scholarly journals Regional Variations of HR-pQCT Morphological and Biomechanical Measurements of Bone Segments and Their Associations With Whole Distal Radius and Tibia Mechanical Properties

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Bin Zhou ◽  
Zhendong Zhang ◽  
Yizhong Jenny Hu ◽  
Ji Wang ◽  
Y. Eric Yu ◽  
...  
Keyword(s):  
Distal Radius ◽  
Imaging Modality ◽  
Quantitative Computed Tomography ◽  
Three Dimensional ◽  
Peripheral Quantitative Computed Tomography ◽  
Distal Segment ◽  
Mechanical Analysis ◽  
Bone Stiffness ◽  
Microstructural Parameters

High-resolution peripheral quantitative computed tomography (HR-pQCT) is a promising imaging modality that provides an in vivo three-dimensional (3D) assessment of bone microstructure by scanning fixed regions of the distal radius and tibia. However, how microstructural parameters and mechanical analysis based on these segment scans correlate to whole distal radius and tibia mechanics are not well-characterized. On 26 sets of cadaveric radius and tibia, HR-pQCT scans were performed on the standard scan segment, a segment distal to the standard segment, and a segment proximal to the standard segment. Whole distal radius and tibia stiffness were determined through mechanical testing. Segment bone stiffness was estimated using linear finite element (FE) analysis based on segment scans. Standard morphological and individual trabecula segmentation (ITS) analyses were used to estimate microstructural properties. Significant variations in microstructural parameters were observed among segments at both sites. Correlation to whole distal radius and tibia stiffness was moderate for microstructural parameters at the standard segment, but correlation was significantly increased for FE-predicted segment bone stiffness based on standard segment scans. Similar correlation strengths were found between FE-predicted segment bone stiffness and whole distal radius and tibia stiffness. Additionally, microstructural parameters at the distal segment had higher correlation to whole distal radius and tibia stiffness than at standard or proximal segments. Our results suggest that FE-predicted segment stiffness is a better predictor of whole distal radius and tibia stiffness for clinical HR-pQCT analysis and that microstructural parameters at the distal segment are more highly correlated with whole distal radius and tibia stiffness than at the standard or proximal segments.

scholarly journals The Effect of Implant Length and Diameter on Stress Distribution around Single Implant Placement in 3D Posterior Mandibular FE Model Directly Constructed Form In Vivo CT

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7344
Author(s):  
Akikazu Shinya ◽  
Yoshiki Ishida ◽  
Daisuke Miura ◽  
Akiyoshi Shinya
Keyword(s):  
High Stress ◽  
Three Dimensional ◽  
Clinical Situation ◽  
Mechanical Analysis ◽  
Fe Model ◽  
High Stress Concentration ◽  
Implant Placement ◽  
Implant Therapy ◽  
Mandibular First Molar

A three-dimensional (3D) finite element (FE) model of the mandibular bone was created from 3D X-ray CT scan images of a live human subject. Simulating the clinical situation of implant therapy at the mandibular first molar, virtual extraction of the tooth was performed at the 3D FE mandibular model, and 12 different implant diameters and lengths were virtually inserted in order to carry out a mechanical analysis. (1) High stress concentration was found at the surfaces of the buccal and lingual peri-implant bone adjacent to the sides of the neck in all the implants. (2) The greatest stress value was approximately 6.0 MPa with implant diameter of 3.8 mm, approx. 4.5 MPa with implant diameter of 4.3 mm, and approx. 3.2 MPa with implant diameter of 6.0 mm. (3) The stress on the peri-implant bone was found to decrease with increasing length and mainly in diameter of the implant.

Bone Evaluation by High-Resolution Peripheral Quantitative Computed Tomography in Patients With Adrenal Incidentaloma

2020 ◽  
Vol 105 (8) ◽  
pp. e2726-e2737
Author(s):  
Aline Barbosa Moraes ◽  
Marcela Pessoa de Paula ◽  
Francisco de Paula Paranhos-Neto ◽  
Emanuela Mello Ribeiro Cavalari ◽  
Felipe Fernandes Cordeiro de Morais ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Bone Mineral Density ◽  
High Resolution ◽  
Distal Radius ◽  
Bone Mineral ◽  
Quantitative Computed Tomography ◽  
Adrenal Incidentaloma ◽  
Peripheral Quantitative Computed Tomography ◽  
Mineral Density ◽  
X Ray

Abstract Context Data regarding high-resolution peripheral quantitative computed tomography (HR-pQCT) in patients with adrenal incidentaloma (AI) are unknown. Purpose To evaluate the areal bone mineral density (aBMD), microstructure, and fractures in patients with nonfunctioning AI (NFAI) and autonomous cortisol secretion (ACS). Methods We evaluated 45 patients with NFAI (1 mg dexamethasone suppression test [DST] ≤1.8 µg/dL) and 30 patients with ACS (1 mg DST 1.9-5.0 µg/dL). aBMD was measured using dual-energy X-ray absorptiometry; vertebral fracture by spine X-ray; and bone geometry, volumetric bone mineral density (vBMD), and microstructure by HR-pQCT. Results Patients with ACS showed lower aBMD values at the spine, femoral neck, and radius 33% than those with NFAI. Osteoporosis was frequent in both groups: NFAI (64.9%) and ACS (75%). Parameters at the distal radius by HR-pQCT were decreased in patients with ACS compared to those with NFAI: trabecular vBMD (Tb.vBMD, P = 0.03), inner zone of the trabecular region (Inn.Tb.vBMD, P = 0.01), the bone volume/tissue volume ratio (BV/TV, P = 0.03) and trabecular thickness (P = 0.04). As consequence, a higher ratio of the outer zone of the trabecular region/inner zone vBMD (Meta/Inn.vBMD, P = 0.003) was observed. A correlation between the cortisol levels after 1 mg DST and Meta/Inn.vBMD ratio was found (r = 0.29; P = 0.01). The fracture frequency was 73.7% in patients with ACS vs 55.6% in patients with NFAI (P = 0.24). Conclusion Our findings point to an association between trabecular bone microarchitectural derangement at the distal radius and ACS. Our data suggest that AI have a negative impact on bone when assessed by HR-pQCT, probably associated to subclinical hypercortisolism.

In vivo rat assay: bone remodeling and steroid effects on juvenile bone by pQCT quantification in 7 days

2003 ◽  
Vol 284 (1) ◽  
pp. E70-E75 ◽  
Author(s):  
Nansie A. McHugh ◽  
Haydee M. Vercesi ◽  
Robert W. Egan ◽  
John A. Hey
Keyword(s):  
Quantitative Computed Tomography ◽  
Peripheral Quantitative Computed Tomography ◽  
Sprague Dawley ◽  
Mineral Density ◽  
Dose Selection ◽  
Adult Disease ◽  
Therapeutic Modalities ◽  
Computed Tomography Scanning ◽  
Efficacy Assessment

Anesthetized Sprague-Dawley weanling rats were scanned for bone mineral density (BMD) values after 7 days of treatment to determine whether resorption/growth at the proximal tibia can be quantified by peripheral quantitative computed tomography scanning techniques. Because the weanling rat is in a rapid growth stage, all groups showed significant increases in change from baseline values of BMD. Bisphosphonate treatment produced significant dose-related changes in BMD with average increases of 195 and 241% (10 and 20 μg/kg) vs. 86% in control rats. We further characterized this model to determine effects of steroids on growing bone. Graded doses of glucocorticoid (3.5, 7.0, 10.5, 14.0, 28.0, and 42.0 mg · kg−1 · wk−1) caused no significant differences in trabecular BMD in 7 days between control and treated rats. Significant decreases in growth (weights) and increases in cortical bone area were observed, indicating that this model may be useful in comparing effects of nonsteroid, anti-inflammatory alternatives on juvenile bone. Although the relevance of this model to adult disease remains to be elucidated, it also provides a tool for mechanistic evaluation of therapeutic modalities or efficacy assessment for dose selection for longerterm models.

scholarly journals Assessment of the healing process in distal radius fractures by high resolution peripheral quantitative computed tomography

Bone ◽  
2014 ◽  
Vol 64 ◽  
pp. 65-74 ◽  
Author(s):  
Joost J.A. de Jong ◽  
Paul C. Willems ◽  
Jacobus J. Arts ◽  
Sandrine G.P. Bours ◽  
Peter R.G. Brink ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Distal Radius ◽  
Healing Process ◽  
Quantitative Computed Tomography ◽  
Peripheral Quantitative Computed Tomography ◽  
Distal Radius Fractures ◽  
Radius Fractures
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