Computerized bone mineralometry (MOC) is the "instrumental examination used to ascertain (diagnose) osteoporosis because it allows you to accurately measure bone density.
It has become known why more and more women perform it when they enter menopause.
However, this test should not be performed by all women entering menopause because it cannot reliably identify those who, in the general population, will be at risk of fracture.
The MOC, in fact, is a useful test to ascertain (diagnostic test) osteoporosis where it is thought to be present and not to verify its absence.
Unlike the pap test which, on the other hand, is used to verify that you have no lesions and therefore must be performed by all women (screening or control exam).
Based on the available scientific evidence, MOC should only be performed on people with known risk factors for fractures, taking into account their age.The test
The examination is quick and painless, uses a limited dose of radiation and requires no special preparation.
It can affect different parts of the skeleton, often the femur or the spine.
It can be performed while remaining fully clothed but without wearing metal objects.
Part of the X-rays emitted by the instrument are absorbed by the body tissues, such as fat and bone, and a special device (detector) allows to produce an "image of the investigated area".
Among the various techniques available, DEXA (dual energy X-ray absorption) is the one that presents the best cost / benefit ratio. Compared to other X-ray examinations, MOC with the DEXA technique uses a much lower level of radiation.
Although it is a very safe procedure, it should not be performed during pregnancy.
Repeated and frequent checks with intervals of less than 18-36 months are useless.
The cases in which the execution of the MOC is indicated are:
- early menopause (before 45 years of age)
- chronic therapies (ongoing or planned) with general corticosteroid, antiepileptic, anticoagulant, immunosuppressant and antiretroviral drugs
- postmenopausal women with relatives, on the maternal side, affected by fractures not caused by trauma before the age of 75
- postmenopausal women with a body mass index of less than 19 kg / m²
- osteoporosis documented by radiography or ultrasound
- conditions recognized as a possible cause of secondary osteoporosis
The assessment (diagnosis) of osteoporosis is based on the comparison between the value of the bone density obtained from the examination and the average value of healthy adults belonging to the same sex.
MOC with the DEXA technique then compares the bone density of the person examined with that expected in a healthy adult of the same age, sex and ethnicity.
To evaluate the result of the exam, parameters are used, the best known of which is the T-score.
According to the World Health Organization, the diagnosis using the DEXA technique must be carried out considering the values of bone density, expressed in T-score according to the following scheme:
- T score greater than or equal (≥) to -1 = normal result
- T score between -1 and -2.5 = result indicative of osteopenia
- T score less than (<) than -2.5 = result indicative of osteoporosis
- T score less than (<) of -2.5 coupled with fracture = result indicative of severe osteoporosis
In the interpretation of the results it must be borne in mind that it is not always easy to compare the results obtained with different equipment or results obtained from the measurement of different bone segments of the same person.
It is therefore recommended to compare only the densitometric investigations performed with the same instrument which obviously must be subjected to periodic quality controls.
Although bone mineral density results can offer a good indication of bone strength, the results of a DEXA MOC cannot predict fracture risk which is a function of other factors such as, for example, bone mass. age, gender or a history of previous falls that your doctor should consider when deciding whether to seek medication.
In general, a densitometry that reports a reduction in bone density does not in itself indicate the presence of osteoporosis but represents a very important data for the formulation of the diagnosis in association with the blood or instrumental tests required by the doctor.Bibliography
Piedmont Region Health and Health Protection Department - Guidelines for Osteoporosis (approved with D.D. n. 233 of 20-09-2007)
World Health Organization (WHO). WHO Scientific Group on the Assessment of Osteoporosis at Primary Health Care Level. Summary Meeting Report