IMAGING FAQS – AN OVERVIEW OF COMMON DIAGNOSTIC PROCEDURES

People who undergo diagnostic exams naturally have questions about their effectiveness, safely and comfort, as well as any special preparation that may be required. This article answers some of the most frequently-asked questions of five of the most common tests recommended and ordered by doctors for the purposes of diagnosis and/or image-guided medical treatment.

X-RAY

What is an x-ray?

An x-ray, also called a radiograph, is one of the oldest, quickest and most common types of diagnostic tests in existence. Most often, x-ray technology is used to view bones to diagnose fracture, infection, arthritis, abnormal growths or cancer, assess alignment or look for foreign objects in the surrounding tissues.

How is it performed?

A specially trained RAO technologist will position you comfortably on an x-ray table and guide a digital plate beneath the table under the body part or area being imaged. While you remain still, the technologist will quickly take a picture. The technologist may reposition you and repeat the process if more than one image is required. Typically, after two or three images are captured, the test is over. Most patients are in and out in under ten minutes.

Is it safe?

An x-ray exposes the area being tested to a small amount of ionizing radiation in order to capture images. Extra care is taken during x-ray examinations to expose patients to the lowest possible dose of radiation. National radiology protection agencies regularly review x-ray standards and equipment to ensure compliance with rigid safety standards. Advanced x-ray systems have more focused beams than early x-ray equipment, limiting exposure to areas not being imaged for superior safety. No radiation remains in the body after the examination is over. However, x-ray is not recommended for women who are or may be pregnant.

Why use x-ray over other imaging methods?

X-ray imaging is the fastest and easiest way to capture images of bone injuries like fracture and joint problems like arthritis. It is comparatively inexpensive to use and is readily available in most doctors’ offices, emergency rooms and radiology practices. Because imaging is quick and requires no special patient preparation, it is one of the most useful tools in providing a rapid diagnosis.

Can x-ray be used to diagnose muscles, tendons or joint conditions?

X-rays are easily absorbed by dense tissues like bones, but largely pass through soft tissues like organs, muscles, tendons and fat, making x-ray a less-than-ideal diagnostic tool for those areas.

MAMMOGRAPHY

What is mammography?

Mammography is a specialized screening x-ray used to spot cancerous or irregular cells in breast tissue while they are still small, often too small to be detected by breast self-exam. It is also used to identify calcifications and determine breast density, a measure of what types of cells compose each patient’s breast tissue.

What are the different types of mammography?

Today in the US, nearly all mammography tests are digital, meaning the computer-based images captured by x-ray produce sharper images with less ionizing radiation than older mammography systems, so they’re safer and more accurate. A more advanced type of digital mammogram is called breast tomosynthesis, also known as a 3D mammography™ exam, which delivers multiple images of breast tissue from varying angles that are reconstructed on a computer screen to produce nearly 3D views of breast tissue, helping to spot lesions earlier and reduce false positive results. Tomosynthesis is the gold standard of mammography and is offered at RAO’s Women’s Imaging Center and TimberRidge Imaging Center.

Who should get a screening mammogram?

The US Department of Health and Human Services and the American College of Radiology recommend that women start having annual screening mammograms once they reach age 40. This provides a baseline image of breast tissue that can easily be digitally stored and compared to future scans, so changes can be caught early when they are easiest to treat. Women whose doctors believe they may be at elevated risk may start receiving annual mammograms as early as age 35, or even younger is certain cases.

Is mammography painful?

To get adequate access to deeper layers of breast tissue for imaging purposes, a trained technician will place one breast at a time between two imaging plates and tighten the plates until the breast is spread out as much as possible. This squeezing sensation can indeed be uncomfortable, but you need to remain still for only a few seconds while the technician has a chance to capture an image, so the test itself is quick. The plates are loosened and the procedure is repeated on the same breast from another angle. Once two images are successfully captured, the technician will perform the same process on the other breast. Barring complications, a screening mammogram can be over in just a few minutes.

How do I prepare for a screening mammogram?

To avoid having superfluous images appear in the scan, it is important not to wear antiperspirant or deodorant, powder, lotion or perfume under the arms or on the chest area. If you have noticed problems like a lump, discharge from a nipple, puckering of the skin or other changes, report them to your technologist. Once the test is over, ask your technologist when you should call your doctor to get your results.

MRI

What is MRI?

Magnetic Resonance Imaging, or MRI, is an imaging test that utilizes a magnetic field, radio waves and a computer to compose detailed pictures of internal organs and systems. MRI is especially useful when viewing musculoskeletal, vascular, gastrointestinal, spinal, head and soft tissue injuries, among others.

What are the benefits of MRI?

MRI provides exceptional detail of internal organs and structures as well as soft tissues, saving countless patients from riskier diagnostic procedures like exploratory surgery and radiation-based tests like x-ray and CT. MRI is non-invasive, doesn’t expose you to ionizing radiation and produces remarkable detail for easier analysis by your doctor and RAO radiologist than many other tests.

What are the drawbacks of MRI?

Because it uses a strong magnetic field to capture images, MRI is not suitable for most people who have metal installed or present anywhere in the body, so devices like pacemakers, metal clips, shunts or stents, cochlear ear implants, etc. usually make a patient ineligible for MRI. It is also contraindicated for women who are or may be pregnant.

Another downside is that, because MRI requires the area being scanned to be surrounded by the imaging equipment and for the patient to remain still between 20-60 minutes, the test can cause some people to feel claustrophobic. MRI is also rather noisy, so you will be supplied with earplugs during your test.

The upside is that RAO offers high-field open MRI equipment, which provides an open environment that relieves patients of a closed-in feeling, for superior physical and emotional comfort. This breakthrough in MRI technology eliminates most concerns about the test for the vast majority of patients. RAO offers the most advanced MRI options available.

Why does having metal in the body preclude most people from having an MRI?

The magnetic field utilized by MRI equipment is so strong that it can cause metal inside the head or body to shift position, which can be dangerous. Your doctor and RAO radiologist will assess your case and tell you if the metal in your body is non-ferrous and anchored in such a way that it isn’t subject to this problem.

Does MRI require an injection with a contrast agent?

Some situations require that a non-iodinated contrast material called gadolinium be injected into the bloodstream to highlight veins, soft tissues or other structures. Unlike some contrast agents, gadolinium is received by the body quite comfortably and presents few to no side effects. Patients with renal problems should discuss receiving a contrast agent with their doctor and/or RAO technologist prior to getting an MRI.

ULTRASOUND

What is ultrasound?

Ultrasound is a gentle, non-invasive test that uses sound waves to create images on a computer screen. A technologist trained in ultrasound is called a sonographer, who has extensive education in this procedure. Because ultrasound does not produce radiation or require a contrast medium to captures images, it is commonly used to examine fetal development during pregnancy, making it one of the most common medial scans utilized today.

What does ultrasound show during pregnancy?

Ultrasound is painless and safe, and provides a wealth of information, including the stage of pregnancy, the baby’s size, when the baby is due, the position of the fetus and its movements, its heart rate and heart function, the presence of certain birth defects, the level of amniotic fluid, and more. Most women are encouraged to have an ultrasound during the first 6 – 9 weeks of pregnancy and again at 16 – 20 weeks, and at other stages depending on the recommendations of your healthcare provider.

Other than pregnancy, what is ultrasound used for?

Ultrasound is an effective exam for a variety of diagnostic procedures, including echocardiograms to evaluate how well the heart is pumping and heart valves are working; to diagnose and keep an eye on congenital heart disease; to review a recently diagnosed heart murmur; to inspect the vascular (blood vessel) system; to examine bones, muscles, tendons, ligaments or joints to discover the cause of pain; to check the abdomen for gallbladder, liver or pelvic problems; to isolate tumors, cysts, blockage and stones in the kidneys; as a follow-up test for a mammogram showing a mass or cyst; to guide a needle for biopsy of a mass or to drain fluid from an infected area; to examine the testicles for masses, infection or excess fluid; and many others. Ultrasound may also be used internally via special transducers introduced into the vagina to inspect the uterus and ovaries, or the rectum to inspect the prostate gland.

How is ultrasound performed?

In most cases you will be asked to lie comfortably on an examination chair or table. Your sonographer or radiologist will apply a clear gel to the skin surrounding the area being examined to facilitate the penetration of sound waves into the body. He or she will gently swab the gelled area with a hand-held wand called a transducer, which produces the sound waves and sends the information to a computer screen for review in real time, capturing still and, when applicable, moving images. When necessary, you may be asked to rest in a few positions so your examiner can gather images from different angles. The skin being swabbed by the transducer may feel warm, which most patients report is painless, even pleasant.

How do you prepare for an ultrasound?

No special preparation is necessary for most ultrasound examinations. The exceptions are a pelvic ultrasound, which may require you to have a full bladder. Your technologist, radiologist or doctor may tell you to drink up to six glasses of water two hours before the exam and avoid urinating until after the exam is over. An ultrasound of the liver, gallbladder, pancreas or spleen may require that you eat a fat-free dinner the evening before the exam and then fast until the procedure it completed the next morning. You will be notified if any special preparation is necessary for your scan.

CT

What is CT?

Computed Tomography, or CT, is a non-invasive medical test used to look at the lungs, bones, soft tissues and/or blood vessels. CT uses an x-ray tube that rotates 360º around the area being scanned, capturing multiple pictures or “slices” as it goes. The anatomical information is sent directly to a computer, where sophisticated software combines the images to create a nearly 3-D composite image of the organ, bone or object.

What is CT used for?

CT Scanning is effective in identifying issues within the chest, heart, abdomen, head and limbs, and for detecting certain cancers, like those in the colon or lung. In fact, a recent government study showed that heavy smokers may reduce their risk of death from lung cancer by 20% simply by having an annual CT scan. CT also assists with cancer treatment staging and monitoring, making it one of the most powerful allies against disease.

Is CT safe?

Computed Tomography uses small amounts of ionizing radiation to produce images, which causes concern for some patients. But advances in CT technology over the past decade have lowered the radiation dose significantly, and the Board Certified radiologists of RAO and expertly-trained technologists are able to adjust and monitor the dose administered based on patient size, so children and smaller patients are exposed only to what’s necessary for image capture, making CT safer than ever. Because of its sophistication, CT is used only when a highly detailed diagnosis is needed, and its benefits in such cases far outweigh any nominal exposure to radiation the test may produce.

How do you prepare for a CT scan?

Preparation for a CT scan can vary depending on the area being examined. Some CT scans, for example those used to look at blood vessels or intestines, require the use of a contrast agent, which may be administered by mouth, injection or enema. You may be asked to remove all detachable metal objects, such as your watch, jewelry, dentures, etc. You may be asked to avoid eating and drinking for a few hours before your test. Your doctor or RAO radiologist or technologist will notify you of any special considerations or steps to take before your scan.

What CT technologies are used by RAO?

RAO’s Medical Imaging Center and TimberRidge Imaging Center offer the 64-slice CT scanner with ASiR, a specialized feature that can reduce the radiation dosage for certain patients. This next-generation CT scanner utilizes four times the number of detectors offered by a conventional CT, enabling it to catch small lesions that may otherwise go undetected. It can scan the entire body in about 30 seconds and produce crisper images with fewer extraneous artifacts for a more complete and accurate 3-D representation than standard CT models.