Comparison of three bone densitometry methods in osteoporotic women

Low BMD is a risk factor for low-energy Colles' fractures in women before and after menopause

Until now, it was unclear if low volumetric bone mineral density at the distal radius was also a risk factor for Colles' fracture, especially in patients with low-energy trauma. In our study, we used peripheral quantitative computed tomography to measure volumetric bone mineral density of a nonfractured distal radius and dual-energy x ray absorptiometry to measure areal bone mineral density at the spine and hip in patients with Colles' fractures, including 45 women who were premenopausal (age range, 40-50 years) and 39 women who were postmenopausal (age range, 51-65 years). In each group, the patients were subdivided into low-energy and high-energy fracture groups. Ninety-five age-matched healthy women who were premenopausal and 90 age-matched healthy women who were postmenopausal without fracture history served as controls. The results showed that patients with low-energy fractures had a lower bone mineral density at all measurement sites, compared with either patients with high-energy fractures or control subjects. More patients were found with a bone mineral density less than -2.5 standard deviations (Z-score) in the premenopausal group (12.5% measured by dual-energy x ray absorptiometry and 41.2% measured by peripheral quantitative computed tomography) than in the postmenopausal group (6.0% measured by dual-energy x ray absorptiometry and 4.8% measured by peripheral quantitative computed tomography). These results suggest that low bone mineral density, particularly measured using peripheral quantitative computed tomography at the distal radius of women who were premenopausal, was an important risk factor for low-energy Colles' fractures.

LEVEL OF EVIDENCE

Prognostic study, Level I-1 (prospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Digital radiogrammetry as a new diagnostic tool for estimation of disease-related osteoporosis in rheumatoid arthritis compared with pQCT

OBJECTIVES

To investigate the potential of a new osteogeometric technology based on digital X-ray radiogrammetry (DXR) as a diagnostic tool for quantification of severity-dependent osteoporosis, and to distinguish between inflammation-mediated and corticoid-induced variations of bone mineralisation in patients suffering from rheumatoid arthritis.

METHODS

Ninety-six patients (duration of disease: <18 months) underwent retrospective calculations of bone mineral density (DXR-BMD) and metacarpal index (MCI) by DXR, which were calculated from plain radiographs of the non-dominant hand. For comparison, pQCT-calculated BMD (total, cortical-subcortical and trabecular partition of bone tissue) was done on the distal radius. Severity was classified using Ratingen Score by two independent radiologists, and divided into three main groups. In addition, the patients were separated into those with corticoid medication (n=44; 5 mg/day over a half year period) and a control group (n=52) without any corticoid therapy.

RESULTS

Correlations between DXR-BMD and MCI versus pQCT parameters were all significant (0.36<R<0.71; p<0.01), independent of corticoid therapy. Only in the group without corticoid application, the correlation between DXR-BMD and pQCT-BMD (cortical) showed no significant association. For patients with corticoid therapy, our data revealed the lowest correlation coefficient between DXR parameters and pQCT-BMD (trabecular). Without a difference in comparison to corticoid therapy, the significant relative decrease of BMD estimated by DXR between the highest and lowest score was between 11.1% and 14.3% and for MCI between 15.8% and 17.8%. The also significant relative decrease of trabecular BMD using pQCT varied from 10.3% to 16.9%, whereas no significant results could be verified for pQCT-BMD (cortical and total).

CONCLUSIONS

Digital radiogrammetry can precisely estimate severity-dependent cortical reduction of bone mineral density in patients suffering from rheumatoid arthritis both with and without corticoid therapy, and seems to be able to distinguish the side effects of antirheumatic treatment from the disease-related periarticular bone loss. The detection and quantification of periarticular osteoporosis by DXR could be an important diagnostic tool in early rheumatoid arthritis.

Reduced bone mineralization in adolescent survivors of malignant bone tumors: comparison of quantitative ultrasound and dual-energy x-ray absorptiometry

PURPOSE

To assess bone mineralization in adolescents with bone tumors at remission using quantitative digital ultrasound (QUS) and dual-energy x-ray absorptiometry (DEXA), and to compare the bone mineralization values obtained by both methods.

METHODS

Patients studied were 36 adolescents (21 boys, 15 girls) who had completed treatment of a bone tumor at the University Hospital of the University of Navarra (Pamplona, Spain). QUS was performed at the distal metaphysis of the proximal phalanxes of the last four fingers of the nondominant hand. A DBM Sonic 1200 Ultrasound densitometer was used. DEXA measurements were made at the lumbar spine (vertebrae L1-L4) using the Hologic QDR 4500 W device. Calcium and vitamin D daily intake and grade of physical activity were recorded.

RESULTS

Mean age at bone mineralization determination was 19.11 years. Disease-free survival was 4.97 years. Decreased bone mineralization was observed by both methods. Bone mineralization absolute values measured by QUS and DEXA were significantly correlated. The sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values of QUS for predicting osteopenia were 36.4%, 80.0%, 66.7%, 44.4%, and 74.1%, respectively. Daily vitamin D intake was below the recommended dietary allowances.

CONCLUSIONS

Adolescents in remission from bone tumors have low bone mineralization determined by DEXA or QUS.

Quantitative ultrasound (QUS) at the calcaneus and hand phalanges in Polish healthy postmenopausal women

In a cross-sectional study, 109 postmenopausal, healthy women, mean age 58.8 years, were studied. The aim of the study was to compare quantitative ultrasound (QUS) performed at two measurement sites of the same persons (correlations between parameters studied, age, and years since menopause (YSM)-related changes, influence of body size). Bone status was established using measurements at the calcaneus by Achilles (Lunar, USA), which measures speed of sound (SOS [m/s], CV% = 0.22%), broadband ultrasound attenuation (BUA [dB/MHz], CV% = 1.8%), stiffness index (SI [%], CV% = 1.3%), and by DBM Sonic 1200 (Igea, Italy), which measures amplitude-dependent speed of sound (Ad-SoS [m/s], CV% = 0.64%) at the hand phalanges. Mean and SD values were: SOS = 1498 +/- 24.8 m/s, BUA = 104.6 +/- 9.4 dB/MHz, SI = 69.2 +/- 12.3%, Ad-SoS = 1879 +/- 90.1 m/s. Age- and YSM-related changes were as follows: age-SOS r = -0.37, p < 0.0001, age-BUA r = -0.33, p < 0.001, age-SI r = -0.36, p < 0.001, age-Ad-SoS r = -0.62, p < 0.00001, YSM-SOS r = -0.27, p < 0.01, YSM-BUA r = -0.32, p < 0.001, YSM-Ad-SoS r = -0.44, p < 0.00001, YSM-SI r = -0.29, p < 0.01. In stepwise, multiple regression analyses of ultrasound parameters on age, YSM, height, and weight, the following equations were obtained: SOS [m/s] = 1564.9 - 1.1 x age [y], r = -0.37, p < 0.0001; BUA [dB/MHz] = 88.7 + 0.28 x weight [kg] - 0.36 x YSM [y], r = -0.51, p < 0.00001; SI [%]) = 79.2 - 0.5 x age [y] + 0.28 x weight [kg], r = -0.47, p < 0.00001; Ad-SoS [m/s] = 2287 to 6.9 x age [y], r = -0.62, p < 0.00001. In conclusion, QUS at the calcaneus and hand phalanges express similar trends in skeletal changes due to aging and the postmenopausal period, although measurements at the phalanges seem to be more sensitive for detecting bone changes, due to faster decrease rate of the Ad-SoS value than calcaneal measurements.

Comparison of absorptiometric evaluations from total-body and local-regional skeletal scans

The most common measurement sites for dual-energy absorptiometry (DXA) in clinical practice are posteroanterior (PA) spine and femur. However, other skeletal regions may provide different bone density information. The purpose of this study was to establish the least number of DXA measurements needed to obtain complete information about bone. A total of 262 normal female subjects, 8-50, were measured on a Lunar DPX-L scanner under total body, PA spine, lateral spine, and femur protocol. Forearm measurements were performed with a Lunar SP2 single-photon absorptiometry scanner. The various measurements were compared based on a linear regression model. The correlation coefficients for bone mineral density (BMD) between adjacent vertebrae were 0.92-0.95, and the associated standard errors of the estimate (SEE) were 4.5-5.5%. Total-body BMD can best predict BMD of the trunk, arms, and legs (SEE<4.3%), but least that of the lateral view of the spine (SEE>13.9%). BMD values of the leg from total-body scans predict those from the femoral neck with an error of 9.0%, and those of the trochanteric region with 11.1%. The error between adjacent vertebrae (6%) is considered acceptable, then a total-body measurement combined with a lateral view of the spine and a femur scan are adequate.