Search results for "cortical bone"
showing 9 items of 69 documents
Assessment of the tibia using ultrasonic guided waves in pubertal girls
2002
The purpose of this study was to compare low frequency ultrasonic guided wave measurements with established ultrasound and bone density measurements in terms of their ability to characterize the tibia in pubertal girls. Subjects were 12-14-year-old girls ( n=106) who were participating in a calcium and vitamin D intervention study. A prototype low frequency pulse transmission device consisting of a uniaxial scanning mechanism and low frequency transducers orientated perpendicularly to the limb was used to measure two ultrasound velocities in the tibia. The first velocity, V1, was that of the first arriving signal, similar to that measured by existing commercial tibial ultrasound devices. Th…
Estimation of structural and geometrical properties of cortical bone by computerized tomography in 78-year-old women
2009
The structural and geometrical properties of the tibia shaft were investigated at two sections by means of computerized tomography (CT) in 78-year-old women with high (n = 19) and low (n = 17) calcaneal bone mineral density (BMD, g/cm3) previously measured by 125I-photon absorption. The high BMD group had a 20-21% higher tibial BMD and 9-12% higher bone cross-sectional area than was observed in the low BMD group. The distribution of bone mass indicated that the low BMD group had lost bone mainly from the endosteal surface, especially in the anterior part of the tibia. However, both groups had a similar basic pattern of mass distribution at the measured sections. The high BMD group had highe…
Bone Mass Distribution in the Sacrum
2017
The trabecular architecture and bone mass distribution of each bone follows biomechanical principles and is an adaption to the stress exhibited during lifetime. In patients with osteoporosis, the bone mass decreases and the bone microarchitecture changes. A distinct bone mass distribution in non-osteoporotic and osteoporotic individuals is demonstrated using statistical modelling in the sacrum. The authors studied the sacral bone mass distribution using a 3D statistical model based on clinical CT scans of 92 Europeans. In the group with worse general bone mass (less than 100 Houndsfeld Units (HU) measured in the body of L5), there were large areas of negative HU in the sacral alae. These “a…
Both Resistance and Agility Training Increase Cortical Bone Density in 75- to 85-Year-Old Women With Low Bone Mass
2004
A randomized, controlled, single-blinded 25-wk prospective study was conducted to compare the effects of group-based resistance and agility training on bone, as measured by both dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT), in older women with low bone mass. Ninety-eight community-dwelling women aged 75-85 yr were randomized to one of three experimental groups: resistance training (n = 32), agility training (n = 34), or stretching (sham exercise) (n = 32). Total hip, femoral neck, and trochanteric bone mineral density (BMD) were measured by DXA. Peripheral QCT measurements were performed at the tibia and radius. The pQCT outcome measures at t…
Correlation of Tibial Low-Frequency Ultrasound Velocity with Femoral Radiographic Measurements and BMD in Elderly Women
2009
The ultrasonic axial transmission technique has been proposed as a method for cortical bone characterization. Using a low enough center frequency, Lamb modes can be excited in long bones. Lamb waves propagate throughout the cortical bone layer, which makes them appealing for characterizing bone material and geometrical properties. In the present study, a prototype low-frequency quantitative ultrasonic axial transmission device was used on elderly women (n = 132) to investigate the relationships between upper femur geometry and bone mineral density (BMD) and tibial speed of sound. Ultrasonic velocities (V) were recorded using a two-directional measurement set-up on the midtibia and compared …
Vergleich radiologischer Verfahren zur präoperativen Beurteilung der Verankerungsfestigkeit von Wirbelsäulenimplantaten
1997
PURPOSE To compare three techniques with regards to their ability to estimate pull out strength of spinal fusion hardware. MATERIAL AND METHODS VDS-screw fixation strength in 50 human cadaveric vertebral bodies was approximated by means of pull out force measurement. Bone quality was assessed by Dual X-ray Absorptiometry (DXA). Quantitative Computed Tomography (QCT) and T2*-relaxation time. For each of these techniques, correlation with axial pull out force strength was investigated. RESULTS Highest correlation was found for cancellous bone density measured by QCT (r = 0.72; p < 0.001). Immediately followed by DXA (r = 0.70; p < 0.001), which involves all bone components. Inverted T2*-relax…
Bestimmung der Knochenqualität vor Wirbelsäuleninstrumentation - Stellenwert verschiedener in vivo-Methoden
2008
OBJECTIVE: The present investigation should elucidate which assessment technique for bone quality is most appropriate to estimate preoperatively fixation strength of instrumental spine fusions. METHODS: VDS-screw fixation strength in 50 human cadaveric vertebral bodies was approximated by means of pullout force assessment. Bone quality was assessed by Dual Energy X-ray Absorptiometry (DEXA), Quantitative Computed Tomography (QCT), MRT and histomorphometry. For each of these techniques, correlation with axial pull out force strength was investigated. RESULTS: Highest correlation was found for cancellous bone density (QCT) (r = 0.72; p < 0.001) and DEXA (r = 0.70; p < 0.001). MRT, cortical bo…
Association between low-frequency ultrasound and hip fractures - comparison with DXA-based BMD
2014
Background: New methods for diagnosing osteoporosis and evaluating fracture risk are being developed. We aim to study the association between low-frequency (LF) axial transmission ultrasound and hip fracture risk in a population-based sample of older women. Methods: The study population consisted of 490 community-dwelling women (78 – 82 years). Ultrasound velocity (V LF ) at mid-tibia was measured in 2006 using a low-frequency scanning axial transmission device. Bone mineral density (BMD) at proximal femur measured using dual-energy x-ray absorptiometry (DXA) was used as the reference method. The fracture history of the participants was collected from December 1997 until the end of 2010. Li…
Evaluation of alveolar cortical bone thickness and density for orthodontic mini-implant placement.
2013
Objective: Mini-implant stability is primarily related to bone quality and quantity. This study evaluated alveolar cortical bone thickness and density differences between interradicular sites at different levels from the alveolar crest, and assessed the differences between adolescents (12-18 years of age) and adults (19-50 years of age), males and females, upper and lower arch, anterior and posterior region of jaws and buccal and oral side. Study Design: In this retrospective study, 48 Computed Tomography scans, performed for oral surgery purposes were selected from dental records of 3,223 Caucasian orthodontic patients. The SimPlant software (Materialise, Leuven, Belgium) was used to measu…