Differences in spine volumetric bone mineral density between grade 1 vertebral fracture and non-fractured participants in the China action on spine and hip status study.

Purpose: This study evaluated the prevalence of vertebral fractures (VF) in middle-aged and elderly Chinese men and women and explored the differences in lumbar spine volumetric bone mineral density (vBMD) derived from quantitative CT (QCT) between those with a grade 1 vertebral fracture and non-fractured individuals. Materials and methods: 3,457 participants were enrolled in the China Action on Spine and Hip Status (CASH) study and had upper abdominal CT examinations. Vertebral fractures were identified by Genant's semi-quantitative method from lateral CT scout views or CT sagittal views. L1-3 vBMD was measured by Mindways QCT Pro v5.0 software. The characteristics of different fracture severity groups were compared using one-way ANOVA, independent-samples t-tests, and Kruskal-Wallis H-tests. Results: 1267 males (aged 62.77 ± 9.20 years) and 2170 females (aged 61.41 ± 9.01 years) were included in the analysis. In men, the prevalence of VF increased from 14.7% at age<50 years to 23.2% at age ≥70 years, and in women from 5.1% at age<50 years to 33.0% at age ≥70 years. Differences in mean age and vBMD were found between the different fracture grade groups. After age stratification, vBMD differences in men aged < 50 years old disappeared (p = 0.162) but remained in the older age bands. There was no significant difference in mean vBMD between those with multiple mild fractures and those with a single mild fracture. Conclusion: In women, the prevalence of VF increased rapidly after age 50, while it grew more slowly in men. In general, with the exception of men <50 years old, participants with a grade 1 VF had lower vBMD than non-fractured individuals. The majority of women younger than 50 with a grade 1 VF had normal bone mass. We recommend that a vertebral height reduction ratio of <25% be diagnosed as a deformity rather than a fracture in people under the age of 50. The presence of multiple mild fractured vertebrae does not imply lower BMD.

Accuracy, Linearity and Precision of Spine QCT vBMD Phantom Measurements for Different Brands of CT Scanner: A Multicentre Study.

We describe a multicenter study using the European Spine Phantom (ESP) to compare the accuracy, linearity and precision of QCT measurements of spine vBMD between different brands of scanner, different models of the same brand and identical units of the same model. Ten scans of the same ESP with repositioning were performed on forty CT scanners from five manufacturers in different hospitals across China, all calibrated with the Mindways QCT system. The three ESP vertebral bodies simulating low (L1), medium (L2) and high (L3) vBMD and their average (L1-3 vBMD) were compared with phantom values. Linearity was assessed using the standard error of the estimate derived from linear regression. Precision errors were expressed as the standard deviation of the ten measurements on each scanner. Median (IQR) vBMD over all forty CT scanners compared with phantom values were: L1: 52.2 (49.9-56.4) vs 51.0; L2: 104.4 (101.2-108.6) vs 102.2; L3: 201.4 (195.0-204.9) vs 200.4; L1-3: 119.3 (116.6-123.2) vs 117.9 mg/cm3. Statistically significant differences in L1-3 vBMD were found between different brands (p= 0.005) and between different models of the same brand and identical units of the same model (both p< 0.001). Cross-calibration using linear regression gave a good fit for all forty systems with a median standard error of the estimate of 1.7 mg/cm3. The median precision error for L1-3 vBMD was 0.61 mg/cm3. Statistically significant differences in spine vBMD measurements between different scanners reinforce the importance of cross-calibration in multi-center studies. Cross-calibration can be reliably performed using linear regression equations.

The accurate relationship between spine bone density and bone marrow in humans.

CONTEXT: The accuracy of QCT measurements of lumbar spine trabecular volumetric bone mineral density (vBMD) is decreased due to differences in the amount of bone marrow adipose tissue (BMAT). OBJECTIVE: To correct vBMD measurements for differences in marrow composition and investigate the true relationship between vBMD and BMAT. DESIGN: Cross-sectional study. SETTING: University teaching hospital. PARTICIPANTS: Healthy Chinese subjects (233 women, 167 men) aged between 21 and 82 years. MAIN OUTCOME MEASURES: vBMD and BMAT were measured using QCT (120 kV) and chemical shift-encoded MRI of the L2-L4 vertebrae. vBMD measurements were standardized to the European Spine Phantom (ESP) and corrected for differences in BMAT. Linear regression was used to analyze BMAT, ESP adjusted vBMD (vBMDESPcorr) and BMAT corrected vBMD (vBMDBMATcorr) against age and corrected vBMD against BMAT. RESULTS: BMAT in the L2-L4 vertebral bodies increased with age in both sexes, with a faster rate of change in women compared with men (0.54%/year vs. 0.27%/year, P < 0.0001). After vBMD measurements were corrected for BMAT there were statistically significant changes in the slope of the regression line with age in both sexes (women: -3.00 ± 0.13 vs. -2.57 ± 0.11 mg/cm3/year, P < 0.0001; men: -1.92 ± 0.15 vs. -1.70 ± 0.14 mg/cm3/year, P < 0.0001). When vBMDBMATcorr was plotted against BMAT, vBMD decreased linearly with increasing BMAT in both sexes (women: -3.30 ± 0.18 mg/cm3/%; men: -2.69 ± 0.25 mg/cm3/%, P = 0.048). CONCLUSION: Our approach reveals the true relationship between vBMD and BMAT and provides a new tool for studying the interaction between bone and marrow adipose tissue.

The association of calcium intake with osteoporotic vertebral fractures in a large Chinese cohort.

The effect of calcium on prevention of osteoporosis and related fracture which are aging issues is unclear. The aim of this study is to explore the association of calcium intake with vertebral fracture. This study enrolled 3,457 participants from China Action on Spine and Hip Status (CASH) study from 2013 and 2017. Dietary calcium intake was collected using validated food frequency questionnaires (FFQ). Vertebral fracture of CT images was defined as the primary outcome. The mean calcium intake of men and women were 522.75mg/day and 507.21mg/day, respectively. 6% reduction in the odds of fracture risk was observed per 100 unit increase of calcium intake from food among females (OR, 0.94; 95% CI, 0.89-0.99), but results among males were not significant. We divided calcium intake into quintiles when modelling its associations with fracture risk, negative associations of fracture risk with calcium intake were found among females. In a population with low usual calcium intake, higher dietary calcium intake was associated with fewer vertebral fracture in women and that no such association was seen in men.

QCT of the femur: Comparison between QCTPro CTXA and MIAF Femur.

QCT is commonly employed in research studies and clinical trials to measure BMD at the proximal femur. In this study we compared two analysis software options, QCTPro CTXA and MIAF-Femur, using CT scans of the semi-anthropometric European Proximal Femur Phantom (EPFP) and in vivo data from 130 Chinese elderly men and women aged 60-80 years. Integral (Int), cortical (Cort) and trabecular (Trab) vBMD, volume, and BMC of the neck (FN), trochanter (TR), inter-trochanter (IT), and total hip (TH) VOIs were compared. Accuracy was determined in the 5 mm wide central portion of the femoral neck of the EPFP. Nominal values were: cross-sectional area (CSA) 4.9 cm2, cortical thickness (C.Th) 2 mm, CortBMD 723 mg/cm3 and TrabBMD 100 mg/cm3. In MIAF the so-called peeled trabecular VOI was analyzed, which excludes subcortical bone to avoid partial volume artefacts at the endocortical border that artificially increase TrabBMD. For CTXA uncorrected, so called raw cortical values were used for the analysis. QCTPro and MIAF phantom results were: CSA 5.9 cm2 versus 5.1 cm2; C.Th 1.68 mm versus 1.92 mm; CortBMD 578 mg/cm3 versus 569 mg/cm3; and TrabBMD 154 mg/cm3 versus 104 mg/cm3. In vivo correlations (R2) of integral and trabecular bone parameters ranged from 0.63 to 0.96. Bland-Altman analysis for TH and FN TrabBMD showed that lower mean values were associated with higher differences, which means that TrabBMD differences between MIAF and CTXA are larger for osteoporotic than for normal patients, which can be largely explained by the inclusion of subcortical BMD in the trabecular VOI analyzed by CTXA in combination with fixed thresholds used to separate cortical from trabecular bone compartments. Correlations between CTXA corrected CortBMD and MIAF were negative, whereas raw data correlated positively with MIAF measurements for all VOIs questioning the validity of the CTXA corrections. The EPFP results demonstrated higher MIAF accuracy of cortical thickness and TrabBMD. Integral and trabecular bone parameters were highly correlated between CTXA and MIAF. Partial volume artefacts at the endocortical border artificially increased trabecular BMD by CTXA, especially for osteoporosis patients. With respect to volumetric cortical measurements with CTXA, the use raw data is recommended, because corrected data cause a negative correlation with MIAF CortBMD.

Quantitative analysis of modified functional muscle-bone unit and back muscle density in patients with lumbar vertebral fracture in Chinese elderly men: a case-control study.

OBJECTIVES: Bone mineral density (BMD) is associated with muscle mass and quality, but little research has been done on functional muscle-bone unit and back muscle density in patients with lumbar vertebral fracture. This study used the "modified functional muscle-bone unit" concept and measured back muscle density to investigate muscle-bone interaction difference between the fracture and control group. METHODS: This was a case-control study. A total of 52 elderly male patients (mean age 75 years) with lumbar vertebral fracture (cases) and 52 control healthy subjects were enrolled. Cross-sectional area (CSA) and density of paravertebral muscle were measured in quantitative computed tomography (QCT) images to represent the muscle mass, while the bone mineral density measured by QCT was used to represent the bone mass. The modified functional muscle-bone unit was calculated as the value of volumetric BMD divided by muscle area. RESULTS: People with vertebral fractures reported significantly lower values in the cross-sectional area and density of paravertebral muscle compared to control group. In the multivariate analysis, BMD (odds ratio, OR = 0.929; 95% confidence intervals, CIs 0.888-0.971), erector muscle density (OR = 0.698; 95% CI 0.547-0.892), and summated muscle CSA (OR = 0.963; 95% CI 0.93-0.991) were independent protective factors for the presence of a fracture. BMD resulted significantly and moderately associated with cross-sectional area and density of paravertebral muscle (r = 0.329-0.396). CONCLUSIONS: There were significant differences between the modified functional muscle-bone unit and back muscle density between the fracture group and control group in elderly men. Lower BMD, loss of muscle mass and density are associated with increased presence of the lumbar vertebral fracture.

The protocol for the Prospective Urban Rural Epidemiology China Action on Spine and Hip status study.

The Prospective Urban Rural Epidemiology (PURE) China Action on Spine and Hip status (CASH) study focused on the prevalence of osteoporosis and spinal fracture in China. The aim of the PURE CASH study is to determine the prevalence of osteoporosis and spinal fracture, and explore the potential relationship between spinal fracture and bone mineral density (BMD). This study is a prospective large-scale population study with a community-based sampling and recruitment strategy. The aim is to determine the prevalence of osteoporosis and vertebral fracture in this population, to evaluate the association between vertebral fractures and BMD values, and to assess the prediction power of BMD for incident fractures. Participants in the PURE CASH study are all from the PURE study in China, recruited from 12 centers in 7 Chinese provinces. The inclusion criteria are that participants should be aged more than 40 years and able to give informed consent. Exclusion criteria are pregnant women, individuals with metal implants in the lumbar spine, use of medications or the existence of any disease or condition known to have a major influence on BMD, and inability to give informed consent. A total of 3,457 participants undergo a quantitative computed tomography (QCT) scan of the upper abdomen. The scanning parameters are as follows: 120 kVp at all centers, mAs between 75 and 200, FOV 40 cm×40 cm. The BMD values of L1 to L3 are measured, and the average BMD calculated. The American College of Radiology QCT criteria for the diagnosis of osteoporosis is applied to determine the presence of osteoporosis. The scout view images of T4-L4 vertebrae are reviewed by two experienced radiologists for semi-quantification of vertebral fractures according to Genant's method.

Reliability of measuring the fat content of the lumbar vertebral marrow and paraspinal muscles using MRI mDIXON-Quant sequence.

PURPOSE: We aimed to assess the reliability of measuring the fat content of the lumbar vertebral marrow and the paraspinal muscles using magnetic resonance imaging (MRI) mDIXON-Quant sequence. METHODS: Thirty-one healthy volunteers were included. All participants underwent liver mDIXON-Quant imaging on a 3.0 T Philips MRI scanner by observer A. Within two weeks, observer B repeated the scan. After the examination, each observer independently measured the fat content of the third lumbar vertebra (L3), and the psoas (PS), erector spinae (ES), and multifidus (MF) muscles on central L3 axial images. After two weeks, each observer repeated the same measurements. They were blinded to their previous results. Reliability was estimated by evaluating the repeatability and reproducibility. RESULTS: The repeatability of the fat content measurements of L3, PS, ES, and MF was high. The intraclass correlation coefficients of the fat content of L3, PS, ES, and MF were 0.997, 0.984, 0.997, and 0.995 for observer A and 0.948, 0.974, 0.963, and 0.995 for observer B, respectively. The reproducibility of the measurement of the fat content of L3, PS, ES, and MF was high, and the interclass correlation coefficients were 0.984, 0.981, 0.977, and 0.998, respectively. CONCLUSION: Using mDIXON-Quant imaging to measure the fat content of the lumbar vertebral marrow and paraspinal muscles shows high reliability and is suitable for use in clinical practice.

Comparison of CT and magnetic resonance mDIXON-Quant sequence in the diagnosis of mild hepatic steatosis.

OBJECTIVE:: To determine the diagnostic performance of CT in the assessment of mild hepatic steatosis by comparison with MR mDIXON-Quant as a reference standard, and to explore their clinical applications. METHODS:: In this prospective study 169 volunteers were included. Each subject underwent CT and MR mDIXON-Quant examinations. Hepatic steatosis evaluations were performed via liver attenuation alone (CT L), liver to spleen attenuation ratio (CT L/S), difference between liver and spleen attenuation (CT L-S), and MR mDIXON-Quant imaging. The effectiveness of CT L, CT L/S, and CT L-S in diagnosing hepatic steatosis severity of ≥5%, ≥10%, and ≥15% was compared, using mDIXON-Quant results as standard. RESULTS:: 65 subjects exhibited mild hepatic steatosis. Hepatic steatosis measurement with mDIXON-Quant was strongly correlated with the three CT methods. Using cutoff value, the sensitivity and specificity of diagnosing hepatic steatosis ≥5, ≥10, and ≥15% were 64.6, 91.3, 100%, and 90.4, 89.7, 93.0% for CT L; 50.8, 87.0, 100%, and 96.2, 98.6, 97.5% for CT L/S; and 67.7, 87.0, 100%, and 81.7, 98.6, 97.5% for CT L-S, respectively. ROC analysis indicated that 58.9, 56.5, and 52.8 HU for CT L; 1.06, 0.98, and 0.90 HU for CT L/S; and 6.21,-1.04, and -4.93 HU for CT L-S were cutoff values for diagnosing hepatic steatosis ≥5%,≥10%, and ≥15%, respectively. CONCLUSIONS:: The three CT methods exhibit better agreements with mDIXON-Quant imaging for diagnosing hepatic steatosis ≥10%. Hence, CT and mDIXON-Quant could serve as suitable tools for the accurate quantification of mild hepatic steatosis. SIGNIFICANT FINDS OF THE STUDY:: The close agreement between the three different CT methods (based on our cutoff values) and mDIXON-Quant imaging suggests that CT could accurately diagnose hepatic steatosis ≥10%. Thus, CT and mDIXON-Quant imaging can accurately measure mild hepatic steatosis. WHAT THIS STUDY ADDS:: Only few studies have compared hepatic steatosis quantification between CT and mDIXON-Quant. We are the first to determine the diagnostic performance of unenhanced CT for quantitatively assessing mild hepatic steatosis, in reference to magnetic resonance mDIXON-Quant imaging.

Validation of goose liver fat measurement by QCT and CSE-MRI with biochemical extraction and pathology as reference.

OBJECTIVES: This study aimed to validate the accuracy and reliability of quantitative computed tomography (QCT) and chemical shift encoded magnetic resonance imaging (CSE-MRI) to assess hepatic steatosis. METHODS: Twenty-two geese with a wide range of hepatic steatosis were collected. After QCT and CSE-MRI examinations, the liver of each goose was removed and samples were taken from the left lobe, upper and lower half of the right lobe for biochemical measurement and histology. Fat percentages by QCT and proton density fat fraction by MRI (MRI-PDFF) were measured within the sample regions of biochemical measurement and histology. The accuracy of QCT and MR measurements were assessed through Spearman correlation coefficients (r) and Passing and Bablok regression equations using biochemical measurement as the "gold standard". RESULTS: Both QCT and MRI correlated highly with chemical extraction [r = 0.922 (p < 0.001) and r = 0.949 (p < 0.001) respectively]. Chemically extracted triglyceride was accurately predicted by both QCT liver fat percentages (Y = 0.6 + 0.866 × X) and by MRI-PDFF (Y = -1.8 + 0.773 × X). CONCLUSIONS: QCT and CSE-MRI measurements of goose liver fat were accurate and reliable compared with biochemical measurement. KEY POINTS: • QCT and CSE-MRI can measure liver fat content accurately and reliably • Histological grading of hepatic steatosis has larger sampling variability • QCT and CSE-MRI have potential in the clinical setting.

Validation of asynchronous quantitative bone densitometry of the spine: Accuracy, short-term reproducibility, and a comparison with conventional quantitative computed tomography.

Asynchronous calibration quantitative computed tomography (QCT) is a new tool that allows the quantification of bone mineral density (BMD) without the use of a calibration phantom during scanning; however, this tool is not fully validated for clinical use. We used the European spine phantom (ESP) with repositioning during scanning and assessed the accuracy and short-term reproducibility of asynchronous QCT. Intra-scanner and intra-observer precision were each calculated as the root mean square of the standard deviation (RMSSD) and the coefficient of variation (CV-RMSSD). We also compared asynchronous and conventional QCT results in 50 clinical subjects. The accuracy of asynchronous QCT for three ESP vertebrae ranged from 1.4-6.7%, whereas intra-scanner precision for these vertebrae ranged from 0.53-0.91 mg/cc. Asynchronous QCT was most precise for a trabecular BMD of 100 mg/cc (CV-RMSSD = 0.2%). For intra-observer variability, overall precision error was smaller than 3%. In clinical subjects there was excellent agreement between the two calibration methods with correlation coefficients ranging from 0.96-0.99. A Bland-Altman analysis demonstrated that methodological differences depended on the magnitude of the BMD variable. Our findings indicate that the asynchronous QCT has good accuracy and precision for assessing trabecular BMD in the spine.

Population-Stratified Analysis of Bone Mineral Density Distribution in Cervical and Lumbar Vertebrae of Chinese from Quantitative Computed Tomography.

OBJECTIVE: To investigate the bone mineral density (BMD) of cervical vertebrae in a population-stratified manner and correlate with that of the lumbar vertebrae. MATERIALS AND METHODS: Five hundred and ninety-eight healthy volunteers (254 males, 344 females), ranging from 20 to 64 years of age, were recruited for volumetric BMD (vBMD) measurements by quantitative computed tomography. Basic information (age, height, weight, waistline, and hipline), and vBMD of the cervical and lumbar vertebrae (C2-7 and L2-4) were recorded. Comparisons among sex, age groups and different levels of vertebrae were analyzed using analysis of variance. Linear regression was performed for relevance of different vertebral levels. RESULTS: The vBMD of cervical and lumbar vertebrae was higher in females than males in each age group. The vBMD of the cervical and lumbar vertebrae in males and the vBMD of lumbar vertebrae in females decreased with aging. In each age group, the vBMD of the cervical vertebrae was higher than that of the lumbar vertebrae with gradual decreases from C2 to C7 except for C3; moreover, the vBMD of C6 and C7 was significantly different from that of C2-5. Correlations of vBMD among different cervical vertebrae (females: r = 0.62-0.94; males: r = 0.63-0.94) and lumbar vertebrae (males: r = 0.93-0.98; females: r = 0.82-0.97) were statistically significant at each age group. CONCLUSION: The present study provided normative data of cervical vertebrae in an age- and sex-stratified manner. Sex differences in vBMD prominently vary with age, which can be helpful to design a more comprehensive pre-operative surgical plan.