How does the bone density measurement work?
No preparation of the patient is necessary. Depending on the procedure, the examiner lies in or under the appropriate device. Bone density is measured in areas that are not superimposed by other bone segments, especially the femoral neck and the lumbar spine. The patient is dressed on a lounger. Metal parts in the examined region such as coins in the trouser pocket can falsify the measurement result and must therefore be discarded. If an artificial hip joint or other metal parts are present in the body, inform the examiner. The entire examination lasts between 10 minutes and half an hour. Sometimes the activity of the bone metabolism is additionally determined by means of certain substances in the urine, with special questions a blood sample may additionally be necessary.
How is the result evaluated?
The personal measured values are compared with normal values of healthy equals (Z-value) as well as healthy about 30-year-old test persons (T-value). Depending on the deviation of the T-value, a distinction is made between normal results, bone poverty (osteopenia) and bone loss (osteoporosis). If the bone loss accompanied by typical fractures, it is called severe osteoporosis. The Z value gives an indication of whether drug therapy may be indicated. However, this decision does not depend solely on the measured value, but is primarily based on the other medical findings.
Will the investigation be repeated?
If osteoporosis has been diagnosed and appropriate therapy initiated, its success should be reviewed. Since reconstruction in the bone takes a certain amount of time and unnecessary radiation exposure should be avoided, a new bone density measurement using X-rays is recommended at the earliest after two years. For certain very high-risk individuals, such as patients undergoing continuous cortisone therapy or after organ transplants, osteodensitometry must be performed at regular intervals (twice a year or annually). In order to be able to compare the examination results with each other, the control measurements on the same device are recommended, ideally with the same examiner.