Reston Radiology Consultants

The Vascular and Interventional Radiology Division of RRC, consists of two board-certified and fellowship trained physicians who diagnose and treat many medical conditions using catheters or other small devices with the aid of imaging technology such as x-ray, ultrasound, Computed Tomography (CT), and Magnetic Resonance Imaging (MRI).

These medical procedures are often used in lieu of traditional surgery and performed through a small skin incision using local anesthesia and sedation. Benefits include less pain, a shorter recovery time, and less time in the hospital.

Patient consultation, diagnostic testing, procedures, and follow up visits are done at MRI of Reston, Reston Hospital Center, Department of Radiology, and the Medical Imaging Center of Reston on the hospital campus.

Some of the following information is provided by the Society of Interventional Radiology
www.SIRweb.org©2004

Interventional Radiology Treatments for Liver Cancer
Minimally Invasive Treatments Help Cancer Patients Extend Life and Improve Quality

Surgical removal of liver tumors offers the best chance for a cure. Unfortunately, liver tumors are often inoperable because the tumor may be too large, or has grown into major blood vessels or other vital structures. Sometimes, many small tumors are spread throughout the liver, making surgery too risky or impractical. Surgical removal is not possible for more than two-thirds of primary liver cancer patients and 90 percent of patients with secondary liver cancer.

Historically, chemotherapy drugs have been generally ineffective at curing liver cancer.

Chemoembolization is minimally invasive treatment for liver cancer than can be used when there is too much tumor to treat with radiofrequency ablation (RFA), when the tumor is in a location that cannot be treated with RFA, or in combination with RFA or other treatments.

Chemoembolization delivers a high dose of chemotherapy (a cancer killing drug) directly to the organ while depriving the tumor of its blood supply by blocking, or embolizing, the arteries providing the blood supply. Using imaging for guidance, the interventional radiologist threads a tiny catheter up the femoral artery in the groin into the blood vessels supplying the liver tumor. The embolic agents keep the chemotherapy drug in the tumor by blocking the flow to other areas of the body. This allows for a higher dose of chemotherapy drug to be used, because less of the drug is able to circulate to the healthy cells in the body. Chemoembolization usually involves a hospital stay of two to four days. Patients typically have lower than normal energy levels for about a month afterwards.

Chemoembolization is a palliative, not a curative, treatment. It can be extremely effective in treating primary liver cancers, especially when combined with other therapies. Chemoembolization has shown promising early results with some types of metastatic tumors. Although the individual materials used in this treatment are FDA approved, the treatment itself is not approved for intra-arterial therapy of liver tumors.

Peripheral Arterial Disease, Renovascular Hypertension and Interventional Radiology
Hardening of the Arteries Is a Red Flag for Vascular Disease, Including Heart Attack and Stroke

Peripheral arterial disease (PAD), also known as peripheral vascular disease (PVD), is a very common condition affecting 12-20 percent of Americans age 65 and older. PAD develops most commonly as a result of atherosclerosis, or “hardening of the arteries,” which occurs when cholesterol and scar tissue build up, forming a plaque inside the arteries that narrows and clogs them, leading to a very serious condition. The clogged arteries cause decreased blood flow to the legs, which can result in pain when walking, and eventually gangrene and amputation. In the renal arteries (the arteries that feed the kidneys), this can cause high blood pressure and renal insufficiency.

Balloon angioplasty and stenting has generally replaced invasive surgery as the first-line treatment of PAD. Early randomized trials have shown interventional therapy to be as effective as surgery for many arterial occlusions, and in the past five to seven years, a very large clinical experience in centers throughout the world has shown that stenting and angioplasty are preferred as a first-line treatment for more and more processes throughout the body.

The long-term clinical results of stent placement to treat PAD are comparable to those of aortofemoral artery bypass surgery, with a much lower risk of associated morbidity and mortality. Surgery should be reserved for the rare patient in whom stenting cannot be done or fails.

Uterine Fibroid Embolization, a Minimally Invasive Treatment for Uterine Fibroids
Highly Effective, Widely Available Interventional Radiology Treatment Is Underutilized

Uterine fibroids are very common non-cancerous (benign) growths that develop in the muscular wall of the uterus. They can range in size from very tiny (a quarter of an inch) to larger than a cantaloupe. Occasionally, they can cause the uterus to grow to the size of a five-month pregnancy. In most cases, there is more than one fibroid in the uterus.

Twenty to forty percent of women ages 35 and older have uterine fibroids of a significant size. African American women are at a higher risk for fibroids: as many as 50 percent have fibroids of a significant size. Uterine fibroids are the most frequent indication for hysterectomy in pre-menopausal women and, therefore, are a major public health issue. Of the 600,000 hysterectomies performed annually in the United States, one-third of these are due to fibroids.

Most fibroids do not cause symptoms—only 10 to 20 percent of women who have fibroids require treatment. Depending on size, location and number of fibroids, symptoms may include:

Uterine fibroid embolization (UFE), also known as uterine artery embolization, is performed by an interventional radiologist, a physician who is trained to perform this and other types of embolization and minimally invasive procedures. It is performed while the patient is conscious, but sedated and feeling no pain. It does not require general anesthesia.

The interventional radiologist makes a tiny nick in the skin, less than one-fourth of an inch, in the groin and inserts a catheter into the femoral artery. Using real-time imaging, the physician guides the catheter through the artery and then releases tiny particles, the size of grains of sand, into the uterine arteries that supply blood to the fibroid tumor. This blocks the blood flow to the fibroid tumor and causes it to shrink.

Fibroid embolization usually requires a hospital stay of one night. Pain-killing medications and drugs that control swelling are typically prescribed following the procedure to treat cramping and pain. Many women resume light activities within a few days and the majority of women are able to return to normal activities within seven to ten days.

There have been numerous reports of pregnancies following uterine fibroid embolization, however prospective studies are needed to determine the effects of UFE on the ability of a woman to have children. One study comparing the fertility of women who had UFE with those who had myomectomy showed similar numbers of successful pregnancies. However, this study has not yet been confirmed by other investigators.

Less than 2 percent of patients have entered menopause as a result of UFE. This is more likely to occur if the woman is in her mid-forties or older and is already nearing menopause.

UFE is a very safe method and, like other minimally invasive procedures, has significant advantages over conventional open surgery. However, there are some associated risks, as there are with any medical procedure. A small number of patients have experienced infection, which usually can be controlled by antibiotics. There is also a less than one percent chance of injury to the uterus, potentially leading to a hysterectomy. These complication rates are lower then those of hysterectomy and myomectomy.

Gynecologists perform hysterectomy and myomectomy surgery. Hysterectomy is the removal of the uterus and is considered major abdominal surgery. It requires three to four days of hospitalization and the average recovery period is six weeks.

Depending on the size and placement of the fibroids, myomectomy can be an outpatient surgery or require two to three days in the hospital. However, myomectomy is usually major surgery that involves cutting out the biggest fibroid or collection of fibroids and then stitching the uterus back together. Most women have multiple fibroids and it is not physically possible to remove all of them because it would remove too much of the uterus. While myomectomy is frequently successful in controlling symptoms, the more fibroids the patient has, generally, the less successful the surgery. In addition, fibroids may grow back several years later.

Myomectomy, like UFE, leaves the uterus in place and may, therefore, preserve the woman’s ability to have children.

After your gynecologist has determined that fibroids are the cause of your symptoms, a consultation with an interventional radiologist is necessary. This is a separate appointment on a day prior to your procedure where the procedure will be explained in detail and any questions you may have can be answered. After your consultation, the procedure can then be scheduled. UFE is best done in the two weeks following a period, but can be performed at any time.

UFE is generally performed in the morning. You will be asked not to eat breakfast and to arrive at Reston Hospital Center at a certain time. Prior to the procedure an IV will be started in the radiology recovery room, as this is necessary to administer fluids and sedation. You will also have an opportunity to speak with your physician again.

UFE will be performed in a nearby interventional radiology suite. Intravenous sedation is utilized so the procedure should be painless. The skin over the artery in the groin is cleansed with a sterile betadine solution. Using local anesthesia, the interventional radiologist will introduce a small catheter into the artery using x-ray guidance. The catheter will then be advanced through the arteries of the uterus and the embolization procedure performed. Most patients do not feel discomfort during the procedure. The catheter will then be removed and pressure is held over the artery for a short time to ensure proper healing.

You will then return to the interventional radiology recovery room for observation. A hospital bed will be arranged and you will stay overnight for recovery and control of any post-procedure cramping or pain. The following morning you will be seen by your interventional radiologist and should be discharged from the hospital.

You will need to come back for two checkups: one that is two days after the exam and another one week after UFE. We would also like to see you in follow up one month after UFE. You should also see your gynecologist two or three months later. We will arrange an MRI six months after UFE. It often takes two or three months for your periods to become normal after UFE.

Your procedure will be performed by one of the interventional radiologists at Reston Hospital Center. All three are sub-specialty trained in interventional radiology. This team has performed thousands of interventional procedures and hundreds of embolizations. Our clinical service also includes three technologists and four nurses. The interventional radiologists at Reston Hospital Center are part of Reston Radiology Consultants, P.C. (RRA).

All procedures are performed at Reston Hospital Center. In addition to the medical staff, experienced and highly qualified technologists and nurses are involved in your care during your procedure and afterwards.

Most insurance companies in this area will cover the cost of UFE, as it is not an experimental procedure. Over four thousand have been performed in the United States. We can assist you in determining whether your insurance company will cover the cost of this procedure.

Varicocele Embolization - Male Infertility Caused by Varicocele
Highly Effective, Nonsurgical Treatment is Underutilized

A varicocele is a varicose vein of the testicle and scrotum that may cause pain, testicular atrophy (shrinkage) or fertility problems. Veins contain one-way valves that work to cause all blood to flow from the testicles and scrotum back to the heart. When these valves fail, they cause blood pools and enlarge the veins around the testicle in the scrotum to cause a varicocele. Open surgical ligation, performed by a urologist, is the most common treatment for symptomatic varicoceles. Varicocele embolization, a nonsurgical treatment performed by an interventional radiologist, is a highly effective, widely available technique to treat symptomatic varicoceles that is greatly underutilized in this country.

Embolization is an equally effective technique to treat male infertility and costs about the same as surgical ligation. Pregnancy rates and recurrence rates are comparable to those following surgical varicocelectomy. In one study, sixty percent conceived who were treated for infertility.

In another study, sperm concentration improved in 83 percent of patients undergoing embolization compared to 63 percent of those surgically ligated. Patients who underwent both procedures expressed a strong preference for embolization.

Currently there are two treatment options for men with varicoceles: catheter-directed embolization or surgical ligation.

Catheter-directed embolization – This is a nonsurgical, outpatient treatment performed by an interventional radiologist using imaging to guide catheters or other instruments inside the body. Through mild IV sedation and local anesthesia, patients are relaxed and pain-free during the procedure, which lasts approximately two hours.

For the procedure, an interventional radiologist makes a tiny nick in the skin at the groin using local anesthesia, through which a thin catheter (much like a piece of spaghetti) is passed into the femoral vein, directly to the testicular vein. The physician then injects contrast dye to provide direct visualization of the veins so he or she can map out exactly where the problem is and where to embolize, or block, the vein. By using coils, balloons or particles, the interventional radiologist blocks the blood flow in the vein, which reduces pressure on the varicocele. By embolizing the vein, blood flow is redirected to other healthy pathways. Essentially, the incompetent vein is “shut off”” internally by preventing flow, accomplishing what the urologist does, but without surgery.

Surgical treatment of varicocele – After the patient receives anesthesia, an incision is made in the skin above the scrotum, cutting down to the testicular veins, and tying them off with sutures. Although patients leave the hospital the same day, there is a two-to-three-week recovery period.

Our division offers the full range of vascular access. This includes the insertion, removal and maintenance of central venous catheters for such therapies as chemotherapy, hemodialysis, antibiotics, total parenteral nutrition (TPN), and long-term IV access. The types of catheters used include Mediports, Peripherally Inserted Central Catheters (PICC’s) and tunneled and non-tunneled central venous catheters.

Also, we perform arteriovenous fistulography and graft studies with thrombolysis and angioplasty as needed.

Venous Disease - Varicose Veins and Venous Insufficiency
Nonsurgical Outpatient Procedure Treats Varicose Veins

Venous insufficiency is an abnormal circulatory condition, with decreased return of blood from the leg veins up to the heart and pooling of blood in the veins. Normally, stop valves in the vein close to keep blood from flowing downward with gravity. When the valves in the vein become weak and do not close properly, they allow blood to flow backward, or reflux. Varicose veins are prominent veins that have lost their valve effectiveness and, as a result of dilation under pressure, become elongated, rope-like, bulged and thickened. A common cause of varicose veins is reflux within the greater saphenous vein in the thigh, which leads to pooling in the visible varicose veins below.

Symptoms caused by venous insufficiency and varicose veins include aching leg pain, easy leg fatigue, and leg heaviness, all of which worsen as the day progresses. Many people find they need to sit down in the afternoon and elevate their legs to relieve these symptoms. In more severe cases, venous insufficiency and reflux can cause skin discoloration and ulceration that may be very difficult to treat. One percent of adults over age 60 have chronic ulceration.

People without visible varicose veins can still have symptoms. The symptoms can arise from spider veins as well as from varicose veins because, in both cases, the symptoms are caused by pressure on nerves by dilated veins.

An interventional radiologist, a doctor specially trained in performing minimally invasive treatments using imaging for guidance, will use duplex ultrasound to assess the venous anatomy, vein valve function, and venous blood flow changes, which can assist in diagnosing venous insufficiency. The doctor will map the greater saphenous vein and examine the deep and superficial venous systems to determine whether the veins are open to pinpoint any reflux. This will help determine if the patient is a candidate for a minimally invasive treatment, known as vein ablation.

This minimally invasive treatment is an outpatient procedure performed using imaging for guidance. After applying local anesthetic to the vein, the interventional radiologist inserts a thin catheter, about the size of a strand of spaghetti, into the vein and guides it up the greater saphenous vein in the thigh. Then laser or radiofrequency energy is applied to the inside of the vein. This heats the vein and seals it closed.

Reflux within the greater saphenous vein leads to pooling in the visible varicose veins below it. When the greater saphenous vein is closed, the twisted and varicosed branch veins, which are close to the skin, shrink and improve in appearance. Once the diseased vein is closed, other healthy veins take over to carry blood from the leg, re-establishing normal flow.

Many insurance carriers cover the vein ablation treatment, based on medical necessity for symptom relief.

Traditionally, surgical ligation or vein stripping was the treatment for varicose veins, but these procedures can be quite painful and often have a long recovery time. In addition, there are high rates of recurrence with the surgical procedures. One study found a 29 percent recurrence rate after ligation and stripping of the great saphenous vein, and a rate of 71 percent of high ligation. These recurrence rates are similar to those reported in other studies.

Ambulatory phlebectomy and injection sclerotherapy are also use. Ambulatory phlebectomy is a minimally invasive surgical technique used to treat varicose veins that are not caused by saphenous vein reflux. The abnormal vein is removed through a tiny incision or incisions using a special set of tools. The procedure is done under local anesthesia, and typically takes under an hour. Recovery is rapid, and most patients do not need to interrupt regular activity after ambulatory phlebectomy.

Injection sclerotherapy can be used to treat some varicose and nearly all spider veins. An extremely fine needle is used to inject the vein with a solution that shrinks the vein.

Venous Disease - Deep Vein Thrombosis
Interventional Radiology Clot-busting Treatment Prevents Permanent Leg Damage

The formation of a blood clot, know as a thrombus, in a deep leg vein can be a very serious condition that can cause permanent damage to the leg, known as post-thrombotic syndrome, irreversible damage in the affected leg veins and their valves. Early treatment with blood thinners is important to prevent a life-threatening pulmonary embolism, but does not treat the existing clot.

Long-term studies show that 73-82 percent of people treated with blood thinners alone developed post-thrombotic syndrome. In many cases, people with continuing leg pain after seven days should seek a second opinion from an interventional radiologist because the clot may need to be removed to avoid permanent leg damage. Contrary to popular belief, anticoagulants do not actively dissolve the clot, they just prevent new clots from forming. The body normally dissolves a clot over time, but often the vein becomes damaged in the meantime.

Treatments

Catheter-directed Thrombolysis:

Catheter-directed thrombolysis is performed under imaging guidance by interventional radiologists. This procedure, performed in a hospital’s interventional radiology suite, is designed to rapidly break up the clot, restore blood flow within the vein, and potentially preserve valve function to minimize the risk of post-thrombotic syndrome. The interventional radiologist inserts a catheter into a leg vein, such as the Popliteal, and threads it into the vein containing the clot using imaging guidance. The catheter tip is placed into the clot and a “clot-busting” drug is infused directly into the thrombus (clot). The fresher the clot, the faster it dissolves – one to two days. Any narrowing in the vein that might lead to future clot formation can be identified by venography, an imaging study of the veins, and treated by the interventional radiologist with balloon angioplasty or stent placement.

In patients in whom this is not appropriate and blood thinners are contraindicated, an interventional radiologist can insert a vena cava filter, a small device that functions like a catcher’s mitt to capture blood clots, but allows normal liquid blood to pass. People with symptoms of DVT should first go to an emergency room to seek help, to receive initial treatment with blood thinners to prevent a pulmonary embolism. After treatment with blood thinners, if symptoms such as leg pain and swelling continue, patients should obtain a consult with an interventional radiologist for further evaluation.

Symptoms

Some of the symptoms include:

Discoloration of the legs
Calf or leg pain or tenderness
Swelling of the leg or lower limb
Warm skin
Increased visibility of surface veins
Leg fatigue

Efficacy

Clinical resolution of pain and swelling and restoration of blood flow in the vein is greater than 85 percent with the catheter-directed technique.

Nonsurgical Vertebroplasty and Kyphoplasty are Effective Pain Treatment for Spinal Fractures Caused by Osteoporosis

Vertebroplasty is a pain treatment for vertebral compression fractures that fail to respond to conventional medical therapy, such as minimal or no pain relief with analgesics or narcotic doses that are intolerable. Vertebroplasty, a nonsurgical treatment performed by interventional radiologists using imaging guidance, stabilizes the collapsed vertebra with the injection of medical-grade bone cement into the spine. This relieves pain, and can prevent further collapse of the vertebra, thereby preventing the height loss and spine curvature commonly seen as a result of osteoporosis. Vertebroplasty dramatically improves back pain within hours of the procedure, provides long-term pain relief and has a low complication rate, as demonstrated in multiple studies.

If the vertebra is not shored up, it can heal in a compressed or flattened wedge shape. Once this occurs, the compression fracture cannot be treated effectively. It is very important for someone with persistent spinal pain lasting more than three months to consult an interventional radiologist, and people who require constant pain relief with narcotics should seek help immediately.

Vertebroplasty is an outpatient procedure using X-ray imaging and conscious sedation. The interventional radiologist inserts a needle through a nick in the skin in the back, directing it under fluoroscopy (continuous, moving X-ray imaging) into the fractured vertebra. The physician then injects the medical-grade bone cement into the vertebra. The cement hardens within 15 minutes and stabilizes the fracture, like an internal cast. The patient stays in the recovery room for approximately four hours following the procedure.

Kyphoplasty is a similar procedure during which a balloon is used to re-expand the compressed vertebra near to its initial height. The same medical-grade bone cement is infused into the cavity created by the balloon to seal the fracture and maintain the vertebral body’s height.

For kyphoplasty, the patient is admitted for observation overnight following the procedure. Once seen by the interventional radiologist the next morning, the patient is generally discharged to home.

Computed Tomography Angiography (CTA)

CT Angiography

CT (computed tomography) angiography (CTA) is an examination that uses x-rays to visualize blood flow in arterial vessels throughout the body, from arteries serving the brain to those bringing blood to the lungs, kidneys, and arms and legs. CT combines the use of x-rays with computerized analysis of the images. Beams of x-rays are passed from a rotating device through the area of interest in the patient's body from several different angles so as to create cross-sectional images, which are then assembled by computer into a three-dimensional picture of the area being studied. Compared to catheter angiography, which involves placing a catheter and injecting contrast material into an artery, CTA is a much less invasive and more patient-friendly procedure—contrast material is injected into a peripheral vein rather than an artery. This exam has been used to screen large numbers of individuals for arterial disease. Most patients have CT angiography without being admitted to a hospital.

Uses of the procedure

CTA is commonly used to:

Examine the pulmonary arteries in the lungs to rule out pulmonary embolism, a serious but treatable condition.
Visualize blood flow in the renal arteries (those supplying the kidneys) in patients with high blood pressure and those suspected of having kidney disorders. Narrowing (stenosis) of a renal artery is a cause of high blood pressure (hypertension) in some patients, and can be corrected. A special computerized method of viewing the images makes CT renal angiography a very accurate examination. This is also done in prospective kidney donors.
Identify aneurysms in the aorta or in other major blood vessels. Aneurysms are diseased areas of a weakened blood vessel wall that bulges out—like a bulge in a tire. Aneurysms are life-threatening because they can rupture.
Identify dissection in the aorta or its major branches. Dissection means that the layers of the artery wall peel away from each other—like the layers of an onion. Dissection can cause pain and can be life-threatening.
Identify a small aneurysm or arterio-venous malformation inside the brain that can be life-threatening.
Detect atherosclerotic disease that has narrowed the arteries to the legs.

CTA also is used to detect narrowing or obstruction of arteries in the pelvis and in the carotid arteries bringing blood from the heart to the brain. When a stent has been placed to restore blood flow in a diseased artery, CT angiography will show whether it is serving its purpose. Examining arteries in the brain may help reach a correct diagnosis in patients who complain of headaches, dizziness, ringing in the ears, or fainting. Injured patients may benefit from CTA if there is a possibility that one or more arteries have been damaged. In patients with a tumor, it may be helpful for the surgeon to know the details of arteries feeding the growth.

Preparation for the procedure

Depending on the part of the body to be examined, you may be asked to take only clear liquids by mouth before CTA. You will be asked whether you have asthma or any allergies to foods or drugs, and what medications you are currently taking. If you are pregnant, you should inform the technologist before the procedure. You probably will not have to undress if you are having an exam of the head, neck, arms or legs but you will have to remove any jewelry, hair clips, dentures and the like that could show up on the x-rays and make them hard to interpret.

The equipment

A CT scanner is a specialized x-ray machine that looks like a large square doughnut. It has an opening measuring about two feet in diameter that surrounds a narrow table. Inside the frame of the scanner is a rotating device with an x-ray tube mounted on one side and a banana-shaped detector opposite it. Nearly all CTA studies use an advanced type of unit called a spiral CT machine that looks like any other type of CT unit, but is able to record a large number of pictures in a short time. This means that patients do not have to hold their breath for a prolonged period.

An example of the radiography equipment that may be used is shown above.

How the procedure works

Before the actual exam begins, you will have a dose of contrast material injected into a vein to make the blood vessels stand out. An automatic injector machine which controls the timing and rate of injection is used, and may continue during part of the time images are recorded. During the examination, the rotating device spins around the patient, creating a fan-shaped beam of x-rays, and the detector takes snapshots of the beam after it passes through the patient. As many as one thousand of these pictures may be recorded in one turn of the detector. The real work of CTA comes after the images are acquired, when powerful computer programs process the images and make it possible to display them in different ways, for instance, in cross-sectional slices or as three-dimensional "casts" of the blood vessels.

How the procedure is performed

Most of the time for a CTA examination is spent setting everything up. Actually recording the images takes only seconds. After changing into a hospital gown and having an IV set up, you will answer questions about things that might complicate the exam (such as allergies) and then will lie down on a narrow table. The part of your body to be examined will be placed inside the opening of the CT unit with the aid of crisscrossed positioning lights. A test image is taken to determine the best position, and a small dose of contrast material is given to see how long it takes to reach the area under study. Then the IV is hooked up to an automatic injector, the contrast material is injected, and the scan begins. Afterwards, the images will be reviewed and, if necessary, some will be repeated. No special measures are needed after the procedure.

What will I experience during the procedure?

CTA takes about 10 to 25 minutes from the time the actual examination begins. Overall, you can expect to be in or near the examining room for 20 to 60 minutes. You may feel warm all over when contrast material is injected before the scan, but you should not feel pain at any time. Any CT study requires that you remain still during the exam. Pillows and foam pads may help make it more comfortable. At the same time, the nurse or technologist may use pads or Velcro straps to keep the area from moving. The examination table will move in and out of the scanner opening, but it is not enclosed and only a small part of your body will be inside at any one time. You may be asked to hold your breath for 10 to 25 seconds to be sure that the images will not be blurred. During the time that no actual imaging is taking place, you are free to ask questions or talk to the technologist, but friends or relatives will not be allowed in the examining room. Once the needed images have been recorded, you will be free to leave. You can eat immediately and it is a good idea to drink plenty of fluids in the hours after the exam to help flush contrast material out of the system.

Interpretation of the results

Typically the results of CTA are available within 24 hours, although in complicated cases, special computer analysis may take somewhat longer. The radiologist will report the findings to your physician, who in turn will discuss them with you.

Benefits vs. risks

Benefits

CTA can be used to examine blood vessels in many key areas of the body, including the brain, kidneys, pelvis, and the arteries serving the lungs. The procedure is able to detect narrowing of arteries in time for corrective surgery to be done.
This method displays the anatomical detail of blood vessels more precisely than magnetic resonance imaging (MRI) or ultrasound. Today many patients can have CTA in place of a conventional catheter angiogram.
CTA is a useful way of screening for arterial disease because it is safer and much less time-consuming than catheter angiography and it is also a cost-effective procedure. In addition, there is less discomfort because contrast material is injected into an arm vein rather than into a large artery in the groin.

Risks

There is a risk of an allergic reaction—which may be serious—whenever contrast material containing iodine is injected. If you have a history of allergy to x-ray dye, your radiologist may advise that you take special medication for 24 hours before CTA to lessen the risk of allergic reaction. Another option is to undergo a different exam that does not call for contrast injection.
CTA should be avoided in patients with kidney disease or severe diabetes because x-ray contrast material can further harm kidney function.
If a large amount of x-ray contrast leaks out under the skin where the IV is placed, skin damage can result. If you feel any pain in this area during contrast injection, you should immediately inform the technologist.
Women should always inform their doctor or x-ray technologist if there is any possibility that they are pregnant.

MR Angiography (MRA)

MR Angiography

Magnetic resonance imaging (MRI) is a method of producing extremely detailed pictures of body tissues and organs without the need for x-rays. The electromagnetic energy that is released when exposing a patient to radio waves in a strong magnetic field is measured and analyzed by a computer, which forms two- or three-dimensional images that may be viewed on a TV monitor. MR angiography (MRA) is an MRI study of the blood vessels. It utilizes MRI technology to detect, diagnose and aid the treatment of heart disorders, stroke, and blood vessel diseases. MRA provides detailed images of blood vessels without using any contrast material, although today a special form of contrast is usually given to make the MRI images even clearer. The procedure is painless, and the magnetic field is not known to cause tissue damage of any kind.

Common uses of the MRA procedure

Many patients with arterial disease now have it treated in the radiology department rather than undergoing surgery in an operating room. MRA is a very useful way of finding problems with blood vessels and determining how to best to treat those problems.
The carotid arteries in the neck that conduct blood to the brain are a common site of atherosclerosis, which may severely narrow or block off an artery, reducing blood flow to the brain and even causing a stroke. If an ultrasound study shows that such disease is present, many surgeons now will do the necessary operation after confirmation by MRA, dispensing with the need for catheter angiography.
MRA has found wide use in checking patients for diseased intracranial (in the head) arteries, so that only those with positive findings will need to have a more invasive catheter study.
MRA also is used to detect disease in the aorta and in blood vessels supplying the kidneys, lungs and legs.
Patients with a family history of arterial aneurysm, a ballooning out of a segment of the vessel wall, can be screened by MRA to see if they have a similar disorder that has not produced symptoms. If an aneurysm is found, it may be eliminated surgically, possibly avoiding serious or fatal bleeding.

Preparation for the procedure

The magnetic field used for MRA will pull on any iron-containing object in the body, such as a heart pacemaker, intrauterine device, vascular access port, metal plate, or pins, screws or staples. You will be given a questionnaire to answer regarding these issues. The radiologist or technologist should know about any such item and also whether you have ever had a bullet in your body, whether you ever worked with metals, or if you have had a joint replacement. If there is any question, an x-ray can be taken to detect metal objects. The radiologist also should know if you have fillings in your teeth, which could distort images of the facial region or brain. Braces make it harder to properly adjust the MRI unit. You will be asked to remove hairpins, jewelry, eyeglasses, hearing aids, and any dental work that can be taken out. Some wigs contain metal and must be removed. Red dyes used in tattoos and permanent eyeliner may contain metallic iron, but this is rarely a problem. You should report any drug allergies to the radiologist or technologist, and should mention if there is any possibility that you might be pregnant.

You can eat normally before the exam (unless told differently), but a young child should not eat or drink for about four hours if they are receiving a sedative. The rules vary at different MRI facilities, so be sure to check with your medical center about eating and drinking before the exam. Medications may be taken as usual. Some patients will feel uncomfortably confined (claustrophobic) when enclosed in an MRI unit. If necessary, you will be given a sedative to help put you at ease, though probably less than one in every 20 patients will need this. You will wear a lightweight medical gown for the exam.

The MRI equipment

The traditional MRI unit is a large tube surrounded by a circular magnet, in which the patient lies without moving for several seconds at a time. The patient is placed on a wheeled bed that is moved into the magnet. In recent years patient-friendly units have been designed, and examination in such units is becoming increasingly available. These machines are both shorter and wider than a conventional MRI unit, and do not fully enclose the patient. Some of the newer C-shaped units are even open on all sides, making them attractive to patients who tend toward claustrophobia. A drawback is that image quality is not as consistently good.

The procedure

Exposing the patient to radio waves in a strong magnetic field generates data that are used by a computer to create images of tissue slices that may be viewed in any plane or from any direction. The magnetic field lines up atomic particles in the tissues called protons, which are then spun by a beam of radio waves and produce signals that are picked up by a receiver in the scanner. It is these signals that are processed by the computer to produce images. The resulting images are very sharp and detailed, which means they are able to detect tiny changes from the normal pattern that are caused by disease or injury.

Special settings are used to image various structures, such as arteries in the case of MRA.

How is the procedure performed?

The patient is placed on a special table and positioned inside the opening of the MRI unit. A typical exam consists of two to six imaging sequences, each taking two to 15 minutes. Each sequence provides a specific image orientation and a specified degree of image clarity or contrast. Depending on the type of exam being done, the total time needed can range from 10 to 60 minutes, not counting the time needed to change clothing, have an IV put in and answer questions. When contrast material is needed, a substance called gadolinium is given by IV injection during one of the imaging sequences. It highlights blood vessels, making them stand out from surrounding tissues.

The radiologist and technologist leave the examining room during the actual imaging process, but the patient can communicate with them at any time using an intercom. We allow a friend to stay nearby, or a parent if a child is being examined. When the exam is completed you will be asked to wait to make sure that more images are not needed.

What is experienced during the MRA procedure?

The technologist will make you as comfortable as possible, but at times the magnet may be within a few inches of your face. For those who become very uncomfortable when enclosed in a small space, a mild sedative is nearly always effective. You may notice a warm feeling in the area being studied. This is normal, but do not hesitate to report it if it bothers you. If you receive a contrast material injection there may be some local discomfort at the IV site. The loud tapping or knocking noises that are heard during certain parts of the exam disturb some patients; earplugs may help.

Interpretation of the results

A radiologist experienced in MRI will analyze the results and send a report to your physician, along with an interpretation of the findings. Your physician in turn will discuss the MRA findings with you. Some centers now send diagnostic reports and images over the Internet, speeding up the process.

Benefits vs. risks

Benefits

Detailed images of blood vessels and blood flow are obtained without having to insert a catheter directly into the area of interest, so that there is no risk of damaging an artery.
The procedure itself and the time needed to recover are shorter than after a traditional catheter angiogram.
MRA is less costly than catheter angiography.
There is no exposure to x-rays during an MRI study.
Contrast material may be injected, but unlike catheter angiography or CT angiography, which make use of iodine-based contrast material, the risk of an allergic reaction from MRA contrast is extremely low and kidney damage does not occur. Even without using contrast material, MRA can provide high-quality images of many blood vessels, making it very useful for patients prone to allergic reactions.
As with catheter-based angiography or CT angiography, it is frequently possible to defer surgery after getting the results of an MRA study. If surgery remains necessary, it can be performed more accurately.

Risks

There are no definite side effects from any type of MRI study, including MR angiography. Claustrophobia may be a problem, however. When it is severe and not relieved by giving a sedative, an alternative imaging method may have to be tried. If a metal implant is present but goes undetected, it may be affected by the strong magnetic field to which the patient is exposed. In addition, if the implant is close to the examination site it may be hard to get high-quality images.
MRI is generally avoided during the first three months of pregnancy. Ultrasound is preferred at this time unless the woman may have a very serious condition that is best detected by MRA. The effects of MRI on the fetus, if any, remain to be determined. The general rule for MRI and other diagnostic studies in pregnancy is that they should be avoided unless there is substantial risk from missing the correct diagnosis because the procedure is not done. Women who are breast-feeding should inform the radiologist and ask how to proceed. They may pump breast milk before the exam for use until the gadolinium contrast material has cleared from the body.

Limitations of MR Angiography

MRA does not image calcium, as does CT angiography. The procedure should be avoided in any patient having a pacemaker, implanted neurostimulator, metallic ear implant, or metallic object within the eye socket. It should also be avoided if there is a bullet fragment or if the patient has a port for delivering insulin or chemotherapy. For patients who are very claustrophobic, adequate nursing staff must be on hand to monitor sedation.

The clearness of MRA images does not yet match those obtained by conventional angiography. MRI of small vessels, in particular, may not be adequate for diagnosis and treatment planning. Sometimes it may be difficult to separate images of arteries from veins by MRA.