Addressing Challenges of Opportunistic Computed Tomography Bone Mineral Density Analysis.

Computed tomography (CT) offers advanced biomedical imaging of the body and is broadly utilized for clinical diagnosis. Traditionally, clinical CT scans have not been used for volumetric bone mineral density (vBMD) assessment; however, computational advances can now leverage clinically obtained CT data for the secondary analysis of bone, known as opportunistic CT analysis. Initial applications focused on using clinically acquired CT scans for secondary osteoporosis screening, but opportunistic CT analysis can also be applied to answer research questions related to vBMD changes in response to various disease states. There are several considerations for opportunistic CT analysis, including scan acquisition, contrast enhancement, the internal calibration technique, and bone segmentation, but there remains no consensus on applying these methods. These factors may influence vBMD measures and therefore the robustness of the opportunistic CT analysis. Further research and standardization efforts are needed to establish a consensus and optimize the application of opportunistic CT analysis for accurate and reliable assessment of vBMD in clinical and research settings. This review summarizes the current state of opportunistic CT analysis, highlighting its potential and addressing the associated challenges.

Internal calibration for opportunistic computed tomography muscle density analysis.

INTRODUCTION: Muscle weakness can lead to reduced physical function and quality of life. Computed tomography (CT) can be used to assess muscle health through measures of muscle cross-sectional area and density loss associated with fat infiltration. However, there are limited opportunities to measure muscle density in clinically acquired CT scans because a density calibration phantom, allowing for the conversion of CT Hounsfield units into density, is typically not included within the field-of-view. For bone density analysis, internal density calibration methods use regions of interest within the scan field-of-view to derive the relationship between Hounsfield units and bone density, but these methods have yet to be adapted for muscle density analysis. The objective of this study was to design and validate a CT internal calibration method for muscle density analysis. METHODOLOGY: We CT scanned 10 bovine muscle samples using two scan protocols and five scan positions within the scanner bore. The scans were calibrated using internal calibration and a reference phantom. We tested combinations of internal calibration regions of interest (e.g., air, blood, bone, muscle, adipose). RESULTS: We found that the internal calibration method using two regions of interest, air and adipose or blood, yielded accurate muscle density values (< 1% error) when compared with the reference phantom. The muscle density values derived from the internal and reference phantom calibration methods were highly correlated (R2 > 0.99). The coefficient of variation for muscle density across two scan protocols and five scan positions was significantly lower for internal calibration (mean = 0.33%) than for Hounsfield units (mean = 6.52%). There was no difference between coefficient of variation for the internal calibration and reference phantom methods. CONCLUSIONS: We have developed an internal calibration method to produce accurate and reliable muscle density measures from opportunistic computed tomography images without the need for calibration phantoms.

"Think of It Like a Game": Older Adults' and Health Professionals' Perspectives on Interactive Exercise Technology Design.

Purpose: Interactive exercise technology (IET) is an effective and practical way to support physiotherapy for older adults. The purpose of this study was to use design thinking to collect feedback on the first iteration of an IET prototype from older adults and health professionals and to use that feedback to gain an understanding of their needs and values, with the goal of developing recommendations to inform the second iteration of the IET prototype. Method: This study was conducted using three steps of design thinking: (1) test, in which four focus groups were conducted, asking older adults and health professionals about their perspectives on an IET prototype; (2) empathize, in which the focus group discussions were recorded and transcribed and thematic content analysis was conducted; and (3) define, in which the needs and values of the participants were identified. Results: The participants were 19 health professionals and four older adults. Four themes, which represented the values that these groups held regarding IET design, were revealed: instruction, safety, accessibility, and motivation. Conclusions: Older adults and health professionals have specific needs for the design of IET, which should be considered in the development of future IET.

Objectif : la technologie des exercices interactifs (TEI) est un moyen efficace et pratique de soutenir la physiothérapie chez les aînés. La présente étude a fait appel à la réflexion conceptuelle pour colliger les commentaires d'aînés et de professionnels de la santé sur la première itération d'un prototype de TEI, s'inspirer de leurs commentaires pour comprendre leurs besoins et leurs valeurs et formuler des recommandations pour éclairer la deuxième itération du prototype de TEI. Méthodologie : la présente étude a été réalisée au moyen des trois étapes de la réflexion conceptuelle : 1) le test, dans le cadre duquel quatre groupes de travail ont été formés pour demander aux aînés et aux professionnels de la santé leurs points de vue sur un prototype de TEI; 2) l'empathie, visant l'enregistrement et la transcription les discussions des groupes de travail, suivis d'une analyse de contenu thématique et 3) la définition, afin de déterminer les besoins et les valeurs des participants. Résultats : les participants étaient 19 professionnels de la santé et quatre aînés. Quatre thèmes sont ressortis, représentatifs des valeurs de ces groupes à l'égard de la TEI : directives, sécurité, accessibilité et motivation. Conclusion : les aînés et leurs professionnels de la santé ont des besoins particuliers à l'égard de la conception de la TEI, dont il faudrait tenir compte dans l'élaboration de futures TEI.

Advancements in Osteoporosis Imaging, Screening, and Study of Disease Etiology.

PURPOSE OF REVIEW: The purpose of this review is to inform researchers and clinicians with the most recent imaging techniques that are employed (1) to opportunistically screen for osteoporosis and (2) to provide a better understanding into the disease etiology of osteoporosis. RECENT FINDINGS: Phantomless calibration techniques for computed tomography (CT) may pave the way for better opportunistic osteoporosis screening and the retroactive analysis of imaging data. Additionally, hardware advances are enabling new applications of dual-energy CT and cone-beam CT to the study of bone. Advances in MRI sequences are also improving imaging evaluation of bone properties. Finally, the application of image registration techniques is enabling new uses of imaging to investigate soft tissue-bone interactions as well as bone turnover. While DXA remains the most prominent imaging tool for osteoporosis diagnosis, new imaging techniques are becoming more widely available and providing additional information to inform clinical decision-making.