| Your doc has asked that you go for a medical scan to | | | | information that the CAT scan doesn't, while CAT |
| take a closer look at what's ailing you-likely one of | | | | scans provide more structural information-about the |
| these tests: a CAT scan, a SPECT scan, a PET scan, | | | | heart, for instance. Together, they can provide the |
| an ultrasound, an MRI-or some combination of these. | | | | most detailed picture of what may be going on inside |
| So how will it help you? Here's an overview of what | | | | of you. |
| each medical imaging device does and what | | | | Nonradioactive scans |
| information it captures: | | | | The two most common are ultrasound and MRI |
| CT scans (aka CAT scans) | | | | (magnetic resonance imaging). Ultrasound uses sound |
| A computed tomography scanner is an X-ray device. | | | | waves to take pictures inside the body. MRI can |
| As a large doughnutlike ring moves over and spins | | | | acquire images both in 2-D and in 3-D; it can look at |
| around the body, the beams are sent through the body | | | | the beating of the heart in real time, as ultrasound can; |
| from one side and the emerging radiation is detected | | | | and it is able to tell tissues apart in ways other |
| and forms images on the other. "When patients go | | | | technologies can't. |
| through a CAT scanner," says Scott Daniel Flamm, | | | | Mind-Reading: EEG Reports |
| M.D., head of cardiovascular imaging at the Cleveland | | | | An electroencephalogram (EEG) can detect problems |
| Clinic in Cleveland, "it takes a series of 3-D pictures or | | | | in the brain's electrical system that may indicate the |
| axial slices very quickly. It's much like getting a chest | | | | presence of a tumor, head injury or diseases, such as |
| X-ray-just a whole lot faster and more sophisticated." | | | | epilepsy and migraine. In the test, up to 25 electrodes |
| SPECT scans | | | | are placed on the patient's scalp; they record changing |
| In a single-photon emission computerized tomography | | | | patterns of electrical activity and convert the electrical |
| (SPECT) scan, a camera photographs the travels of a | | | | signals into a series of spiky lines drawn on a moving |
| radioactive tracer that is injected into the body. Dr. | | | | piece of graph paper. The doctor can then read the |
| Flamm explains: "How it moves in different areas of | | | | print-out to see if there are any abnormalities. |
| the body can highlight possible problems, such as | | | | During an EEG, patients often have to stay motionless, |
| inadequate blood supply." | | | | because any movement may alter the results. |
| PET scans | | | | Sometimes a patient is asked to breathe deeply and |
| Positron emission tomography (PET) scanners use a | | | | rapidly or to look at a bright flickering light. |
| different kind of radioactive tracer and are considered | | | | The procedure is very safe. If it happens to trigger a |
| a more powerful imaging tool. Both SPECT and PET | | | | seizure, the person performing the EEG is trained to |
| scans usually produce no side effects, but PET scans | | | | ensure the patient's safety. |
| are considered better because they are more | | | | It's useful to know how medical imaging tools work. |
| sensitive to some metabolic activities, such as the | | | | After viewing your scan results, a doctor obtains |
| amount of glucose or oxygen used in different parts | | | | precise information that could help make a diagnosis or |
| of the brain. A SPECT scan focuses more on blood | | | | guide treatment. And that's what really matters: getting |
| flow. | | | | the care you need. |
| Combo scans | | | | Writer: John McIntosh |
| SPECT and PET scanners can be combined with | | | | ©REMEDY, Summer 2007 |
| CAT scanners (at which point they're called | | | | Get a FREE 2-year subscription to REMEDY, one of |
| SPECT-CT scanners or PET-CT scanners). SPECT | | | | MediZine, LLC's award-winning health magazines. Sign |
| and PET scans give some physiological and functional | | | | up today! |