- Email: [email protected]
Spine Trabecular Bone Score (TBS) Cross-Calibration for GE Prodigy and iDXA Scanners
Abstracts 5 Vertebral Fracture Assessment in a Paediatric Population Using Dual-Energy X-ray Absorptiometry Sheila Shepherd; Developmental Endocrinology Research Group Andreas Kyriakou Background: Vertebral Fractures (VF) are recognized as an important aspect of bone health in children and adolescents. The clinical utility of Vertebral Fracture Assessment (VFA) using Dual-energy X-ray Absorptiometry (DXA) has not been evaluated in the paediatric population. Method: VFA was performed independently by two non-radiologist observers, in 165 patients (77M/88F) as part of their investigation for low bone mineral density. Lateral thoracolumbar x-ray images (LXR) were obtained in 20/165 patients. The median age of the patients was 13.4yrs (3.6,18). Lateral DXA images of the spine from T6 to L4 were obtained using Lunar Prodigy DXA device. The diagnosis of VF was performed according to Genant’s Semi-quantitative classification. Results: Interobserver agreement in vertebral readability using VFA was 94% (kappa, 0.73 [95%CI, 0.68, 0.73]). The vertebrae not readable by both observers were 287/1815 (16%) and 266/287 (93%) were located between T6 and T9. Conversely, 1134/1155 (98%) of vertebrae from T10 through L4 were adequately visualised (p!0.0001). Among the 1528 vertebrae visualised by both observers, 72 (4.7%) in 45 (27%) patients and 84 (5.5%) in 48 (29%) patients were classified as VF by observer 1 and by observer 2, respectively. Interobserver per-vertebra agreement for the presence of VF was 99% (kappa, 0.85 [95%CI, 0.79, 0.91]). Interobserver per-patient agreement was 91% (kappa, 0.78 [95%CI, 0.66, 0.87]). The two observers had in common 67 (4.5%) VF in 39 (24%) patients and 18 (27%) of them were classified as moderate or severe. The anatomical distribution of VF was biphasic, with peaks located on T9 (odds ratio, 2.1 [1.1,4.2]) and L4 (odds ratio, 1.7 [1.0,3.4]). Among those who underwent both LXR and VFA, 24 (11%) VF in 6 (30%) patients and 20 (9%) VF in 5 (25%) patients were identified by LXR and VFA, respectively. Per-vertebra agreement was 95% (kappa, 0.79 [95%CI, 0.62, 0.92]) and per-patient agreement was 95% (kappa, 0.88 [95%CI, 0.58, 1.0]). Specificity of VFA was 98.4% per-vertebra and 100% per-patient. Conclusion: VFA reaches an excellent level of agreement between observers and a high level of specificity in identifying VF in paediatric population. The readability of vertebrae from T6 to T9 is suboptimal and interpretation at this level should be exercised with caution.
6 High Subcutaneous Fat Measured by DXA is Associated with Low Grip Strength and Poor Physical Capacity in Older Men The STRAMBO Study Pawel Szulc; INSERM UMR 1033, University of Lyon, Hospital Edouard Herriot Francois Duboeuf, Roland Chapurlat Background: The association of sarcopenia (low muscle mass) with obesity is characterized by dynapenia (low muscle strength) and poor physical capacity. The association of visceral or subcutaneous fat with dynapenia and physical capacity is not clear. Our aim was to assess the association of subcutaneous and visceral fat mass with grip strength and physical capacity in older men. Methods: In 897 men aged 50 we assessed regional body composition (Hologic Discovery A), i.e. gynoid fat (subcutaneous fat) and android fat (abdominal subcutaneous and visceral fat). Upper limb relative appendicular skeletal muscle mass (RASM-u.l.) is calculated as the sum of arm lean mass divided by (height)2. Lower limb RASM (RASM-l.l.) is calculated similarly. Men had measures of grip strength and clinical tests of muscle strength and balance. We calculated a score accounting for the ability and time to perform each test (0-16). Results: After adjustment for age, height, alcohol intake, physical activity, diabetes mellitus, hypertension, Parkinson disease, and RASM-u.l., higher body mass index was associated with lower grip strength. Grip strength determinants were analyzed by stepwise linear regression including the above variables. Gynoid fat was retained in the model as a significant (p!0.001) determinant of grip strength. Android fat was not significant and not retained. In a similar stepwise linear regression model, subcutaneous abdominal fat was retained in the model as a significant (p!0.001) determinant of grip strength. Again, visceral fat was not retained. Both higher gynoid fat and higher subcutaneous abdominal fat were associated with lower grip strength (p!0.02 and p50.005, respectively). Men in the upper quartile of subcutaneous abdominal fat had 6% lower grip strength (p50.02) vs.
423 the lowest quartile. By contrast, higher android fat and higher visceral fat were not associated with grip strength. Low physical capacity score (!9) was found in 219 men (24%). After adjustment for RASM-l.l. and other variables, higher gynoid fat was associated with poor physical capacity (upper vs. first quartile, OR56.34, p!0.001), whereas higher android fat was not associated. High subcutaneous fat was associated with poor physical capacity (OR52.46, p!0.005), whereas higher visceral fat was not. Conclusion: In older men, higher subcutaneous fat is associated with lower grip strength and poor physical capacity of the lower limbs, whereas higher visceral fat is not.
Posters P01
An Evaluation of Lumbar Spine BMD and TBS Precision
Jessie Libber; University of Wisconsin Diane Krueger, Neil Binkley ISCD currently recommends that lumbar spine DXA reports include at least two vertebral bodies. This recommendation is based on the poorer precision observed when smaller bone regions are reported. However, spine DXA is often confounded by degenerative changes, fracture and surgical hardware, thus necessitating exclusion of three or all four vertebrae. Thus, it is plausible that future recommendations might allow diagnosis and monitoring using a single vertebra. Similarly, while trabecular bone score (TBS) is less confounded by degenerative changes, other confounders could affect it, (e.g., metallic hardware) making monitoring using fewer than 4 vertebral bodies appropriate. As such, knowledge regarding individual vertebral precision is needed; this project reports BMD and TBS precision of individual vertebral bodies compared to routine L1-L4 analysis. Scans previously obtained as part of a research precision assessment acquired by one ISCD certified technologist were used and re-analyzed to obtain TBS data. All scans were acquired using a GE Lunar iDXA and analyzed with enCORE version 14.0 and Medimaps TBS software version 2.1.0. Two AP spine scans were acquired in routine manner i.e., with repositioning between, in 30 men and 30 women (mean age 75.1 6.5/72.5 6 years and BMI 25.9 2.94/27.1 4.6). BMD and TBS least significant change (LSC) were calculated using the ISCD precision calculator (Table). Precision was compared between sites using the F-Test (Excel). Overall, BMD and TBS precision is similar between males and females across individual vertebral bodies and at the L1-4 spine. As might be expected, BMD and TBS precision is reduced when less than four vertebral bodies are considered. This reduced precision for both BMD and TBS must be considered when fewer than four vertebral bodies are used to monitor change over time
Table. BMD and TBS LSC Values Male
Female
Site
BMD
%CV
TBS
%CV
BMD
%CV
TBS
%CV
L1 L2 L3 L4 L1-2 L1-3 L1-4
0.066* 0.083* 0.055 0.073* 0.053 0.041 0.040
1.9 2.5 1.7 2.0 1.5 1.2 1.2
0.130* 0.104* 0.093* 0.078 0.082* 0.067 0.056
3.9 2.9 2.5 2.1 2.4 1.9 1.6
0.062* 0.089* 0.053 0.063* 0.060* 0.045 0.040
2.3 3.0 1.8 2.0 2.0 1.5 1.3
0.200* 0.098* 0.097* 0.085* 0.081* 0.066 0.054
6.0 2.8 2.6 2.3 2.4 1.9 1.5
*5 Different from L1-L4 p ! 0.05
P02 Spine Trabecular Bone Score (TBS) Cross-Calibration for GE Prodigy and iDXA Scanners William Leslie; University of Manitoba Didier Hans (Lausanne University Hospital) Aims: Spine Trabecular Bone Score (TBS), a gray-level measurement derived from lumbar spine DXA image texture, is related to fracture risk independently
Journal of Clinical Densitometry: Assessment & Management of Musculoskeletal Health
Volume 18, 2015
424 of BMD. Our aim was to evaluate the level of agreement between GE Prodigy and iDXA scanners within the framework of instrument cross-calibration performed at the time of scanner replacement. Methods: A convenience sample of 109 subjects (predominantly women) underwent spine DXA on the same day with GE Prodigy and iDXA scanners. Simple linear correlations and Bland-Altman plots (without external BMD or TBS phantoms) were analyzed for between-scanner agreement in spine BMD and spine TBS (Figure). Results: Spine BMD (L1-4) showed excellent agreement between the Prodigy and iDXA scanners (mean difference iDXA-Prodigy 0.001 g/cm2, p50.613): BMD (iDXA) 5 1.008 x BMD (Prodigy) - 0.007 (p50.610 for slope51, p50.673 for intercept 0, standard error of the estimate [SEE]50.028 g/cm2, SEE 2.53% of mean). In contrast, spine TBS (L1-4) showed significant between-scanner differences (mean difference 0.038, p!0.001): TBS (iDXA) 5 0.692 x TBS (Prodigy) + 0.422 (p!0.001 for slope51, p!0.001 for intercept 0, SEE50.068, SEE 5.37% of mean). Results were worse for 23 scans acquired in thick mode (slope 0.565, intercept 0.582, SEE 0.067, SEE 5.69% of mean, mean difference 0.092) compared to the 86 scans acquired in standard mode (slope 0.835, intercept 0.234, SEE 0.064, SEE 4.96% of mean, mean difference 0.024). Conclusions: Direct comparison of spine TBS measurements from GE Prodigy and iDXA scanners is unreliable without the use of cross-calibration phantoms. This justifies the development and application of a TBS phantom to accommodate between-scanner differences as part of the TBS software installation.
Figure. Cross-calibration for spine BMD (upper) and spine TBS (lower).
P03 TBS Precision and Comparison between the Hologic and GE-Lunar DXA Scanners Bo Fan; University of California San Francisco Michael Lewiecki (New Mexico Clinical Research & Osteoporosis Center), Paul D. Miller, Harry K. Genant, John A. Shepherd Minimizing precision errors in bone architecture is critical since lower precision error allows for the detection of smaller changes in architecture. Here we compared the short-term precision of two fan-beam DXA devices, the Lunar Prodigy (GE Medical Systems) and the Delphi A (Hologic), a new measure for lumbar spine architecture, trabecular bone score (TBS). Ninety women from three centers with a mean age of 62 years old (ranging 50 to 82 years) were measured in duplicate with repositioning on each densitometer. An ISCD-certified researcher used manufacturer-recommended analysis procedures for both instruments. All of the scans were performed using the 30-second scan modes. Then the scan batch analyzed using Medimaps TBS clinical Data Analyzer 2.2.1. Three subject were excluded for both devices because of an anatomic anomaly. Precision error was then calculated as the root-mean-square standard deviation and coefficient of variation (%CV) for the repeated measurements.
Abstracts An F-test was used to compare the precision error (variance) to determine if there was significance of any observed precision differences. Spearmen rank correlation and liner regression analysis were used to test the TBS relationship between the two systems.The Spine TBS precision errors (%CV and 95% CI) for Prodigy were significantly less than the Delphi: 1.79% vs. 1.98%, p!0.05. The TBS scores were correlated between the scanners r50.73. The regression equation had a significant intercept and slopes of the regression were 0.78 from Hologic to Prodigy and 0.63 from Prodigy to Delphi. We conclude that the TBS precision on Prodigy was significantly better than the Delphi A. Precision is vitally important to clinicians when determining 1) whether an observed change in measured TBS is a true biological change in the patient, and 2) the time required between follow-up scans to detect a significant change in TBS. The TBS scores were correlated but not equivalent between two different scanners.
P04
TBS Increases Over Time in Pre-Teen Girls
Jessie Libber; University of Wisconsin Diane Krueger, Tamara Scerpella, Neil Binkley Muscle and loading force application alters bone structure and increases bone mineral density (BMD), particularly during growth. However, how trabecular bone score (TBS) changes during growth is unknown. We hypothesized that TBS would be positively correlated with growth and higher in growing girls participating in regular physical exercise. Sixty-eight girls (mean age 12 0.3 years; BMD 18 2.8 kg/m2) were recruited from two middle-schools in Madison, WI. A school-based intervention incorporated a limited resistance training intervention into their routine physical education classes. DXA scans were obtained at three time points, fall 2011, spring 2012 and spring 2013, using a GE Lunar iDXA with software v13.31. Lumbar spine TBS was analyzed using MediMaps software v2.1.1. Tanner staging was obtained by self-report coincident with each DXA scan; resistance exercise intensity was assessed by observation during year 1 only. Mean L1-L4 BMD increased 20% (p ! 0.01) over 18 months, 0.846 (0.12) to 1.024 (0.13) grams/cm2. Over the same interval, TBS increased (p ! 0.01) 5.5% from 1.269 (0.08) at baseline to 1.342 (0.08) at month 18. These observations persisted (p ! 0.01) when limiting the sample to those categorized as Tanner stage (2 or 3) at baseline (n 5 52) or with high intensity of resistance training (n 5 15) demonstrating respective change in BMD of 22 and 23% and TBS of 5.6 and 5.8% at 18 months. In conclusion, this first report of TBS in adolescent girls demonstrated BMD and TBS increases as they age. The apparent greater increase in BMD vs. TBS may suggest that bone microarchitecture has largely been established by age 12 and that the primary growth activity is bone mass/size accrual. It is important to note limitations; importantly that TBS is impacted by soft tissue thickness and as a result these TBS data may differ after recalculating for the smaller amount of soft tissue present in most young girls. Additionally, results may differ using groups with higher intensity resistance training, longer follow-up or larger sample size. Further research documenting TBS changes during growth, and potential ways of optimizing skeletal structure in adolescents, is indicated.
P05 Effects of Glucocorticoids Treatment on Bone BMD and TBS in Men Edward Leib; University of Vermont College of Medicine Renaud Winzenrieth (MediMaps) Aim: The aim of the study was to evaluate whether microarchitectural texture changes as measured by Trabecular Bone Score (TBS) can identify those male patients on glucocorticoid (GC) therapy presently who are more likely to fracture. Material and Methods: This mono-centric study involves US white men aged 45 and older who at the time of bone density testing gave a history of present or past use of GC. They were compared to a group of control subjects. Control subject exclusions included one or more historical fractures, or a past or present treatment or illness influencing bone metabolism. Subjects included in the GC treated group received prednisone 5mg/day for 3 months or equivalent treatment. BMD was assessed at the lumbar spine (L1-L4) using a Prodigy device (GE-Lunar,Madison,USA). TBS was calculated at L1-L4 using the TBS iNsightÒ (v2.1, Medimaps, France). Clinical data, presence of osteoporotic fracture (OPF), GC treatment and common clinical risk factors (CRFs) were documented. Results: From the database, 73 men treated with GC and 90 control men were matched for age and BMI (pO0.4). Characteristics of the patients are shown in table. No correlation was observed when comparing spine TBS, spine BMD and BMI in either treated or cont. groups (-0.16 r 0.23). When compared to normal values, no TBS difference was observed in the control group whereas the GC group had a significantly lower TBS value (see table). GC subjects had
Journal of Clinical Densitometry: Assessment & Management of Musculoskeletal Health
Volume 18, 2015
6 High Subcutaneous Fat Measured by DXA is Associated with Low Grip Strength and Poor Physical Capacity in Older Men The STRAMBO Study Pawel Szulc; INSERM UMR 1033, University of Lyon, Hospital Edouard Herriot Francois Duboeuf, Roland Chapurlat Background: The association of sarcopenia (low muscle mass) with obesity is characterized by dynapenia (low muscle strength) and poor physical capacity. The association of visceral or subcutaneous fat with dynapenia and physical capacity is not clear. Our aim was to assess the association of subcutaneous and visceral fat mass with grip strength and physical capacity in older men. Methods: In 897 men aged 50 we assessed regional body composition (Hologic Discovery A), i.e. gynoid fat (subcutaneous fat) and android fat (abdominal subcutaneous and visceral fat). Upper limb relative appendicular skeletal muscle mass (RASM-u.l.) is calculated as the sum of arm lean mass divided by (height)2. Lower limb RASM (RASM-l.l.) is calculated similarly. Men had measures of grip strength and clinical tests of muscle strength and balance. We calculated a score accounting for the ability and time to perform each test (0-16). Results: After adjustment for age, height, alcohol intake, physical activity, diabetes mellitus, hypertension, Parkinson disease, and RASM-u.l., higher body mass index was associated with lower grip strength. Grip strength determinants were analyzed by stepwise linear regression including the above variables. Gynoid fat was retained in the model as a significant (p!0.001) determinant of grip strength. Android fat was not significant and not retained. In a similar stepwise linear regression model, subcutaneous abdominal fat was retained in the model as a significant (p!0.001) determinant of grip strength. Again, visceral fat was not retained. Both higher gynoid fat and higher subcutaneous abdominal fat were associated with lower grip strength (p!0.02 and p50.005, respectively). Men in the upper quartile of subcutaneous abdominal fat had 6% lower grip strength (p50.02) vs.
423 the lowest quartile. By contrast, higher android fat and higher visceral fat were not associated with grip strength. Low physical capacity score (!9) was found in 219 men (24%). After adjustment for RASM-l.l. and other variables, higher gynoid fat was associated with poor physical capacity (upper vs. first quartile, OR56.34, p!0.001), whereas higher android fat was not associated. High subcutaneous fat was associated with poor physical capacity (OR52.46, p!0.005), whereas higher visceral fat was not. Conclusion: In older men, higher subcutaneous fat is associated with lower grip strength and poor physical capacity of the lower limbs, whereas higher visceral fat is not.
Posters P01
An Evaluation of Lumbar Spine BMD and TBS Precision
Jessie Libber; University of Wisconsin Diane Krueger, Neil Binkley ISCD currently recommends that lumbar spine DXA reports include at least two vertebral bodies. This recommendation is based on the poorer precision observed when smaller bone regions are reported. However, spine DXA is often confounded by degenerative changes, fracture and surgical hardware, thus necessitating exclusion of three or all four vertebrae. Thus, it is plausible that future recommendations might allow diagnosis and monitoring using a single vertebra. Similarly, while trabecular bone score (TBS) is less confounded by degenerative changes, other confounders could affect it, (e.g., metallic hardware) making monitoring using fewer than 4 vertebral bodies appropriate. As such, knowledge regarding individual vertebral precision is needed; this project reports BMD and TBS precision of individual vertebral bodies compared to routine L1-L4 analysis. Scans previously obtained as part of a research precision assessment acquired by one ISCD certified technologist were used and re-analyzed to obtain TBS data. All scans were acquired using a GE Lunar iDXA and analyzed with enCORE version 14.0 and Medimaps TBS software version 2.1.0. Two AP spine scans were acquired in routine manner i.e., with repositioning between, in 30 men and 30 women (mean age 75.1 6.5/72.5 6 years and BMI 25.9 2.94/27.1 4.6). BMD and TBS least significant change (LSC) were calculated using the ISCD precision calculator (Table). Precision was compared between sites using the F-Test (Excel). Overall, BMD and TBS precision is similar between males and females across individual vertebral bodies and at the L1-4 spine. As might be expected, BMD and TBS precision is reduced when less than four vertebral bodies are considered. This reduced precision for both BMD and TBS must be considered when fewer than four vertebral bodies are used to monitor change over time
Table. BMD and TBS LSC Values Male
Female
Site
BMD
%CV
TBS
%CV
BMD
%CV
TBS
%CV
L1 L2 L3 L4 L1-2 L1-3 L1-4
0.066* 0.083* 0.055 0.073* 0.053 0.041 0.040
1.9 2.5 1.7 2.0 1.5 1.2 1.2
0.130* 0.104* 0.093* 0.078 0.082* 0.067 0.056
3.9 2.9 2.5 2.1 2.4 1.9 1.6
0.062* 0.089* 0.053 0.063* 0.060* 0.045 0.040
2.3 3.0 1.8 2.0 2.0 1.5 1.3
0.200* 0.098* 0.097* 0.085* 0.081* 0.066 0.054
6.0 2.8 2.6 2.3 2.4 1.9 1.5
*5 Different from L1-L4 p ! 0.05
P02 Spine Trabecular Bone Score (TBS) Cross-Calibration for GE Prodigy and iDXA Scanners William Leslie; University of Manitoba Didier Hans (Lausanne University Hospital) Aims: Spine Trabecular Bone Score (TBS), a gray-level measurement derived from lumbar spine DXA image texture, is related to fracture risk independently
Journal of Clinical Densitometry: Assessment & Management of Musculoskeletal Health
Volume 18, 2015
424 of BMD. Our aim was to evaluate the level of agreement between GE Prodigy and iDXA scanners within the framework of instrument cross-calibration performed at the time of scanner replacement. Methods: A convenience sample of 109 subjects (predominantly women) underwent spine DXA on the same day with GE Prodigy and iDXA scanners. Simple linear correlations and Bland-Altman plots (without external BMD or TBS phantoms) were analyzed for between-scanner agreement in spine BMD and spine TBS (Figure). Results: Spine BMD (L1-4) showed excellent agreement between the Prodigy and iDXA scanners (mean difference iDXA-Prodigy 0.001 g/cm2, p50.613): BMD (iDXA) 5 1.008 x BMD (Prodigy) - 0.007 (p50.610 for slope51, p50.673 for intercept 0, standard error of the estimate [SEE]50.028 g/cm2, SEE 2.53% of mean). In contrast, spine TBS (L1-4) showed significant between-scanner differences (mean difference 0.038, p!0.001): TBS (iDXA) 5 0.692 x TBS (Prodigy) + 0.422 (p!0.001 for slope51, p!0.001 for intercept 0, SEE50.068, SEE 5.37% of mean). Results were worse for 23 scans acquired in thick mode (slope 0.565, intercept 0.582, SEE 0.067, SEE 5.69% of mean, mean difference 0.092) compared to the 86 scans acquired in standard mode (slope 0.835, intercept 0.234, SEE 0.064, SEE 4.96% of mean, mean difference 0.024). Conclusions: Direct comparison of spine TBS measurements from GE Prodigy and iDXA scanners is unreliable without the use of cross-calibration phantoms. This justifies the development and application of a TBS phantom to accommodate between-scanner differences as part of the TBS software installation.
Figure. Cross-calibration for spine BMD (upper) and spine TBS (lower).
P03 TBS Precision and Comparison between the Hologic and GE-Lunar DXA Scanners Bo Fan; University of California San Francisco Michael Lewiecki (New Mexico Clinical Research & Osteoporosis Center), Paul D. Miller, Harry K. Genant, John A. Shepherd Minimizing precision errors in bone architecture is critical since lower precision error allows for the detection of smaller changes in architecture. Here we compared the short-term precision of two fan-beam DXA devices, the Lunar Prodigy (GE Medical Systems) and the Delphi A (Hologic), a new measure for lumbar spine architecture, trabecular bone score (TBS). Ninety women from three centers with a mean age of 62 years old (ranging 50 to 82 years) were measured in duplicate with repositioning on each densitometer. An ISCD-certified researcher used manufacturer-recommended analysis procedures for both instruments. All of the scans were performed using the 30-second scan modes. Then the scan batch analyzed using Medimaps TBS clinical Data Analyzer 2.2.1. Three subject were excluded for both devices because of an anatomic anomaly. Precision error was then calculated as the root-mean-square standard deviation and coefficient of variation (%CV) for the repeated measurements.
Abstracts An F-test was used to compare the precision error (variance) to determine if there was significance of any observed precision differences. Spearmen rank correlation and liner regression analysis were used to test the TBS relationship between the two systems.The Spine TBS precision errors (%CV and 95% CI) for Prodigy were significantly less than the Delphi: 1.79% vs. 1.98%, p!0.05. The TBS scores were correlated between the scanners r50.73. The regression equation had a significant intercept and slopes of the regression were 0.78 from Hologic to Prodigy and 0.63 from Prodigy to Delphi. We conclude that the TBS precision on Prodigy was significantly better than the Delphi A. Precision is vitally important to clinicians when determining 1) whether an observed change in measured TBS is a true biological change in the patient, and 2) the time required between follow-up scans to detect a significant change in TBS. The TBS scores were correlated but not equivalent between two different scanners.
P04
TBS Increases Over Time in Pre-Teen Girls
Jessie Libber; University of Wisconsin Diane Krueger, Tamara Scerpella, Neil Binkley Muscle and loading force application alters bone structure and increases bone mineral density (BMD), particularly during growth. However, how trabecular bone score (TBS) changes during growth is unknown. We hypothesized that TBS would be positively correlated with growth and higher in growing girls participating in regular physical exercise. Sixty-eight girls (mean age 12 0.3 years; BMD 18 2.8 kg/m2) were recruited from two middle-schools in Madison, WI. A school-based intervention incorporated a limited resistance training intervention into their routine physical education classes. DXA scans were obtained at three time points, fall 2011, spring 2012 and spring 2013, using a GE Lunar iDXA with software v13.31. Lumbar spine TBS was analyzed using MediMaps software v2.1.1. Tanner staging was obtained by self-report coincident with each DXA scan; resistance exercise intensity was assessed by observation during year 1 only. Mean L1-L4 BMD increased 20% (p ! 0.01) over 18 months, 0.846 (0.12) to 1.024 (0.13) grams/cm2. Over the same interval, TBS increased (p ! 0.01) 5.5% from 1.269 (0.08) at baseline to 1.342 (0.08) at month 18. These observations persisted (p ! 0.01) when limiting the sample to those categorized as Tanner stage (2 or 3) at baseline (n 5 52) or with high intensity of resistance training (n 5 15) demonstrating respective change in BMD of 22 and 23% and TBS of 5.6 and 5.8% at 18 months. In conclusion, this first report of TBS in adolescent girls demonstrated BMD and TBS increases as they age. The apparent greater increase in BMD vs. TBS may suggest that bone microarchitecture has largely been established by age 12 and that the primary growth activity is bone mass/size accrual. It is important to note limitations; importantly that TBS is impacted by soft tissue thickness and as a result these TBS data may differ after recalculating for the smaller amount of soft tissue present in most young girls. Additionally, results may differ using groups with higher intensity resistance training, longer follow-up or larger sample size. Further research documenting TBS changes during growth, and potential ways of optimizing skeletal structure in adolescents, is indicated.
P05 Effects of Glucocorticoids Treatment on Bone BMD and TBS in Men Edward Leib; University of Vermont College of Medicine Renaud Winzenrieth (MediMaps) Aim: The aim of the study was to evaluate whether microarchitectural texture changes as measured by Trabecular Bone Score (TBS) can identify those male patients on glucocorticoid (GC) therapy presently who are more likely to fracture. Material and Methods: This mono-centric study involves US white men aged 45 and older who at the time of bone density testing gave a history of present or past use of GC. They were compared to a group of control subjects. Control subject exclusions included one or more historical fractures, or a past or present treatment or illness influencing bone metabolism. Subjects included in the GC treated group received prednisone 5mg/day for 3 months or equivalent treatment. BMD was assessed at the lumbar spine (L1-L4) using a Prodigy device (GE-Lunar,Madison,USA). TBS was calculated at L1-L4 using the TBS iNsightÒ (v2.1, Medimaps, France). Clinical data, presence of osteoporotic fracture (OPF), GC treatment and common clinical risk factors (CRFs) were documented. Results: From the database, 73 men treated with GC and 90 control men were matched for age and BMI (pO0.4). Characteristics of the patients are shown in table. No correlation was observed when comparing spine TBS, spine BMD and BMI in either treated or cont. groups (-0.16 r 0.23). When compared to normal values, no TBS difference was observed in the control group whereas the GC group had a significantly lower TBS value (see table). GC subjects had
Journal of Clinical Densitometry: Assessment & Management of Musculoskeletal Health
Volume 18, 2015