Ultrasound transmission as a sensitive indicator of bone change in Japanese women in the perimenopausal period

Evaluation of ultrasound transmission velocity and 3-dimensional radiology in different bone types for dental implantology: a comparative ex vivo study

OBJECTIVE

To evaluate ultrasound transmission velocity (UTV) for assessment of mechanical bone quality, an ex vivo comparison of different bone types measured with UTV, 2-dimensional (2D) histomorphometry and with 3-dimensional (3D) radiology (cone-beam computerized tomography [CBCT], computerized microtomography [μCT]) was conducted.

STUDY DESIGN

Clinical cortical, cancellous, and mixed bone (each n = 6) was measured via UTV (m/s), CBCT (white pixel/black pixel ratio [WP/BP]), μCT (bone volume/total volume [μBV/TV]), and histomorphometry (bone volume/total volume [hBV/TV]). UTV values were correlated with 2D-histomorphometry and 3D-radiologic results.

RESULTS

For the cortical, cancellous, and mixed bone samples, respectively, UTV values were 1,945.17, 1,266.9,and 1472.2 m/s, WP/BP quotients were 0.96, 0.15, and 0.33, μBV/TV quotients were 0.94, 0.2, and 0.47, and hBV/TV quotients were 0.96, 0.24 and 0.39. Significant correlations between UTV and the other methods were seen (P < .0001).

CONCLUSIONS

Similar to the other methods, UTV is able to discriminate between different bone types ex vivo.

Ultrasound transmission velocity for noninvasive evaluation of jaw bone quality in vivo before dental implantation

For the insertion of dental implants, mechanical bone properties at the implantation site have great impact both for therapeutic regimes as well as for the overall long-term success, making a reliable method for the preoperative assessment of the bone quality desirable. Ultrasound transmission velocity (UTV) has been introduced as a noninvasive method to analyze mechanical properties of bone. The aim of this study was the first intra-oral in vivo assessment of alveolar crest UTV values of edentulous jaws. Partly or fully edentulous patients (n = 108) were enrolled in this study, taking into account possible influence factors that affect bone quality (osteoporosis, radiation therapy). Six intra-oral measurement points were used: left side region, right side region and frontal region, for upper and lower jaw, respectively. Ultrasound transmission velocity values were measured bicortically (in bucco-oral direction) and correlated to sex, age, measurement site and history of osteoporosis or radiation therapy. We found a minimum mouth opening of 30 mm, as well as a residual alveolar ridge height of 8 mm as thresholds for a reliable intra-oral placement of the device. Xerostomia was no contraindication. Assessment of intra-oral UTV showed significantly higher values both for mandibular side regions (female 1713 +/- 153 m/s, male 1734 +/- 221 m/s) and the maxillary frontal region (female 1665 +/- 189 m/s, male 1648 +/- 82 m/s) than for maxillary side regions (female 1538 +/- 177 m/s, male 1583 +/- 90 m/s). These data were even more clarified by intra-individual correlation of upper and lower jaw side region UTV values. We found no correlation between assessed UTV values and the variables sex, age, osteoporosis or radiation therapy. The use of a small UTV device in this study allowed the recording of intra-oral UTV values in a large and heterogeneous patient collective for the first time. Assessment of alveolar-ridge UTV might offer the possibility to identify critical bone quality before implantation or to monitor bone healing (mineralization) after augmentation procedures.

The role of quantitative ultrasound in the assessment of bone: a review

Quantitative ultrasound (QUS) bone measurement is a promising, relatively new technique for the diagnosis of osteoporosis. Unlike to the more established method of bone densitometry [measurement of bone mineral density (BMD) e.g. using dual X-ray absorptiometry (DEXA)], QUS does not use ionizing radiation. It is cheaper, takes up less space and is easier to use than densitometry techniques. The two QUS parameters currently measured are broadband ultrasound attenuation (BUA) and speed of sound (SOS). The reported age-related changes for healthy women range from -0.27% to -1.62% per year for BUA and from -0.06% to -0.19% per year for SOS. Precision ranges from 1.0 to 3.8% (CV) for BUA and from 0.19 to 0.30% (CV) for SOS. The new method of imaging ultrasound has improved the precision of QUS measurements. QUS is significantly correlated with BMD. Studies with the latest equipment have shown r-values between 0.6 and 0.9 in site-specific measurements, and QUS is thus believed to reflect mainly BMD. However, other studies indicate that QUS measures something other than the actual mineral content of bone, namely bone quality, e.g. in vitro studies have shown that QUS reflects trabecular orientation independently of BMD. In both cross-sectional and prospective studies, QUS seems to be as good a predictor of osteoporotic fractures as BMD. In two large prospective studies, QUS also predicted fracture risk independently of BMD. QUS has just begun to be used systematically for monitoring the response to anti-osteoporotic treatments in prospective trials. In the studies performed, QUS has been found to be useful in the follow-up of patients. QUS is thus a promising new technique for bone assessment.

Influence of weight and gonadal status on total and regional bone mineral content and on weight-bearing and non-weight-bearing bones, measured by dual-energy X-ray absosorptiometry

OBJECTIVE

To evaluate the influence of weight on total body bone mineral content (BMCTB) and regional body bone mineral content (head, arms, trunk and legs). This was studied in accordance with gonadal status and the weight-bearing or non-weight-bearing status of each region.

METHODS

The study included 94 postmenopausal women (mean age 60.6 +/- 10.5 years), 36 perimenopausal women (mean age 49.0 +/- 2.3 years) and 60 premenopausal women (mean age 36.1 +/- 6.9 years). Full-body bone densitometry (DXA), for measuring total body bone and regional bone mineral content, was carried out in all the women.

RESULTS

Among these groups, the influence of 1 kg of body weight on total and regional bone mineral content (percent) did not differ (paired test P ns). In the overall group of women, paired comparison showed differences between the head and other zones measured (P = 0.036-0.004). In the overall group of women, no differences were found in the percent influence of 1 kg body weight on bone mineral content in any study zone (by ANOVA, Fisher's PLSD post hoc test and the Kruskal-Wallis test). In the overall group of women, Fisher's r to z test revealed a non-significant relationship between weight and the bone mineral content of the head (r = 0.49, P ns) but in every other region the relationship between weight and bone mineral content was significant (r = 0.36-0.54, P < 0.0001 in all).

CONCLUSIONS

The effect of body weight on BMCTB and regional did not differ significantly with either gonadal status or weight-bearing (legs) and non-weight-bearing bones (arms).

The role of ultrasound in the assessment of osteoporosis: a review

Osteoporosis is now being recognized as a "silent epidemic" and there is an increasing need to improve its diagnosis and management. Quantitative ultrasound (QUS) measurement [broadband ultrasound attenuation (BUA) and velocity] is emerging as an alternative to photon absorptiometry techniques in the assessment of osteoporosis. The fundamental principles governing ultrasound measurements are discussed, and some of the commercially available clinical systems are reviewed, particularly in relation to data acquisition methods. A review of the published in vivo and in vitro data is presented. The general consensus is that ultrasound seems to provide structural information in addition to density. The diagnostic sensitivity of ultrasound measurement of the calcaneus in the prediction of hip fracture has been shown by recent large prospective studies to be similar to hip bone mineral density (BMD) measured with dual-energy X-ray absorptiometry (DXA) and superior to spine BMD. Ultrasound has also been shown to correlate better with the type of hip fracture (intertrochanteric or cervical) than BMD and to provide comparable diagnostic sensitivity to spine BMD in vertebral fractures. It has also been observed that combining the results of both ultrasound and DXA BMD significantly improved hip fracture prediction. Areas where further research is required are identified.

Transmenopausal change of trabecular bone density and structural pattern assessed by peripheral quantitative computed tomography in Japanese women

Trabecular bone pattern, related to connectivity, was analyzed along with a separate measurement of cortical and trabecular bone mineral density (BMD) at the distal radius by peripheral quantitative computed tomography (pQCT) in 48 perimenopausal women, consisting of 25 premenopausal women aged 41 to 52 (mean 46.6 +/- 2.9 years) and 23 early postmenopausal women aged 46 to 59 (mean 53.2 +/- 3.2 years) within 5 years of the menopause (mean 2.7 +/- 1.5 years). No significant difference was found in either cortical or trabecular bone density between premenopausal and postmenopausal women despite a significant difference in age (premenopause vs postmenopausal: 46.7 +/- 2.9 years vs 53.2 +/- 3.1 years, p < 0.00001), including a slow change of BMD, if any, before and within 5 years of the menopause. However, analysis of trabecular fragments and perforation revealed a significant increase of the number of perforations in postmenopausal compared with premenopausal women (premenopausal vs postmenopausal: 0.9 +/- 1.6 vs 2.9 +/- 2.3, p < 0.002), indicating that disconnectivity has already increased before a significant reduction of BMD. Furthermore, chi-square analysis showed that even postmenopausal women with trabecular BMD more than 160 mg/cm3 were about 11 times more likely to have three or more perforations than premenopausal ones (odds ratio: 11.42, F = 0.030). These data suggest that trabecular bone connectivity is more sensitive that BMD in the detection of the early changes of postmenopausal osteoporosis.

Ultrasound velocity, through bone predicts incident vertebral deformity

We followed 130 postmenopausal women without evidence of vertebral deformity by lateral spine radiographs on entry into study for 2 years, and repeat spine radiographs were taken at the end of that time. Incident deformities occurring within this 2 year period were detected by two methods, a level-specific radiogrammetric approach and visual inspection by skilled clinicians. Fourteen incident deformities were detected by the radiogrammetric method, and 19 by the clinicians. Ultrasound transmission velocity was measured at the patella in each subject on entry. Values for ultrasound velocity were significantly correlated with incident fracture occurrence, with individuals having velocity values more than one standard deviation below the mean for the group exhibiting from 3.3 to 4.6 times the probability of incident fracture as individuals with velocity values more than one standard deviation above the mean. Thus, low values for ultrasound transmission velocity at the patella detect yet-unexpressed bony fragility at the spine and predict future fracture.

Clinical determination of bone quality: is ultrasound an answer?

Progress in clinical characterization of bone relies on developing a means to clinically assess all of the important determinants of bone quality, specifically, the intrinsic material properties of a bone (stiffness and brittleness) versus the macroscopic structural properties [apparent mass density (g/cc), structural shape and distribution of cortical mass, trabecular architecture, extent of unrepaired microdamage, and defects associated with the accelerated remodeling in early menopause]. Ultrasound devices currently measure parameters related to either of only two basic properties: bone ultrasound attenuation (BUA) or the apparent velocity of wave propagation (AVU). Theory and repeated corroboration in the laboratory have shown that the velocity of sound in solids such as bone has a quantitative relationship to the elastic modulus (or stiffness) and mass density. Although no comparable physical model exists for BUA, growing in vitro and in vivo empirical evidence shows a relationship to stiffness and mass density as well. Therefore, the question of ultrasound's ability to provide additional, clinically useful information about bone quality reduces to this: Does bone quality depend significantly on bone stiffness and does stiffness depend on factors other than bone mass alone? Clinical study results provide mounting evidence of ultrasound's abilities. (1) Numerous studies compare either velocity or BUA with BMC or BMD. The correlation coefficients vary widely between studies, even when repeated by the same investigators and laboratories. Two studies demonstrated this by comparing groups of subjects who are indistinguishable by BMD at the lumbar spine, but whose mean AVU readings are significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)