Chapter One
For Those Who Have Eyes,
Let Them See:
Images Into the Mind
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What is SPECT? An acronym for single photon emissioncomputerized tomography, it is a sophisticated nuclearmedicine study that "looks" directly at cerebral blood flow and indirectly atbrain activity (or metabolism). In this study, a radioactive isotope (which, aswe will see, is akin to myriad beacons of energy or light) is bound to asubstance that is readily taken up by the cells in the brain.
A small amount of this compound is injected into the patient'svein, where it runs through the bloodstream and is taken up by certainreceptor sites in the brain. The radiation exposure is similar tothat of a head CT or an abdominal X ray. The patient then lies on atable for about fifteen minutes while a SPECT "gamma" camera rotatesslowly around his head. The camera has special crystals that detectwhere the compound (signaled by the radioisotope acting like abeacon of light) has gone. A supercomputer then reconstructs offlineimages of brain activity levels. The elegant brain snapshots that resultoffer us a sophisticated blood flow/metabolism brain map. Withthese maps, physicians have been able to identify certain patterns ofbrain activity that correlate with psychiatric and neurological illnesses.
SPECT studies belong to a branch of medicine called nuclearmedicine. Nuclear (refers to the nucleus of an unstable or radioactiveatom) medicine uses radioactively tagged compounds (radiopharmaceuticals).The unstable atoms emit gamma rays as they decay, witheach gamma ray acting like a beacon of light. Scientists can detectthose gamma rays with film or special crystals and can record an accumulationof the number of beacons that have decayed in each areaof the brain. These unstable atoms are essentially tracking devices—theytrack which cells are most active and have the most blood flowand those that are least active and have the least blood flow. SPECTstudies actually show which parts of the brain are activated when weconcentrate, laugh, sing, cry, visualize, or perform other functions.
Nuclear medicine studies measure the physiological functioningof the body, and they can be used to diagnose a multitude of medicalconditions: heart disease, certain forms of infection, the spread ofcancer, and bone and thyroid disease. My own area of expertise innuclear medicine, the brain, uses SPECT studies to help in the diagnosisof 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 inmany cases by the sophisticated anatomical CAT and later MRI studies.The resolution of those studies was far superior to SPECT's indelineating tumors, cysts, and blood clots. In fact, they nearly eliminatedthe use of SPECT studies altogether. Yet despite their clarity,CAT scans and MRIs could offer only images of a static brain and itsanatomy; they gave little or no information on the activity in a workingbrain. It was analogous to looking at the parts of a car's enginewithout being able to turn it on. In the last decade, it has become increasinglyrecognized that many neurological and psychiatric disordersare not disorders of the brain's anatomy, but problems in how itfunctions.
Two technological advancements have encouraged the use, onceagain, of SPECT studies. Initially, the SPECT cameras were singleheaded,and they took a long time—up to an hour—to scan a person'sbrain. People had trouble holding still that long, and the imageswere fuzzy, hard to read (earning nuclear medicine the nickname"unclear medicine"), and did not give much information about thefunctioning deep within the brain. Then multiheaded cameras weredeveloped that could image the brain much faster and with enhancedresolution. The advancement of computer technology alsoallowed for improved data acquisition from the multiheaded systems.The higher-resolution SPECT studies of today can see into thedeeper areas of the brain with far greater clarity and show what CATscans 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 whenthey look at a SPECT study? We examine it for symmetry and activitylevels, indicated by shades of color (in different color scales selecteddepending on the physician's preference, including grayscales), and compare it to what we know a normal brain looks like.The black-and-white images in this book are mostly two kinds ofthree-dimensional (3-D) images of the brain.
One kind is a 3-D surface image, looking at the blood flow of thebrain's cortical surface. These images are helpful for picking up areasof good activity as well as underactive areas. They are helpful wheninvestigating, for instance, strokes, brain trauma, and the effects ofdrug abuse. A normal 3-D surface scan shows good, full, symmetricalactivity across the brain's cortical surface.
The 3-D active brain image compares average brain activity to thehottest 15 percent of activity. These images are helpful for picking upareas of overactivity, as seen, for instance, in active seizures,obsessive-compulsive disorder, anxiety problems, and certain forms ofdepression. A normal 3-D active scan shows increased activity (seen bythe light color) in the back of the brain (the cerebellum and visual oroccipital cortex) and average activity everywhere else (shown by thebackground grid).
Physicians are usually alerted that something is wrong in one ofthree ways: they see too much activity in a certain area; they see toolittle activity in a certain area; or they see asymmetrical areas of activitythat ought to be symmetrical.
In the rest of the book, I will go into greater detail about how thisremarkable technology has touched people's lives. For now, however,I will simply offer a sample of five common ways in which SPECTstudies are utilized in medicine.
1. To make early intervention possible. Ellen, sixty-three, wassuddenly paralyzed on the right side of her body. Unable even to speak,she was in a panic and her family was extremely concerned. As drasticas these symptoms were, two hours after the event, her CAT scanwas still normal. Suspecting a stroke, the emergency room physicianordered a brain SPECT study that showed a hole of activity in herleft frontal lobe caused by a clot that had choked off the blood supplyto this part of the brain. From this information, it was clear thatEllen had had a stroke, and her doctors were able to take measures tolimit the extent of the damage. CAT scans are generally not abnormaluntil twenty-four hours after a stroke.
2. To evaluate the patient accurately so that future illness can beprevented. Nancy was a fifty-nine-year-old woman suffering from severedepression that had been nonresponsive to treatment. She wasadmitted to a psychiatric hospital, where a SPECT study was doneto evaluate her condition. Since she had not experienced any symptomsthat would point to this, I was surprised to see that she had hadtwo large strokes. Nearly immediately her nonresponsive depressionmade more sense to me. Sixty percent of the people who have frontallobe strokes experience severe depression within a year. As a result ofthe SPECT study, I sought immediate consultation with a neurologist,who evaluated her for the possible causes of the stroke, such asplaques in the arteries of the neck or abnormal heart rhythms. Hefelt the stroke had come from a blood clot and placed her on blood-thinningmedication to prevent further strokes.
3. To help the physician elicit understanding and compassion from thepatient's family. When Frank, a wealthy, well-educated man, enteredhis seventies, he began to grow forgetful. At first it was over smallthings, but as time went on, the lapses of memory progressed to thepoint 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, notunderstanding his change in behavior, were annoyed with his absentmindednessand often angry at him for it. Frank's SPECT studyshowed a marked suppression across the entire brain, but especiallyin the frontal lobes, parietal lobes, and temporal lobes. This was aclassic Alzheimer's disease pattern. By showing the family these imagesand pointing out the physiological cause of Frank's forgetfulnessin living images, I helped them understand that he was nottrying 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 developedstrategies to deal more effectively with the problems ofliving with a person who has Alzheimer's disease. In addition, I placedFrank on new treatments for Alzheimer's disease that seemed toslow the progression of the illness.
4. To differentiate between two problems with similar symptoms. Ifirst met Margaret when she was sixty-eight years old. Her appearancewas ragged and unkempt. She lived alone, and her family wasworried because she appeared to have symptoms of serious dementia.They finally admitted her to the psychiatric hospital where I workedafter she nearly burned the house down by leaving a stove burner on.When I consulted with the family, I also found out that Margaretoften forgot the names of her own children and frequently got lostwhen driving her car. Her driving habits deteriorated to the pointwhere the Department of Motor Vehicles (DMV) had to take awayher license after four minor accidents in a six-month period. At thetime when Margaret's family saw me, some members had hadenough and were ready to put her into a supervised living situation.Other family members, however, were against the idea and wantedher hospitalized for further evaluation.
While at first glance it may have appeared that Margaret was sufferingfrom Alzheimer's disease, the results of her SPECT studyshowed full activity in her parietal and temporal lobes. If she hadAlzheimer's, there should have been evidence of decreased bloodflow in those areas. Instead, the only abnormal activity shown onMargaret's SPECT was in the deep limbic system at the center of thebrain, where the activity was increased. Often, this is a finding inpeople suffering from depression. Sometimes in the elderly it can bedifficult to distinguish between Alzheimer's disease and depressionbecause the symptoms can be similar. Yet with pseudodementia (depressionmasquerading as dementia), a person may appear demented,yet not be at all. This is an important distinction, because adiagnosis of Alzheimer's disease would lead to prescribing a set ofcoping strategies to the family and possibly new medications,whereas a diagnosis of some form of depression would lead to prescribingan aggressive treatment of antidepressant medication for thepatient along with psychotherapy.
The results of Margaret's SPECT study convinced me that sheshould try the antidepressant Wellbutrin (bupropion). After threeweeks, she was talkative, well groomed, and eager to socialize withthe other patients. After a month in the hospital she was released togo home. Before discharge she asked if I would write a letter to theDMV to help her get her driver's license back. Since I drive on thesame highways she does, I was a bit hesitant. I told her that if in sixmonths she remained improved and she was compliant with treatment,I would write to the DMV for her. Six months later she remainedmarkedly improved. I repeated her SPECT study. It wascompletely normal. I wrote the letter to the DMV, and it gave herback her license!
5. To discern when a problem is the result of abuse and remove thepatient from a dangerous environment. Betty was the most beautifuleighty-eight-year-old woman I had ever met. She was very properand very proud. When she was young she had emigrated from Englandafter marrying an American soldier. It was not her nine-year-oldhusband 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 cognitiveproblems. Yet during the evaluation process it was clear that Bettyhad severe memory problems; she did not know where she lived, herphone number, or her husband's name. I ordered a SPECT studythat showed a dent in the right side of Betty's frontal lobe. It was obviousto 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 andcry; 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 hewas abusive toward her. Sometimes he would grabher by the hair and slam her head into the wall. The sister wantedBetty to go to the police, but Betty had said it would only makethings worse.
Shortly after Betty was hospitalized, her husband began pressuringme to send her home. He kept protesting that there was nothingwrong with her, yet I knew that Betty needed to be removed fromher home environment, so I contacted Adult Protective Services. AtBetty's hearing, I used her SPECT studies to convince the judge thather 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 thata doctor who can give an accurate diagnosis can be the greatest frienda patient can have. By now, you may be starting to understand whythis technology has so forcefully grabbed my attention.
Continues...
Excerpted from Change Your Brain, Change Your Lifeby Daniel G. Amen Copyright © 1999 by Daniel G. Amen. Excerpted by permission.
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