What is a Bone Density Test?

In medical terms, bone density is defined as the amount of mineral matter per cubic centimeter of bones. It is measured in three parameters, viz., bone density in g/cm³, the z-score  and the t-score (standard deviation above/below the mean of the patient's and normal healthy person age and gender respectively).

It is measured by a technique called densitometry in the radiology department, which is the technical term for a bone density test. It is used to diagnose osteoporosis, a disease in which the bones become very fragile and are at a high risk of fracture.

This test is the key factor in the diagnosis of osteoporosis. Before the advent of technology, it was difficult to diagnose the disease, and it would be detected only at a very advanced stage. But with this test, it has become easy to diagnose and prevent it accordingly.

Performing a timely test can reduce the bone breakage risk, give an exact idea of the state of the patient's bones, and what type of treatment they require.

Losing a certain amount of bone mass is a part of aging process, in which the bones simply get thinner and lose their normal density. This process known as osteopenia in medical terms. This happens due to the loss of calcium and other minerals in the bone.

This is a gradual process that eventually leads to osteoporosis, making the bones weaker and prone to fractures. According to research statistics, women above 65 years of age are more prone to this condition as compared to men of the same age.

This test actually calculates the density of the bone minerals, mainly calcium, which is the most important of all. The test is performed with the help of various methods that use CT scan (Computer Tomography scan), X-ray, or ultrasound technique. Some of these tests are explained here briefly:

This is the most basic test that is performed in order to diagnose any primary bone-related problem. An ultrasound machine uses sound waves of frequencies greater than the upper limit of the human hearing range through water or air to perform the task.

This test is painless, fast, and has no harmful radiations. It is a very basic test, and hence is unable to detect complicated bone problems.

DXA is a very successful method of measuring the bone density and hence the most popular one. It utilizes two different X-ray beams to determine the density of the bone, and is preferred for calculating the density of spinal and hip bones.

In this test, bone mineral density is found out by the amount of X-ray beams absorbed by the bone, and it can measure as little as 2% loss of bone density per year. This test is fast, but is costlier than ultrasound testing. Single-energy X-ray absorptiometry (SXA test) is used for the bones of forearms and heels.

This is a form of DXA test that is used to measure the density of bones in arms, wrists, and legs. P-DXA test machines are portable, which is why most of the physicians have them, and one need not go to a radiology center for this test. This test cannot detect the effect of medication on bones, and hence it is not as popular as DXA test.

DPA test is done to estimate the density of bones in the hip and spinal region. It uses certain radioactive elements for this purpose. This test also uses low radiations, but it is not as popular due to its slow test results.

Q-CT scan is done to measure the bone density in the vertebral (spinal) region. The Peripheral Quantitative Computer Tomography (P Q-CT) scan is used to measure the density of arms and legs. This test is not very famous as it is expensive, utilizes a high amount of radiation, and is not accurate.

Women are generally advised to get this test done after menopause, as that is when they start losing calcium from their bodies rapidly. These tests are very helpful, because if the bone density of a person is less than normal, then he/she can start taking precautionary measures in order to increase the bone strength.

Some of the best measures of increasing and retaining the remaining density are weight training exercises, walking, and taking vitamin D and calcium supplements. But these measures should only be implemented after proper consultation with a physician.

Disclaimer: This website story is for informative purposes only, and should not be used as a replacement for expert medical advice.