Why SPECT?
WHAT BRAIN SPECT IMAGING CAN TELL CLINICIANS AND PATIENTS
If we agree that mental disorders and difficult behaviors may be related to functional problems in the brain, then a logical next step is to consider physically evaluating the brain itself when faced with people who struggle with complex problems or who are unresponsive to our best diagnostic and treatment efforts. Why are psychiatrists the only physicians who rarely look at the organ they treat?1
It is time to change. Amen Clinics, Inc. (ACI) has provided leadership and understanding on the clinical use of brain imaging in psychiatry. Over the past eighteen years, ACI has built the world’s largest database of brain scans related to emotional, learning, and behavioral problems. The study we do is called brain SPECT imaging. SPECT stands for “single photon emission computed tomography.” It is a nuclear medicine procedure widely used in medicine to study heart, liver, thyroid, bone, and brain problems. Brain SPECT imaging is a proven safe, reliable measure of cerebral blood flow. Because brain activity is directly related to blood flow, SPECT effectively shows us the patterns of activity in the brain.2 SPECT allows physicians to look deep inside the brain to observe three things: areas of the brain that work well, areas of the brain that work too hard, and areas of the brain that do not work hard enough. ACI has performed over fifty thousand scans on patients from age ten months to 101 years and has scanned many normal, “healthy brain” individuals as well.
The procedure guidelines of the Society of Nuclear Medicine lists the evaluation of suspected brain trauma, evaluation of patients with suspected dementia, presurgical location of seizures, and the detection and evaluation of cerebral vascular disease as common indications for brain SPECT.3 The guidelines also say that many additional indications appear promising. At ACI, because of our experience, we have added the indications of evaluating violence, substance abuse, the subtypes of ADD, anxiety and depression, complex or resistant psychiatric problems, and general health screening for brain SPECT.
An important question for today’s mental health clinicians is “When and why would I order a SPECT study for my patients or get one for myself or loved one?” My purpose in this appendix is to answer this question and to point out some of the benefits and caveats for using this powerful tool.
Benefits of SPECT Brain Imaging
A SPECT scan can provide distinct benefits to clinicians and to the patient and the patient’s family. There are also some things that should not be expected from a SPECT scan.
BENEFITS FOR PHYSICIANS AND CLINICIANS
1. A SPECT scan can show:
a. Areas of the brain implicated in specific problems, such as the prefrontal cortex with executive function and the medial temporal lobes with long-term memory storage
b. Unexpected findings that may be contributing to the presenting problem(s), such as toxicity, potential areas of seizure activity, or past brain trauma
c. Potential seizure activity, in many cases more accurately seen by SPECT than standard electroencephalograms (EEGs), especially in the areas of the medial temporal lobe. There are over forty-one studies with more than thirteen hundred patients on SPECT and epilepsy (see www.amenclinic.com for references).
d. Targeted areas for treatment, such as overactive basal ganglia or anterior cingulate gyrus (seen on anxiety and obsessive-compulsive spectrum disorders) or an underactive temporal lobe (seen in seizure disorders and trauma)
e. Specific effects of medication on the brain to help guide us in adjusting dosages or augmenting treatment. Often patients report that selective serotonin reuptake inhibitors (SSRIs) are helpful but also cause decreased motivation or memory problems, seen as decreased prefrontal or temporal lobe activity on SPECT.
f. Changes in brain function with treatment, improved or worsened. You can review many before-and-after scans at www.amenclinic.com.
2. The image occurs at the time of injection and outside the imaging camera, which gives SPECT several significant advantages. Most notably, we are able to sedate people after they have been injected so that they can lie still for the scan, often difficult for hyperactive or autistic children or demented adults (motion artifact ruins the scan in all of these imaging techniques).
3. A SPECT scan can provide explanations for refractory symptoms and help clinicians ask better and more targeted questions (e.g., about toxic exposure, brain injuries, anoxia, inflammation, or infections that patients may have denied or forgotten).
4. A SPECT scan can help us avoid prescribing treatments that make the problem worse, such as unnecessarily stimulating an already overactive brain or calming an underactive one.
5. A SPECT scan can help evaluate risk for dementia. The brain starts to change long before people show symptoms. There is usually a loss of 30 percent of hippocampal tissue before symptoms occur. Using autopsy data in fifty-four patients, Bonte reported that brain SPECT had a positive predictive value for Alzheimer’s disease of 92 percent.4
6. A SPECT scan can also help differentiate among types of dementia. Early in the disease, Alzheimer’s disease, frontal temporal lobe dementia, Lewy body dementia, and multi-infarct dementia each have their own patterns. There are over eighty-three studies with more than forty-five hundred patients on this subject (see www.amenclinic.com for references).
7. A SPECT scan helps clinicians understand the rationale for using certain medications (such as anticonvulsants to stabilize temporal lobe function or calm focal areas of marked hyperactivity; stimulants to enhance decreased prefrontal perfusion; or SSRIs to calm basal ganglia and anterior cingulate hyperactivity).
8. A SPECT scan can identify specific areas of the brain affected by trauma; better target treatment; and help deal with insurance, legal, and rehabilitation issues. There are over seventy-two studies with more than seventeen hundred patients on brain trauma (see www.amenclinic.com for references).
9. A SPECT scan can often identify factors contributing to relapse in people recovering from substance abuse, eating disorders, or sexual addictions. For example, the patient may have suffered an injury to the prefrontal cortex or temporal lobes or have overactivity in the anterior cingulate gyrus, basal ganglia, limbic system, or prefrontal cortex, each of which could indicate comorbid disorders requiring treatment.
10. A SPECT scan can often identify a specific cause that contributes to recovering alcoholics’, drug addicts’, sexual addicts’, or eating-disordered people’s relapse behavior. For example, the patient may have suffered an injury in the prefrontal cortex or temporal lobes or have overactivity in the anterior cingulate gyrus, basal ganglia, limbic system, or prefrontal cortex, each of which could contribute to the relapsing behaviors.
11. A SPECT scan is also useful to determine if further adjustment of medication is needed. Scans of patients on medication will reveal areas of the brain still overactive or underactive.
BENEFITS FOR PATIENTS AND THEIR FAMILIES
1. A SPECT scan helps develop a deeper understanding of the problem, resulting in reduced shame, guilt, stigma, and self-loathing. This can promote self-forgiveness, often the first step in healing. Patients can see that their problems are, at least in part, medical and physical.
2. A SPECT scan allows patients to see a physical representation of their problems that is accurate and reliable and helps to increase compliance. Pictures are powerful and can influence a patient’s willingness and ability to accept and adhere to the treatment program. She can then better understand that not taking medication for anxiety, depression, rage, ADD, and so on is similar to not wearing corrective prescription glasses.
3. A SPECT scan helps families understand when permanent brain damage from an injury will not get better, so they can better accept the condition and provide accordingly.
4. A SPECT scan shows substance abusers the damage they have done to their own brain, thus helping to decrease denial, provide motivation for treatment, and support perseverance in sobriety.
5. A SPECT scan shows patients how treatments have impacted (improved or worsened) brain function.
6. A SPECT scan helps motivate abusive spouses to follow medication protocols by showing that there is a physical abnormality contributing to their problems.
7. A SPECT scan is useful for cancer patients suffering with a “chemotherapy toxic brain.” It gives them insight into their cognitive struggles and also helps their doctors see the neurophysiologic and emotional effects of having cancer and its treatment.
8. A SPECT scan can help take modern psychopharmacology from mystery and unknown consequences to reality and more predictable outcomes.
9. A SPECT scan allows patients to understand why specific treatments are indicated, which medications are likely to be most helpful, and what other interventions may be indicated.
What a SPECT Scan Cannot Provide
Despite the many benefits that might be derived from a SPECT scan, there are clearly some things that it cannot provide.
1. SPECT scans cannot give a diagnosis in the absence of clinical information.
2. SPECT scans cannot give the date of a head injury, infection, or toxic exposure.
3. SPECT scans cannot assess or evaluate IQ.
4. SPECT scans cannot assess or evaluate the guilt, innocence, motivation, or sanity of a criminal defendant.
5. SPECT scans cannot guarantee a perfect diagnosis, or a cure.
How SPECT Scans Differ from Magnetic Resonance Imaging Scans
A SPECT scan is similar to a magnetic resonance imaging (MRI) scan in that both can show three-dimensional images and “slices” of the brain. However, whereas MRI shows the physical anatomy of the brain, SPECT shows brain functional activity. That is, SPECT yields images showing where the brain is functioning well, where it is working too hard, and where it is not working hard enough. A newer version of MRI, functional MRI or “fMRI,” is also capable of showing brain activity and is used extensively in scientific research on brain function. An fMRI shows instantaneous neural activity so you can see, for example, how the brain responds to a specific stimulus event. With SPECT we see brain activity averaged over a few minutes so it is better at showing the brain doing everyday activities such as concentrating, meditating, reading, and so on. Positron emission tomography, another nuclear imaging technique, is very similar to SPECT but is much more costly.
Ensuring High-Quality SPECT Images
Although a SPECT scan is simple from the patient’s perspective, it takes considerable skill and experience to dependably generate accurate brain SPECT images suitable for psychiatric applications. Equally important is the need for total consistency in imaging techniques among patients so that results are quantifiable, repeatable, and consistent. The following factors 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 physician needs 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 with 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 documented high interrater and intrarater reliability.
IMAGE DISPLAY
Scans must be clear, understandable, easily illustrative of brain function, and available to the patient on a timely basis. We believe our three-dimensional 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 for, such as 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 scans have the same resolution as PET scans with considerably lower cost, better insurance coverage, greater availability, and fewer image artifacts.5 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 computerized axial tomography scan) and is a safe procedure, according to the guidelines established by the American Academy of Neurology.6 These other procedures are routinely ordered for many common medical conditions (e.g., 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 associated with a SPECT scan.
Concern: What is considered normal?
Response: In the SPECT literature over the past twenty years, there have been more than forty-three studies looking at “normal” issues in over 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 and colleagues reported that at birth, cortical regional cerebral blood flow (rCBF) was lower than those for adults.7 After birth, it increased by five or six years of age to values 50–85 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 make clinical determinations. But a SPECT scan is ordered when the physician is confused, the patient hasn’t responded to the doctor’s best treatment, or the patient’s situation is otherwise complicated.
Concern: Lack of reproducibility
Response: An article by Villanueva-Meyer and colleagues elegantly answers this question, showing that there is less than 3 percent variability in SPECT scans over time for the same activity.8 Our own clinical experience, scanning people sequentially, and sometimes twelve years apart, finds that SPECT patterns remain the same unless you do something to change the brain. A SPECT scan is a reproducible and reliable method for sequential evaluation.
Conclusion
At the Amen Clinics we feel that our experience with more than thirty-five thousand 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, requiring 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:
1. Evaluating memory problems, dementia, and distinguishing among different types of dementia and pseudodementia (depression that looks like dementia)
2. Evaluating seizure activity
3. Evaluating blood vessel diseases, such as stroke
4. Evaluating the effects of mild, moderate, and severe head trauma
5. Suspicion of underlying organic brain condition, such as seizure activity contributing to behavioral disturbance, prenatal trauma, or exposure to toxins
6. Evaluating atypical or unresponsive aggressive behavior
7. Determining extent of brain impairment caused by drug or alcohol abuse
8. Typing anxiety, depression, and ADDs when clinical presentation is not clear
9. Evaluating people who are atypical or resistant to treatment
10. General health screening
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 them until after the second scan, if one is ordered. It is generally not practical to stop taking medications such as Prozac because they last in the body for four to six weeks. Check with your doctor for specific 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 IV. After another short period of time, the patient lies 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 EEGs, PET studies, and MRIs. PET studies and fMRI are considerably more costly and they are performed mostly in research setting. 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? Reimbursement 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 it 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 over two thousand physicians and mental health professionals in the United States have referred patients to us for scans.
1. B. L. Holman and M. D. Devous, “Functional brain SPECT: The emergence of a powerful clinical method,” Journal of Nuclear Medicine 33 (1992): 1888–1904.
2. D. Amen, S. Bracha, J. C. Wu, “Functioning neuroimaging in clinical practice,” The Comprehensive Textbook of Psychiatry, ed. Kaplan and Sadock, 373–385 (Philadelphia: Lippincott Williams & Wilkins, 2000).
3. M. S. George, Neuroactivation and Neuroimaging with SPECT (New York: Springer-Verlag, 1991).
4. F. J. Bonte, M. F. Weiner, E. H. Bigio, et al., “Brain blood flow in the dementias: SPECT with histopathologic correlation in 54 patients,” Radiology 202 (1997): 793–797.
5. D. Amen, C. Blake, J. C. Wu, “The clinical use of brain SPECT imaging in neuropsychiatry,” Alasbimn Journal 5(19) (2003): http://www2.alasbimnjournal.cl/alasbimn/CDA/sec_b/0,1206,SCID%253D3212,00.htm.
6. Report of the Therapeutics and Technology Assessment Subcommittee of the American
7. Academy of Neurology: Assessment of brain SPECT 46 (1996): 278–285.
8. C. Chiron, C. Raynaud, B. Maziere, et al., “Changes in regional cerebral blood flow during brain maturation in children and adolescents,” Journal of Nuclear Medicine 3(5)(1992): 696–703.
9. J. Villanueva-Meyer, I. Mena, B. Miller, et al., “Cerebral blood flow during a mental activation task: Responses in normal subjects and in early Alzheimer disease patients,” Alasbimn Journal 1(3) (1999): http://www.alasbimnjournal.cl/revistas/3/villanuevaa.htm.