It's not just for babies anymore. We use our Ultrasound to find flaws and telltale signs of vascular disease in all parts of the body, Ultrasound is another great way to get the in-depth information needed for diagnosis and treatment.

FAQs

What is Venous Ultrasound Imaging?

All ultrasound exams use very high-frequency sound waves and echoes to obtain images of structures inside the body. Different signals are produced when the beam of sound waves is focused at a particular site and the waves bounce back from different types of tissue and body fluid. The resulting pattern of echoes forms an accurate picture of whatever is being examined, in this case the veins throughout the body that carry blood back to the heart. Ultrasound studies differ from x-rays in one very important respect: there is no exposure to ionizing radiation. Another term for an ultrasound exam is "sonography."

The principle of ultrasound imaging is very much like that of sonar—a method used by navy ships to detect submarines (or by fishing boats to locate large schools of fish). The echo pattern of the returning sound waves that bounce off the object make it stand out from the background pattern. Another example is the bat which, when flying about, replaces eyesight with a sonar-type system to avoid colliding with nearby objects and to find insects to eat. In medical use, the procedure is used to detect disease that changes the appearance of organs or tissues, or abnormal masses such as tumors. When a blood clot develops inside a vein, venous ultrasound can show the clot and also the slowing or complete block of blood flow that it causes.

What are some common uses of the procedure?
 
The most common reason for a venous ultrasound exam is to search for blood clots, especially in the veins of the leg. These clots may break off and pass into the lungs where they can cause a dangerous condition called pulmonary embolism. If found in time, there are treatments that can prevent this from happening.

Other reasons to do a venous ultrasound study are to:

• Find the cause of long-standing leg swelling. In people with varicose veins, a common condition, the valves that keep blood flowing in the right direction may not work well, and venous ultrasound can help the surgeon decide how best to deal with this condition. 

• Aid placement of a needle or catheter in a large interior vein. Sonography can help locate the exact site of the vein and avoid complications such as bleeding or air in the chest cavity. 

• Map out the veins in the leg or arm so that segments may be removed and used to bypass an area of disease. An example is using pieces of vein from the leg to surgically bypass narrowed coronary arteries. 

• Examine a blood vessel graft used for dialysis if it is not working as expected; an area of narrowing in the graft may be responsible. 

How should I prepare for the procedure?
 
You should dress comfortably, but will have to remove all clothing and jewelry in the area to be examined. Otherwise there are no special measures that need be taken. You may have heard that a period of fasting is necessary, but this is important only if you are to have an examination of veins in your abdomen. In this case you probably will be asked not to take any food or fluids except water for six to eight hours ahead of time.

What does the equipment look like?
 
You will be taken into an examining room with a scanning machine that may look like a computer with a TV screen. A small hand-held device called a transducer, which looks like a microphone, is placed over the area of interest. Transducers are available that conform to different parts of the body, such as the leg for doing a venous ultrasound study. They range in size from that of a fat pen to one resembling a deck of cards. Once the exam begins, the ultrasound image can be seen in black and white on the screen (or in color if a special type of exam called color flow or power Doppler ultrasound is done to monitor blood flow in the veins). 

How does the procedure work?
 
The ultrasound transducer generates sound waves that pass through the skin and also serves as a microphone to record the returning sounds—the echoes. When pressed against the skin, the transducer directs high-frequency sound waves toward the veins being studied, and records any changes in the pitch and direction of the returning echoes. The bounce-back echoes, called the signature, are automatically measured by the computer and converted electronically to a picture that shows what is happening at that instant—creating a so-called "real time" image on the monitor screen. These images can be videotaped, or they may be frozen in time to obtain still pictures. If a Doppler study is done, changes in blood flow can be displayed in color on the screen and actually heard as a change in pitch.

How is the procedure performed?
 
After positioning the patient on the adjustable examination table, the technologist will apply a liquid jelly to the skin to make close contact between the skin and transducer, eliminating air pockets. This will ensure that the sound waves are freely conducted into and out of the body. The radiologist or technologist presses the transducer firmly to the skin and moves it back and forth to obtain complete images of areas of interest. The entire area of interest will be scanned, obtaining images from different perspectives. Sometimes the examiner may want to obtain images while you are standing upright. You will be asked to relax and remain calm during the examination. The radiologist also may ask you health-related questions during the exam and may repeat some images to clarify the findings.

What will I experience during the procedure?
 
You will not hear any of the ultrasound emission or the echoes sent back to the screen, although you may hear pulse-like sounds if a Doppler examination is ordered. You probably will lie on your back, and the table may be tilted or moved to provide better access to a particular area. Often you will have a chance to watch the screen along with the examiner, though it will not be easy to make sense out of what you see. You should feel free to ask the radiologist or technologist what the exam is showing at any time. Most ultrasound studies take no longer than a half hour. Venous ultrasound is a completely painless examination. 

Who interprets the results and how do I get them?
  
When the exam is over the technologist will ask you to get dressed and wait until the radiologist can review the images. If no additional images are needed you will be free to leave. A technologist usually performs the procedure itself, but a radiologist who is experienced at interpreting ultrasound images will make the official reading and inform your physician. After receiving a summary of the findings, your physician will discuss with you what they mean and what should be done next. Some centers now pass on diagnostic reports and the images themselves over the Internet, speeding up the process considerably. 

What are the benefits vs. risks?

Benefits

• Ultrasound scanning is widely available and less expensive than other imaging methods. It is rapidly completed, and no radiation exposure is involved. Furthermore, this procedure is noninvasive, requiring no penetration of the skin or any body cavity. 

• Ultrasound scanning gives a clear picture of soft tissues that do not show up well on x-ray images. 

• Venous ultrasound helps to detect blood clots in the veins of the legs before they become dislodged and pass to the lungs. It also can show the movement of blood within blood vessels.

• Compared to venography, which requires injecting contrast material into a vein, venous ultrasound is nearly as accurate for detecting blood clots in the calf and almost fully as accurate in finding clots in veins of the thigh. 

• Sonography is easily carried out, painless, and causes no health problems. It may be repeated as often as is necessary. 

Risks

• For standard diagnostic ultrasound there are no known harmful effects to humans. 

What are the limitations of Venous Ultrasound Imaging?
 
Veins lying deep beneath the skin, especially small veins in the calf, may be hard to see clearly. It can be difficult to tell whether a blood clot has totally closed off a vein or whether a small amount of blood is still getting through.

Arterial Blood Flow Studies Of The Leg

What Does This Test Measure?

The blood flow study for the legs, sometimes called a segmented Doppler study, measures the blood pressures and pulses in your legs and ankles. The pressure in your legs will be compared with the pressure in your arms. Normally the blood pressure in the arm is the same as in the leg. If they are not the same, you may have a blockage with the blood flow (circulation) in your legs.

How Is The Test Done?

Your blood pressure will be taken in both arms. Blood pressures will be taken at several different places along your legs and ankles. A tracing of the strength of the pulses in your legs and feet will be made with each blood pressure.

The test takes 20-30 minutes and is usually done in the vascular laboratory. You do not need to do anything to prepare for it. You will be awake and lying down during this test.

Will this Test Be Painful?

You will feel some tightness as the blood pressure cuff is inflated. You may have discomfort during the test if you already have pain in your legs.

Your doctor may want to know what the blood pressures are in your legs during light exercise. A blood flow problem may get worse when you exercise because an exercising muscle needs increased blood flow . If exercise is done as part of the test, you will be asked to walk on a treadmill or in a hallway for no longer than 5 minutes. After you walk, your leg blood pressure will be measured again.