Methods for Post Hoc Quantitative Computed Tomography Bone Density Calibration: Phantom-Only and Regression

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Jacob M. Reeves ◽  
Nikolas K. Knowles ◽  
George S. Athwal ◽  
James A. Johnson
Keyword(s):  
Computed Tomography ◽  
Quantitative Computed Tomography ◽  
Calibration Method ◽  
Regression Method ◽  
Regression Calibration ◽  
Mineral Density ◽  
Tube Voltage ◽  
Calibration Equation ◽  
Calibration Phantom ◽  
Post Hoc

Quantitative computed tomography (qCT) relies on calibrated bone mineral density data. If a calibration phantom is absent from the CT scan, post hoc calibration becomes necessary. Scanning a calibration phantom after-the-fact and applying that calibration to uncalibrated scans has been used previously. Alternatively, the estimated density is known to vary with CT settings, suggesting that it may be possible to predict the calibration terms using CT settings. This study compares a novel CT setting regression method for post hoc calibration to standard and post hoc phantom-only calibrations. Five cadaveric upper limbs were scanned at 11 combinations of peak tube voltage and current (80–140 kV and 100–300 mA) with two calibration phantoms. Density calibrations were performed for the cadaver scans, and scans of the phantoms alone. Stepwise linear regression determined if the calibration equation terms were predictable using peak tube voltage and current. Peak tube voltage, but not current, was significantly correlated with regression calibration terms. Calibration equation slope was significantly related to the type of phantom (p < 0.001), calibration method (p = 0.026), and peak tube voltage (p < 0.001), but not current (p = 1.000). The calibration equation vertical intercept was significantly related to the type of phantom (p < 0.001), and peak tube voltage (p = 0.006), but not calibration method (p = 0.682), or current (p = 0.822). Accordingly, regression can correlate peak tube voltage with density calibration terms. Suggesting that, while standard qCT calibration is preferable, regression calibration may be an acceptable post hoc method when necessary.

scholarly journals Computed Tomography Osteodensitometry for Assessment of Bone Mineral Density of the Canine Head—Preliminary Results

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1413
Author(s):  
Glynn Woods ◽  
Nicolas Israeliantz Gunz ◽  
Ian Handel ◽  
Tiziana Liuti ◽  
Richard J. Mellanby ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Bone Mineral Density ◽  
Bone Mineral ◽  
Quantitative Computed Tomography ◽  
Calcium Hydroxyapatite ◽  
Healthy Population ◽  
Mineral Density ◽  
Calibration Phantom ◽  
Metabolic Bone ◽  
The Mean

Despite bone mineral density (BMD) being regularly measured in human patients, BMD studies in clinical cohorts of dogs is lacking. In order to facilitate BMD assessment and in turn better identify dogs suffering from metabolic bone disease, rapid, easy and precise computed tomography (qCT) techniques are required. In this study we aimed to assess the utility of quantitative computed tomography (qCT) bone mineral density (BMD) measurement of the canine calvarium using a semiautomated osteodensitometry software and define host factors associated with canine bone mineral density in a skeletally healthy population. Calvarial qCT at the level of the temporomandibular joints was performed on 323 dogs using a dedicated osteodensitometry calibration phantom during a clinically indicated head computed tomography (CT). Calvarial BMD was analyzed using a dedicated semiautomatic osteodensitometry software for contouring of the calvarial lamellar bone margins and BMD calculation. The mean duration of the calvarial qCT scanning was 64.6 s, and the mean duration of BMD analysis was 34 s, with a mean of two manual adjustments required for the bone margin tracing. The median BMD of all dogs in our study was 659 mg Calcium hydroxyapatite/mL. There was a negative linear correlation between BMD and body weight, but no correlation with age, sex or neutered status. Canine BMD assessment using qCT of the calvarium is a practical and fast technique that can be added to a clinical CT examination with minimal extra time requirements. Canine BMD host-dependent factors exhibit different relationships from that of humans; however, further investigation is warranted.

scholarly journals Experimental investigation of bone mineral density in Thoroughbreds using quantitative computed tomography

2015 ◽  
Vol 26 (3) ◽  
pp. 81-87 ◽  
Author(s):  
Kazutaka YAMADA ◽  
Fumio SATO ◽  
Tohru HIGUCHI ◽  
Kaori NISHIHARA ◽  
Mitsunori KAYANO ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Bone Mineral Density ◽  
Experimental Investigation ◽  
Bone Mineral ◽  
Quantitative Computed Tomography ◽  
Mineral Density

Radiology of Osteoporosis

2016 ◽  
Vol 67 (1) ◽  
pp. 28-40 ◽  
Author(s):  
Thomas M. Link
Keyword(s):  
Computed Tomography ◽  
Fracture Risk ◽  
New Technologies ◽  
Assessment Tool ◽  
Quantitative Computed Tomography ◽  
Osteoporotic Fractures ◽  
Fragility Fractures ◽  
Bone Architecture ◽  
Mineral Density ◽  
Fracture Risk Assessment Tool

The radiologist has a number of roles not only in diagnosing but also in treating osteoporosis. Radiologists diagnose fragility fractures with all imaging modalities, which includes magnetic resonance imaging (MRI) demonstrating radiologically occult insufficiency fractures, but also lateral chest radiographs showing asymptomatic vertebral fractures. In particular MRI fragility fractures may have a nonspecific appearance and the radiologists needs to be familiar with the typical locations and findings, to differentiate these fractures from neoplastic lesions. It should be noted that radiologists do not simply need to diagnose fractures related to osteoporosis but also to diagnose those fractures which are complications of osteoporosis related pharmacotherapy. In addition to using standard radiological techniques radiologists also use dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT) to quantitatively assess bone mineral density for diagnosing osteoporosis or osteopenia as well as to monitor therapy. DXA measurements of the femoral neck are also used to calculate osteoporotic fracture risk based on the Fracture Risk Assessment Tool (FRAX) score, which is universally available. Some of the new technologies such as high-resolution peripheral computed tomography (HR-pQCT) and MR spectroscopy allow assessment of bone architecture and bone marrow composition to characterize fracture risk. Finally radiologists are also involved in the therapy of osteoporotic fractures by using vertebroplasty, kyphoplasty, and sacroplasty. This review article will focus on standard techniques and new concepts in diagnosing and managing osteoporosis.

scholarly journals Use of Carboxymethyl Cellulose and Collagen Carrier with Equine Bone Lyophilisate Suggests Late Onset Bone Regenerative Effect in a Humerus Drill Defect – A Pilot Study in Six Sheep

2010 ◽  
Vol 4 (1) ◽  
pp. 181-187 ◽  
Author(s):  
Jonas Jensen ◽  
Casper Bindzus Foldager ◽  
Thomas Vestergaard Jakobsen ◽  
Kjeld Søballe ◽  
Cody Bünger ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Carboxymethyl Cellulose ◽  
Late Onset ◽  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Quantitative Computed Tomography ◽  
Drill Hole ◽  
Micro Computed Tomography ◽  
Mineral Density ◽  
Total Bone Mineral Density

We assessed the use of a filler compound together with the osteoinductive demineralized bone matrix (DBM), Colloss E. The filler was comprised of carboxymethyl-cellulose and collagen type 1. The purpose of the study was to see if the filler compound would enhance the bone formation and distribute the osteoinductive stimulus throughout the bone defect. Six sheep underwent a bilateral humerus drill defect. The drill hole was filled with a compound consisting of 100 mg CMC, 100 mg collagen powder, and 1 ccm autologous full blood in one side, and a combination of this filler compound and 20 mg Colloss E in the other. The animals were divided into three groups of two animals and observed for 8, 12 and 16 weeks. Drill holes was evaluated using quantitative computed tomography (QCT), micro computed tomography (µCT) and histomorphometry. Mean total bone mineral density (BMD) of each implantation site was calculated with both QCT and µCT. Bone volume to total volume (BV/TV) was analyzed using µCT and histomorphometry. Although not statistically significant, results showed increased bone BMD after 16 weeks in µCT data and an increased BV/TV after 16 weeks in both µCT and histology. Correlation between QCT and µCT was R2 = 0.804. Correlation between histomorphometry and µCT BV/TV data was R2 = 0.8935 and with an average overrepresentation of 8.2% in histomorphometry. In conclusion the CMC-Collagen + Colloss E filler seems like a viable osteogenic bone filler mid- to long term. A correlation was found between the analytical methods used in this study.

scholarly journals Bone densitometry measurements in children with neurofibromatosis Type 1 using quantitative computed tomography

2021 ◽  
Author(s):  
O Tezol ◽  
Y Balcı ◽  
M Alakaya ◽  
B Gundogan ◽  
EC Cıtak
Keyword(s):  
Computed Tomography ◽  
Neurofibromatosis Type 1 ◽  
Quantitative Computed Tomography ◽  
Neurofibromatosis Type ◽  
Significant Negative Correlation ◽  
Urinary Calcium ◽  
Volumetric Bone Mineral Density ◽  
Z Score ◽  
Mineral Density

Introduction: Neurofibromatosis type 1 (NF 1) is an autosomal dominant neurocutaneous disease characterised by multisystemic involvement, including bone tissue. Deformities and reduced bone mass are the main bone manifestations in NF1. Quantitative computed tomography (QCT) provides true volumetric bone mineral density (BMD) measurement. This study aimed to evaluate bone metabolism parameters and BMD in children with NF1 using QCT. Methods: The data of 52 paediatric NF1 patients (23 female, 29 male) was evaluated retrospectively. We investigated anthropometric measurements, biochemical parameters like total calcium, phosphate, magnesium, alkaline phosphatase, 25-hydroxyvitamin D (25OHD), parathyroid hormone, calcitonin, urinary calcium/creatinine ratio, and QCT parameters like lumbar trabecular and cortical BMD, trabecular area and cortical thickness. Comparisons of gender and puberty status were performed. Results: 25% of patients had skeletal deformities and 42.3% had 25OHD inadequacy (< 20 ng/mL). The frequency of 25OHD inadequacy was significantly higher in pubertal/postpubertal patients than prepubertal patients (61.9% vs. 29.0%, p = 0.019). Trabecular BMD Z-score was < −2.0 in 11.5% of patients; all with low BMD were at the pubertal/postpubertal stage. There was a significant negative correlation between age and trabecular Z-score (r = −0.41, p = 0.003). Mean cortical BMD was statistically similar between the genders and puberty groups. Puberty status, anthropometric Z-scores, and biochemical and QCT parameters were statistically similar between the genders (p > 0.05). Conclusion: Paediatric NF1 patients may present with low BMD and 25OHD inadequacy, especially at puberty. QCT may be a useful tool to evaluate trabecular and cortical bone separately in NF1 patients.

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