Quantitative Computed Tomography Values Research Articles

Dynamic Spine Hyperflexion Is Related to Vertebral Compression Fractures in Postmenopausal Women.

Previous studies on osteoporotic vertebral fractures are usually based on the neutral posture of spine; however, the fractures are usually associated with the flexion posture of spine. Therefore, we aimed to ascertain the relationship between vertebral compression fractures and thoracolumbar hyperflexion Cobb angles (TLHCobb) and determine the clinical cut-off of the TLHCobb angle. In this retrospective case-control study, TLHCobbs were collected from 154 postmenopausal women (67.45 ± 6.68 years) with vertebral compression fractures (study group) and 310 postmenopausal women (66.57 ± 8.22 years) without vertebral compression fractures (control group) from June 2017 to July 2019. Demographic data, clinical data, and quantitative computed tomography (QCT) findings were compared between the groups. Chi-squared tests, unpaired t-tests, and Mann Whitney U were used to assess the group characteristics and proportions. Logistic regression was used to examine the association between vertebral compression fractures and TLHCobb. The cut-off of the TLHCobb was determined by ROC curve and Youden's index. Fracture prevalence was higher in the higher TLHCobb study group than that in the control group [OR=2.81 (2.15-3.67)] after adjusting for age, BMI, and QCT findings. TLHCobbs at and >20.05° were associated with an increased fracture prevalence and ORs of 2.79 (1.82-4.27) and 4.83 (3.24-7.20), respectively. TLHCobb, disk height (semiquantitative grading score) and QCT values differed between the study and control groups (p < 0.001 for all three). There were no significant differences in body mass index (BMI), or coronal TLCobb between the two groups. There was an association between the prevalence of vertebral compression fractures and TLHCobbs in postmenopausal women, and a TLHCobb > 20.05° can be an indicator of vertebral fracture.

Using QCT to evaluate bone mineral and abdominal adipose changes in patients with primary hyperparathyroidism and comparing it to DXA for bone status assessment: a retrospective case-control study.

BackgroundPatients with primary hyperparathyroidism (PHPT) show changes in bone metabolism and adipose tissue, but the results are inconsistent. Quantitative computed tomography (QCT) was reported useful for detecting bone mineral and adipose tissue change, but information on the role of QCT in PHPT is limited. We aimed to explore the changes of lumbar bone mineral density (BMD) and abdominal adipose tissue in patients with PHPT using QCT based on existed CT images, and to assess the consistency between QCT and dual-energy X-ray absorptiometry (DXA) in assessing bone status.MethodsThis retrospective case-control study was conducted on 48 PHPT patients, with healthy controls (HCs) matched by their age (±3 years) and gender, and the case-to-control ratio was approximately 1:3. Volumetric bone mineral density (vBMD), visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and total adipose tissue (TAT) were measured by QCT in both PHPT and control groups and compared with the independent samples T-test. In the PHPT group, areal bone mineral density (aBMD) was measured by DXA. Pearson correlation analysis was used to investigate the association between QCT-derived vBMD and DXA-derived aBMD. Weighted kappa consistency analysis was used to clarify the agreement between QCT and DXA.ResultsCompared with HCs, the PHPT group had significantly lower vBMD (114.30±41.71 vs. 136.92±42.23 mg/cm3; P=0.002) and higher TAT (261.98±74.65 vs. 236.69±69.00 cm2; P=0.033); however, differences in SAT (120.81±40.19 vs. 109.94±36.83 cm2; P=0.085) and VAT (141.17±48.11 vs. 126.75±50.50 cm2; P=0.085) were not statistically significant. There was a strong correlation between QCT-derived vBMD and DXA-derived aBMD (all r>0.68; P<0.001), and a moderate consistency [kappa(w) =0.48; 95% CI: 0.29 to 0.68; P<0.001] was presented when defining bone status according to the respective diagnostic criteria.ConclusionsOur study may provide useful information regarding bone status and abdominal adipose tissue change in patients with PHPT without requiring additional scan and may further extend the clinical application value of QCT.

Comparison of Quantitative Computed Tomography and Dual X-Ray Absorptiometry: Osteoporosis Detection Rates in Diabetic Patients

IntroductionDiabetes mellitus (DM) adversely affects the skeletal system and is associated with an increased risk of osteoporosis and fragility fractures. This study aimed to assess the diagnostic accuracy of quantitative computed tomography (QCT) in osteoporosis detection in patients with DM.MethodsA cross-sectional diagnostic accuracy study was conducted at the diabetic clinic of a tertiary care teaching hospital in North India. A total of 30 individuals with DM were subjected to spinal QCT and lumbar spine and hip dual x-ray absorptiometry (DXA). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratios of QCT were measured against DXA and the diagnostic discordance between QCT and DXA was investigated.ResultsQCT, compared to the gold standard DXA, has a sensitivity/specificity of 92.8% (95% CI 92.4%-93.2%)/81.2% (95% CI 80.6%-81.8%). The PPV/NPV of QCT was 81.2% (95% CI 80.6%-81.8%)/92.8% (95% CI 92.4%-93.2%). The positive likelihood ratio/negative likelihood ratio was 4.95 (95% CI 4.79-5.11)/0.087 (95% CI 0.082-0.093). Area under the curve was 0.871 (95% CI 0.731-1.00). Minor diagnostic discordance was present in 36.6% of patients with diabetes.Conclusion The current study assessed the diagnostic accuracy of QCT in osteoporosis detection in people with diabetes. DXA is the gold standard diagnostic tool; however, its availability is limited. The current study showed that QCT is an excellent diagnostic tool. Based on these results, this study recommends that QCT may serve as a problem-solving investigation tool where DXA is unavailable, or it may be the primary investigation tool for bone mineral density measurement and osteoporosis detection if a dedicated DXA scanner is inaccessible. This study also recommends further investigating the feasibility of opportunistic osteoporosis screening in routine abdominal and chest CT. Finally, considering the silent nature of osteoporosis and the high prevalence of osteoporosis in individuals with diabetes, a proactive approach is required in the screening of osteoporosis.

Thoracolumbar flexion dysfunction and thoracolumbar compression fracture in postmenopausal women: a single-center retrospective study

ObjectiveTo investigate whether thoracolumbar flexion dysfunctions increase the risk of thoracolumbar compression fractures in postmenopausal women.MethodsThe records of postmenopausal women with thoracolumbar vertebral compression fractures and without vertebral compression fractures were surveyed. Demographic data, clinical data, and quantitative computed tomography (QCT) findings were compared between the groups. Chi-squared tests, unpaired t-tests, Spearman, and Mann–Whitney U were used to assess the group characteristics and proportions. The relationship between the risk of fracture and the difference of Cobb’s angle of thoracolumbar segment (DCTL) was evaluated by logistic regression. DCTL was calculated by subtracting thoracolumbar Cobb’s angles (TLCobb’s) from thoracolumbar hyperflexion Cobb’s angles (TLHCobb’s). Quantitative computed tomography (QCT) values and spinal osteoarthritis (OA) of postmenopausal women in the two groups were compared.Results102 of 312 were enrolled to the study group of postmenopausal women with the fracture, and 210 of 312 were enrolled to the control group of postmenopausal women without the fracture. There were significant differences in QCT values and spinal OA including disc narrowing (DSN) and osteophytes (OPH) between the two groups (p < 0.001 for all four). The risk of thoracolumbar compression fractures in the postmenopausal women with DCTL ≤ 8.7° was 9.95 times higher (95% CI 5.31–18.64) than that with > 8.7° after adjusting for age, BMI, and QCT values.ConclusionLow DCTL may be a risk factor of thoracolumbar compression fractures in postmenopausal women, and a DCTL ≤ 8.7° can be a threshold value of thoracolumbar compression fractures.

Correlation of Bone Density Values of Quantitative Computed Tomography and Hounsfield Units Measured in Native Computed Tomography in 902 Vertebral Bodies

Due to the increasing age of patients, the evaluation of bone density is crucial, especially in preparation for spinal surgery. The aim of this study was to determine bone density using a computed tomography (CT) and to correlate Hounsfield units (HU) with bone density values of a quantitative computed tomography (QCT). The study is a monocentric, retrospective data analysis. We examined 902 vertebral bodies from a total of 369 patients who received a CT of the thoracolumbar spine in the period from 2015 to 2019 and compared the HU with values of a QCT. A general equation for calculation the QCT values was established. We found a significant correlation between the Hounsfield units and the corresponding QCT-values (r= 0.944, P < 0.001). We also demonstrated that the calculated QCT values are independent of patient sex (P < 0.942). Furthermore, we could not demonstrate differences in the correlation of the 3 measured levels (axial, sagittal, and coronary) to the QCT values. The QCT-values can be calculated on the basis of a native CT of the lumbar spine using the equation: QCT= 17.8+ 0.7× HU. The equation allows calculating bone density values without the need for an additional QCT and without further radiation exposure or costs. With this measuring method it is possible to obtain additional information from a computed tomography.

Guiding significance of lumbar quantitative computed tomography in percutaneous vertebroplasty for osteoporotic vertebral compression fractures

To investigate the guiding significance of lumbar quantitative computed tomography (QCT) in percutaneous vertebroplasty (PKP) for osteoporotic vertebral compression fractures (OVCF). The clinical data of 90 patients with OVCF underwent PKP from December 2017 to December 2018 were retrospectively analyzed. There were 24 femalesand66males, withanaverage agedof (74.47±6.60) yearsold. Allpatientswere received QCT examination before surgery, andaccording to the QCT value oflumbarspine, the patientswere dividedinto osteopenia decrease group (80 to 120 g/L, 17 cases, 30 vertebrae), osteoporosis group (40 to 80 g/L, 44 cases, 66 vertebrae) and severe osteoporosis group (<40 g/L, 29 cases, 39 vertebrae). Bone cement was injected into vertebral body, AP and lateral X-rays were done during operation. The diffusion and leakage of bone cement in injured vertebrae of patients with different QCT values were observed. Unilateral approach was used for patients whose bone cement diffused beyond the midline of the vertebral body, otherwise, and bilateral approach was adopted, and guiding significance of QCT in PKP for OVCF was analyzed. In 90 cases of 135 vertebrae, 72 cases of 98 vertebral bone cement diffused beyond the midline, accounting for 72.59%. Unilateral approach was used for the 72 patients whose bone cement diffused beyond the midline of the vertebral body, among them, there were 5 cases with 8 vertebrae in osteopenia group, 40 cases with 55 vertebrae in osteoporosis group and 27 cases with 35 vertebrae in severe osteoporosis group. There was significant difference in the bone cement dispersion between three groups (χ2=41.397, P=0.000). Moreover, no bone cement leakage occurred in osteopenia group, 3 cases of 4 vertebrae occurred in osteoporosis group and 2 cases of 3 vertebrae in severe osteoporosis group. However, none of the patients with bone cement leakage caused nerve injury and other symptoms, and there was no significant difference in bone cement leakage between the three groups (χ2=2.242, P=0.326). According to the QCT examination of lumbar spine, defining the degree of osteoporosis and guiding the puncture method can shorten the operation time, reduce the number of fluoroscopy, and effectively improve the safety of vertebroplasty.

Guiding significance of lumbar quantitative computed tomography in percutaneous vertebroplasty for osteoporotic vertebral compression fractures

To investigate the guiding significance of lumbar quantitative computed tomography (QCT) in percutaneous vertebroplasty (PKP) for osteoporotic vertebral compression fractures (OVCF). The clinical data of 90 patients with OVCF underwent PKP from December 2017 to December 2018 were retrospectively analyzed. There were 24 femalesand66males, withanaverage agedof (74.47±6.60) yearsold. Allpatientswere received QCT examination before surgery, andaccording to the QCT value oflumbarspine, the patientswere dividedinto osteopenia decrease group (80 to 120 g/L, 17 cases, 30 vertebrae), osteoporosis group (40 to 80 g/L, 44 cases, 66 vertebrae) and severe osteoporosis group (<40 g/L, 29 cases, 39 vertebrae). Bone cement was injected into vertebral body, AP and lateral X-rays were done during operation. The diffusion and leakage of bone cement in injured vertebrae of patients with different QCT values were observed. Unilateral approach was used for patients whose bone cement diffused beyond the midline of the vertebral body, otherwise, and bilateral approach was adopted, and guiding significance of QCT in PKP for OVCF was analyzed. In 90 cases of 135 vertebrae, 72 cases of 98 vertebral bone cement diffused beyond the midline, accounting for 72.59%. Unilateral approach was used for the 72 patients whose bone cement diffused beyond the midline of the vertebral body, among them, there were 5 cases with 8 vertebrae in osteopenia group, 40 cases with 55 vertebrae in osteoporosis group and 27 cases with 35 vertebrae in severe osteoporosis group. There was significant difference in the bone cement dispersion between three groups (χ2=41.397, P=0.000). Moreover, no bone cement leakage occurred in osteopenia group, 3 cases of 4 vertebrae occurred in osteoporosis group and 2 cases of 3 vertebrae in severe osteoporosis group. However, none of the patients with bone cement leakage caused nerve injury and other symptoms, and there was no significant difference in bone cement leakage between the three groups (χ2=2.242, P=0.326). According to the QCT examination of lumbar spine, defining the degree of osteoporosis and guiding the puncture method can shorten the operation time, reduce the number of fluoroscopy, and effectively improve the safety of vertebroplasty.

Magnetic resonance-based computed tomography metal artifact reduction using Bayesian modelling

Metal artifact reduction (MAR) algorithms reduce the errors caused by metal implants in x-ray computed tomography (CT) images and are an important part of error management in radiotherapy. A promising MAR approach is to leverage the information in magnetic resonance (MR) images that can be acquired for organ or tumor delineation. This is however complicated by the ambiguous relationship between CT values and conventional-sequence MR intensities as well as potential co-registration issues. In order to address these issues, this paper proposes a self-tuning Bayesian model for MR-based MAR that combines knowledge of the MR image intensities in local spatial neighborhoods with the information in an initial, corrupted CT reconstructed using filtered back projection. We demonstrate the potential of the resulting model in three widely-used MAR scenarios: image inpainting, sinogram inpainting and model-based iterative reconstruction. Compared to conventional alternatives in a retrospective study on nine head-and-neck patients with CT and T1-weighted MR scans, we find improvements in terms of image quality and quantitative CT value accuracy within each scenario. We conclude that the proposed model provides a versatile way to use the anatomical information in a co-acquired MR scan to boost the performance of MAR algorithms.

The study protocol for the China Health Big Data (China Biobank) project.

Osteoporosis, obesity, and fatty liver are increasingly common chronic diseases that seriously threaten people's health. Low-dose chest computed tomography (LDCT) scan is frequently used for lung cancer screening in health screenings and checkups. Quantitative computed tomography (QCT) enables the accurate measurement of volumetric bone mineral density (vBMD), liver fat content, and abdominal fat area using the existing LDCT data without extra radiation. We initiated a new project, the China Health Big Data (China Biobank), which combines the LDCT scan images from lung cancer screening of participants in health checkup with QCT to investigate the added value of QCT to LDCT, in order to establish the normative reference database and diagnosis criteria for the three aforementioned conditions. The China Biobank project is a prospective nationwide multicenter cohort study that will combine QCT technology with LDCT scans to measure bone mineral density (BMD), intra-abdominal fat distribution, and liver fat content of the generally healthy checkup participants. Mindways QCT calibration phantom (Mindways Software Inc., Austin, TX, USA) and analysis software QCT PRO v6.0 will be used for all centers. Before data collection begins, the European Spine Phantom (ESP) will be used for quality control analysis at each collaborating center. The inclusion criteria are a healthy checkup participant aged 30-90 years, with LDCT as a part of his/her health checkup protocol. Exclusion criteria are pregnant women or participants with a metal implant in the CT scan area. The LDCT images will be transferred to the Mindways workstation for analysis, and vBMD in the L1 and L2 vertebrae, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and liver fat content will be measured. As part of the health checkup, the demographic, anthropometric parameters, blood pressure, and a routine blood laboratory test will be collected. The estimated sample size will be about 30,000. The combination of QCT with LDCT of the chest was validated in this project. The vBMD of spine, visceral fat and liver fat can be measured with a LDCT chest scan. The China Biobank project will assess the added value of QCT to LDCT, and enable accurate evaluation of the prevalence of osteoporosis, obesity, and fatty liver disease in a very large Chinese cohort.

Reproducibility of quantitative susceptibility mapping in lumbar vertebra.

To evaluate the reliability and reproducibility of quantitative susceptibility mapping (QSM) in the lumbar vertebra. From May 2017 to September 2017, 61 subjects who underwent QSM MRI and quantitative computed tomography (QCT) were consecutively enrolled in this prospective study. QSM examination was performed two times with an interval of less than 1 week for each subject. For each data set, the QSM and QCT values on L1-L4 vertebral bodies were measured independently by two radiologists. The correlation coefficient between QSM and QCT values was calculated on L1-L4 vertebral bodies. The intraclass correlation coefficient (ICC) and Bland-Altman plots were used to evaluate the inter-observer reliability and the inter-scan reproducibility on QSM. A total of 61 subjects (mean age, 55.5±13.7 years) with 244 vertebral bodies were analyzed. Overall, QSM and QCT showed good correlation in the L1-L4 vertebral body, especially in the L3 (R=-0.75). QSM value showed excellent inter-observer reliability (ICC, 0.992, 95% CI: 0.985-0.996) with a mean difference of 0.35 and 95% limits of agreements of within -22.74 to 23.45 ppb, and very good inter-scan reproducibility (ICC, 0.932, 95% CI: 0.886-0.959) with a mean difference of -7.60 ppb and 95% limits of agreements of within of -92.85 to 77.62 ppb. QSM in the lumbar vertebra is a reliable and reproducible technique for evaluating bone mineral density.

Preliminary application study of quantitative susceptibility mapping in evaluating the osteoporosis

Objective To explore the efficacy of quantitative susceptibility mapping (QSM) in the assessment of osteoporosis and the impact factors on the QSM values. Methods A total of 105 volunteers (35 males and 70 females) were recruited in this study. The height, weight, waistline and hipline were measured, and the body mass index was calculated. All the subjects underwent MRI-based QSM and quantitative computed tomography (QCT). The measurement of QSM and QCT values was performed on L3 vertebrae body. According to QCT value, the subjects were divided into three groups (normal, osteopenia and osteoporosis). According to age, the subjects were divided into group 1 (21-30 years old), group 2 (31-40 years old), group 3 (41-50 years old), group 4 (51-60 years old), and group 5 (>60 years old). Differences among all groups were compared using one-way ANOVA or Kruskal-Wallis. Results According to QCT value, 54 subjects were normal, 22 osteopenic and 29 osteoporotic. The QSM value for the subjects with osteoporosis [148.60(109.42, 188.81)ppb] was significantly higher than that of normal (P 0.05). With the increasing of age, the QSM value showed a gradual increasing trend. And there were significant differences of QSM values among the different age groups (P 60 years old) was significantly higher than that of group 1, group 2, and group 3 (P 0.05).The QSM value of 96.62 (28.62,143.99) ppb for group 4 (51-60 years old) was significantly higher than that of group 1 and group 2 (P 0.05). The QSM value of group 1, group 2, and group 3 showed no significant difference (P>0.05). Conclusions The QSM of bone is feasible in the assessment of osteoporosis and has the potential to be a biomarker providing new insights into osteoporosis. And age is the critical factor affecting QSM value. Key words: Osteoporosis; Magnetic resonance imaging; Age factors

Inhalation lung injury induced by smoke bombs in children: CT manifestations, dynamic evolution features and quantitative analysis.

This retrospective study aimed to investigate the computed tomography (CT) manifestations, short-term dynamic evolution features and quantitative lung CT analysis of inhalation lung injury induced by smoke bomb flare. Eleven pediatric patients (aged 11 to 13) who inhaled the smoke of smoke bombs underwent several low-dose chest CT scans. The image characteristics and their dynamic changes were observed and quantitative CT values were analyzed. The quantitative CT indicators included lung injury CT score (LICTS), lung fibrosis CT score (LFCTS), mean lung density (MLD), normally aerated volume ratio (NAVR) and reductively aerated volume ratio (RAVR). Box-plot was used to analyze the dynamic changes of each indicator and Spearman statistical method was used to analyze the correlation between any two indicators. (I) In most cases, there were multiple consolidation and massive ground-glass opacities (GGOs) in the two lungs, which aggravated in the early stage and then gradually dissoluted in the later stage. LICTS was positively correlated with MLD (r=0.811, P=0.000), while it was negatively correlated with NAVR (r=-0.712, P=0.000). There existed interstitial fibrosis in the later stage, and LFCTS was positively correlated with RAVR (r=0.382, P=0.028). (II) In one case, the patterns were like layered cake, i.e., consolidation with air bronchus signs in the accumulation area, GGOs in the aforementioned area and normal lung in the top area. The patterns aggravated in the early stage and quickly dissolved in the later stage, and only a few residual fibrotic lesions existed on the final scan. (III) For severe cases, pneumomediastinum and subcutaneous emphysema aggravated in the early stage and then gradually dissolved in the later stage. The chest CT manifestations of inhalation lung injury induced by smoke bombs are predominantly GGOs and consolidation. They aggravate in the early stage and gradual dissolute in the later stage. CT quantitative values can contribute to evaluating the extent of this disease, and NAVR and RAVR can be used to assess pulmonary function.

Bone susceptibility mapping with MRI is an alternative and reliable biomarker of osteoporosis in postmenopausal women.

To investigate the efficacy of quantitative susceptibility mapping (QSM) in the assessment of osteoporosis for postmenopausal women. Between May and September 2017, a total of 70 postmenopausal women who underwent MRI-based QSM and quantitative computed tomography (QCT) were consecutively enrolled in this prospective study. The measurement of QSM and QCT values was performed on the L3 vertebrae body. On the basis of QCT value, all individuals were divided into three groups (normal, osteopenia and osteoporosis). On the basis of QCT, 18 individuals were normal (25.7%), 26 osteopenic (37.1%) and 26 osteoporotic (37.1%). The QSM value was age-related (p = 0.04) and significantly higher in the osteoporosis group than in either the normal or osteopenia group (for all, p < 0.001). In addition, the QSM value was highly correlated with QCT value (r = - 0.720, p < 0.001). For QSM, the area under the curve (AUC), sensitivity and specificity for differentiating osteopenia from non-osteopenia were 0.88, 86.5% and 77.8%, respectively, and for differentiating osteoporosis from non-osteoporosis they were 0.86, 80.8% and 77.3%, respectively. MRI-based QSM could be used for quantifying susceptibility in vertebrae and has the potential to be a new biomarker in the assessment of osteoporosis for postmenopausal women. • Osteoporosis significantly increases risk of fracture for postmenopausal women. • QSM value was correlated with QCT value (r = - 0.72, p < 0.001). • QSM is feasible in the assessment of osteoporosis for postmenopausal women. • QSM offers the quantification of susceptibility within bone.

Inverse Correlation at the Hip Between Areal Bone Mineral Density Measured by Dual-Energy X-ray Absorptiometry and Cortical Volumetric Bone Mineral Density Measured by Quantitative Computed Tomography

Quantitative computed tomography (QCT) is considered to measure true volumetric bone mineral density (vBMD; mg/cm3) and enables differentiation between cortical and trabecular bone. We aimed to determine the value of QCT by correlating areal BMD (aBMD) by dual-energy X-ray absorptiometry (DXA) with vBMD when using a fixed threshold to delineate cortical from trabecular bone. In a cross-sectional study, 98 postmenopausal women had their hip scanned by DXA and by QCT. At the total hip and the trabecular bone compartment, aBMD correlated significantly with vBMD (r = 0.74 and r = 0.63; p < 0.01, respectively). A significant inverse correlation was found between aBMD and cortical vBMD (r = −0.57; p < 0.01). Total hip volume by QCT did not change with aBMD. However, increased aBMD was associated with a decreased trabecular bone volume (r = −0.36; p < 0.01) and an increased cortical volume (r = 0.69; p < 0.01). Changing the threshold used to delineate cortical from trabecular bone from default 350 mg/cm3 to either 300 or 400 mg/cm3 did not affect integral vBMD (p = 89) but had marked effects on estimated vBMD at the cortical (p < 0.001) and trabecular compartments (p < 0.001). Furthermore, increasing the threshold decreased cortical thickness (p < 0.001), whereas the strength parameter in terms of buckling ratio increased (p < 0.001). Our results show good agreement between aBMD and integral vBMD. However, using a fixed threshold to differentiate cortical from trabecular bone causes an apparent increase in cortical volume with a decrease in cortical density as aBMD increases. This may be caused by the classification of a larger part of the transition zone as cortical bone with increased aBMD.

Interrelationships between Morphological, Densitometric and Mechanical Properties of Eggs in Japanese Quails (Coturnix Japonica).

Eggshell quality in birds results from mineral density and composition determining its mechanical endurance. The aim of the study was to determine interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Twenty four eggs randomly collected from 17-week-old quails were subjected to morphological, denstiometric and mechanical evaluation using dual-energy X-ray absorptiometry (DEXA), quantitative computed tomography (QCT) and three-point bending test. Weight, height and width of eggs were positively correlated with the densitometric parameters obtained using DEXA (egg mineral density (EMD) and egg mineral content (EMC)) and QCT (total egg volume (TEvol) and total eggshell volume (TESvol)). Positive correlations were stated between TEvol and TESvol (r=0.52; P<0.05) and EMD and EMC r=0.83; P<0.05). Egg mineral density revealed positive correlations with TEvol and mean volumetric eggshell mineral density (MvESMD), while EMC was positively correlated with TEvol, TESvol and MvESMD (all P<0.05). Eggshell breaking strength was positively correlated with MvESMD (r=0.53; P<0.05) and negatively correlated with eggshell thickness (r=−0.50; P<0.05). In conclusion, the results obtained in this study showed numerous interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Both DEXA and QCT were shown to be valuable tools for evaluation of whole egg and eggshell quality with superior prognostic value of QCT for eggshell mechanical endurance prediction. The elaborated experimental model may serve for further investigations on physiological, pharmacological, environmental, nutritional and toxicological factors influencing egg quality.

Establishing normal reference values in quantitative computed tomography of emphysema.

Quantitative computed tomography (QCT) can provide reliable and valid measures of lung structure and volumes. Similar to lung function measured by spirometry, lung measures obtained by QCT vary by demographic and anthropomorphic factors including sex, race/ethnicity, and height in asymptomatic nonsmokers. Hence, accounting for these factors is necessary to define abnormal from normal QCT values. Prediction equations for QCT may be derived from a sample of asymptomatic individuals to estimate reference values. This review article describes the methodology of reference equation development using, as an example, quantitative densitometry to detect pulmonary emphysema. The process described is generalizable to other QCT measures, including lung volumes, airway dimensions, and gas-trapping. Pulmonary emphysema is defined morphologically by airspace enlargement with alveolar wall destruction and has been shown to correlate with low lung attenuation estimated by QCT. Deriving reference values for a normal quantity of low lung attenuation requires 3 steps. First, criteria that define normal must be established. Second, variables for inclusion must be selected on the basis of an understanding of subject-specific, scanner-specific, and protocol-specific factors that influence lung attenuation. Finally, a reference sample of normal individuals must be selected that is representative of the population in which QCT will be used to detect pulmonary emphysema. Sources of bias and confounding inherent to reference values are also discussed. Reference equation development is a multistep process that can define normal values for QCT measures such as lung attenuation. Normative reference values will increase the utility of QCT in both research and clinical practice.

One-dimensional mean computed tomography value evaluation of ground-glass opacity on high-resolution images

ObjectiveDifferentiation of atypical adenomatous hyperplasia (AAH), bronchioloalveolar carcinoma (BAC), and invasive carcinoma on computed tomography (CT) is useful for determining “follow-up or resection” strategies for lesions displaying ground-glass opacity (GGO). The purpose of this study is to evaluate one-dimensional quantitative CT values of GGO on high-resolution CT (HRCT) images using computer-aided diagnosis.MethodsBetween April 2001 and March 2010, a total of 44 nodules in 42 patients with pure or mixed GGOs ≤2 cm were retrospectively evaluated. Maximum diameter and one-dimensional mean CT (m-CT) value of the diameter were measured using a computer graphics support system (HOPE/DrABLE-EX, Fujitsu, Tokyo, Japan) that displays a CT density profile across the tumor.Resultsm-CT values were −682 ± 64 HU (range) for AAH lesions, −544 ± 179 (range) for Type A lesions, −496 ± 147 (range) for Type B lesions, and −371 ± 142 (range) for invasive lesions. AAH lesions had a significantly lower m-CT value than Type B lesions. AAH, Type A, and Type B lesions had significantly lower m-CT values than invasive lesions (p < 0.05). All seven GGO lesions with a maximum diameter ≤1 cm and m-CT value ≤−600 HU were pre-invasive lesions, while 16 of 22 (73 %) cases with maximum diameter >1 cm and m-CT value >−600 HU were invasive lesions.ConclusionObservation may be indicated for GGO lesions with a maximum diameter ≤1 cm and m-CT value ≤−600 HU.

The reliability of computed tomography (CT) values and dimensional measurements of the oropharyngeal region using cone beam CT: comparison with multidetector CT

To evaluate the reliability of cone beam CT (CBCT) values and dimensional measurements of oropharyngeal air spaces as compared with those of multidetector row CT (MDCT). A soft tissue equivalent phantom with different sized holes was used. The phantom was scanned using CBCT and MDCT. In addition, a volunteer was examined using both methods for clinical comparison. The CT data were retrieved to a personal computer and treated using image processing software for three-dimensional rendering and dimensional measurements. The CT values of air, water and soft tissues were measured experimentally and the CT values of air, fat and muscle were measured in a clinical case. The diameter of each hole drilled in the phantom was measured on CBCT and MDCT images using the software tool and digimatic callipers. The CBCT values were quite different from the Hounsfield units obtained with a typical MDCT system. The standard deviations were almost ten times larger with CBCT. In vivo assessment showed that the CBCT values for fat had a wide range that partially overlapped the values for muscle. The measurement of distances greater than 4 mm was consistent for all methods. The difference for holes was less than 0.2 mm. The phantom study showed that CBCT provides limited quantitative CT values for each pixel on sliced images for differentiating air, water and soft tissues. However, the measurement of air spaces with CBCT was quite accurate.

Evaluation of Bone Mineral Density of the Lumbar Spine in Patients With β-Thalassemia Major With Dual-Energy X-Ray Absorptiometry and Quantitative Computed Tomography

Osteoporosis is a common, multifactorial cause of morbidity in patients with beta-thalassemia. The present study was performed to compare bone mineral density (BMD) results in the lumbar spine of thalassemic patients measured by both dual-energy x-ray absorptiometry (DEXA) and quantitative computed tomography (QCT), and to determine their correlations with the markers of bone turnover. BMD was measured in the lumbar spine of 13 regularly transfused patients with beta-thalassemia major by both DEXA and QCT. Blood and urine samples were obtained for the determination of biochemical and hormonal profiles. Both T-scores and Z-scores were higher when measured by QCT (T-score = -0.41 +/- 1.31, Z-score = -0.56 +/- 1.08, mean +/- SD) compared with the values given by DEXA (T-score = -2.57 +/- 0.88, Z-score = -2.32 +/- 1.11, P = 0.0005). In comparison to DEXA, QCT T-scores were more closely correlated with age (r = -0.19 vs. r = -0.70, P = 0.0068). Strong negative correlation was found between QCT values and age (r = -0.67, P = 0.01). In comparison to DEXA T-scores, QCT T-scores were more closely correlated with osteocalcin, urine N-telopeptide cross-links of type I collagen, and deoxypyridinoline, but without statistical significance. DEXA T-scores were better correlated only with urine C-terminal telopeptides of type I collagen, but again without statistical significance. These results imply that the two methods cannot be used interchangeably in assessing BMD in thalassemic patients. However, which one of these two techniques more precisely determines the overall strength of vertebrae in patients with beta-thalassemia remains to be investigated.

Spinal Volumetric Bone Mineral Density and Vertebral Fractures in Female Patients with Adrenal Incidentalomas: The Effects of Subclinical Hypercortisolism and Gonadal Status

Although adrenal incidentalomas (AI) are not associated with clinically evident syndromes, some patients display biochemical features of subclinical hypercortisolism (SH). Previous studies indicated a negative effect of SH on bone in AI patients, but the prevalence of vertebral fractures and the roles of SH and gonadal status in volumetric bone mineral density are unknown. In 70 female AI patients and 84 controls, the prevalence of vertebral fractures and spinal bone mineral density (by quantitative computed tomography) were evaluated. Subjects were subdivided according to menopausal status into groups Pre (21 patients and 23 controls) and Post (49 patients and 61 controls); there were 14 and 35 patients without SH (SH(-)) and 7 and 14 patients with SH (SH(+)) in groups Pre and Post, respectively. The prevalence of fractures was higher in SH(+) than in controls and in SH(-) subjects in both groups Pre [SH(+), 42.9%; controls, 0% (P = 0.001); SH(-), 7.1% (P = 0.049)] and post [SH(+), 78.6%; controls, 37.7% (P = 0.006); SH(-) 42.9% (P = 0.024)]. In group Post, the mean z-score quantitative computed tomography values were lower in SH(+) patients (-0.78 +/- 0.29) than in controls (0.06 +/- 0.14; P = 0.011) and SH(-) patients (0.02 +/- 0.19; P = 0.034). Evaluation of spinal bone is indicated in female AI patients with SH.