Densitometric Parameter Research Articles

Correlation between DXA and laboratory parameters in normal weight, overweight, and obese patients

The aim of this study was to review the existence and types of correlations between body composition densitometric parameters and laboratory values associated to cardiometabolic risk. We retrospectively analyzed data from 316 individuals in the weight range from normality to super-obesity, submitted to total body dual-energy x-ray absorptiometry (DXA) scans and routine biochemistry at S.Orsola-Malpighi Hospital from June 2010 to March 2014. The study included 182 women, 45.8 ± 13.4 y of age, with a body mass index (BMI) of 31.5 (± 11) kg/m2 (group F) and 134 men, 45.4 ± 13.6 y of age, with a BMI of 27.6 (± 7.8) kg/m2 (group M). All patients underwent whole-body scan (Lunar iDXA, GE Healthcare, Madison, WI, USA) and laboratory analysis (blood fasting glucose, total cholesterol, high-density lipoprotein cholesterol, tricylglycerides [TGs], aspartate aminotransferase, and alanine aminotransferase). Correlation between laboratory values and total body and regional fat mass (including visceral adipose tissue [VAT] and subcutaneous adipose tissue in the android region), and lean mass parameters were analyzed with linear and stepwise regressions analysis (significance limit, P < 0.05). Receiver operating characteristic curves were performed to assess the accuracy of the best-fit DXA parameter (VAT) to identify at least one laboratory risk factor. In both groups, BMI and densitometric parameters showed a linear correlation with fasting blood glucose and TG levels and an inverse correlation with high-density lipoprotein cholesterol (P < 0.05), whereas no correlation was observed with total cholesterol levels. The only densitometric parameter retained in the final model of stepwise multiple regression was VAT for fasting blood glucose (group F: β = 0.4627, P < 0.0001; group M: β = 0.6221, P < 0.0001) and TG levels (group F: β = 0.4931, P < 0.0001; group M: β = 0.1990, P < 0.0261) independently of BMI. The optimal cutoff points of VAT to identify the presence of at least one laboratory risk factor were >1395 g and >1479 cm3 for men and >1281 g and >1357 cm3 for women. DXA analysis of VAT is associated with selected laboratory parameters used for the evaluation of cardiometabolic risk and could be per se a helpful parameter in the assessment of clinical risk.

Abilities of a Densitometric Analysis of Computed Tomography Images and Hemorrhagic Parameters to Predict Outcome Favorability in Patients With Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) is one of the most devastating subtypes of stroke. A rapid assessment of ICH severity involves the use of computed tomography (CT) and derivation of the hemorrhage volume, which is often estimated using the ABC/2 method. However, these estimates are highly inaccurate and may not be feasible for anticipating outcome favorability. To predict patient outcomes via a quantitative, densitometric analysis of CT images, and to compare the predictive power of these densitometric parameters with the conventional ABC/2 volumetric parameter and segmented hemorrhage volumes. Noncontrast CT images of 87 adult patients with ICH (favorable outcomes = 69, unfavorable outcomes = 12, and deceased = 6) were analyzed. In-house software was used to calculate the segmented hemorrhage volumes, ABC/2 and densitometric parameters, including the skewness and kurtosis of the density distribution, interquartile ranges, and proportions of specific pixels in sets of CT images. Nonparametric statistical analyses were conducted. The densitometric parameter interquartile range exhibited greatest accuracy (82.7%) in predicting favorable outcomes. The combination of skewness and the interquartile range effectively predicted mortality (accuracy = 83.3%). The actual volume of the ICH exhibited good coherence with ABC/2 (R = 0.79). Both parameters predicted mortality with moderate accuracy (<78%) but were less effective in predicting unfavorable outcomes. Hemorrhage volume was rapidly estimated and effectively predicted mortality in patients with ICH; however, this value may not be useful for predicting favorable outcomes. The densitometric analysis exhibited significantly higher power in predicting mortality and favorable outcomes in patients with ICH.

Morphological, densitometric and mechanical properties of mandible in 5-month-old Polish Merino sheep.

BackgroundAmong bones building the axial and appendicular skeleton, the mandible is characterized by unique morphological and functional traits. The aim of the study was to evaluate morphological, densitometric and mechanical properties of mandible in 5-month-old Polish Merino sheep. Using quantitative computed tomography, volumetric bone mineral density (vBMD) and calcium hydroxyapatite density of the cortical bone (CbCa-HA), mean vBMD (MvBMD) and total bone volume were determined. Using computed tomography cross-sectional scans of the mandible, cross-sectional area, second moment of inertia, mean relative wall thickness and cortical index were determined. Three-point bending test was applied to determine mechanical properties. Serum concentration of insulin-like growth factor I (IGF-I) and bone-specific alkaline phosphatase (BAP) was also measured.ResultsAll the investigated morphometric, densitometric and mechanical parameters of the right and left mandibular halves were not significantly different (P > 0.05). There was no correlation of final body weight, MvBMD, CbCa-HA, BAP and IGF-I with all the analyzed parameters of mandible (P > 0.05). However, positive correlations between the other investigated morphometric, densitometric and mechanical parameter of mandible were found (P < 0.05).ConclusionsRelationships between morphological, densitometric and mechanical parameters of the mandible indicate that the elaborated experimental model may serve for further studies on metabolic responses of skeletal system to physiological, nutritional, pharmacological, toxicological and environmental factors.

Value of two-phase dynamic multidetector computed tomography in differential diagnosis of post-inflammatory strictures from esophageal cancer.

To characterize the computed tomography (CT) findings in patients with post-inflammatory esophageal strictures (corrosive and peptic) and reveal the optimal scanning phase protocols for distinguishing post-inflammatory esophageal stricture and esophageal cancer. Sixty-five patients with esophageal strictures of different etiology were included in this study: 24 patients with 27 histopathologically confirmed corrosive strictures, 10 patients with 12 peptic strictures and 31 patients with esophageal cancer were evaluated with a two-phase dynamic contrast-enhanced MDCT. Arterial and venous phases at 10 and 35 s after the attenuation of 200 HU were obtained at the descending aorta, with a delayed phase at 6-8 min after the start of injection of contrast media. For qualitative analysis, CT scans of benign strictures were reviewed for the presence/absence of the following features: "target sign", luminal mass, homogeneity of contrast medium uptake, concentric wall thickening, conically shaped suprastenotic dilatation, smooth boundaries of stenosis and smooth mucous membrane at the transition to stenosis, which were compared with a control group of 31 patients who had esophageal cancer. The quantitative analysis included densitometric parameter acquisition using regions-of-interest measurement of the zone of stenosis and normal esophageal wall and the difference between those measurements (ΔCT) at all phases of bolus contrast enhancement. Esophageal wall thickening, length of esophageal wall thickening and size of the regional lymph nodes were also evaluated. The presence of a concentric esophageal wall, conically shaped suprastenotic dilatation, smooth upper and lower boundaries, "target sign" and smooth mucous membrane at the transition to stenosis were suggestive of a benign cause, with sensitivities of 92.31%, 87.17%, 94.87%, 76.92% and 82.05%, respectively, and specificities of 70.96%, 89.66%, 80.65%, 96.77% and 93.55%, respectively. The features that were most suggestive of a malignant cause were eccentric esophageal wall thickening, tuberous upper and lower boundaries of stenosis, absence of mucous membrane visualization, rupture of the mucous membrane at the upper boundary of stenosis, cup-shaped suprastenotic dilatation, luminal mass and enlarged regional lymph nodes with specificities of 92.31% 94.87%, 67.86%, 100%, 97.44%, 94.87% and 82.86%, respectively and sensitivities of 70.97%, 80.65%, 96.77%, 80.65%, 54.84%, 87.10% and 60%, respectively. The highest tumor attenuation occurred in the arterial phase (mean attenuation 74.13 ± 17.42 HU), and the mean attenuation difference between the tumor and the normal esophageal wall (mean ΔCT) in the arterial phase was 23.86 ± 19.31 HU. Here, 11.5 HU of ΔCT in the arterial phase was the cut-off value used to differentiate esophageal cancer from post-inflammatory stricture (P = 0.000). The highest attenuation of post-inflammatory strictures occurred in the delayed phase (mean attenuation 71.66 ± 14.28 HU), and the mean ΔCT in delayed phase was 34.03 ± 15.94 HU. Here, 18.5 HU of ΔCT in delayed phase was the cut-off value used to differentiate post-inflammatory stricture from esophageal cancer (P < 0.0001). The described imaging findings reveal high diagnostic significance in the differentiation of benign strictures from esophageal cancer.

Assessing temperature signal in X-RAY densitometric data of norway spruce and the earliest instrumental record from the Carpathi

Radiodensity data derived from Norway spruce were studied from a southern Carpathian site. Maximum density record showed significant positive relationship (r=0.59) with the growing season (April-September) air temperature and minimum density (MND) record showed clear and significant negative response (r=-0.41) to June-July mean air temperature. This significant MND response to climate is a novel result as traditionally this densitometric parameter was regarded not to carry any meaningful climatic signal. Derived temperature sensitive proxy records were compared to instrumental data of Sibiu (Nagyszeben/Hermannstadt) the oldest available regional station. Results of the running window correlation analysis pointed out notable inhomogeneities in the instrumental data before 1906. The Sibiu temperature series should be subjected to scrutiny revision to clean it from inhomogeneities.

Monitoring the Progress of Emphysema by Repeat Computed Tomography Scans with Focus on Noise Reduction

Emphysema is a major constituent of lung pathology in chronic obstructive pulmonary disease, and emphysema is characterized by loss of lung tissue. Computed tomography (CT) generates detailed information on tissue densities, and lung density by CT has the potential of being both more sensitive and specific for monitoring emphysema in clinical trials than more traditional outcome measures such as pulmonary function tests. However, CT measurements of lung density are subject to many sources of noise, such as variations in the scanning procedure (technical noise) and variations in patient performance (biological noise). A multi-detector array scanner and a low-dose volumetric scanning protocol are recommendable, and images should be reconstructed using a soft filter. In longitudinal studies the percentile density (PD) is the most reproducible densitometric parameter, and confounding due to variations in inspiratory level can be adjusted for by a physiologic model that assumes that the lung behaves like a sponge. Work remains to be done to standardize and validate CT lung density, before it can become established as the primary outcome measure in clinical trials of new treatments for chronic obstructive pulmonary disease.

Quantitative Assessment of Air Trapping in Chronic Obstructive Pulmonary Disease Using Inspiratory and Expiratory Volumetric MDCT

The purpose of our study was to determine the attenuation threshold value for the detection and quantification of air trapping using paired inspiratory and expiratory volumetric MDCT scans and to assess whether the densitometric parameter can be used for the quantification of airway dysfunction in chronic obstructive pulmonary disease (COPD) regardless of the degree of emphysema. This study included 36 patients with COPD who underwent 64-MDCT. The entire lung volume with attenuation between -500 and -1,024 H was segmented as whole lung. The lung volume with attenuation between -500 and -950 H was segmented as limited lung, while the lung volume of less than -950 H was segmented as emphysema and eliminated. The relative volumes for limited lung (relative volume(n-950)) with attenuation values below thresholds (n) ranging from -850 to -950 H, and relative volume for whole lung (relative volume(<n)) were obtained on inspiratory and expiratory CT. Then the differences of relative volumes after expiration in whole lung (relative volume change(<n)) and limited lung (relative volume change(n-950)) were calculated. Patients were classified into two groups according to mean relative volume less than -950 H. Correlations between densitometry parameters and pulmonary function tests (PFTs) reflecting airway dysfunction were evaluated. The highest correlation with PFTs was observed at the upper threshold of -860 H. In the moderate to severe emphysema group (relative volume(<-950) > 15%), relative volume change(860-950) significantly correlated with the results of PFTs, whereas no significant correlations were seen between relative volume change(<-860) and PFTs. In the minimal or mild emphysema group (inspiratory relative volume(<-950) < 15%), all densitometric parameters correlated with PFTs. The densitometric parameter of relative volume change calculated on paired inspiratory and expiratory MDCT using the threshold of -860 H in limited lung correlated closely with airway dysfunction in COPD regardless of the degree of emphysema.

Optimization and standardization of lung densitometry in the assessment of pulmonary emphysema.

Currently, lung densitometry for the assessment of pulmonary emphysema has been fully validated against pathology, pulmonary function, and health status, and it is therefore being applied in pharmacotherapeutic trials. Nevertheless, its application for the early detection of emphysema has not yet been introduced in daily clinical practice. The main reason for this is the fact that it is not yet regarded a fully optimized and standardized technique. In this work, an overview is given on the current status of different standardization aspects that play an important role in this, ie, image acquisition, choice of densitometric parameter and image processing. To address these issues, solutions have been sought from the literature and from original data from previous studies. Standardization and optimization of lung densitometry has reached a more advanced stage than has been reported so far. If normal values will become available, this technique will be feasible for clinical practice. As a result, standardization for the detection and assessment of other density-related lung diseases can be achieved in a shorter period of time.

The bone mass concept: problems in short stature.

Bone densitometry is currently one of the mainstays in the evaluation of systemic bone diseases in adults and is also increasingly used to assess primary or secondary bone disorders in children and adolescents. The purpose of carrying out densitometric studies in such circumstances is to measure the densitometric indicators of bone stability. Following procedures which were established for diagnosing adult osteoporosis, a decrease in densitometric surrogates of bone stability is usually interpreted as indicating increased fracture risk. The most basic densitometric parameter is bone mineral content (BMC), which can be measured with most densitometric techniques. BMC is either defined as the mass of mineral contained in an entire bone or as the mass of mineral per unit bone length. While mineral mass can be expected to be a good surrogate for bone stability, BMC is obviously a size-dependent parameter, since small bones weigh less than big bones. This is a drawback in paediatric use, since many children and adolescents who are examined by densitometry suffer from chronic disorders and are small-for-age. Short children will have a lower BMC than their healthy age-matched peers, even if their (smaller) bones are otherwise completely normal.

Chronic obstructive pulmonary disease: evaluation with spirometrically controlled CT lung densitometry.

To compare the computed tomographic (CT) lung densitometry results in patients with chronic obstructive pulmonary disease (COPD) and in control subjects (healthy persons). Spirometrically gated CT sections at 5 cm above and 5 cm below the carina at 90% and 10% vital capacity (VC) were imaged in patients and controls. Various densitometric parameters were derived from the CT data, and results were compared between the two levels of inspiration. Densitometric results in patients with emphysema were substantially different from those in patients with chronic bronchitis and in controls at 90% and 10% VC. Differences in patients with chronic bronchitis and in controls were not significant at 90% VC but were significant at 10% VC (P < .001). The mean changes in densitometric parameters between 90% and 10% VC were substantially greater in controls than in patients with COPD. It may be possible to classify lung disease with only two CT sections obtained at the same anatomic level, one at 90% and one at 10% VC, irrespective of the densitometric parameter used.

Journal of Bone and Mineral Research

Eighty one women with vertebral osteoporosis were treated for up to 2 years with fluoride administered either as monofluorophosphate (MFP, 200 mg/day, i.e., 26.4 mg fluoride-ion) or sodium fluoride (NaF, 50 mg/day, i.e., 22.6 mg fluoride-ion). All patients received calcium supplementation (1 g of Ca2+/day) taken apart from NaF and in the same tablet for MFP. Despite almost similar fluoride dosage of both regimens, the early increase in the bone mineral density (BMD) of the lumbar spine was higher with MFP than with NaF, reaching 11% and 4%, respectively, at 1 year (p = 0.007), and 21% and 6%, respectively, at 18 months (p less than 0.001). The incidence of lower extremity pain syndrome related to benign stress microfractures was also higher with MFP than with NaF (35% and 15%, respectively, p less than 0.01). Urinary fluoride levels were higher in the MFP than in the NaF group (9.6 +/- 3.5 vs. 6.8 +/- 3.4 at one year, p = 0.003), suggesting that this difference in efficacy and tolerance is related to a better bioavailability of fluoride provided by MFP than by NaF. The occurrence of a stress microfracture could not be predicted by any clinical, biochemical, or densitometric parameter before treatment, but patients presenting with a stress microfracture during the course of the treatment had a higher gain in bone mass than those without stress fractures (at 1 yr+11 vs. +5%, p = 0.03 and at 18 months +18 vs. +6.9%, p less than 0.02). In conclusion, there is a clear correlation between the efficacy and the occurrence of side effects of fluoride therapy in osteoporosis.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of balloon dilatation on post-stenotic myocardial perfusion before and after stimulation of coronary flow reserve: evaluation by the densitometric parameter 'mean rise time'.

From densitometric evaluation of digital subtraction cineangiocardiograms the parameter 'Mean Rise Time' (MRT), defined as the time from the onset of local myocardial contrast medium opacification to the point of maximal opacification can be derived; this parameter revealed a close correlation with the results on myocardial perfusion obtained by Thallium-201 scintigraphy. A prolonged 'Mean Rise Time' was indicative of an impairment of myocardial perfusion. We have developed a heart-phase gated real-time digitization procedure and computer-supported method for the densitometric estimation of the MRT to obtain information about the effect of coronary balloon dilatation on myocardial perfusion before and after stimulation of coronary flow reserve by Moxaverin. In 22 patients with single vessel coronary artery disease Moxaverin caused a significant prolongation of the post-stenotic MRT (2.3 +/- 1.2s (mean +/- s.d.) vs. 2.9 +/- 1.1s, p less than 0.05), while after successful dilatation of the obstructive lesion a significant shortening of the MRT was found after stimulation of the coronary flow reserve (2.5 +/- 1.2s vs. 1.9 +/- 0.9s, p less than 0.05). A highly significant decrease in MRT after Moxaverin was measured post-dilatation in comparison to the initial pre-dilatation results (2.9 +/- 1.1s vs. 1.9 +/- 0.9s, p less than 0.005); this shows that the effect of successful balloon dilatation on the post-stenotic myocardial perfusion can be described very well by this parameter. These results demonstrate that information about post-stenotic myocardial perfusion during interventional heart catheterization can be obtained from digital densitometry.