Brainstem and Central Nervous System (CNS) Explained
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Bone densitometry is an instrumental technique to assess the mineral density of bones, thereby making it a valuable tool in diagnosing and monitoring osteoporosis.
Osteoporosis is a progressive skeletal disorder characterized by a significant decrease in bone mineral density (BMD) and the deterioration of bone microarchitecture. These changes compromise bone strength, greatly increasing the risk of fractures even from minor traumas such as a fall from standing height. The condition is often referred to as a "silent disease" because it can develop unnoticed over many years, without symptoms until a bone fracture occurs.
Osteoporosis risk is influenced by genetics, with a family history significantly raising the likelihood of developing the condition. Age-related bone density loss is another factor, especially in post-menopausal women due to lower estrogen levels. Inadequate intake of calcium and vitamin D also weakens bones. Additionally, lifestyle choices like limited physical activity, excessive alcohol, and smoking accelerate bone density loss.
Bone densitometry, also known as dual-energy x-ray absorptiometry (DXA), is the gold standard for diagnosing osteoporosis. This non-invasive test measures bone mineral density at various sites of the body, typically the hip and spine, and is crucial in assessing fracture risk. The results of a DXA scan are compared to the bone density of a healthy young adult and are reported as a T-score. A T-score of -2.5 or lower is diagnostic for osteoporosis.
Early detection of decreased bone density through regular screening can lead to the implementation of preventative strategies that can significantly decrease the risk of fractures. These strategies include lifestyle modifications such as increasing physical activity, improving nutrition, and, when appropriate, starting pharmacological treatments to enhance bone density and strength.
Bone densitometry employs a minimal dose of X-rays to measure the amount of calcium and other minerals present in a particular bone segment. The radiation doses are so minimal that even frequent examinations do not pose any health risk to the patient.
Among the various types of equipment used, Dual-energy X-ray absorptiometry (DEXA) is the most commonly used.
The entire process of bone densitometry is swift, taking approximately ten minutes. It is a painless procedure, and patients do not require any specific dietary or pharmacological preparations. Post-examination, patients can resume their regular activities.
However, if a patient has recently undergone a scintigraphic or radiological examination with a barium contrast medium, the densitometry should be postponed for a few days. Additionally, any metal objects such as coins, buckles, watches, and bracelets should be removed from the examination field.
The bone segments examined during bone densitometry depend on the patient's characteristics. Generally, the lumbar spine is evaluated in younger women (under 65 years), while the femoral neck is examined in older women and those with spinal pathologies. Sometimes, the examination may be conducted on both segments or at the radius (forearm).
Bone densitometry is highly recommended for individuals with significant risk factors for osteoporosis, which include:
If one or more of these risk factors are present, it is crucial to consult a healthcare professional to consider undergoing bone densitometry.
The diagnosis of osteoporosis is based on the comparison of the densitometric result with the average result of healthy adult subjects of the same sex and aged 25-30 years (T-score) and/or the average result of subjects of the same age and sex (Z-score).
As per the World Health Organization (WHO), the diagnosis of osteoporosis should be conducted, limited to the DEXA technique, considering the densitometric values, expressed in T-score as follows:
A T-score equal to 0 indicates that the examined subject has a bone density equal to the average of young individuals, while a T-score equal to or greater than -1 is still considered normal. If a T-score is between -1 and -2.5, the subject has reduced bone density, which is not severe enough to be considered osteoporosis but is significant enough to necessitate an effective treatment plan to prevent further bone demineralization. A T-score equal to or lower than -2.5 indicates the presence of osteoporosis and the need for appropriate medical care. Once the treatment has been initiated, the doctor can evaluate its effectiveness by subjecting the patient to periodic bone densitometry.