FAQs
You may be asked to wear a gown during the exam or you may be allowed to wear your own clothing if it is loose-fitting and has no metal fasteners.

Guidelines about eating and drinking before an MRI exam vary with the specific exam and also with the facility. Unless you are told otherwise, you may follow your regular daily routine and take medications as usual.

Some MRI examinations may require the patient to swallow contrast material or receive an injection of contrast into the bloodstream. The radiologist or technologist may ask if you have allergies of any kind, such as allergy to iodine or x-ray contrast material, drugs, food, the environment, or asthma. However, the contrast material used for an MRI exam, called gadolinium, does not contain iodine and is less likely to cause an allergic reaction.

The radiologist should also know if you have any serious health problems and what surgeries you have undergone. Some conditions, such as severe kidney disease may prevent you from having an MRI with contrast material.

Women should always inform their physician or technologist if there is any possibility that they are pregnant. MRI has been used for scanning patients since the 1980's with no reports of any ill effects on pregnant women or their babies. However, because the baby will be in a strong magnetic field, pregnant women should not have this exam unless the potential benefit from the MRI is assumed to outweigh the potential risks.

If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your physician for a prescription for a mild sedative.

Jewelry and other accessories should be left at home if possible, or removed prior to the MRI scan. Because they can interfere with the magnetic field of the MRI unit, metal and electronic objects are not allowed in the exam room. These items include:
  • jewelry, watches, credit cards and hearing aids, all of which can be damaged.
  • pins, hairpins, metal zippers and similar metallic items, which can distort MRI images.
  • removable dental work.
  • pens, pocketknives and eyeglasses.
  • body piercings.
In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the following implants cannot be scanned and should not enter the MRI scanning area unless explicitly instructed to do so by a radiologist or technologist who is aware of the presence of any of the following:
  • internal (implanted) defibrillator or pacemaker
  • cochlear (ear) implant
  • some types of clips used on brain aneurysms
You should tell the technologist if you have medical or electronic devices in your body, because they may interfere with the exam or potentially pose a risk. Examples include but are not limited to:
  • artificial heart valves
  • implanted drug infusion ports
  • implanted electronic device, including a cardiac pacemaker
  • artificial limbs or metallic joint prostheses
  • implanted nerve stimulators
  • metal pins, screws, plates or surgical staples.
In general, metal objects used in orthopedic surgery pose no risk during MRI. However, a recently placed artificial joint may require the use of another imaging procedure. If there is any question of their presence, an x-ray may be taken to detect the presence of any metal objects.

Patients who might have metal objects in certain parts of their bodies may also require an x-ray prior to an MRI. Dyes used in tattoos may contain iron and could heat up during MRI, but this is rarely a problem. Tooth fillings and braces usually are not affected by the magnetic field but they may distort images of the facial area or brain, so the radiologist should be aware of them.

Benefits

  • MRI is a noninvasive imaging technique that does not involve exposure to radiation.
  • MR images of the soft-tissue structures of the body—such as the heart, liver and many other organs— is more likely to identify and characterize abnormalities and focal lesions than other imaging methods. This detail makes MRI an invaluable tool in early diagnosis and evaluation of many focal lesions and tumors.
  • MRI has proven valuable in diagnosing a broad range of conditions, including cancer, heart and vascular disease, and muscular and bone abnormalities.
  • MRI enables the detection of abnormalities that might be obscured by bone with other imaging methods.
  • MRI allows physicians to assess the biliary system noninvasively and without contrast injection.
  • The contrast material used in MRI exams is less likely to produce an allergic reaction than the iodine-based materials used for conventional x-rays and CT scanning.
  • MRI provides a fast, noninvasive alternative to x-ray angiography for diagnosing problems of the heart and blood vessels.

Risks

  • The MRI examination poses almost no risk to the average patient when appropriate safety guidelines are followed.
  • If sedation is used there are risks of excessive sedation. The technologist or nurse monitors your vital signs to minimize this risk.
  • Although the strong magnetic field is not harmful in itself, medical devices that contain metal may malfunction or cause problems during an MRI exam.
  • There is a very slight risk of an allergic reaction if contrast material is injected. Such reactions usually are mild and easily controlled by medication.
  • Nephrogenic systemic fibrosis is currently a recognized, but rare, complication of MRI believed to be caused by the injection of high doses of MRI contrast material in patients with poor kidney function.

You should wear comfortable, loose-fitting clothing to your exam. You may be given a gown to wear during the procedure.

Metal objects including jewelry, eyeglasses, dentures and hairpins may affect the CT images and should be left at home or removed prior to your exam. You may also be asked to remove hearing aids and removable dental work.

You may be asked not to eat or drink anything for several hours beforehand, especially if a contrast material will be used in your exam. You should inform your physician of any medications you are taking and if you have any allergies. If you have a known allergy to contrast material, or "dye," your doctor may prescribe medications to reduce the risk of an allergic reaction.

Also inform your doctor of any recent illnesses or other medical conditions, and if you have a history of heart disease, asthma, diabetes, kidney disease or thyroid problems. Any of these conditions may increase the risk of an unusual adverse effect.

The radiologist also should know if you have asthma, multiple myeloma or any disorder of the heart, kidneys or thyroid gland, or if you have diabetes—particularly if you are taking Glucophage.

Benefits

  • Viewing a CT scan, an experienced radiologist can diagnose many causes of abdominal pain with very high accuracy, enabling faster treatment and often eliminating the need for additional, more invasive diagnostic procedures.
  • When pain is caused by infection and inflammation, the speed, ease and accuracy of a CT examination can reduce the risk of serious complications such as those caused by a burst appendix or ruptured diverticulum and the subsequent spread of infection.
  • CT scanning is painless, noninvasive and accurate.
  • A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time.
  • Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, and blood vessels.
  • CT examinations are fast and simple; in emergency cases, they can reveal internal injuries and bleeding quickly enough to help save lives.
  • CT has been shown to be a cost-effective imaging tool for a wide range of clinical problems.
  • CT is less sensitive to patient movement than MRI.
  • CT can be performed if you have an implanted medical device of any kind, unlike MRI.
  • CT imaging provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies and needle aspirations of many areas of the body, particularly the lungs, abdomen, pelvis and bones.
  • A diagnosis determined by CT scanning may eliminate the need for exploratory surgery and surgical biopsy.
  • No radiation remains in a patient's body after a CT examination.
  • X-rays used in CT scans usually have no side effects.
  • Many patients can undergo CT angiography instead of a conventional catheter angiogram.
  • Compared to catheter angiography, which involves placing a catheter (plastic tube) and injecting contrast material into a large artery or vein, CT angiography is a much less invasive and more patient-friendly procedure.
  • CT angiography gives more precise anatomical detail of blood vessels than magnetic resonance imaging (MRI).
  • A major advantage of CT is that it is able to image bone, soft tissue and blood vessels all at the same time.
  • Unlike conventional x-rays, CT scanning provides very detailed images of many types of tissue as well as the lungs, bones, and blood vessels.
  • Spinal CT scanning is a rapid procedure and offers an accurate evaluation of bone and most soft tissues. Using the latest equipment, the spine may be displayed in multiple planes and three-dimensional imaging is an option.

Risks

  • There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
  • CT scanning is, in general, not recommended for pregnant women unless medically necessary because of potential risk to the baby.
  • Nursing mothers should wait for 24 hours after contrast material injection before resuming breast-feeding.
  • The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.
  • Children should have a CT study only if it is essential for making a diagnosis and should not have repeated CT studies unless absolutely necessary.
  • The risk of serious allergic reaction to contrast materials that contain iodine is extremely rare, and radiology departments are well-equipped to deal with them.

Before scheduling a mammogram, the American Cancer Society (ACS) and other specialty organizations recommend that you discuss any new findings or problems in your breasts with your doctor. In addition, inform your doctor of any prior surgeries, hormone use, and family or personal history of breast cancer.

Do not schedule your mammogram for the week before your period if your breasts are usually tender during this time. The best time for a mammogram is one week following your period. Always inform your doctor or x-ray technologist if there is any possibility that you are pregnant.

The ACS also recommends you:
  • Do not wear deodorant, talcum powder or lotion under your arms or on your breasts on the day of the exam. These can appear on the mammogram as calcium spots.
  • Describe any breast symptoms or problems to the technologist performing the exam.
  • If possible, obtain prior mammograms and make them available to the radiologist at the time of the current exam.
Ask when your results will be available; do not assume the results are normal if you do not hear from your doctor or the mammography facility.

Benefits

  • Imaging of the breast improves a physician's ability to detect small tumors. When cancers are small, the woman has more treatment options and a cure is more likely.
  • The use of screening mammography increases the detection of small abnormal tissue growths confined to the milk ducts in the breast, called ductal carcinoma in situ (DCIS). These early tumors cannot harm patients if they are removed at this stage and mammography is the only proven method to reliably detect these tumors. It is also useful for detecting all types of breast cancer, including invasive ductal and invasive lobular cancer.
  • No radiation remains in a patient's body after an x-ray examination.
  • X-rays usually have no side effects in the diagnostic range.

Risks

  • There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.

You will likely be instructed not to eat or drink after midnight on the night before your exam. You may also be asked to take a mild laxative (in either pill or liquid form) the evening before the procedure.

You should inform your physician of any medications you are taking and if you have any allergies, especially to iodinated contrast materials. Also inform your doctor about recent illnesses or other medical conditions.

You may be asked to remove some or all of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, eye glasses and any metal objects or clothing that might interfere with the x-ray images.
  • Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so as not to expose the fetus to radiation. If an x-ray is necessary, precautions will be taken to minimize radiation exposure to the baby Because x-ray imaging is fast and easy, it is particularly useful in emergency diagnosis and treatment.
To ensure the best possible image quality, your stomach must be empty of food. Therefore, you will likely be asked not to eat or drink anything (including any medications taken by mouth, especially antacids) and to refrain from chewing gum and smoking after midnight on the day of the examination.

Benefits

  • Imaging of the urinary tract with IVP is a minimally invasive procedure.
  • IVP images provide valuable, detailed information to assist physicians in diagnosing and treating urinary tract conditions from kidney stones to cancer.
  • An IVP can often provide enough information about kidney stones and obstructions to direct treatment with medication and avoid more invasive surgical procedures.
  • No radiation remains in a patient's body after an x-ray examination.
  • X-rays usually have no side effects in the diagnostic range.
  • Radiology examinations such as the lower GI can often provide enough information to avoid more invasive procedures such as colonoscopy..
  • The results of the upper GI series usually lead to accurate evaluation of the esophagus, stomach and duodenum.
  • Because barium is not absorbed into the blood, allergic reactions are extremely rare.

Risks

  • Contrast materials used in IVP studies can cause adverse allergic reactions in some people, sometimes requiring medical treatment.
  • In rare cases, the barium could leak through an undetected hole in the lower GI tract producing inflammation in surrounding tissues.
  • Occasional patients may be allergic to the flavoring added to some brands of barium. If you have experienced allergic reactions after eating chocolate, certain berries or citrus fruit, be sure to tell your physician or the technologist before the procedure.

On the day of the exam you may eat normally. You should not take calcium supplements for at least 24 hours before your exam.

You should wear loose, comfortable clothing, avoiding garments that have zippers, belts or buttons made of metal. Objects such as keys or wallets that would be in the area being scanned should be removed.

You may be asked to remove some or all of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, eye glasses and any metal objects or clothing that might interfere with the x-ray images.

Inform your physician if you recently had a barium examination or have been injected with a contrast material for a computed tomography (CT) scan or radioisotope scan. You may have to wait 10 to 14 days before undergoing a DXA test.

Benefits

  • DXA bone densitometry is a simple, quick and noninvasive procedure.
  • No anesthesia is required.
  • The amount of radiation used is extremely small—less than one-tenth the dose of a standard chest x-ray, and less than a day's exposure to natural radiation.
  • DXA bone density testing is the most accurate method available for the diagnosis of osteoporosis and is also considered an accurate estimator of fracture risk.
  • DXA equipment is widely available making DXA bone densitometry testing convenient for patients and physicians alike.
  • No radiation remains in a patient's body after an x-ray examination.
  • X-rays usually have no side effects in the diagnostic range.

Risks

  • There is always a slight chance of cancer from excessive exposure to radiation. However, the benefit of an accurate diagnosis far outweighs the risk.
  • The effective radiation dose from this procedure is about 0.01 mSv, which is about the same as the average person receives from background radiation in one day. Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant.
  • No complications are expected with the DXA procedure.

You should wear comfortable, loose-fitting clothing for your ultrasound exam. You will need to remove all clothing and jewelry in the area to be examined.

You may be asked to wear a gown during the procedure.

It is best to perform hysterosonography one week after menstruation to avoid the risk of infection. At this time in the menstrual cycle, the endometrium is at its thinnest, which is the best time to determine if the endometrium is normal. The timing of the exam may vary, however, depending on the symptoms and their suspected origins. Hysterosonography should not be performed if you are pregnant.

If an ultrasound is ordered by your clinician early in your pregnancy, you may be instructed to have a full bladder for the procedure. Air interferes with sound waves, so if your bladder is distended, the air-filled bowel is pushed out of the way by the bladder and an image of the uterus and embryo or fetus is obtained.

About an hour before the procedure you should empty your bladder. You may be instructed to drink up to six glasses of water and avoid urinating until the procedure is completed. After the first two to three months of pregnancy, a full bladder is not usually necessary for imaging.

The radiologist or sonographer may elect to examine an early pregnancy by means of transvaginal ultrasound. This requires an empty urinary bladder.

Tell your doctor if you have had a barium enema or a series of upper GI (gastrointestinal) tests within the past two days. Barium that remains in the intestines can interfere with the ultrasound test.

Other preparations depend on the type of ultrasound you are having.
  • For a study of the liver, gallbladder, spleen, and pancreas, you may be asked to eat a fat-free meal on the evening before the test and then to avoid eating for eight to 12 hours before the test.
  • For ultrasound of the kidneys, you may be asked to drink four to six glasses of liquid about an hour before the test to fill your bladder. You may be asked to avoid eating for eight to 12 hours before the test to avoid gas buildup in the intestines.
  • For ultrasound of the aorta, you may need to avoid eating for eight to 12 hours before the test.
Other preparation depends on the type of examination you will have. For some scans your doctor may instruct you not to eat or drink for as many as 12 hours before your appointment. For others you may be asked to drink up to six glasses of water two hours prior to your exam and avoid urinating so that your bladder is full when the scan begins.

A full bladder helps to visualize the uterus, ovaries, bladder wall and prostate gland for transabdominal ultrasound.

A period of fasting is necessary only if you are to have an examination of veins in your abdomen. In this case, you will probably be asked not to ingest any food or fluids except water for six to eight hours ahead of time. Otherwise, there is no other special preparation for a venous ultrasound.

Prior to a needle biopsy, you should report to your doctor all medications that you are taking, including herbal supplements, and if you have any allergies, especially to anesthesia. Your physician will advise you to stop taking aspirin or a blood thinner three days before your procedure.

Also, inform your doctor about recent illnesses or other medical conditions.

Benefits

  • Most ultrasound scanning is noninvasive (no needles or injections) and is usually painless.
  • Ultrasound is widely available, easy-to-use and less expensive than other imaging methods.
  • Ultrasound imaging uses no ionizing radiation.
  • Ultrasound scanning gives a clear picture of soft tissues that do not show up well on x-ray images.
  • Ultrasound causes no health problems and may be repeated as often as is necessary.
  • Ultrasound is the preferred imaging modality for the diagnosis and monitoring of pregnant women and their unborn babies.
  • Ultrasound has been used to evaluate pregnancy for nearly four decades and there has been no evidence of harm to the patient, embryo or fetus. Nevertheless, ultrasound should be performed only when clinically indicated.
  • Ultrasound allows the doctor to see inside the uterus and provides much information about the pregnancy.
  • Ultrasound provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as cortisone injections, needle biopsies and needle aspiration of fluid in joints or elsewhere.
  • Ultrasound imaging can help detect lesions in women with dense breasts.
  • Ultrasound may help detect and classify a breast lesion that cannot be interpreted adequately through mammography alone.
  • Using ultrasound, physicians are able to determine that many areas of clinical concern are due to normal tissue (such as fat lobules) or benign cysts. For most women 30 years of age and older, a mammogram will be used together with ultrasound. For women under age 30, ultrasound alone is often sufficient to determine whether an area of concern needs a biopsy or not.
  • If a carotid ultrasound exam shows narrowing of one or both carotid arteries, treatment can be taken to restore the free flow of blood to the brain. Many strokes are prevented as a result.
  • Unlike the strong magnetic field of magnetic resonance imaging (MRI), ultrasound is not affected by cardiac pacemakers, ferromagnetic implants or fragments within the body. Ultrasound is also an excellent alternative to MRI for claustrophobic patients.
  • Ultrasound may actually have advantages over MRI in seeing tendon structure, which is better appreciated by ultrasound than MRI.
  • Pelvic ultrasound can help to identify and evaluate a variety of urinary and reproductive system disorders in both sexes without even the minimal risks associated with x-ray exposure.
  • Ultrasound is widely available, easy-to-use and less expensive than other imaging methods.
  • Venous ultrasound helps to detect blood clots in the veins of the legs before they become dislodged and pass to the lungs. It can also 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 veins of the thigh up to the knee. In the calf, because the veins become very small, ultrasound is less accurate. However, the majority of potentially dangerous venous clots are in the larger veins.
  • Ultrasound-guided breast biopsy reliably provides tissue samples that can show whether a breast lump is benign or malignant.
  • Compared with stereotactic breast biopsy, the ultrasound method is faster and avoids the need for ionizing radiation exposure.
  • With ultrasound it is possible to follow the motion of the biopsy needle as it moves through the breast tissue.
  • Ultrasound-guided breast biopsy is able to evaluate lumps under the arm or near the chest wall, which are hard to reach with stereotactic biopsy.
  • Ultrasound-guided biopsy is less expensive than stereotactic biopsy.
  • Recovery time is brief and patients can soon resume their usual activities.

Risks

  • For standard diagnostic ultrasound there are no known harmful effects on humans.
  • Interpretation of a breast ultrasound examination may lead to additional procedures such as follow-up ultrasound and/or aspiration or biopsy. Many of the areas thought to be of concern on an ultrasound turn out to be non-cancerous.
  • Because the vacuum-assisted device removes slightly larger pieces of tissue than other types of needles, there is a risk of bleeding and forming a hematoma, or a collection of blood at the biopsy site. The risk, however, appears to be less than one percent of patients.
  • An occasional patient has significant discomfort, which can be readily controlled by non-prescription pain medication.
  • Any procedure where the skin is penetrated carries a risk of infection. The chance of infection requiring antibiotic treatment appears to be less than one in 1,000.
  • Doing a biopsy of tissue located deep within the breast carries a slight risk that the needle will pass through the chest wall, allowing air around the lung that could collapse a lung. This is a rare occurrence.