QUANTITATIVE BONE DENSITOMETRY:
We are pleased to provide low cost, state-of-the-art Quantitative Bone Densitometry with our "24 slice" Helical CT. The Helical CT allows us to measure the bone density of the spine and provides medical professionals with a very accurate assessment.
Osteoporosis is a common disorder affecting a large number of adults. In the United States more than 25 million people are afflicted, particularly women. Many suffer disabling fractures of the spine, which is the most common site of involvement.
Osteoporosis is believed to be responsible for about 1.3 million fractures annually including more than 500,000 spine, 250,000 hip, and 240,000 wrist fractures.
Up to 30% of elderly people with hip fractures die within 6 months of their injury. The difference in sex distribution in osteoporosis is especially significant as women who are 65 years of age or older represent the fastest growing segment of the population in the United States. The worldwide increase in life expectancy will most likely result in a concomitant rise in the prevalence of osteoporotic fractures of all kinds over the next decades.
During the past decades, osteoporosis, called the "silent epidemic," has gained increased attention. The involvement chiefly of women and the insidious loss of bone manifested primarily as crush fractures of the spine, hip and wrist are widely known facts. Public awareness of this disorder also has been heightened by the resulting increase in health care expenditure that is currently estimated to be in excess of 7 billion dollars.Computed tomography (CT) is widely utilized for non-invasive quantitative determination of the bone mineral content. The advantage of quantitative CT is its ability to measure either trabecular or cortical bone in the central or peripheral skeleton. In the spine it can provide precise three dimensional anatomic localization allowing direct density measurement of trabecular bone separate from cortical bone. In the lumbar vertebrae only a portion of the bone is high turnover trabecular bone. Other techniques, such as DXA, measure compact and cancellous bone together, decreasing the sensitivity of the test.
Quantitative CT measures change in trabecular mineral content in the spine with great sensitivity and precision. The principle of quantitative CT is based on a display of the x-ray attenuation coefficient of volume elements (voxels). Using a mineral reference standard of material that mimics bone, a bone mineral equivalent value of a given region of interest in a CT image can be calculated. Solid state phantoms have replaced liquid phantoms because of their statbility. Quantitative CT measurements of the axial skeleton are performed visualizing three or four consecutive lumbar vertebrae. 8-10 mm slices are performed through the midportion of these vertebral boides. A volume of purely trabecular bone is selected as a region of interest and the density of this region is converted to a mineral equivalent value. The exam is performed in 5-10 minutes. Radiation exposure is approximately 10% of a routine CT study.
Quantitative CT has made it possible to obtain a multitude of clinical observations on age related trabecular bone loss and the effects of menopause and estrogen replacement. The rate of spinal trabecular bone loss after surgical removal of the ovaries has been found to be greater than bone loss after natural menopause. With respect to these studies the evidence linking estrogen to maintenance of skeletal mass in women is convincing. The rates of postmenopausal spine or trabecular bone loss observed with quantitative CT were found to be greater than those observed by DXA.