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