It is known that the stores of calcium in the body begin to be depleted, starting from the age of 30 years. Therefore, it is important to start diagnosing osteoporosis as early as possible, especially for women. For these purposes, the newest technique, densitometry of bones, has been developed. This method of research allows you to quickly and accurately determine the mineral density of bone tissue.
What is the difference between ultrasonic and x-ray densitometry of bones?
The two types of surveys described are based on fundamentally different effects.
The first indicated method assumes the establishment of mineral density with the help of densitometry of heel and radius bone. Ultrasound oscillations are faster in the tissue than it is denser. The data thus obtained is processed by a computer, the results are given in the form of indices showing deviations of the calcium concentration from normal values. This method is considered very accurate, as it allows to diagnose osteoporosis at the earliest stage.
X-ray densitometry is the imaging of the lumbar and thoracic spine in the lateral projection. In this case, bone density is calculated by means of special equipment based on the images obtained.
As a rule, the ultrasound method is more informative, but after performing such a densitometry, a complete radiographic study is appointed to confirm the diagnosis.
Preparing for bone densitometry
No special preparation is required before the examination. The only requirement is not to take calcium preparations 24 hours before densitometry.
For convenience, it is worth the following recommendations:
- Wear comfortable loose clothing without metal fasteners, zippers and buttons.
- Remove jewelry and glasses.
- Warn doctor about possible pregnancy.
It is worth noting that there is no need to prepare for ultrasound diagnostics, this is a very simple and fast procedure.
How do computer densitometry of bones?
Monoblock ultrasound devices have a small niche in which a foot, finger or hand is placed. After 15 minutes (sometimes - less) of painless effects, the measurement results are output to the computer. The diagnosis is established on the basis of two integral indicators - T and Z. The first value corresponds to the ratio (in points) of the measured bone density with the same value in healthy people under the age of 25 years. The Z-index reflects the concentration of calcium compared to the normal mineral content in the corresponding age group of the patient.
Estimates in excess of -1 point are characteristic of healthy people. Values ranging from -1 to -2.5 suggest the presence of osteopenia - the initial stage of demineralization of bones. If the score is below -2.5 points, there is reason to establish a diagnosis of osteoporosis.
How is X-ray densitometry of bones performed?
Stationary examination systems consist of a table with a soft covering where the person (lying down) is located, as well as a mobile "sleeve" that moves along the body and is localized over
A X-ray generator is built into the table, and a digital image processing device for the images is placed in the sleeve. After densitometry, they are displayed on the computer screen.
During the procedure, it is important to lie down without moving, sometimes experts ask to hold your breath for a short while to avoid blurring the picture.
The results are described by the radiologist, indicating the estimated scores of calcium concentration in the bones and tissue density.