Search results for " densitometry"
showing 8 items of 8 documents
Scientific Merits and Analytical Challenges of Tree‐Ring Densitometry
2019
X-ray microdensitometry on annually resolved tree-ring samples has gained an exceptional position in last-millennium paleoclimatology through the maximum latewood density (MXD) parameter, but also increasingly through other density parameters. For 50 years, X-ray based measurement techniques have been the de facto standard. However, studies report offsets in the mean levels for MXD measurements derived from different laboratories, indicating challenges of accuracy and precision. Moreover, reflected visible light-based techniques are becoming increasingly popular, and wood anatomical techniques are emerging as a potentially powerful pathway to extract density information at the highest resol…
Early diagnosis of osteoporosis by means of orthopantomograms and oral x-rays: a systematic review.
2011
Osteoporosis is a systemic bone disease that is characterized by a generalized reduction of the bone mass. It is the main cause of fractures in elderly women. Bone densitometry is used in the lumbar spine and hip in order to detect osteoporosis in its early stages. Different studies have observed a correlation between the bone mineral density of the jaw (BMD) and that of the lumbar spine and/or hip. On the other hand, there are studies that evaluate the findings in the orthopantomograms and perapical X-rays, correlating them with the early diagnosis of osteoporosis and highlighting the role of the dentist in the early diagnosis of this disease. Materials and methods: A search was carried ou…
Valutazione quantitativa tridimensionale del parenchima polmonare affetto da fibrosi cistica : risultati preliminari
2007
Purpose. The aim of this study was to assess the feasibility of three-dimensional (3D) reconstructions and quantitative analysis of the volume of each component of the lung with cystic fibrosis (CF). Materials and methods. Twenty-two patients with CF (mean age 17±8 yeas) were included in the study. The patients underwent an unenhanced single-slice spiral computed tomography (CT) chest scan with the following parameters: collimation 3 mm, table feed 6 mm×rot-1, reconstruction interval 1 mm, soft tissue reconstruction kernel. Four image data sets were obtained: native axial slices, cine-mode display, virtual bronchographic volumerendered images with algorithm for tissue transition display and…
Computer-aided system for morphometric mandibular index computation (Using dental panoramic radiographs)
2012
Objective: We propose and validate a computer—aided system to measure three different mandibular indexes: cortical width, panoramic mandibular index and, mandibular alveolar bone resorption index. Study Design: Repeatability and reproducibility of the measurements are analyzed and compared to the manual estimation of the same indexes. Results: The proposed computerized system exhibits superior repeatability and reproducibility rates compared to standard manual methods. Moreover, the time required to perform the measurements using the proposed method is negligible compared to perform the measurements manually. Conclusions: We have proposed a very user friendly computerized method to measure …
Imaging of metabolic bone disease
2018
Osteoporosis is the most important metabolic bone disease, with a wide distribution among the elderly. It is characterized by low bone mass and micro architectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk. Identify bone weakening with an appropriate and accurate use of diagnostic imaging is of critical importance in the diagnosis and follow-up of osteoporotic patients. The aim of this review is to evaluate the detection rates of the different imaging modalities in the evaluation of bone strength, in the assessment of fracture risk and in the management of fragility fractures. (www.actabiomedica.it)
Genome-wide meta-analysis identifies 56 bone mineral density loci and reveals 14 loci associated with risk of fracture
2012
Bone mineral density (BMD) is the most widely used predictor of fracture risk. We performed the largest meta-analysis to date on lumbar spine and femoral neck BMD, including 17 genome-wide association studies and 32,961 individuals of European and east Asian ancestry. We tested the top BMD-associated markers for replication in 50,933 independent subjects and for association with risk of low-trauma fracture in 31,016 individuals with a history of fracture (cases) and 102,444 controls. We identified 56 loci (32 new) associated with BMD at genome-wide significance (P < 5 × 10 -8). Several of these factors cluster within the RANK-RANKL-OPG, mesenchymal stem cell differentiation, endochondral…
Validation of lung densitometry threshold at CT for the distinction between senile lung and emphysema in elderly subjects
2015
Background and Aims. An ageing lung is characterised by distal airspace enlargement without alveolar wall destruction: therefore the anatomical distinction between senile lung and emphysema is clear-cut. In clinical settings the definition of precise boundaries between normalcy and pathology is more difficult with the risk of overdiagnosis. CT is an important diagnostic advancement in the field of COPD. Most methods for the evaluation of emphysema are based on the detection and measurement of areas characterised by a density level below a threshold assumed to characterize parenchymal destruction. Methods. Our retrospective study included 47 healthy subjects (65-91 years), 36 never smokers a…
CT densitometry-based differential diagnosis between emphysematous and non-emphysematous lungs in elderly patients.
2010
Purpose Methods and Materials Results Conclusion References Personal Information