Types and differences of x–rays
In some cases, standard x–ray tests are not enough for diagnosis of the pain source. In these instances, there are a number of specialized x–ray tests available, including:

CAT scan (computed axial tomography). This noninvasive or minimally invasive test uses multiple x–ray images, taken from different angles, to create three–dimensional images of body structures. It may be performed alone or with the use of a special dye called a contrast medium. This test may be used when an area inside the body needs to be viewed from multiple angles and in greater detail.

Arthrography. This minimally invasive test involves injection of a contrast medium into a joint, followed by a standard x-ray, CAT scan or MRI (magnetic resonance imaging). Its uses include identification of tendon and ligament injuries, torn rotator cuff and loosening of joint replacements or other prostheses.

Discography. This test is often performed on patients who are considering back surgery or who have not responded well to conventional treatments for back pain caused by conditions such as degenerative disc disease or a herniated disc. The patient wears a metal–free hospital gown and lies on an imaging table. After the skin is numbed with anesthetic, a needle is inserted into the intervertebral disc using x–rays as guidance. Once in place, the needle injects contrast dye to outline any damaged areas and CAT scans are taken. Pain medicines may be administered if pain persists beyond the usual recovery time, typically about one hour.

Fluoroscopy. This type of test uses x–rays to image internal body organs while they are in motion. A continuous x–ray beam is focused on the part of the patient being examined to create a detailed, moving image that appears on a monitor, much like a movie. Fluoroscopy can be used in pain management - for example, to guide corticosteroid injections inside a joint.

DEXA scan (dual-energy x-ray absorptiometry). Also known as a bone density scan, DEXA is the standard method of measuring bone mineral density. DEXA scans are often used to screen for the bone-thinning disease osteoporosis, especially in women after menopause. Some DEXA units use ultrasound instead of x-rays.

Angiography. This is an x–ray procedure in which contrast material is injected into one of the arteries of the heart. This allows the physician to detect if there is obstruction in coronary arteries. Angiography may be performed if the patient is experiencing chest pain.

Barium x-rays. These imaging tests use a chalky element called barium as the contrast medium. They include:

Upper GI (gastrointestinal) barium tests, such as barium swallow, barium meal and small-bowel series. Fluoroscopy or other x-ray techniques are performed after the patient consumes a liquid or solid containing barium. These tests can be used in diagnosing conditions that cause esophageal or abdominal pain, such as gastroparesis (delayed emptying of the stomach).

Barium enema. The patient is given an enema with a solution containing barium. The barium coats the insides of the intestines, allowing this area to be viewed in greater detail with an x–ray. This test may be used to determine causes of intestinal or pelvic pain, such as colon cancer.

Intravenous pyelography (IVP). These x-rays of the urinary tract use a contrast medium to help detect conditions such as kidney stones, bladder cancer and prostate enlargement (benign prostatic hyperplasia).

Mammography. Mammograms are specialized x-rays that create detailed images of the breasts. They are used to screen for and diagnose breast cancer and other breast conditions, such as cysts. The American Cancer Society recommends that women have annual mammograms starting at age 40.

If a contrast medium will be used, patients may be asked not to eat or drink after midnight before the test, and the physician may make minor changes in how the patient takes medication. The physician will ask about the patient’s history of allergies to screen for a potential allergic reaction to the dye.

A radiology technician or specially trained nurse generally takes x–ray films. At the time of the test, the examiner will ask the patient to remove any objects that may show up on the image (e.g., clothing, jewelry, wigs, watches or dentures). Splints or prosthetic limbs may also be removed in some cases.

Patients should inform the examiner if they have had an x–ray using a contrast dye or barium in the past few days. They should also make sure the examiner is aware of all medications that have been taken recently, including over–the–counter medications.

Female patients should be sure to inform the examiner if they are or may be pregnant because x–rays can be harmful to fetuses in rare cases. In cases where the benefits of the x–ray outweigh the potential risks, pregnant women may wear a lead apron over their abdomen during the test.

A lead apron is also often worn by patients to help protect sex organs from x–rays. In high doses, women’s eggs and men’s sperm can be affected by radiation. However, the risk of this occurring as a result of an x–ray test is extremely low. Women should also inform the examiner if they have an IUD (a form of birth control) implanted.