Understanding tests used to detect bone problems

Bones can be damaged by fractures or other injuries, as well as irritations. The damage can also be caused by diseases, such as osteoarthritis, infections or cancer. Various tests and examinations can help to find out what is causing problems in the bones and joints.

Before more specific bone examinations are performed, preliminary tests are typically done, which typically include a detailed discussion with your doctor, a physical examination, and blood tests if necessary. These preliminary tests are used to help decide whether any further diagnostic testing is a good idea and to prevent any unneeded treatment. The tests are also important to correctly interpret the results of any scans.

For instance, an x-ray image can easily detect a bone fracture, but it doesn't give doctor much information about back pain. Modern, high-resolution equipment can often detect changes in bones, tendons or cartilage that don’t have any medical significance. Once they have been detected, these kinds of changes can easily result in unneeded treatment, though.

Bone tests and examinations may have side effects or involve exposure to radiation as well. So there are good reasons to be cautious about these kinds of diagnostic procedures.

X-ray examinations

X-ray examinations are especially useful for examining the skeleton, but less so for examining soft tissues. This is because the different types of tissue allow different amounts of radiation to pass through. Bones absorb almost all the radiation because they are so dense – so they appear as white or gray outlines on the x-ray image. Soft tissues like fat or muscles let almost all the radiation pass through – they appear as black areas on the x-ray image.

X-ray examinations always involve exposure to radiation, which is why they should only be done if medically necessary. Pregnant women only have x-rays in emergency situations.

When is this approach used?

X-ray examinations are used to detect problems like fractures, abnormal positions of bones, or bone diseases like osteoarthritis. They are also used to plan surgery or to check the position of a prosthesis after an operation. Dentists use x-rays to detect things like diseases in the roots of the teeth.

What does it involve?

Before having an x-ray you are asked to remove any clothing and jewelry from the part of the body that is to be x-rayed. Depending on the part of the body to be examined, you may need to lie down, sit or stand. While the x-ray is being taken, your body is positioned between the radiation source and the x-ray film. Genitals are protected from radiation by a lead apron if possible. The medical staff will usually also wear lead aprons for protection or briefly leave the x-ray room. It only takes a few seconds to get the image.

Computed tomography

Computed tomography (CT) makes it possible to get more exact x-ray images of the body. The x-rays are sent through the body from different directions. CT scans do not consist of one x-ray image of the part of the body that is being examined. Instead, different x-ray images are taken in thin layers (“slices”). A dye is sometimes put into the body before the scan to make certain structures more visible on the x-ray image.

A computer uses the data from these individual images to put together a multidimensional cross-sectional image of the part of the body that was scanned. In CT examinations people are exposed to considerably higher levels of radiation than in simple x-ray examinations.

When is this approach used?

Computed tomography may be used to see changes in the bones that cannot be seen, or can only be seen very poorly, using conventional x-ray images. Things like fractures, bone tumors and dead bone tissue can be shown in more detail and their position can be described more accurately.

What does it involve?

During the examination, you are moved through a ring-shaped CT scanner while lying down. An x-ray source in the CT scanner rotates around the part of your body that is being scanned. Depending on how much of the body is scanned, the procedure takes about 5 to 30 minutes in total.

Magnetic resonance imaging (MRI)

MRI scans are particularly useful for examining soft tissues like muscles, ligaments or joint cartilage.

Magnetic resonance imaging also produces detailed cross-sectional images of the body. Instead of x-rays, this technique uses magnetic fields and radio waves, hence the name.

Put in simple terms, the MRI scanner measures the activity of the body’s hydrogen atoms. The signals measured during this procedure are converted into visual information and can be seen on a computer as two- or three-dimensional images of bones, joints and soft tissues.

When is this approach used?

MRI examinations are used for things like knee, shoulder or spine problems. MRI imaging can show slipped discs, meniscus injuries, and tendon injuries in the shoulder.

People with metallic implants might not be able to have MRI scans, like people who have a .

What does it involve?

An MRI scanner is a large, tunnel-like device containing special coils that produce magnetic fields and radio waves. To do the examination you are asked to lie down on an examination table which is then moved into the machine as far as needed, depending on which part of your body is being examined. While the images are being taken you will hear loud tapping noises.

Some people may find the small space and unusual sounds distressing. An MRI scan can take about 15 to 30 minutes in total. Nowadays some practices and hospitals have open MRI scanners, which can be helpful for people who are frightened of being in a confined space or who are very overweight.

Bone density tests (bone densitometry)

Bone density tests (also called bone densitometry or osteodensitometry) measure the amount of minerals in the bones. The results tell us how stable the bones are. Bone density is measured using a special x-ray technique called dual energy x-ray absorptiometry (DXA or DEXA).

DEXA sends weak x-rays through the bones of the and the top of the thigh bone. The test measures how easily x-rays pass through the bones. The lower the bone density, the more x-rays pass through them. People who undergo DEXA are exposed to less radiation than in a conventional x-ray examination.

Age-related changes to the spine can affect the reliability of the bone density measurements. That is why measurements are usually done on the thigh bone, unless somebody has two artificial hips.

When is this approach used?

Bone densitometry can be used to find out whether someone has osteoporosis. But the risk of a fracture doesn’t only depend on bone density. That is why the bone density measurement should always be looked at together with other risk factors and a person’s general state of health.

What does it involve?

To have a DEXA scan, you will be asked to lie flat on your back. If the density of the bones in your spine is being measured, your legs will be raised at a 90° angle. To measure the neck of the femur, your legs will lie flat.

A generator below the examination table produces x-rays while a scanner moves above your body to measure how much radiation was absorbed by your body. The examination takes about 5 to 10 minutes.

Bone scans

Bone scans (bone scintigraphy) produce images of bone metabolism. A weak radioactive substance is injected into your body before the examination. It accumulates in the bones, making it easier to see the bones’ metabolic activities in the image.

When is this approach used?

Bone scintigraphy is used to detect cancerous metastases and inflammations in the bones. Because cancerous and inflamed tissues have especially active metabolisms, they store more of the radioactive substance than healthy tissue. But the scan can also be used to detect dead tissue: It can no longer be seen in the image because it no longer has a metabolism. Bone scans also involve exposure to radiation.

What does it involve?

To prepare for the examination, the doctor injects the radioactive substance into a vein. It takes a few hours for this substance to spread throughout your body. Then you lie down and a special camera takes images as it moves over your body.

Bone biopsies and bone marrow biopsies

In bone biopsies, the doctor takes some tissue out of the bone using a thin needle.

In bone marrow biopsies, the tissue is taken from the bone marrow. The bone marrow is inside the bone and contains the blood stem cells that produce new blood cells. The bone marrow also produces immune cells for the body’s immune system.

When is this approach used?

Bone biopsies are special tests that are used in particular to examine rare bone tumors.

Bone marrow biopsies are mainly used to diagnose different types of blood cancer such as leukemia.

What does it involve?

The skin above the bone is first numbed using a local anesthetic. A small cut is then made to insert the biopsy needle.

In bone marrow biopsies, the sample is usually taken from the upper part of the pelvic bone (the iliac crest) or from the breastbone. The sample is then tested in a laboratory.

Kauffmann G, Sauer R, Weber W. Radiologie: Bildgebende Verfahren, Strahlentherapie, Nuklearmedizin und Strahlenschutz. München: Urban und Fischer; 2011.

Niethard FU, Pfeil J, Biberthaler P. Orthopädie und Unfallchirurgie. Thieme; 2017.

Pschyrembel Online. 2022.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on April 25, 2023

Next planned update: 2026


Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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