE: The average radiation exposure for one SPECT scan is 0.7 rem (similar to a nuclear bone scan or brain CAT scan) and is a safe procedure, according to the guidelines established by the American Academy of Neurology.5 These other procedures are routinely ordered for many common medical conditions (i.e., bone fractures or head trauma), further suggesting that the levels of radiation exposure are generally acceptable in medical practice. Ineffective treatment of psychiatric illness has many more risks than the low levels of radiation a.s.sociated with a SPECT scan.
CONCERN: What is normal?
RESPONSE: In the SPECT literature over the past twenty years, there have been more than forty-three studies looking at "normal" issues in more than 2,450 patients, including 150 children from birth on (see www.amenclinic.com for references). These do not include the thousands of control subjects used in studies of specific neurological and psychiatric conditions. Chiron et al. reported that at birth, cortical regional cerebral blood flow (rCBF) was lower than those for adults.6 After birth, it increased by five or six years of age to values 50 percent to 85 percent higher than those for adults, thereafter decreasing to reach adult levels between fifteen and nineteen years. At the age of three, however, children had the same relative blood-flow patterns as adults. Other common findings in normal studies suggest that women have generally higher perfusion than men and that age, drug abuse, and smoking have a negative effect on rCBF.
CONCERN: Some physicians say, "I don"t need a scan for diagnosis; I can tell clinically."
RESPONSE: Often, well-trained physicians can tell clinically. But that is not when you order a SPECT scan. You order scans when you are confused, the patient hasn"t responded to your best treatment, or the patient"s situation is complicated.
CONCERN: Lack of reproducibility.
RESPONSE: The paper by Javier Villanueva-Meyer, MD, et al. elegantly answers this question, showing that there is less than 3 percent variability in SPECT scans over time for the same activity.7 Our own clinical experience, scanning people sequentially, and sometimes twelve years apart, is that SPECT patterns are the same unless you do something to change the brain. SPECT is a reproducible and reliable method for sequential evaluation.
Conclusion At the Amen Clinics we feel that our experience with more than 35,000 brain SPECT scans over sixteen years guides us in being the best in the world for brain-SPECT imaging.
Common Questions About Brain-SPECT Imaging Here are several common questions and answers about brain-SPECT imaging.
Will the SPECT study give me an accurate diagnosis? No. A SPECT study by itself will not give a diagnosis. SPECT studies help the clinician understand more about the specific function of your brain. Each person"s brain is unique, which may lead to unique responses to medicine or therapy. Diagnoses about specific conditions are made through a combination of clinical history, personal interview, information from families, diagnostic checklists, SPECT studies, and other neuropsychological tests. No study is "a doctor in a box" that can give accurate diagnoses on individual patients.
Why are SPECT studies ordered? Some of the common reasons include: Evaluating memory problems, dementia, and distinguishing between different types of dementia and pseudodementia (depression that looks like dementia) Evaluating seizure activity Evaluating blood-vessel diseases, such as stroke Evaluating the effects of mild, moderate, and severe head trauma Suspicion of underlying organic brain condition, such as seizure activity contributing to behavioral disturbance, prenatal trauma, or exposure to toxins Evaluating atypical or unresponsive aggressive behavior Determining the extent of brain impairment caused by the drug or alcohol abuse Typing anxiety, depression, and attention deficit disorders when clinical presentation is not clear Evaluating people who are atypical or resistant to treatment.
Do I need to be off medication before the study? This question must be answered individually between you and your doctor. In general, it is better to be off medications until they are out of your system, but this is not always practical or advisable. If the study is done while on medication, let the technician know so that when the physician reads the study, he will include that information in the interpretation of the scan. In general, we recommend patients try to be off stimulants at least four days before the first scan and remain off of them until after the second scan if one is ordered. It is generally not practical to stop medications such as Prozac because they last in the body for four to six weeks. Check with your specific doctor for recommendations.
What should I do the day of the scan? On the day of the scan, decrease or eliminate your caffeine intake and try to not take cold medication or aspirin (if you do, please write it down on the intake form). Eat as you normally would.
Are there any side effects or risks to the study? The study does not involve a dye and people do not have allergic reactions to the study. The possibility exists, although in a very small percentage of patients, of a mild rash, facial redness and edema, fever, and a transient increase in blood pressure. The amount of radiation exposure from one brain SPECT study is approximately the same as one abdominal X-ray.
How is the SPECT procedure done? The patient is placed in a quiet room and a small intravenous (IV) line is started. The patient remains quiet for approximately ten minutes with his or her eyes open to allow their mental state to equilibrate to the environment. The imaging agent is then injected through the I V. After another short period of time, the patient lays on a table and the SPECT camera rotates around his or her head (the patient does not go into a tube). The time on the table is approximately fifteen minutes. If a concentration study is ordered, the patient returns on another day.
Are there alternatives to having a SPECT study? In our opinion, SPECT is the most clinically useful study of brain function. There are other studies, such as electroencephalograms (EEGs), Positron Emission Tomography (PET) studies, and functional MRIs (fMRI). PET studies and fMRI are considerably more costly and they are performed mostly in research settings. EEGs, in our opinion, do not provide enough information about the deep structures of the brain to be as helpful as SPECT studies.
Does insurance cover the cost of SPECT studies? Reimburs.e.m.e.nt by insurance companies varies according to your plan. It is often a good idea to check with the insurance company ahead of time to see if a SPECT study is a covered benefit.
Is the use of brain-SPECT imaging accepted in the medical community? Brain-SPECT studies are widely recognized as an effective tool for evaluating brain function in seizures, strokes, dementia, and head trauma. There are literally hundreds of research articles on these topics. In our clinic, based on our experience for over a decade, we have developed this technology further to evaluate aggression and nonresponsive psychiatric conditions. Unfortunately, many physicians do not fully understand the application of SPECT imaging and may tell you that the technology is experimental, but more than a thousand physicians and mental health professionals in the United States have referred patients to us for scans.
1. Holman, B. L., and M. D. Devous Sr. "Functional Brain SPECT: The Emergence of a Powerful Clinical Method." Journal of Nuclear Medicine 1992; 33:18881904.
2. Amen, D. Comprehensive Textbook of Psychiatry, edited by Kaplan and Sadock, Neuroimaging Chapter, 2000.
3. Bonte F. J., M. F. Weiner, E. H. Bigio, and C. L. White. "Brain Blood Flow in the Dementias:" SPECT with Histopathologic Correlation in 54 Patients." Radiology 1997; 202:793797.
4. George, M. S. Neuroactivation and Neuroimaging with SPECT. (New York: Springer-Verlag, 1991).
5. Report of the Therapeutics and Technology a.s.sessment Subcommittee of the American Academy of Neurology: a.s.sessment of Brain SPECT 1996; 46: 278285.
6. Chiron C., C. Raynaud, B. Maziere, M. Zilbovicius, L. Laflamme, M. C. Masure, O. Dulac, M. Bourguignon, A. Syrota. Changes in Regional Cerebral Blood Flow During Brain Maturation in Children and Adolescents. Journal of Nuclear Medicine 1992;33(5):696703.
7. Villanueva-Meyer, Javier M.D. et al. "Cerebral Blood Flow During a Mental Activation Task: Responses In Normal Subjects and in Early Alzheimer Disease Patients." Alasbimn Journal: 1(3): BY DANIEL G. AMEN, M.D.
Magnificent Mind at Any Age.
Making a Good Brain Great.
Preventing Alzheimer"s (with neurologist William R. Shankle).
Healing Anxiety and Depression (with psychiatrist Lisa Routh).
Healing the Hardware of the Soul.
Images of Human Behavior: A Brain SPECT Atlas.
Healing ADD Power Program.
Healing ADD
Change Your Brain, Change Your Life
Firestorms into the Brain
New Skills for Frazzled Parents
Mind Coach
Would You Give Two Minutes a Day for a Lifetime of Love?
The Most Important Thing in Life I Learned from a Penguin
Ten Steps to Building Values Within Children
ADD in Intimate Relationships
Healing the Chaos Within
A Teenagers Guide to A.D.D.
(written with Antony Amen and Sharon Johnson)
A Child"s Guide to ADD.
A Sibling"s Guide to ADD.
The Secrets of Successful Students.
How to Get Out of Your Own Way.
Glossary.
Acetylcholine (ACh)-a neurotransmitter involved with memory formation, mostly excitatory, that has been implicated in problems with muscles, Alzheimer"s disease, and learning problems.
Amygdala-found on the front, inside aspect of the temporal lobes, part of the limbic or emotional system of the brain, is involved with tagging emotional valences to experiences or events.