BMD-DEXA stands for Bone Mineral Density - Dual Xray Absorptiometry. It is used to ascertain the density and strength of bones. It is a non-invasive test lasting around 10-15 minutes. The patient is not inconvenienced during the test. No prior preparation is needed for the test. The patient has to lie down on the machine while it conducts a head to toe scan.The test is evaluated by comparing the bone density of the patient with that of a healthy 30-year-old male. It is denoted by T-score, which is a standard deviation from the mean, which is an average healthy30- year old male. So if the bone quality of the patient is exactly like that of an average healthy 30-year old male, the T-score would be 0.A T-score of +1.0 to -1.0 is considered to be Normal.A T-score of -1.0 to -2.5 is considered to be osteopenia (insufficiency).A T-score of less than -2.5 is considered to be frank osteoporosis.DEXA scan is performed by passing X-rays through specific areas of bone, usually near the hip (proximal femur) and the lower back (lumbar spine), as these areas are more prone to developing osteoporotic fractures..The X-rays pass partially through the bone and cast a "shadow" on the film which acts like a receptor. The denser the bone, the darker the shadow, as a smaller amount of the X-rays are able to penetrate a denser bone.The penetrating X-rays are then quantified to determine the bone mineral density.In the clinical setting, it is performed to evaluate the strength of the bones of at-risk patients, in order to start corrective therapy. It determines at how much risk is a patient at, of developing fractures with a trivial trauma.In the research setting, it is evaluated to measure the starting and the end points of a study.Recommended for:Those who are at-risk includes men and women over the age of 65 years.Postmenopausal women.People with renal insufficiency.People with malnourishment.People with metabolic bone diseases.People with intestinal disorders.People with malabsorption syndromes..DrawbacksA theoretical possibility of cancer in the future due to exposure to ionising radiation, though the incidence of DEXA-induced cancers is remarkably small.Also, because the test picturises a complex 3D structure using 2-D imagery, a larger but less dense bone can give a false result of sufficient density. In other words, the test tends to give false negative results in larger individuals.Dr Hrishikesh Patkar is Consulting Orthopedic Surgeon
BMD-DEXA stands for Bone Mineral Density - Dual Xray Absorptiometry. It is used to ascertain the density and strength of bones. It is a non-invasive test lasting around 10-15 minutes. The patient is not inconvenienced during the test. No prior preparation is needed for the test. The patient has to lie down on the machine while it conducts a head to toe scan.The test is evaluated by comparing the bone density of the patient with that of a healthy 30-year-old male. It is denoted by T-score, which is a standard deviation from the mean, which is an average healthy30- year old male. So if the bone quality of the patient is exactly like that of an average healthy 30-year old male, the T-score would be 0.A T-score of +1.0 to -1.0 is considered to be Normal.A T-score of -1.0 to -2.5 is considered to be osteopenia (insufficiency).A T-score of less than -2.5 is considered to be frank osteoporosis.DEXA scan is performed by passing X-rays through specific areas of bone, usually near the hip (proximal femur) and the lower back (lumbar spine), as these areas are more prone to developing osteoporotic fractures..The X-rays pass partially through the bone and cast a "shadow" on the film which acts like a receptor. The denser the bone, the darker the shadow, as a smaller amount of the X-rays are able to penetrate a denser bone.The penetrating X-rays are then quantified to determine the bone mineral density.In the clinical setting, it is performed to evaluate the strength of the bones of at-risk patients, in order to start corrective therapy. It determines at how much risk is a patient at, of developing fractures with a trivial trauma.In the research setting, it is evaluated to measure the starting and the end points of a study.Recommended for:Those who are at-risk includes men and women over the age of 65 years.Postmenopausal women.People with renal insufficiency.People with malnourishment.People with metabolic bone diseases.People with intestinal disorders.People with malabsorption syndromes..DrawbacksA theoretical possibility of cancer in the future due to exposure to ionising radiation, though the incidence of DEXA-induced cancers is remarkably small.Also, because the test picturises a complex 3D structure using 2-D imagery, a larger but less dense bone can give a false result of sufficient density. In other words, the test tends to give false negative results in larger individuals.Dr Hrishikesh Patkar is Consulting Orthopedic Surgeon
