Osteodensitometry is a clinical investigation which measures the bone density and represents a method to identify osteoporosis, as well as other problems of the bone tissue.
DEXA osteodensitometry is one of the most advanced techniques, which uses x-rays of various densities that go through the bone, allowing the assessment of the bone density and the degree of bone rarefaction, respectively.
The advantages of this system are multiple:
- the technique is not painful;
- the efficient radiation doses are very low (it identifies very small modifications of the bone density with a minimal radiation exposure);
- it can be performed at various levels, more frequently for the hip (femoral neck), spinal cord, forearm;
- the dimensions of the scanning mass carry the benefit of examining patients with a body weight of up to 160 kg;
The indication of ostedensitometry is determined by the attending physician who can request the approval of the orthopedic doctor, internal medicine doctor, rheumatologist or endocrinologist. The recommendation for an investigation and timely capture of the bone rarefaction (osteoporosis) is for:
- all women who are at menopause;
- men after 50 years of age, firstly smokers and individuals with chronic diseases treated with cortisone for a long time (bronchial asthma, etc.);
- children during the growth period who show vicious positions.
Diagnosis of osteoporosis
Considered to be a normal state of old people, osteoporosis is at the present moment a disease, even a major public health issue, because it affects more and more people. The assessment of the osteoporosis risk is based on the measurement of the mineral bone density. The measurement of the bone density is mainly performed by means of dual-energy X-ray absorbtiometry, shortly DEXA or DXA, considered to be the „gold standard” in the diagnosis of osteoporosis and in assessing the risk of osteoporosis fractures. The method uses X-rays, but the radiation exposure is very small: the patient is exposed to a dose of radiations 20 - 30 smaller than a chest X-ray. DEXA technology is also efficient for the follow-up of the effects of the treatment administered for osteoporosis and for the identification of other diseases that cause the loss of the bone tissue.
What skeletal regions are investigated? The mineral bone density is measured in the skeletal regions that are representative for osteoporosis: lumbar spine, hip, forearm or the entire skeleton. The choice of the region is made only by the specialist depending on the particular features of the patient. The result of the investigation is represented by the measured value of the mineral bone density and by T and Z score. The parameter that is suggestive for the diagnosis is the T score which shows how different is the mineral density of the patient from that of a young adult; this parameter is essential in the assessment of the bone mass.
Is classic radiography still necessary for the diagnosis of osteoporosis? Osteoporosis as a bone mass loss is visible on simple X-ray scan just in an advanced stage (after 30% of the bone mass has been lost); moreover, it is an inaccurate method to assess the mineral bone density. Attention! Even decreases of the bone density equal to 33% can be left out of the classic radiography. Sometimes rarefactions of up to 70% go unnoticed during the classic examination. Classic radiography of the skeletal segments is mandatory but for the diagnosis of vertebral fractures which can be the consequence of osteoporosis. Due to this reason, the patients who come for the densitometry assessment must also perform the profile X-ray of the dorsal spine, and lumbar spine, respectively. Due to the increased performance of DEXA equipment, it currently allows the fast scanning of the spinal cord in order to automatically assess the vertebral compressions with a lower exposure to radiation compared to the classic X-ray. DEXA equipment provided by the Academica Medical Centre allows the automatic diagnosis of vertebral fractures (through vertebral morphometrics) and then the replacement of the profile spinal cord X-ray for the diagnosis of vertebral compressions, given the conditions of a lower radiation and reduction of the time period and discomfort of the patient due to an additional visit to the radiology department.
How is osteoporosis diagnosed? The diagnosis of osteoporosis is determined based on the value of the T score measured only by DXA method.
- T score between 0 and -1: normal
- T score between -1 and -2,5: osteopenia (bone with a lower density, but not osteoporosis)
- T score under -2,5 suggests osteoporosis
This classification is valid only for women at menopause and for men over 50 years of age!
The diagnosis of osteoporosis based on the T score measured by DXA is subject to special rules in other situations (women who are not at menopause, young men, children, etc.) It is recommended that the diagnosis of osteoporosis should always be made before a frailty fracture because once the complications occurred the risk for a fracture increases very much. Osteoporosis is a disease that affects the entire skeleton and is described as the reduction of the bone mass and impairment of the bone resistance with the increase of the fracture risk. The complications of osteoporosis are frailty fractures, that are fractures which usually occur when falling from one’s own height. Osteoporosis fractures are as follows:
- Forearm fracture;
- Vertebral compression;
- Femoral neck fracture
- Other types of fractures in a suggestive setting (corticotherapy).
The equipment in our clinic allows the accurate assessment of the dimensions of the vertebrae by a rapid scanning of the entire spinal cord from the side, with a radiation much smaller than the conventional radiography. This assessment should be included in any examination for the diagnosis of osteoporosis because the patient may have fractures/vertebral compression which he/she is not aware of. Their presence cannot be identified through usual spinal cord densitometry and they can modify the therapeutic indications. For example, a patient may have some relatively good values of the densitometry upon the performance of DXA relative to the lumbar spine, hip or forearm, but he/she can have a compressed vertebra in the chest. Without an X-ray or vertebral morphometry the diagnosis can be wrong and the patient does not receive a treatment even though he/she has severe osteoporosis.
Exact evaluation of the body composition
The determination of the ratio between the muscle mass and fatty tissue is important both for specialists in medical rehabilitation and nutritionists. The osteodensitometry equipment at Academica Medical Centre assesses the proportion of the somatic development by calculating the percentage of fatty tissue and active muscle mass. Under the influence of a balanced diet and physical exercises muscle fibers develop and the fatty tissue carries variations depending on these factors throughout the entire life. The determination of the body composition is important for the correct assessment of the nutrition state and monitoring of the treatment administered for nutrition imbalances, as well as for the elaboration of some suitable therapeutic indications. DEXA is also considered the gold standard in the determination of the composition of the body, more precisely in the determination of fat percentage, muscle mass and water in the human body. What is this useful for? In the diets recommended for losing weight, the scale may sometimes provide inaccurate results: for example, a patient who at the beginning of the diet has 40 kg of fat out of the 100 shown by the scale, after the diet he/she loses 10 kg (apparently, a very good result) and may discover that he/she still remained with 40 kg of fat and the 10 kg were lost from the muscle mass. Opposite to this, another patient who, despite all efforts, does not seem to be losing weight on the scale, may discover that he/she is left with only 30 kg of fat to lose and that his/her muscle mass has increased which makes the diet a successful one. Bioimpedance equipment is frequently used for the assessment of the body composition, because they are more accessible and they are promoted within the cosmetic salon; though, the sensitivity of this method is much lower compared to densitometry.
The assessment of the growth and development process of the child
The osteodensitometry equipment at Academica Medical Centre supports the specialists by means of the pediatric software. Therefore, this equipment provides information about the stage, evolution of growth, growth differentiation between various segments of the child’s skeleton, together with the assessment of the risk for bone fractures. The growth and development of the child represents an extremely dynamic process which shows many modifications along its course. The mechanism of growth and development is genetically conditioned and influenced by external factors (diet, life conditions, physical exercises in the first years of life, various trauma, etc.) and internal factors (genetic and hormone factors). It can also calculate the percentage ratio of the bone tissue, the fatty tissue and the muscle tissue. At the same time it provides the timely evaluation of growth disorders, metabolic disorders, unwanted effects occurred after some treatments or consequences of some chronic diseases.
Visualization of calcifications of the abdominal aorta
An extremely recent application of the rapid scanning for vertebral morphometry is represented by the visualization of the calcifications of the abdominal aorta. These can be evaluated according to a scale named AAC (abdominal aortic calcification) with values ranging from 8 to 24 (AAC 8 or AAC 24). Both scales have the same value, it just needs to be stated which of the two scales was used. What is it useful for? A score over 3 for AAC 8 and over 5 for AAC 24, respectively, is a significant risk for coronary disease and stroke; the information is valuable when it comes to the start of a suitable cardiologic treatment: for example, a young patient with a slightly increased value of blood pressure would have an indication for a treatment against arterial hypertension while the calcifications of the abdominal aorta would indicate a rapid start of a much more aggressive and complex treatment.
Evaluation of the assembly of hip prosthesis
When other therapies to relieve the pain caused by the destruction of the hip fail, the replacement of the joint may be the answer. The replacement of the hip, named total hip arthroplasty, can relieve pain and bring the mobility we all need on a daily basis. A total hip replacement is a surgical procedure through which the cartilage and affected bones in the hip are replaced with an artificial material. Because of the software of the orthopedic prosthesis, the osteodensitometry equipment recognizes an already existing prosthesis, making the difference between the bone tissue and the material the prosthesis is made from. Therefore, the level of the bone density is real and we can diagnose the periprosthetic ossifications (bone formations which go around the total hip prosthesis) which can be responsible for the limitation of the movements of the joint. The postoperative clinical course of this complex procedure must be monitored and evaluated in order to identify potential complications. The real problem of a simple X-ray examination consists of its interpretation because the presence of the metal causes the occurrence of artifacts (except for some alloys, especially titanium).