Bone Mineral Densitometry Reporting: Pearls and Pitfalls

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.

National Survey of the Bone Densitometry Evaluation Process Within an Integrated Healthcare System

BACKGROUND

To assess the current state of bone mineral density evaluation services via dual energy x-ray absorptiometry (DXA) provided to Veterans with fracture risk through the development and administration of a nationwide survey of facilities in the Veterans Health Administration.

METHODOLOGY

The Bone Densitometry Survey was developed by convening a Work Group of individuals with expertise in bone densitometry and engaging the Work Group in an iterative drafting and revision process. Once completed, the survey was beta tested, administered through REDCap, and sent via e-mail to points of contact at 178 VHA facilities.

RESULTS

Facility response rate was 31 % (56/178). Most DXA centers reported positively to markers of readiness for their bone densitometers: less than 10 years old (n=35; 63 %); in "excellent" or "good" condition (n=44; 78 %, 32 % and 46 %, respectively); and perform phantom calibration (n=43; 77 %). Forty-one DXA centers (73 %) use intake processes that have been shown to reduce errors. Thirty-seven DXA centers (66 %) reported their technologists receive specialized training in DXA, while 14 (25 %) indicated they receive accredited training. Seventeen DXA centers (30 %) reported performing routine precision assessment.

CONCLUSIONS

Many DXA centers reported using practices that meet minimal standards for DXA reporting and preparation; however, the lack of standardization, even within an integrated healthcare system, indicates an opportunity for quality improvement to ensure consistent high quality bone mineral density evaluation of Veterans.

Detecting whether L1 or other lumbar levels would be excluded from DXA bone mineral density analysis during opportunistic CT screening for osteoporosis using machine learning

PURPOSE

One or more vertebrae are sometimes excluded from dual-energy X-ray absorptiometry (DXA) analysis if the bone mineral density (BMD) T-score estimates are not consistent with the other lumbar vertebrae BMD T-score estimates. The goal of this study was to build a machine learning framework to identify which vertebrae would be excluded from DXA analysis based on the computed tomography (CT) attenuation of the vertebrae.

METHODS

Retrospective review of 995 patients (69.0% female) aged 50 years or greater with CT scans of the abdomen/pelvis and DXA within 1 year of each other. Volumetric semi-automated segmentation of each vertebral body was performed using 3D-Slicer to obtain the CT attenuation of each vertebra. Radiomic features based on the CT attenuation of the lumbar vertebrae were created. The data were randomly split into training/validation (90%) and test datasets (10%). We used two multivariate machine learning models: a support vector machine (SVM) and a neural net (NN) to predict which vertebra(e) were excluded from DXA analysis.

RESULTS

L1, L2, L3, and L4 were excluded from DXA in 8.7% (87/995), 9.9% (99/995), 32.3% (321/995), and 42.6% (424/995) patients, respectively. The SVM had a higher area under the curve (AUC = 0.803) than the NN (AUC = 0.589) for predicting whether L1 would be excluded from DXA analysis (P = 0.015) in the test dataset. The SVM was better than the NN for predicting whether L2 (AUC = 0.757 compared to AUC = 0.478), L3 (AUC = 0.699 compared to AUC = 0.555), or L4 (AUC = 0.751 compared to AUC = 0.639) were excluded from DXA analysis.

CONCLUSIONS

Machine learning algorithms could be used to identify which lumbar vertebrae would be excluded from DXA analysis and should not be used for opportunistic CT screening analysis. The SVM was better than the NN for identifying which lumbar vertebra should not be used for opportunistic CT screening analysis.

Utility of iliac crest tetracycline-labelled bone biopsy in osteoporosis and metabolic bone disease: An evaluation of 95 cases over a period of 25 years

Background

Metabolic bone diseases (MBD) are typically diagnosed by non-invasive imaging and clinical biomarkers. However, imaging does not provide structural information, and biomarkers can be transiently affected by many systemic factors. Bone biopsy and pathologic evaluation is the gold standard for diagnosis of MBD, however, it is rarely utilized. We describe our technique for iliac crest tetracycline-labelled bone using a cannulated drill and assess the utility of bone biopsies to provide diagnostic and therapeutic guidance.

Methods

In the 25-year period between March 1998 and January 2023, a total of 95 bone biopsies were performed on 94 patients for an osteological indication at Vanderbilt University Medical Center (VUMC). Patient demographics, bone biopsy indications, complications, diagnostic utility, and subsequent therapeutic guidance were retrospectively reviewed and analyzed.

Results

The procedure had minimal complications and was well tolerated by patients. This technique provided good quality specimens for pathology, which helped establish a diagnosis and treatment change in most patients. Patients that had biopsy-guided treatment alterations showed significant increases in Dual-Energy X-ray Absorptiometry (DEXA) bone mineral density (BMD) scores post-biopsy and subsequent treatment.

Conclusion

Despite scientific and technological progress in non-invasive diagnostic imaging, clinical biomarkers, and procedures for MBD, there remains a small but significant subset of patients who may benefit from inclusion of tetracycline-labelled bone biopsy into the diagnostic and therapeutic picture. Future prospective comparison studies are warranted.

Mini abstract

Tetracycline-labelled bone biopsies are under-utilized. Biopsy led to a histological diagnosis and ensuing treatment alteration in most patients with significant increases in bone mineral density. The biopsy procedure used herein provided good specimens with low pain/adverse events. Bone biopsy remains a valuable tool in a small, though significant, subset of patients.

A Rare Pitfall in Bone Mineral Densitometry: Gaucher Disease

ABSTRACT

We report a rare case of type 3 Gaucher disease presenting with calcified mesenteric lymph nodes that interfere with bone mineral densitometric measurements.

BatchBMD as an Efficient and Accurate Dual-Energy X-ray Absorptiometry Report Generator

Dual-energy X-ray absorptiometry is the gold standard for evaluating Bone Mineral Density (BMD); however, a typical BMD report is generated in a time-inefficient manner and is prone to error. We developed a rule-based automated reporting system, BatchBMD, that accelerates DXA reporting while improving its accuracy over current systems. BatchBMD generates a structured report, customized to the specific clinical purpose. To compare BatchBMD to a Web-based Reporting (WBR) system for efficiency and accuracy, 500 examinations were randomly chosen from those performed at the Taipei Municipal Wanfang Hospital from January to March 2021. The final assessment included all 2326 examinations conducted from September 2020 to March 2021. The average reporting times were 6.7 and 10.8 min for BatchBMD and the WBR system, respectively, while accuracy was 99.4% and 98.2%, respectively. Most of the errors made by BatchBMD were digit errors in the appendicular skeletal muscle index. After correcting this, 100% accuracy across all 2326 examinations was validated. This automated and accurate BMD reporting system significantly reduces report production workload for radiologists and technicians while increasing productivity and quality. Additionally, the portable software, which employs a simple framework, can reduce deployment costs in clinical practice.

Longitudinal Changes of Circulating miRNAs During Bisphosphonate and Teriparatide Treatment in an Animal Model of Postmenopausal Osteoporosis

MicroRNAs regulate bone homeostasis, and circulating microRNAs have been proposed as novel bone biomarkers. The effect of anti-osteoporotic treatment on circulating microRNAs has not been described in detail. Therefore, we performed a comprehensive analysis of microRNA serum levels in ovariectomized (OVX) and sham-operated (SHAM) rats over 12 weeks of antiresorptive or osteoanabolic treatment. Forty-two Sprague Dawley rats underwent SHAM surgery (n = 10) or ovariectomy (n = 32). After 8 weeks, OVX rats were randomized to antiresorptive treatment with zoledronate (n = 11), osteoanabolic treatment with teriparatide (n = 11), or vehicle treatment (n = 10). Serum samples were collected at weeks 8, 12, 16, and 20 after surgery. A total of 91 microRNAs were analyzed by RT-qPCR in serum samples collected at week 20. Based on the results, 29 microRNAs were selected for longitudinal analysis at all four study time points. Changes in bone mineral density and microstructure were followed up by in vivo micro-CT and ex vivo nano-CT. Ovariectomy resulted in the loss of trabecular bone, which was reversed by osteoanabolic and antiresorptive treatment. Differential expression analysis identified 11 circulating miRNAs that were significantly regulated after treatment. For example, miR-107 and miR-31-5p increased in vehicle-treated OVX animals, whereas they decreased during teriparatide treatment. Additional miRNAs were identified that showed significant correlations to bone microstructure or bone miRNA expression, including miR-203a-3p, which exhibited a significant negative correlation to vertebral and tibial trabecular bone volume fraction (%). Longitudinal analysis confirmed eight microRNAs with significant changes in serum over time that were prevented by teriparatide and zoledronate treatment (miR-34a-5p, miR-31-5p, miR-30d-3p, miR-378a-5p) or teriparatide treatment only (miR-375-3p, miR-183-5p, miR-203a-3p, miR-203b-3p). Gene target network analysis identified WNT and Notch signaling as the main signaling pathways controlled by these miRNAs. Thus, ovariectomy results in time-dependent deregulation of circulating miRNAs compared with SHAM animals. Anti-osteoporotic treatments can rescue this effect, showing that bone-related miRNAs might act as novel biomarkers for treatment monitoring. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).