What Student Need to Know about Venography – Blood Flow Examination of Veins In Radio Diagnosis. скачать в хорошем качестве

What Student Need to Know about Venography – Blood Flow Examination of Veins In Radio Diagnosis.

Venography is an invasive X-Ray imaging test that takes pictures of a contrast dye flowing through the veins of any part of the body (frequently the legs), allowing the radiologist to determine the location and type of any vein abnormality, (like an abnormal anatomy, blockages/clots, enlargements, malformations) or to ensure that catheters are placed correctly for treatments such as an infusion of a drug to dissolve a blood clot. Although venography has been the “gold standard” for diagnosis of DVT, other diagnostic studies are accurate when performed by a skilled technologist and, in most patients, may replace the need for routine contrast venography. Venography is moderately uncomfortable, requires the injection of a contrast material that may cause allergic reaction or renal injury, and may result in phlebitis in approximately 5% of patients. How does the procedure work? X-rays are a form of radiation like light or radio waves. X-rays pass through most objects, including the body. Once it is carefully aimed at the part of the body being examined, an x-ray machine produces a small burst of radiation that passes through the body, recording an image on photographic film or a special detector. Different parts of the body absorb the x-rays in varying degrees. Dense bone absorbs much of the radiation while soft tissue, such as muscle, fat and organs, allow more of the x-rays to pass through them. As a result, bones appear white on the x-ray, soft tissue shows up in shades of gray and air appears black. Veins cannot be seen on an x-ray; therefore, an iodine-based contrast material is injected through an IV line into veins to make them visible on the x-ray. How is the procedure performed? This examination is usually done on an outpatient basis. A venogram is done in a hospital x-ray department. A venogram is performed in the x-ray department or in an interventional radiology suite, sometimes called special procedures suite. You will lie on an x-ray table. Depending on the body part being examined (e.g., the legs), the table may be situated to a standing position. If the table is repositioned during the procedure, you will be secured with safety straps. The physician will insert a needle or catheter into a vein to inject the contrast agent. Where that needle is placed depends upon the area of your body where the veins are being evaluated. As the contrast material flows through the veins being examined, several x-rays are taken. You may be moved into different positions so that the x-rays can take pictures of your veins at different angles. What will I experience during and after the procedure? You will be asked to remove some of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, removable dental appliances, eye-glasses and any metal objects or clothing that might interfere with the x-ray images. You will feel a slight pinch when the needle is inserted into your vein for the IV line and when the local anesthetic is injected. Most of the sensation is at the skin incision site. This is numbed using local anesthetic. You may feel pressure when the catheter is inserted into the vein or artery. However, you will not feel serious discomfort. As the contrast material passes through your body, you may feel warm. This will quickly pass. You may have a metallic taste in your mouth. Your arm or leg may feel like it is getting numb or "falling asleep." After the test is complete, this feeling will go away. You must hold very still and may be asked to keep from breathing for a few seconds while the x-ray picture is taken to reduce the possibility of a blurred image. The technologist will walk behind a wall or into the next room to activate the x-ray machine. When the examination is complete, you may be asked to wait until the radiologist determines that all the necessary images have been obtained. A venogram takes between 30 and 90 minutes to perform. Fluids will be run through your IV to remove the contrast material from your veins. You will also be instructed to drink a lot of fluids for the next day. After the catheter is removed, a bandage will be placed on the IV site. Then you will be observed for any signs of complications, such as bleeding from the injection site, infection or an allergic reaction. Who interprets the results and how do I get them? A radiologist, a physician specifically trained to supervise and interpret radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will discuss the results with you. Sometimes a follow-up exam is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. A follow-up exam may also be done to see if there has been any change in an abnormality over time. Follow-up exams are sometimes the best way to see if treatment is working or if an abnormality is stable or has changed.