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Chapter One

For Those Who Have Eyes,

Let Them See:

Images Into the Mind

* * *

What is SPECT? An acronym for s ingle p hoton e mission c omputerized t omography, it is a sophisticated nuclear medicine study that "looks" directly at cerebral blood flow and indirectly at brain activity (or metabolism). In this study, a radioactive isotope (which, as we will see, is akin to myriad beacons of energy or light) is bound to a substance that is readily taken up by the cells in the brain.

    A small amount of this compound is injected into the patient's vein, where it runs through the bloodstream and is taken up by certain receptor sites in the brain. The radiation exposure is similar to that of a head CT or an abdominal X ray. The patient then lies on a table for about fifteen minutes while a SPECT "gamma" camera rotates slowly around his head. The camera has special crystals that detect where the compound (signaled by the radioisotope acting like a beacon of light) has gone. A supercomputer then reconstructs offline images of brain activity levels. The elegant brain snapshots that result offer us a sophisticated blood flow/metabolism brain map. With these maps, physicians have been able to identify certain patterns of brain activity that correlate with psychiatric and neurological illnesses.

    SPECT studies belong to a branch of medicine called nuclear medicine. Nuclear (refers to the nucleus of an unstable or radioactive atom) medicine uses radioactively tagged compounds (radiopharmaceuticals). The unstable atoms emit gamma rays as they decay, with each gamma ray acting like a beacon of light. Scientists can detect those gamma rays with film or special crystals and can record an accumulation of the number of beacons that have decayed in each area of the brain. These unstable atoms are essentially tracking devices--they track which cells are most active and have the most blood flow and those that are least active and have the least blood flow. SPECT studies actually show which parts of the brain are activated when we concentrate, laugh, sing, cry, visualize, or perform other functions.

    Nuclear medicine studies measure the physiological functioning of the body, and they can be used to diagnose a multitude of medical conditions: heart disease, certain forms of infection, the spread of cancer, and bone and thyroid disease. My own area of expertise in nuclear medicine, the brain, uses SPECT studies to help in the diagnosis of head trauma, dementia, atypical or unresponsive mood disorders, strokes, seizures, the impact of drug abuse on brain function, and atypical or unresponsive aggressive behavior.

    During the late '70s and '80s SPECT studies were replaced in many cases by the sophisticated anatomical CAT and later MRI studies. The resolution of those studies was far superior to SPECT's in delineating tumors, cysts, and blood clots. In fact, they nearly eliminated the use of SPECT studies altogether. Yet despite their clarity, CAT scans and MRIs could offer only images of a static brain and its anatomy; they gave little or no information on the activity in a working brain. It was analogous to looking at the parts of a car's engine without being able to turn it on. In the last decade, it has become increasingly recognized that many neurological and psychiatric disorders are not disorders of the brain's anatomy, but problems in how it functions.

    Two technological advancements have encouraged the use, once again, of SPECT studies. Initially, the SPECT cameras were singleheaded, and they took a long time--up to an hour--to scan a person's brain. People had trouble holding still that long, and the images were fuzzy, hard to read (earning nuclear medicine the nickname "unclear medicine"), and did not give much information about the functioning deep within the brain. Then multiheaded cameras were developed that could image the brain much faster and with enhanced resolution. The advancement of computer technology also allowed for improved data acquisition from the multiheaded systems. The higher-resolution SPECT studies of today can see into the deeper areas of the brain with far greater clarity and show what CAT scans and MRIs cannot--how the brain actually functions.

    SPECT studies can be displayed in a variety of different ways. Traditionally the brain is examined in three different planes: horizontally (cut from top to bottom), coronally (cut from front to back), and sagittally (cut from side to side). What do physicians see when they look at a SPECT study? We examine it for symmetry and activity levels, indicated by shades of color (in different color scales selected depending on the physician's preference, including gray scales), and compare it to what we know a normal brain looks like. The black-and-white images in this book are mostly two kinds of three-dimensional (3-D) images of the brain.

    One kind is a 3-D surface image, looking at the blood flow of the brain's cortical surface. These images are helpful for picking up areas of good activity as well as underactive areas. They are helpful when investigating, for instance, strokes, brain trauma, and the effects of drug abuse. A normal 3-D surface scan shows good, full, symmetrical activity across the brain's cortical surface.

    The 3-D active brain image compares average brain activity to the hottest 15 percent of activity. These images are helpful for picking up areas of overactivity, as seen, for instance, in active seizures, obsessive-compulsive disorder, anxiety problems, and certain forms of depression. A normal 3-D active scan shows increased activity (seen by the light color) in the back of the brain (the cerebellum and visual or occipital cortex) and average activity everywhere else (shown by the background grid).

    Physicians are usually alerted that something is wrong in one of three ways: they see too much activity in a certain area; they see too little activity in a certain area; or they see asymmetrical areas of activity that ought to be symmetrical.

    In the rest of the book, I will go into greater detail about how this remarkable technology has touched people's lives. For now, however, I will simply offer a sample of five common ways in which SPECT studies are utilized in medicine.

    1. To make early intervention possible. Ellen, sixty-three, was suddenly paralyzed on the right side of her body. Unable even to speak, she was in a panic and her family was extremely concerned. As drastic as these symptoms were, two hours after the event, her CAT scan was still normal. Suspecting a stroke, the emergency room physician ordered a brain SPECT study that showed a hole of activity in her left frontal lobe caused by a clot that had choked off the blood supply to this part of the brain. From this information, it was clear that Ellen had had a stroke, and her doctors were able to take measures to limit the extent of the damage. CAT scans are generally not abnormal until twenty-four hours after a stroke.

    2. To evaluate the patient accurately so that future illness can be prevented. Nancy was a fifty-nine-year-old woman suffering from severe depression that had been nonresponsive to treatment. She was admitted to a psychiatric hospital, where a SPECT study was done to evaluate her condition. Since she had not experienced any symptoms that would point to this, I was surprised to see that she had had two large strokes. Nearly immediately her nonresponsive depression made more sense to me. Sixty percent of the people who have frontal lobe strokes experience severe depression within a year. As a result of the SPECT study, I sought immediate consultation with a neurologist, who evaluated her for the possible causes of the stroke, such as plaques in the arteries of the neck or abnormal heart rhythms. He felt the stroke had come from a blood clot and placed her on blood-thinning medication to prevent further strokes.

    3. To help the physician elicit understanding and compassion from the patient's family. When Frank, a wealthy, well-educated man, entered his seventies, he began to grow forgetful. At first it was over small things, but as time went on, the lapses of memory progressed to the point where he often forgot essential facts of his life: where he lived, his wife's name, and even his own name. His wife and children, not understanding his change in behavior, were annoyed with his absentmindedness and often angry at him for it. Frank's SPECT study showed a marked suppression across the entire brain, but especially in the frontal lobes, parietal lobes, and temporal lobes. This was a classic Alzheimer's disease pattern. By showing the family these images and pointing out the physiological cause of Frank's forgetfulness in living images, I helped them understand that he was not trying to be annoying, but had a serious medical problem.

    Consequently, instead of blaming him for his memory lapses, Frank's family began to show compassion toward him, and they developed strategies to deal more effectively with the problems of living with a person who has Alzheimer's disease. In addition, I placed Frank on new treatments for Alzheimer's disease that seemed to slow the progression of the illness.

    4. To differentiate between two problems with similar symptoms. I first met Margaret when she was sixty-eight years old. Her appearance was ragged and unkempt. She lived alone, and her family was worried because she appeared to have symptoms of serious dementia. They finally admitted her to the psychiatric hospital where I worked after she nearly burned the house down by leaving a stove burner on. When I consulted with the family, I also found out that Margaret often forgot the names of her own children and frequently got lost when driving her car. Her driving habits deteriorated to the point where the Department of Motor Vehicles (DMV) had to take away her license after four minor accidents in a six-month period. At the time when Margaret's family saw me, some members had had enough and were ready to put her into a supervised living situation. Other family members, however, were against the idea and wanted her hospitalized for further evaluation.

    While at first glance it may have appeared that Margaret was suffering from Alzheimer's disease, the results of her SPECT study showed full activity in her parietal and temporal lobes. If she had Alzheimer's, there should have been evidence of decreased blood flow in those areas. Instead, the only abnormal activity shown on Margaret's SPECT was in the deep limbic system at the center of the brain, where the activity was increased. Often, this is a finding in people suffering from depression. Sometimes in the elderly it can be difficult to distinguish between Alzheimer's disease and depression because the symptoms can be similar. Yet with pseudodementia (depression masquerading as dementia), a person may appear demented, yet not be at all. This is an important distinction, because a diagnosis of Alzheimer's disease would lead to prescribing a set of coping strategies to the family and possibly new medications, whereas a diagnosis of some form of depression would lead to prescribing an aggressive treatment of antidepressant medication for the patient along with psychotherapy.

    The results of Margaret's SPECT study convinced me that she should try the antidepressant Wellbutrin (bupropion). After three weeks, she was talkative, well groomed, and eager to socialize with the other patients. After a month in the hospital she was released to go home. Before discharge she asked if I would write a letter to the DMV to help her get her driver's license back. Since I drive on the same highways she does, I was a bit hesitant. I told her that if in six months she remained improved and she was compliant with treatment, I would write to the DMV for her. Six months later she remained markedly improved. I repeated her SPECT study. It was completely normal. I wrote the letter to the DMV, and it gave her back her license!

    5. To discern when a problem is the result of abuse and remove the patient from a dangerous environment. Betty was the most beautiful eighty-eight-year-old woman I had ever met. She was very proper and very proud. When she was young she had emigrated from England after marrying an American soldier. It was not her nine-year-old husband who brought her to the hospital to see me, however, it was her sister. Her husband, far from being supportive, angrily denied that his wife was suffering from serious cognitive problems. Yet during the evaluation process it was clear that Betty had severe memory problems; she did not know where she lived, her phone number, or her husband's name. I ordered a SPECT study that showed a dent in the right side of Betty's frontal lobe. It was obvious to me that she had at some point suffered a significant head injury. When I asked her about it, all she could do was look down and cry; she could not give me details of the event. When I asked her sister, she reported that Betty and her husband had a stormy relationship and that he was abusive toward her. Sometimes he would grab her by the hair and slam her head into the wall. The sister wanted Betty to go to the police, but Betty had said it would only make things worse.

    Shortly after Betty was hospitalized, her husband began pressuring me to send her home. He kept protesting that there was nothing wrong with her, yet I knew that Betty needed to be removed from her home environment, so I contacted Adult Protective Services. At Betty's hearing, I used her SPECT studies to convince the judge that her home held potential danger. He then ordered her to have a conservator, and she went to live with her sister.

    It will be clear from these and many other stories in this book that a doctor who can give an accurate diagnosis can be the greatest friend a patient can have. By now, you may be starting to understand why this technology has so forcefully grabbed my attention.

Copyright © 1998 Daniel G. Amen. All rights reserved.