Bone Marrow Adiposity and Imaging Techniques

Bone marrow adiposity refers to the presence and behaviour of fat cells within the marrow cavity, a compartment traditionally associated with blood production and bone turnover. Far from being inert, marrow adipose tissue (BMAT) has emerged as an active player in skeletal health, systemic metabolism and haematopoiesis. Imaging techniques have evolved to capture both quantity and quality of BMAT, revealing its dynamic changes in ageing, disease and even extreme environments such as spaceflight. Magnetic resonance imaging (MRI) and spectroscopy (MRS) now provide non-invasive quantification of fat fraction and fatty acid composition, while X-ray–based modalities and computed tomography (CT) furnish complementary measures of mineral density. Positron emission tomography (PET) with 18F-FDG has extended our view to metabolic activity, and advanced MRI mapping techniques such as R2* and diffusion imaging probe microarchitectural and compositional tissue changes. Together, these modalities have transformed our understanding of how marrow fat interacts with bone mass, endocrine factors and mechanical loading, and have opened new avenues to monitor osteoporosis, metabolic disorders and therapy responses in clinical and research settings.

Research from Nature Portfolio

Recent research has demonstrated that prolonged space missions induce significant downregulation of lumbar vertebral BMAT in astronauts within weeks of return to Earth. Spectral MRI and MRS analyses revealed depletion of marrow lipid reserves concomitant with enhanced erythropoiesis and local bone anabolism, suggesting that BMAT serves as a preferential energy source during recovery from the hypermetabolic demands of spaceflight. This work highlights the remarkable plasticity of marrow fat in extreme physiological stress and underscores its potential as a biomarker of bone health and metabolic adaptation.

Research from all publishers

Studies in weight-discordant monozygotic twins have shown that higher body weight is linked to increased insulin-stimulated glucose uptake in vertebral marrow, while a six-month exercise intervention selectively enhanced femoral marrow metabolism regardless of genetic background. Research on interventional weight loss in obesity has revealed that caloric restriction and bariatric surgery modify BMAT in a site- and sex-dependent manner, with gastric bypass generally reducing marrow fat in diabetic and postmenopausal patients, whereas sleeve gastrectomy may increase it. In first-time diagnosed type 1 diabetes, high-field MRI assessments of marrow fat fraction have uncovered significant expansions of adiposity associated with alterations in trabecular microarchitecture, indicating that acute metabolic derangement drives marrow fat accumulation and compromised bone microstructure.

Bone Marrow Adiposity and Imaging Techniques publication trend

The graph below shows the total number of articles in bone marrow adiposity and imaging techniques across all publications each year (not limited to Nature Index journals).

Technical terms

Bone marrow adiposity: accumulation of fat cells within the bone marrow cavity influencing both haematopoiesis and skeletal metabolism.

Bone marrow adipose tissue (BMAT): the lipid-rich component of the bone marrow measured by imaging to assess marrow fat content.

Proton density fat fraction (PDFF): quantitative MRI metric representing the proportion of fat protons relative to total protons in marrow.

Magnetic resonance spectroscopy (MRS): technique that resolves the chemical composition of marrow by measuring resonance frequencies of different nuclei.

18F-FDG positron emission tomography (FDG-PET): imaging modality using a glucose analogue to measure metabolic activity in bone marrow.

R2* mapping: MRI parameter reflecting tissue magnetic susceptibility changes, indicative of fat and mineral content.

Chemical shift encoding-based water–fat imaging: MRI method separating water and lipid signals to quantify fat fraction in tissues.

References

1. Bone marrow adiposity modulation after long duration spaceflight in astronauts. Nature Communications (2023).
2. Bone marrow metabolism is affected by body weight and response to exercise training varies according to anatomical location. Diabetes Obesity and Metabolism (2023).
3. The Impact of Interventional Weight Loss on Bone Marrow Adipose Tissue in People Living with Obesity and Its Connection to Bone Metabolism. Nutrients (2023).
4. Associations of marrow fat fraction with MR imaging based trabecular bone microarchitecture in first-time diagnosed type 1 diabetes mellitus. Frontiers in Endocrinology (2024).
5. Correlation of R2* with fat fraction and bone mineral density and its role in quantitative assessment of osteoporosis. European Radiology (2023).
6. Anatomical Variation of Age-Related Changes in Vertebral Bone Marrow Composition Using Chemical Shift Encoding-Based Water–Fat Magnetic Resonance Imaging. Frontiers in Endocrinology (2018).
7. Marrow Fat and Bone: Review of Clinical Findings. Frontiers in Endocrinology (2015).
8. Diffusion MRI for Assessment of Bone Quality; A Review of Findings in Healthy Aging and Osteoporosis. Journal of Magnetic Resonance Imaging (2019).