No abstract

Osteoporosis is a metabolic bone disorder that is characterized by reduced bone mass and a deterioration of bone structure which results in an increased fracture risk. Since the disease is preventable, diagnostic techniques are of major importance. Standard techniques determine bone mineral density, whereas some of the newer techniques focus on trabecular structure. This article reviews structure analysis techniques in the diagnosis of osteoporosis. Imaging techniques applied to the assessment of trabecular bone structure include conventional radiography, magnification radiography, high-resolution CT (HRCT) and high-resolution MR imaging (HRMRI). The best results were obtained using high-resolution tomographic techniques. The highest spatial resolutions in vivo were achieved using HRMRI. The most common texture analysis techniques that have been used are morphological parameters (analogous to bone histomorphometry). Fractal dimension, co-occurrence matrices, mathematical filter techniques and autocorrelation functions are more complex techniques. Most of the studies evaluating structure analysis show that texture parameters and bone mineral density both predict bone strength and osteoporotic fractures, and that combining both techniques yields the best results in the diagnosis of osteoporosis.

The authors discuss current capabilities of three common bone densitometry techniques--single photon absorptiometry, dual photon absorptiometry, and quantitative computed tomography--and potential capabilities of new innovations of each of these techniques. They believe that use of bone densitometry is valid in the following four clinical applications and recommend its usage to (a) assess patients with metabolic diseases known to affect the skeleton, (b) assess perimenopausal women for initiation of estrogen replacement therapy, (c) establish a diagnosis of osteoporosis or assess its severity in the context of general clinical care, and (d) monitor the efficacy of treatment interventions or the natural course of disease.

Prevention of fragility fractures in older people has become a public health priority, although the most appropriate and cost-effective strategy remains unclear.

Noninvasive bone densitometry techniques have significantly improved our understanding of the pattern and magnitude of bone loss over the life span. Quantitative computed tomography (QCT) is capable of selectively measuring highly labile trabecular bone in the central portion of the vertebrae. Trabecular bone mineral density (mg/ml) was determined in 538 healthy women ranging in age from 20 to 80 using GE CT/T scanners at 80 kVp. Various statistical regressions were performed for the entire population to describe the general pattern of bone loss from the spine; a cubic model (r = -0.69, SEE = 26.0 mg/ml) was found to be statistically superior (p less than 0.01) to linear, quadratic, or exponential models. An average bone loss was approximated from these regression analyses with a yearly absolute rate of -2.02 +/- 0.097 mg/ml per year (p less than 0.0001). The average rate of change for premenopausal women was -0.45 mg/ml per year (p less than 0.05), for perimenopausal women was -4.39 mg/ml per year (p less than 0.0001) and for postmenopausal women was -1.99 mg/ml per year (p less than 0.0001). QCT values were also stratified into 5 and 10 year age groups and analyzed separately for pre- and postmenopausal women. The 5 and 10 year interval stratification revealed no identifiable bone density decrements prior to midlife using analysis of variance statistical methods; significant losses of bone mineral density were noted to correspond with the usual time of menopause and to continue into old age. Various two-phase regressions were employed using age and menstrual status to improve the description of age- and menopause-related bone loss.(ABSTRACT TRUNCATED AT 250 WORDS)