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Colon cancer screening occurs at younger ages than osteoporosis screening. Bone density measurements using virtual colonoscopy performed for colon cancer screening can provide an early warning sign of patients at potential risk for osteoporosis-related fractures. Earlier identification may improve treatment and potentially fracture prevention. Opportunistic osteoporosis screening with computed tomography colonography (CTC) offers an opportunity to capitalize on earlier colorectal cancer screening to identify patients at risk of future fractures. The purpose of this study is to evaluate 10-year fracture and specifically hip fracture risk based on Hounsfield units (HU) obtained from CTC. We identified all CTC scans between 2004 and 2007 of patients 40 years and older with 10 years minimum follow-up. Hounsfield units were measured within the proximal femur and fractures identified via worldwide military records. Patients were stratified into two cohorts based on the presence or lack of a fracture in the wrist, spine, hip, or proximal humerus. Hounsfield unit measurements were compared between groups using Student’s t test and the HU threshold was calculated that best approximated an 80% sensitivity to optimally screen patients for fracture risk. The odds ratio, negative predictive value, 10-year incidence of fracture, and survival curves were calculated. We identified 3711 patients with 183 fractures over 10 years. The HU threshold that corresponded with an 80% sensitivity to identify fractures was 112 HU. The negative predictive value (NPV) for overall fractures and hip fractures was over 97%. The 10-year fracture incidence was higher in patients below 112 HU compared to those above for both overall fractures (6.3% vs 1.7%) and hip fractures (2.7% vs 0.07%). The 112 HU threshold corresponds with an odds ratio for overall fracture and hip fractures of 2.5 (95% confidence interval (CI), 1.7–3.6) and 24.5 (95% CI, 3.3–175.5), respectively. In the 10 years following CTC, patients who experienced a fracture had lower hip HU. Decreasing HU on CTC may be an early warning sign of fracture potential.

Purpose The objective of this study was to analyze changes in serum markers of bone turnover across multiple decades in osteoporotic women compared with nonosteoporotic controls, to determine their utility as potential predictors for osteoporosis . Early prediction of those at risk for osteoporosis can enable early intervention before the irreversible loss of critical bone mass. Methods Serum samples were obtained from 20 women given the diagnosis of osteoporosis after age 46 years and 20 age-matched women with normal bone mineral density from 4 time points in their life (ages 25–31, 32–38, 39–45, and 46–60 years). Serum levels of bone turnover markers (propeptide of type I collagen , parathyroid hormone , bone-specific alkaline phosphatase , osteocalcin , C-terminal telopeptide of type I collagen, sclerostin , osteoprotegerin , osteopontin , and 25-OH vitamin D) were measured using commercially available arrays and kits. We used logistic regression to assess these individual serum markers as potential predictors of osteoporosis, and mixed-effects modeling to assess the change in bone turnover markers between osteoporotic and control groups over time, then performed fivefold cross-validation to assess the classification ability of the models. Results Markers of bone turnover, bone-specific alkaline phosphatase, C-terminal telopeptide of type I collagen, sclerostin, and osteocalcin were all independent predictors at multiple time points; osteopontin was an independent predictor in the 39- to 45-year age group. Receiver operating characteristic analyses demonstrated moderately strong classification ability at all time points. Sclerostin levels among groups diverged over time and were higher in the control group than the osteoporotic group, with significant differences observed at time points 3 and 4. Conclusions Serum markers of bone turnover may be used to estimate the likelihood of osteoporosis development in individuals over time. Although prospective validation is necessary before recommending widespread clinical use, this information may be used to identify patients at risk for developing low bone mineral density long before traditional screening would ostensibly take place. Type of study/level of evidence Diagnostic II.

Quantifying bone mineral density (BMD) on CT using commercial software demonstrates good-to-excellent correlations with dual-energy x-ray absorptiometry (DEXA) results. However, previous techniques to measure Hounsfield units (HUs) within the proximal femur demonstrate less successful correlation with DEXA results. An effective method of measuring HUs of the proximal femur from CT colonoscopy might allow for opportunistic osteoporosis screening.(1) Do proximal femur HU measurements from CT colonoscopy correlate with proximal femur DEXA results? (2) How effective is our single HU measurement technique in estimating the likelihood of overall low BMD? (3) Does the relationship between our comprehensive HU measurement and DEXA results change based on age, sex, or time between studies?This retrospective study investigated the measurement of HU of the femur obtained on CT colonoscopy studies compared with DEXA results. Between 2010 and 2017, five centers performed 9085 CT colonoscopy studies; of those, 277 (3%) also had available DEXA results and were included in this study, whereas 8809 (97%) were excluded for inadequate CT imaging, lack of DEXA screening, or lack of proximal femur DEXA results. The median number of days between CT colonoscopy and DEXA scan was 595 days; no patient was excluded based on time between scans because bone remodeling is a long-term process and this allowed subgroup analysis based on time between scans. Two reviewers performed HU measurements at four points within the proximal femur on the CT colonoscopy imaging and intraclass correlation coefficients were used to evaluate interrater reliability. We used Pearson correlation coefficients to compare the comprehensive (average of eight measurements) and a single HU measurement with each DEXA result-proximal femur BMD, proximal femur T-score, femoral neck BMD, and femoral neck T-score-to identify the best measurement technique within this study. Based on their lowest DEXA T-score, we stratified patients to a diagnosis of osteoporosis, osteopenia, or normal BMD. We then calculated the area under the receiver operator characteristic curves (AUCs) to evaluate the classification ability of a single HU value to identify possible threshold(s) for detecting low BMD. For each subgroup analysis, we calculated Pearson correlation coefficients between DEXA and HUs and evaluated each subgroup's contribution to the overall predictive model using an interaction test in a linear regression model.The Pearson correlation coefficient between both the comprehensive and single HU measurements was highest compared with the proximal femur T-score at 0.75 (95% confidence interval [CI], 0.69-0.80) and 0.74 (95% CI, 0.68-0.79), respectively. Interobserver reliability, measured with intraclass correlation coefficients, for the comprehensive and single HU measurements was 0.97 (95% CI, 0.72-0.99) and 0.96 (95% CI, 0.89-0.98), respectively. Based on DEXA results, 20 patients were osteoporotic, 167 had osteopenia, and 90 patients had normal BMD. The mean comprehensive HU for patients with osteoporosis was 70 ± 30 HUs; for patients with osteopenia, it was 110 ± 36 HUs; and for patients with normal BMD, it was 158 ± 43 HUs (p0.001). The AUC of the single HU model was 0.82 (95% CI, 0.77-0.87). A threshold of 214 HUs is 100% sensitive and 59 HUs is 100% specific to identify low BMD; a threshold of 113 HUs provided 73% sensitivity and 76% specificity. When stratified by decade age groups, each decade age group demonstrated a positive correlation between the comprehensive HU and proximal femur T-score, ranging between 0.71 and 0.83 (95% CI, 0.59-0.91). Further subgroup analysis similarly demonstrated a positive correlation between the comprehensive HU and proximal femur T-score when stratified by6 months or6 months between CT and DEXA (0.75; 95% CI, 0.62-0.84) as well as when stratified by sex (0.70-0.76; 95% CI, 0.48-0.81). The linear regression model demonstrated that the overall positive correlation coefficient between HUs and the proximal femur T-score is not influenced by any subgroup.Our measurement technique provides a reproducible measurement of HUs within the proximal femur HUs on CT colonoscopy. Hounsfield units of the proximal femur based on this technique can predict low BMD. These CT scans are frequently performed before initial DEXA scans are done and therefore may lead to earlier recognition of low BMD. Future research is needed to validate these results in larger studies and to determine if these results can anticipate future fracture risk.Level III, diagnostic study.

Osteoporosis is a costly and morbid disease with the first presentation often with a fragility fracture. The purpose of this study was to assess whether Hounsfield unit (HU) measurements on shoulder computed tomography could identify patients at risk of osteoporosis and aid in its diagnosis.We identified patients who had both a computed tomography scan of the glenoid and a dual-energy x-ray absorptiometry scan. Dual-energy x-ray absorptiometry results and HU measurements of the patients' glenoid were recorded. Differences in HU measurements between patients with normal and abnormal central bone mineral density (BMD) were assessed. Correlations were calculated, and receiver operating characteristics were examined.A total of 51 glenoids met the criteria. The mean glenoid HU measurement was 140.6 (95% confidence interval [CI], 120.1-161.1) in the osteoporotic group, 168.1 (95% CI, 152.7-183.5) in the osteopenic group, and 233.2 (95% CI, 210.1-256.4) in the normal BMD group (P .001). There was a significant correlation between mean glenoid HU measurement and patients' t scores in the femoral neck (r = 0.581), total hip (r = 0.524), and lumbar spine (r = 0.345). The area under the receiver operating characteristic curve was 0.918. With 197 HUs used as the cutoff for diagnosis of abnormal BMD, the positive predictive value was 96.6%. With 257.1 HUs used as the cutoff, the negative predictive value was 100%.A patient with an HU measurement below 197 has a 97% chance of having low BMD, and a patient with a measurement over 257 likely has normal BMD. In patients with measurements between these values, a definitive diagnosis should be aggressively pursued. Opportunistic screening for a modifiable disease that has significant morbidity and mortality rates at no additional cost, radiation, or time is of great value.

Purpose Distal ulnar Hounsfield unit (HU) measurements obtained from computed tomography (CT) scans of the wrist can be used to accurately screen for low bone mineral density. It is unknown whether HU measurements can also predict the risk of future fragility fractures. Therefore, the purpose of this study was to determine if the HU values of the distal ulna correlate to fragility fracture risk. Methods An electronic database of radiographs at a single institution was searched for all wrist CT scans, obtained for any reason, between January 1, 2002, and December 31, 2008, to allow a minimum of 5-year follow-up. Manual measurement of HU on sequential coronal CT slices of the distal ulnar head was taken, and mean values were recorded. Previously determined cutoff values for the diagnosis of low bone mineral density were implemented to stratify patients as at risk or not at risk for future fragility fracture. Medical records were then manually reviewed for the occurrence of any future fragility fracture (hip, spine, proximal humerus, or rib). Results There were 161 CTs in 157 patients and 34 fragility fractures in 21 patients, with a prevalence of 13.4%. The mean HU in the fragility fracture group was significantly lower (134.2 vs 197.1 HU). The percentage of low HU patients with fragility fractures was significantly higher (22.7% vs 3.8%). The odds ratio for fragility fracture in the low HU group was 7.4 (95% confidence interval, 2.1–26.2). Using previously determined cutoff values, the sensitivity and specificity of distal ulna HU values for identifying patients who would sustain at least 1 future fragility fracture were 85.7% and 55.2%, respectively. Conclusions Patients with low distal ulnar HU were significantly more likely to sustain a subsequent fragility fracture. A determination of distal ulnar HUs represents a quick, simple tool to identify patients potentially at risk for fragility fractures. Type of study/level of evidence Prognostic IV.