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What we do! QVI uses ultrasound and various other technologies to evaluate the arterial and venous systems. We can obtain high resolution images and/or obtain blood flow information from virtually every artery and vein outside the chest. (We don't evaluate heart arteries.) The good news - all our testing is non-invasive and hence involves no needles, injections, or dyes, and there is no radiation used as in an x-ray or CT scan. It produces no risk to the person and there is little or no discomfort for the patient. 1. Of special interest, all tests are begun with a thorough explanation of what we do and why. If you have any questions, please feel free to ask during the testing. QVI staff will take a history from you trying to determine the reason your physician sent you to us. While you come to us for a specific reason, unless we fully understand your symptoms, we are less likely to provide all the necessary information to your doctor to best manage your care. You will be asked to fill out a short questionnaire and Bring a list of you medications along as we include that information on the report. 2. The vascular technologist will then perform a physical exam. As vascular specialists, we are specially trained to check for physical findings that may indicate a vascular problem. This varies depending upon the reasons your physician sent you and may include feeling pulses, taking blood pressures, listening for sounds with a stethoscope, and observing the skin and digits for signs of diminished blood flow. 3. You will typically asked to lie on an examination table and the examination is performed. This may take anywhere between15" and 1 1/2 hours depending upon the part of the body we are examining. (For example, it takes longer to evaluate both legs that it does to look at the carotid arteries.) The time may also depend upon the complexity of your particular anatomy and what we find - but don't assume that because it takes a while, there is something wrong!
Instruments we use. Duplex Ultrasound - is the primary testing instrument used in the evaluation of arteries and veins in a vascular laboratory. An ultrasound examination is a simple painless test and there is no special preparation unless we are evaluating abdominal vessels in which case you should fast after midnight. Ultrasound is a high frequency sound wave, similar to a sonar device. The sound waves bounce off the structures of interest, are reflected back, and are detected by the instrument. Two types of information are obtained, hence the term Duplex ultrasound - an image of the structures and information about blood flow. Different tissues reflect the ultrasound differently, so we can differentiate one from another. For example, the vessel wall appears different from the blood, the surrounding tissues, or plaque buildup inside the artery. At the same time, a special processing of the returning sound waves called Doppler allows us to get information about blood flow. Doppler is a physics principal that deals with the change in the frequency of sound waves because of motion. We know the frequency of the sound waves we send into the body. If they bounce off something that is moving, the frequency of the returning sound waves is changed. We compare the frequency of the sound waves we sent with the frequency of the returning sound waves and if different, we know they bounced off something moving, usually blood cells. If the blood flow is moving away from the transducer, the frequency is lower - if towards, the returning frequency is higher. In practice, we obtain an image of the blood vessel, surrounding tissues and any plaque or other abnormality inside along with simultaneous information about the blood flow. So if there is any plaque inside the artery, we can measure how much and importantly determine what effect it has on blood flow. In practice, a small plastic transducer will be moved along the area of interest. A gel is used to create good contact with the skin. Sometimes, the technologist may have to push slightly, you will not feel anything from the ultrasound, and you should experience no real discomfort. After you are gone, we perform a large number of additional measurements and calculations on the information we obtain and organize it into a report. The results will be reviewed by a physician and the report sent to your doctor. While your doctor will tell you what the findings mean to you, the technologist can provide much information about the disease and the testing process. You should feel free to ask questions.
Our new duplex instrumentation from Philips Medical is one of only a few such instruments in the State of Florida. Utilizing a super-computer operating at 2 billion instructions per second, it compounds multiple scan planes into a single image, similar to an x-ray CT but in real time and without ionizing radiation. The result - images of astonishing clarity revealing minute details about vascular disease process. This instrument was chosen by NASA and is currently in space serving on the International Space Station!
Physiologic instrumentation - We also use what is commonly referred to as indirect or physiologic testing and is primarily used in arm and leg artery testing. This modality allows us to obtain blood pressure and blood volume information and proves to be very valuable in determining the overall clinical significance of artery blockages. Most "significant" blockages that limit blood flow enough to result in symptoms occur in the larger arteries and these can be readily visualized with the ultrasound. However, the body is often good at compensating for blockages by enlarging smaller vessels - in essence creating many small bypasses. These are usually too small to be seen directly so the physiologic testing allows us to determine the "bottom line" - how much blood is getting to the leg! This testing involves using a series of blood pressure cuffs on the limb to measure blood pressure and blood volume at various levels. A blood pressure is also obtained at each arm for a comparison. In a normal artery, the pressure should be essentially the same throughout. For example, if your arm pressure is 120 mm/Hg, the pressure at your ankle should essentially be the same. If the pressure at the ankle is 60 mm/Hg, there is a problem. Additionally, we will sometimes find individuals with complete blockages that still have normal blood flow to the foot - the body has done a good job developing collateral channels to get blood flow around the blockage. (see section on exercise) Every time your heart contracts and pumps blood into the leg, the size of the leg actually gets slightly larger - proportional to the amount of blood going into the leg with every heart beat. We can measure this volume change at various levels throughout the limb and calculate how much blood enters the limb with every heartbeat. Coupled with the pressure information, this physiologic testing allows us to determine the overall significance of the blockages.
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bschroedter@qualityvascular.com with
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