Rare Causes of Musculoskeletal Pain: Thinking beyond Common Rheumatologic Diseases.

Objectives: Rare metabolic bone diseases can present with symptoms mimicking more common rheumatological conditions including spondyloarthritis, osteoarthritis, and fibromyalgia. Increasing awareness of these rare diseases within the rheumatology community is vital to ensure that affected patients are diagnosed and appropriately treated. The literature includes several reports of tumour-induced osteomalacia initially diagnosed as rheumatic disease, but other rare diseases such as X-linked hypophosphatemia (XLH) and hypophosphatasia (HPP) also deserve attention. Here, we describe two cases of adult patients incorrectly diagnosed with ankylosing spondylitis and osteoarthritis who, upon referral to a metabolic bone disease specialist, were subsequently diagnosed with XLH and HPP, respectively, profoundly altering their management. Methods: The cases were collected from Brigham and Women's Hospital, Boston, MA, USA, and Vanderbilt University Medical Center, Nashville, TN, USA. Results: Details of the patients' respective medical and family histories are presented, and the clinical and biochemical investigations undertaken to reach the correct diagnoses are described. Conclusion: Rheumatologists should be encouraged to think beyond common rheumatological diseases when faced with symptoms such as bone pain, muscle pain, and stiffness, especially when accompanied by manifestations including atraumatic fractures, poor dentition, and hearing loss. In cases where one of these rare diseases is suspected, referral to a metabolic bone disease specialist for confirmation of diagnosis is encouraged as effective treatment options have recently become available.

Reporting of Full-Length Femur Imaging to Detect Incomplete Atypical Femur Fractures: 2023 Official Positions of the International Society for Clinical Densitometry.

Incomplete atypical femur fractures (iAFFs) are associated with the long-term use of anti-resorptive therapies. Although X-rays are typically used to screen for iAFFs, images from dual-energy X-ray absorptiometry (DXA) offer an alternate method for detecting iAFFs. Although a previous 2019 ISCD Official Position on this subject exists, our task force aimed to update the literature review and to propose recommendations on reporting findings related to iAFFs that may be observed on DXA images. The task force recommended that full-length femur imaging (FFI) from DXA can be used as a screening tool for iAFFs. The presence of focal lateral cortical thickening and transverse lucencies should be reported, if identified on the FFI. This task force proposed a classification system to determine the likelihood of an iAFF, based on radiographic features seen on the FFI. Lastly, the task force recommended that the clinical assessment of prodromal symptoms (pain) is not required for the assessment of FFI.

DXA Reporting Updates: 2023 Official Positions of the International Society for Clinical Densitometry.

INTRODUCTION: Professional guidance and standards assist radiologic interpreters in generating high quality reports. Initially DXA reporting Official Positions were provided by the ISCD in 2003; however, as the field has progressed, some of the current recommendations require revision and updating. This manuscript details the research approach and provides updated DXA reporting guidance. METHODS: Key Questions were proposed by ISCD established protocols and approved by the Position Development Conference Steering Committee. Literature related to each question was accumulated by searching PubMed, and existing guidelines from other organizations were extracted from websites. Modifications and additions to the ISCD Official Positions were determined by an expert panel after reviewing the Task Force proposals and position papers. RESULTS: Since most DXA is now performed in radiology departments, an approach was endorsed that better aligns with standard radiologic reports. To achieve this, reporting elements were divided into required minimum or optional. Collectively, required components comprise a standard diagnostic report and are considered the minimum necessary to generate an acceptable report. Additional elements were retained and categorized as optional. These optional components were considered relevant but tailored to a consultative, clinically oriented report. Although this information is beneficial, not all interpreters have access to sufficient clinical information, or may not have the clinical expertise to expand beyond a diagnostic report. Consequently, these are not required for an acceptable report. CONCLUSION: These updated ISCD positions conform with the DXA field's evolution over the past 20 years. Specifically, a basic diagnostic report better aligns with radiology standards, and additional elements (which are valued by treating clinicians) remain acceptable but are optional and not required. Additionally, reporting guidance for newer elements such as fracture risk assessment are incorporated. It is our expectation that these updated Official Positions will improve compliance with required standards and generate high quality DXA reports that are valuable to the recipient clinician and contribute to best patient care.

Reporting Fewer Than Four Vertebrae: 2023 Official Positions of the International Society for Clinical Densitometry.

The precision for spine bone mineral density (BMD) worsens as vertebrae are excluded, so recommendations are needed for least significant change (LSC) for spine BMDs based on fewer than 4 vertebrae. The task force recommends re-analysis of each facility's L1-L4 in-house precision study to determine the precision in order to calculate the LSC for each combination of 2 or 3 reported vertebrae. The task force recommended not reporting spine BMDs based on single vertebral bodies for either the diagnosis or monitoring of osteoporosis. Specific data for studies assessing the precision of two non-contiguous vertebrae are mixed, but ultimately the task force recommended that spine BMD based on 2 non-contiguous vertebrae can be used for the diagnosis and monitoring of osteoporosis.

Bilateral hip DXA Reporting: 2023 Official Positions of the International Society for Clinical Densitometry.

INTRODUCTION: This position development conference (PDC) Task Force examined the use and reporting of bilateral hip bone mineral density (BMD) measurements. This was deemed appropriate as increased availability of Dual-energy X-ray Absorptiometry (DXA) technology offering bilateral hip measurement resulted in more routine clinical use. The International Society for Clinical Densitometry Official Positions accept bilateral hip BMD measurement for clinical use but currently do not include recommendations for reporting those studies. METHODS: Four key questions regarding bilateral hip reporting were proposed by the PDC Steering Committee. Relevant literature was identified using PubMed. Questions included whether bilateral hip measurements are appropriate for diagnostic classification or monitoring, as well as which bilateral hip regions of interest should be reported for diagnosis and monitoring. Additionally, the appropriate nomenclature for bilateral hip acquisition was defined. RESULTS: The literature review demonstrated that bilateral hip measurement is appropriate and diagnostic classification should be based on the lowest T-score at the right or left side femoral neck or total hip; the mean T-score should not be used for diagnostic purposes. Mean bilateral total hip is preferred for BMD monitoring. The terms hip, or total hip were deemed appropriate nomenclature instead of femur or total proximal femur. CONCLUSION: Bilateral hip acquisition is clinically appropriate and reporting and nomenclature standards are offered herein when a bilateral hip study is acquired. In terms of future research, the impact of discordant hips on diagnosis and monitoring was identified as a significant knowledge gap.

Tumor-induced osteomalacia treated with T12 tumor resection.

Summary: Tumor-induced osteomalacia (TIO) is a rare form of osteomalacia caused by fibroblast growth factor-23 (FGF23)-secreting tumors. Most of these tumors are phosphaturic mesenchymal tumors (PMTs) typically involving soft tissue in the extremities and bone of the appendicular skeleton and cranium. We report the case of a 60-year-old woman with about 3 years of persistent bone pain and multiple fractures, initially diagnosed as osteoporosis, who was found to have hypophosphatemia with low 1,25-dihydroxyvitamin D and elevated alkaline phosphatase and inappropriately normal FGF23 consistent with TIO. Her symptoms improved with phosphate supplementation, vitamin D and calcitriol. 68Ga-DOTATATE imaging revealed a T12 vertebral body lesion confirmed on biopsy to be a PMT. She underwent resection of the PMT with resolution of TIO and increased bone density. This rare case of TIO secondary to a PMT of the thoracic spine highlights some of the common features of PMT-associated TIO and draws attention to PMT-associated TIO as a possible cause of unexplained persistent bone pain, a disease entity that often goes undiagnosed and untreated for years. Learning points: Tumor-induced osteomalacia (TIO) is typically caused by phosphaturic mesenchymal tumors (PMTs) that are usually found in the soft tissue of the extremities and bone of the appendicular skeleton/cranium and rarely in the spine. TIO may be misdiagnosed as osteoporosis or spondyloarthritis, and the correct diagnosis is often delayed for years. However, osteoporosis, in the absence of fracture, is not associated with bone pain. The hallmark of TIO is hypophosphatemia with inappropriately normal or low 1,25-dihydroxyvitamin D and elevated or inappropriately normal fibroblast growth factor-23 (FGF23) levels. In patients with unexplained persistent bone pain, a serum phosphate should be measured. Consider PMT-associated TIO as a potential cause of unexplained persistent bone pain and hypophosphatemia. PMTs express somatostatin receptors and may be identified with 68Ga-DOTATATE imaging. Complete surgical resection is the preferred treatment for spinal PMTs associated with TIO.

Effect of Positioning of the Region of Interest on Bone Density of the Hip.

BACKGROUND: Large changes in positioning of the global region of interest (ROI) influence the measurement of bone mineral density (BMD) in the hip and forearm regions. However, it is unknown whether minor shifts in the positioning of the bottom of the global hip ROI affect the measurement of total hip BMD. METHODS: The hip BMDs of 40 clinical densitometry patients were analyzed at baseline with the bottom of the global hip ROI positioned as usual, 10 mm distal to the base of the lesser trochanter (position 0). Then the hip was reanalyzed by shifting the bottom of the global hip ROI 1 mm proximally 10 times (positions +1 through +10) and then by shifting the bottom of the global hip ROI 1 mm distally 10 times (positions -1 through -10). The significance of the differences between mean values at the various distances from baseline was assessed using a Wilcoxon signed-rank test. RESULTS: The mean total hip area, bone mineral content and BMD decreased as the bottom of the global hip ROI was shifted proximally; the decrease was significant when shifted by even 1 mm (p < 0.001). The mean total hip area, bone mineral content and BMD increased as the bottom of the global hip ROI was shifted distally; the increase was significant when shifted by even 1 mm (p < 0.001). The change in BMD with each 1 mm shift was uniform across the range studied from positions +10 through -10, and was approx 0.54%/mm. When the least significant change was based on 40 pairs of measurements, where each pair was comprised of the baseline scan and the same scan at -1 position, the least significant change was 0.01 g/cm2. CONCLUSIONS: The BMD of the total hip is sensitive to even minor changes in the positioning of the bottom of the global hip ROI. Although a 1 mm change in the bottom of the global hip ROI positioning would make little difference in the reported T-score, it could easily affect the determination of significance in changes in BMD over time.

Bone Densitometry in Transgender and Gender Non-Conforming (TGNC) Individuals: 2019 ISCD Official Position.

The indications for initial and follow-up bone mineral density (BMD) in transgender and gender nonconforming (TGNC) individuals are poorly defined, and the choice of which gender database to use to calculate Z-scores is unclear. Herein, the findings of the Task Force are presented after a detailed review of the literature. As long as a TGNC individual is on standard gender-affirming hormone treatment, BMD should remain stable to increasing, so there is no indication to monitor for bone loss or osteoporosis strictly on the basis of TGNC status. TGNC individuals who experience substantial periods of hypogonadism (>1 yr) might experience bone loss or failure of bone accrual during that time, and should be considered for baseline measurement of BMD. To the extent that this hypogonadism continues over time, follow-up measurements can be appropriate. TGNC individuals who have adequate levels of endogenous or exogenous sex steroids can, of course, suffer from other illnesses that can cause osteoporosis and bone loss, such as hyperparathyroidism and steroid use; they should have measurement of BMD as would be done in the cisgender population. There are no data that TGNC individuals have a fracture risk different from that of cisgender individuals, nor any data to suggest that BMD predicts their fracture risk less well than in the cisgender population. The Z-score in transgender individuals should be calculated using the reference data (mean and standard deviation) of the gender conforming with the individual's gender identity. In gender nonconforming individuals, the reference data for the sex recorded at birth should be used. If the referring provider or the individual requests, a set of "male" and "female" Z-scores can be provided, calculating the Z-score against male and female reference data, respectively.

THE USE OF VITAMINS AND MINERALS IN SKELETAL HEALTH: AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND THE AMERICAN COLLEGE OF ENDOCRINOLOGY POSITION STATEMENT.

ABBREVIATIONS: 25(OH)D = 25-hydroxyvitamin D; BMD = bone mineral density; CV = cardiovascular; GI = gastrointestinal; IOM = Institute of Medicine; PTH = parathyroid hormone; RCT = randomized controlled trial; αTF = α-tocopherol; ucOC = undercarboxylated osteocalcin; VKA = vitamin K antagonist; WHI = Women's Health Initiative.

Effect of Positioning of the ROI on BMD of the Forearm and Its Subregions.

Inconsistent positioning of patients and region of interest (ROI) is known to influence the precision of bone mineral density (BMD) measurements in the spine and hip. However, it is unknown whether minor shifts in the positioning of the ROI along the shaft of the radius affect the measurement of forearm BMD and its subregions. The ultradistal (UD-), mid-, one-third, and total radius BMDs of 50 consecutive clinical densitometry patients were acquired. At baseline the distal end of the ROI was placed at the tip of the ulnar styloid as usual, and then the forearm was reanalyzed 10 more times, each time shifting the ROI 1 mm proximally. No corrections for multiple comparisons were necessary since the differences that were significant were significant at p < 0.001. The UD-radius BMD increased as the ROI was shifted proximally; the increase was significant when shifted even 1 mm proximally (p < 0.001). These same findings held true for the mid- and total radius bone density, though the percent increase with moving proximally was significantly greater for the UD radius than for the other subregions. However, there was no significant change in the one-third radius BMD when shifted proximally 1-10 mm. Minor proximal shifts of the forearm ROI substantially affect the BMD of the UD-, mid- and total radius, while having no effect on the one-third radius BMD. Since the one-third radius is the only forearm region usually reported, minor proximal shifts of the ROI should not influence forearm BMD results significantly.

Enhanced Precision of the New Hologic Horizon Model Compared With the Old Discovery Model Is Less Evident When Fewer Vertebrae Are Included in the Analysis.

The International Society for Clinical Densitometry guidelines recommend using locally derived precision data for spine bone mineral densities (BMDs), but do not specify whether data derived from L1-L4 spines correctly reflect the precision for spines reporting fewer than 4 vertebrae. Our experience suggested that the decrease in precision with successively fewer vertebrae is progressive as more vertebrae are excluded and that the precision for the newer Horizon Hologic model might be better than that for the previous model, and we sought to quantify. Precision studies were performed on Hologic densitometers by acquiring spine BMD in fast array mode twice on 30 patients, according to International Society for Clinical Densitometry guidelines. This was done 10 different times on various Discovery densitometers, and once on a Horizon densitometer. When 1 vertebral body was excluded from analysis, there was no significant deterioration in precision. When 2 vertebrae were excluded, there was a nonsignificant trend to poorer precision, and when 3 vertebrae were excluded, there was significantly worse precision. When 3 or 4 vertebrae were reported, the precision of the spine BMD measurement was significantly better on the Hologic Horizon than on the Discovery, but the difference in precision between densitometers narrowed and was no longer significant when 1 or 2 vertebrae were reported. The results suggest that (1) the measurement of in vivo spine BMD on the new Hologic Horizon densitometer is significantly more precise than on the older Discovery model; (2) the difference in precision between the Horizon and Discovery models decreases as fewer vertebrae are included; (3) the measurement of spine BMD is less precise as more vertebrae are excluded, but still quite reasonable even when only 1 vertebral body is included; and (4) when 3 vertebrae are reported, L1-L4 precision data can reasonably be used to report significance of changes in BMD. When 1 or 2 vertebrae are reported, precision data for 1 or 2 vertebrae, respectively, should be used, because the exclusion of 2-3 vertebrae significantly worsens precision.

Direct Comparison of the Precision of the New Hologic Horizon Model With the Old Discovery Model.

Previous publications suggested that the precision of the new Hologic Horizon densitometer might be better than that of the previous Discovery model, but these observations were confounded by not using the same participants and technologists on both densitometers. We sought to study this issue methodically by measuring in vivo precision in both densitometers using the same patients and technologists. Precision studies for the Horizon and Discovery models were done by acquiring spine, hip, and forearm bone mineral density twice on 30 participants. The set of 4 scans on each participant (2 on the Discovery, 2 on the Horizon) was acquired by the same technologist using the same scanning mode. The pairs of data were used to calculate the least significant change according to the International Society for Clinical Densitometry guidelines. The significance of the difference between least significant changes was assessed using a Wilcoxon signed-rank test of the difference between the mean square error of the absolute value of the differences between paired measurements on the Discovery (Δ-Discovery) and the mean square error of the absolute value of the differences between paired measurements on the Horizon (Δ-Horizon). At virtually all anatomic sites, there was a nonsignificant trend for the precision to be better for the Horizon than for the Discovery. As more vertebrae were excluded from analysis, the precision deteriorated on both densitometers. The precision between densitometers was almost identical when reporting only 1 vertebral body. (1) There was a nonsignificant trend for greater precision on the new Hologic Horizon compared with the older Discovery model. (2) The difference in precision of the spine bone mineral density between the Horizon and the Discovery models decreases as fewer vertebrae are included. (3) These findings are substantially similar to previously published results which had not controlled as well for confounding from using different subjects and technologists.

ADVERSE EVENT REPORTING IN PATIENTS TREATED WITH THYROID HORMONE EXTRACT.

OBJECTIVE: Thyroid hormone extract is used for the treatment of thyroid disorders, but limited data exist on adverse events commonly noted by the physicians associated with this use. The purpose of this survey was to report adverse events observed by expert physicians managing patients treated for thyroid disease with thyroid hormones. METHODS: Members of the American Thyroid Association, The Endocrine Society, and the American Association of Clinical Endocrinologists developed a survey instrument modeled on the U.S. Food and Drug Administration (FDA)'s reported adverse events for levothyroxine that would effectively assess the clinical experience of frequent prescribers of thyroid hormone. Survey links were emailed to physicians, and the websites of each society provided links to the data collection form. RESULTS: A total of 174 reports of adverse events occurring in patients on thyroid hormone extract were received. Ninety-one of these reports were accompanied by alterations in thyrotropin values and were further analyzed. Of these, 62 (68%) subjects had developed new symptoms associated with altered thyroid-stimulating hormone (TSH). A majority of TSH changes and symptoms described were consistent with thyrotoxicosis (65%), and 2 patients had developed arrhythmias. Reporters noted difficulty in dose adjustment by primary care providers due to confusion in interpreting thyroid function test results while on thyroid extract, which often necessitated subspecialty referrals. CONCLUSION: These adverse event reports should stimulate consideration by the FDA to regulate and monitor thyroid hormone extract use and consider standardizing these extracts to meet current standards of manufacture, hormone content, availability, and shelf-life, like the rigor with which preparations such as levothyroxine are monitored. ABBREVIATIONS: AE = adverse event ATA = American Thyroid Association FDA = Food and Drug Administration LT3 = liothyronine LT4 = levothyroxine PTF = Pharmacovigilance Task Force T3 = triiodothyronine TSH = thyroid-stimulating hormone.

Should We Screen for Vitamin D Deficiency?: Grand Rounds Discussion From Beth Israel Deaconess Medical Center.

The U.S. Preventive Services Task Force (USPSTF) recently issued guidelines on screening for vitamin D deficiency. The guidelines were based on randomized trials of vitamin D deficiency screening and treatment, as well as on case-control studies nested within the Women's Health Initiative. The USPSTF concluded that current evidence is insufficient to assess the benefits and harms of screening for vitamin D deficiency in asymptomatic adults. Compared with placebo or no treatment, vitamin D was associated with decreased mortality; however, benefits were no longer seen after trials of institutionalized persons were excluded. Vitamin D treatment was associated with a possible decreased risk for at least 1 fall and the total number of falls per person but not for fractures. None of the studies examined the effects of vitamin D screening versus not screening on clinical outcomes. In this Grand Rounds, 2 prominent endocrinologists debate the issue of screening for vitamin D deficiency in a 55-year-old, asymptomatic, postmenopausal woman. They review the data on which the USPSTF recommendations are based and discuss the potential benefits and risks, as well as the challenges and controversies, of screening for vitamin D deficiency in primary care practice.

Effect of Clothing on Measurement of Bone Mineral Density.

It is unknown whether allowing patients to have BMD (bone mineral density) studies acquired while wearing radiolucent clothing adlib contributes appreciably to the measurement error seen. To examine this question, a spine phantom was scanned 30 times without any clothing, while draped with a gown, and while draped with heavy winter clothing. The effect on mean BMD and on SD (standard deviation) was assessed. The effect of clothing on mean or SD of the area was not significant. The effect of clothing on mean and SD for BMD was small but significant and was around 1.6% for the mean. However, the effect on BMD precision was much more clinically important. Without clothing the spine phantom had an least significant change of 0.0077 gm/cm(2), while when introducing variability of clothing the least significant change rose as high as 0.0305 gm/cm(2). We conclude that, adding clothing to the spine phantom had a small but statistically significant effect on the mean BMD and on variance of the measurement. It is unlikely that the effect on mean BMD has any clinical significance, but the effect on the reproducibility (precision) of the result is likely clinically significant.

Utility of Reviewing Radiology Studies in Electronic Medical Records When Preparing Bone Mineral Density Reports.

We quantitated how often review of recent radiology studies provides information useful to the densitometrist. While preparing bone mineral density (BMD) reports on 1012 consecutive patients, radiology reports in electronic medical records (EMRs) for the previous 5 years at potentially relevant sites (lumbar spine X-rays, abdominal computed tomography (CT) scans, and so forth) were reviewed. When a study was found, it received a grade according to how relevant findings were to the BMD report: "1" for studies that were irrelevant, "2" for those that confirmed the impression formed from review of the BMD images, "3" for those that clarified the impression that was unclear after reviewing the BMD images, and "4" for those that revealed new relevant data when no abnormality was noted on review of the BMD images. A total of 562 patients (55.5%) had a radiologic study at a site of potential interest within the past 5 years. Fifty-three patients (5.2% of all patients) had a grade 4 study, 88 patients (8.7% of all patients) had a grade 3 study, and 185 patients (18.3% of all patients) had a grade 2 study. Two hundred sixty-four patients (25.8%) had a grade 2 or 3 study, and 299 (29.5%) had a grade 2-4 study. The radiographic study that was most likely to be found in patients' EMR was chest X-ray (34.7% of all patients), but it was also the one that was least likely to have any relevance to the reader; only 10.5% of the total chest X-rays were graded 2-4. The next most likely studies to be found in patients' EMR were abdominal CT scans (18.0% of all patients) and lumbar spine X-rays (14.4% of all patients), but these studies were much more likely to be useful to the reader, as 62.6% of abdominal CT scans and 78.1% of lumbar spine X-rays were graded 2-4. The likelihood of a patient having radiologic examinations in the EMR at sites potentially relevant to the BMD reader is high, but the likelihood that these clarify abnormalities noted on BMD is only moderate. Review of the EMR is unlikely to be relevant when the dual-energy X-ray absorptiometry images are normal.

Inconsistency in filling in the bottom of the spine bone map affects reported spine bone mineral density.

OBJECTIVE: We hypothesized that variability from year to year in how much of the bone map was filled in at the bottom of the spine region of interest (ROI) contributes substantially to variability in measurement of spine bone mineral density (BMD). METHODS: A total of 110 spine BMDs with defects in the bone mapping at the bottom were reanalyzed, with the only change being manually drawing a straight line across the bottom of the ROI and filling in the bone map. RESULTS: The mean (SD) change in area, bone mineral content, and BMD for total spine when the bottom of the bone map was filled in was 0.919 (0.411) cm2, 0.201 (0.121) g, and -0.0098 (0.0043) g/cm2, respectively, and all changes were significant (P<.0001). The largest individual change in total spine BMD with reanalysis was 0.0238 g/cm2, close to the least significant change (LSC) of 0.026 g/cm2 in our center. To quantify variability due to this change in analysis, we calculated an LSC(fill), in which the pairs of scans consisted of the same scan before and after filling in the bottom of the spine bone map, without any other change. The LSC(fill) attributable just to the reanalysis of missing bone map at the bottom of the spine was 0.021 g/cm2, suggesting substantial variance due to variability in mapping the bottom of the spine. CONCLUSION: When there is a noticeable defect in the bottom of the spine bone map, filling this defect in consistently eliminates a significant source of variability in analysis of spine BMDs and might allow us to achieve smaller LSCs.

Lifting Disabled Patients onto the Densitometer with a Ceiling Lift: Effect of the Sling on Measurement of BMD.

OBJECTIVE: Lifting disabled patients onto a densitometer manually is dangerous for both the patient and the densitometry staff; using a ceiling lift is the preferred method of transfer. This system requires the use of a sling underneath the patient. Unless extra time is taken for its removal, the sling remains underneath the patient as bone mineral density (BMD) is measured. The aim of this study was to determine whether leaving this sling in place during scan acquisition affects the BMD measurement. METHODS: Measurements were taken of a spine phantom 30 times by itself, 30 times with a standard sling underneath the spine phantom, and 16 times with a disposable sling underneath the spine phantom. RESULTS: We found that mean BMD was significantly different versus the phantom alone when a sling was used, due to differences in area, bone mineral content, or both. The disposable sling affected the mean BMD to a much greater extent than did the standard sling (+1.9% vs. -0.41%; P for the difference between slings <.001). The standard sling did not increase the variance in the BMD measurement compared with the spine phantom alone, whereas the disposable sling did increase the variance in the BMD measurements. CONCLUSION: Commercially available ceiling-lift slings affect BMD measurements of spine phantoms. This effect is expected to persist when BMD is measured in patients and suggests that when lifting a patient onto the densitometer using these slings, it is best to take the time to remove the sling from under the patient after transfer and before scanning.