Fully-automated segmentation of muscle and inter-/intra-muscular fat from magnetic resonance images of calves and thighs: an open-source workflow in Python.

Background: INTER- and INTRAmuscular fat (IMF) is elevated in high metabolic states and can promote inflammation. While magnetic resonance imaging (MRI) excels in depicting IMF, the lack of reproducible tools prevents the ability to measure change and track intervention success.

Methods: We detail an open-source fully-automated iterative threshold-seeking algorithm (ITSA) for segmenting IMF from T1-weighted MRI of the calf and thigh within three cohorts (CaMos Hamilton (N = 54), AMBERS (N = 280), OAI (N = 105)) selecting adults 45-85 years of age.

The Role of Frailty and Myosteatosis in Predicting All-Cause Mortality in Older Adults with Cancer.

Frailty and myosteatosis are each prognostic of all-cause mortality (ACM) in patients with cancer. However, it is unclear whether myosteatosis adds value to frailty for predicting ACM. We assessed whether myosteatosis improves the predictive ability of frailty for ACM in older adults undergoing chemotherapy.

Correction: The impact of sarcopenia on clinical outcomes in men with metastatic castrate-resistant prostate cancer.

[This corrects the article DOI: 10.1371/journal.pone.

Correlates and predictors of sarcopenia among men with metastatic castrate-resistant prostate cancer.

Introduction: Sarcopenia is a predictor of clinical outcomes in men with metastatic castrate-resistant prostate cancer (mCRPC); however, correlates and predictors of sarcopenia are poorly understood in this population. The aim of this study was to examine correlates and predictors of sarcopenia in men with mCRPC prior to treatment.

Methods: A secondary analysis of an observational study was performed.

Correlates of Circulating Osteoprotegerin in Women with a Pathogenic or Likely Pathogenic Variant in the BRCA1 Gene.

Background: Lower levels of osteoprotegerin (OPG), the decoy receptor for receptor activator of NFκB (RANK)-ligand, have been reported among women with a BRCA1 mutation, suggesting OPG may be marker of cancer risk. Whether various reproductive, hormonal, or lifestyle factors impact OPG levels in these women is unknown.

Methods: BRCA1 mutation carriers enrolled in a longitudinal study, no history of cancer, and a serum sample for OPG quantification, were included.

A Fracture Risk Assessment Tool for High Resolution Peripheral Quantitative Computed Tomography.

Most fracture risk assessment tools use clinical risk factors combined with bone mineral density (BMD) to improve assessment of osteoporosis; however, stratifying fracture risk remains challenging. This study developed a fracture risk assessment tool that uses information about volumetric bone density and three-dimensional structure, obtained using high-resolution peripheral quantitative compute tomography (HR-pQCT), to provide an alternative approach for patient-specific assessment of fracture risk. Using an international prospective cohort of older adults (n = 6802) we developed a tool to predict osteoporotic fracture risk, called μFRAC.

Bone Microarchitecture Phenotypes Identified in Older Adults Are Associated With Different Levels of Osteoporotic Fracture Risk.

Prevalence of osteoporosis is more than 50% in older adults, yet current clinical methods for diagnosis that rely on areal bone mineral density (aBMD) fail to detect most individuals who have a fragility fracture. Bone fragility can manifest in different forms, and a "one-size-fits-all" approach to diagnosis and management of osteoporosis may not be suitable. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides additive information by capturing information about volumetric density and microarchitecture, but interpretation is challenging because of the complex interactions between the numerous properties measured.

Vertebral Fractures: Which Radiological Criteria Are Better Associated With the Clinical Course of Osteoporosis?

Study Purpose: Morphometric methods categorize potential osteoporotic vertebral fractures (OVF) on the basis of loss of vertebral height. A particular example is the widely used semiquantitative morphometric tool proposed by Genant (GSQ). A newer morphologic algorithm-based qualitative (mABQ) tool focuses on vertebral end-plate damage in recognizing OVF.

Bisphosphonate Use Is Protective of Radiographic Knee Osteoarthritis Progression Among those With Low Disease Severity and Being Non-Overweight: Data From the Osteoarthritis Initiative.

Antiresorptive medications have been explored for treating knee osteoarthritis (OA); however, little data exist on the effects of today's more potent nitrogen-containing oral bisphosphonates on radiographic disease-progression in patients with varying disease-severity, especially those who are not overweight. The primary objective of this cohort study was to determine if the use of bisphosphonates is protective against 2-year radiographic-progression of knee OA in Osteoarthritis Initiative (OAI) participants, stratified by baseline radiographic disease status. Secondary objectives were to examine effects in non-overweight participants (body mass index [BMI] < 25 kg/m ) and cumulative bisphosphonate exposure effects.

Cortical and trabecular bone microarchitecture as an independent predictor of incident fracture risk in older women and men in the Bone Microarchitecture International Consortium (BoMIC): a prospective study.

Background: Although areal bone mineral density (aBMD) assessed by dual-energy x-ray absorptiometry (DXA) is the clinical standard for determining fracture risk, most older adults who sustain a fracture have T scores greater than -2·5 and thus do not meet the clinical criteria for osteoporosis. Importantly, bone fragility is due to low BMD and deterioration in bone structure. We assessed whether indices of high-resolution peripheral quantitative CT (HR-pQCT) were associated with fracture risk independently of femoral neck aBMD and the Fracture Risk Assessment Tool (FRAX) score.

A Comparison of Peripheral Imaging Technologies for Bone and Muscle Quantification: A Review of Segmentation Techniques.

Musculoskeletal science has developed many overlapping branches, necessitating specialists from 1 area of focus to often require the expertise in others. In terms of imaging, this means obtaining a comprehensive illustration of bone, muscle, and fat tissues. There is currently a lack of a reliable resource for end users to learn about these tissues' imaging and quantification techniques together.

Osteoporotic fractures and obesity affect frailty progression: a longitudinal analysis of the Canadian multicentre osteoporosis study.

Background: Despite knowing better how to screen older adults, understanding how frailty progression might be modified is unclear. We explored effects of modifiable and non-modifiable factors on changes in frailty in community-dwelling adults aged 50+ years who participated in the Canadian Multicentre Osteoporosis Study (CaMos).

Methods: Rates of change in frailty over 10 years were examined using the 30-item CaMos Frailty Index (CFI).

Investigating the Effects of Motion Streaks on pQCT-Derived Leg Muscle Density and Its Association With Fractures.

Lower peripheral quantitative computed tomography (pQCT)-derived leg muscle density has been associated with fragility fractures in postmenopausal women. Limb movement during image acquisition may result in motion streaks in muscle that could dilute this relationship. This cross-sectional study examined a subset of women from the Canadian Multicentre Osteoporosis Study.

A Comparison of Peripheral Imaging Technologies for Bone and Muscle Quantification: a Mixed Methods Clinical Review.

Purpose Of Review: Bone and muscle peripheral imaging technologies are reviewed for their association with fractures and frailty. A narrative systematized review was conducted for bone and muscle parameters from each imaging technique. In addition, meta-analyses were performed across all bone quality parameters.

Development of a Skeletal Muscle Mimic Phantom Compatible with QCT and MR Imaging.

Objective: The purpose of this study was to develop a skeletal muscle mimic phantom compatible with quantitative computed tomography (QCT) and magnetic resonance imaging, yielding physiologically appropriate values.

Methods: Agar-based phantoms contained varying concentrations of CuCl and EDTA to adjust T2 relaxation time and phantom density concurrently. T2 relaxation times were quantified using a 4-mm single-slice fast spin echo sequence repeated for six serial echo times at 937-μm resolution.

Improving reliability of pQCT-derived muscle area and density measures using a watershed algorithm for muscle and fat segmentation.

In peripheral quantitative computed tomography scans of the calf muscles, segmentation of muscles from subcutaneous fat is challenged by muscle fat infiltration. Threshold-based edge detection segmentation by manufacturer software fails when muscle boundaries are not smooth. This study compared the test-retest precision error for muscle-fat segmentation using the threshold-based edge detection method vs manual segmentation guided by the watershed algorithm.

Haemodynamic responses to angiotensin II in conscious lambs: role of nitric oxide and prostaglandins.

It was hypothesized that nitric oxide (NO) and prostaglandins (PGs) play a synergistic role in modulating haemodynamic responses to angiotensin II (ANG II) in an age-dependent manner. To this end, experiments were carried out in conscious, chronically instrumented lambs aged ∼1 week (N = 9) and ∼6 weeks (N = 10) to evaluate the haemodynamic responses to ANG II, before and after treatment with the L: -arginine analogue, N-nitro-L: -arginine methyl ester (L: -NAME), as well as the cyclooxygenase inhibitor, indomethacin (INDO). Pressor and renal blood flow responses to ANG II were measured before (control) and after administration of L: -NAME (20 mg kg(-1)), following pretreatment with either vehicle (VEH) (experiment 1) or INDO (1 mg kg(-1), experiment 2).

Multiplanar reconstruction recovers morphological cartilage assessment reproducibility from maloriented coronal MRI scans.

The study's purpose was to assess the effect of multiplanar reconstruction on precision of weight-bearing medial and lateral femoral cartilage (cMF, cLF) morphometry in maloriented coronal MR images. Twenty knees were scanned four times with a 1.0 Tesla extremity imager using a fat-suppressed T1-weighted three-dimensional spoiled gradient recalled echo sequence; twice with "best as" double bull's-eye orientation of the femoral condyles, and once each with 5° internal and external rotation.