Relationship between NMR transverse relaxation, trabecular bone architecture, and strength.

Chung, Hsiao‐Wen; Wehrli, Félix W.; Williams, John L.; Kugelmass, Steven D.

doi:10.1073/pnas.90.21.10250

Cited by 137 publications

(105 citation statements)

References 18 publications

Supporting

Mentioning

100

Contrasting

Order By: Relevance

“…Surfaces were modeled with triangular elements of constant magnetic surface charge density, which allows the induced field to be computed from eqn (5). The data indicated the width of the induced field distributions to be narrowest for the polarizing field applied parallel to the preferred orientation of the trabeculae, confirming previous experimental findings (40). Figure 2 shows a histogram of the induced magnetic field, derived from 3D MR images of bovine tibia with the magnetic field oriented along each of three orthogonal directions.…”

Section: Nature Of the Susceptibility-induced Fieldsupporting

confidence: 76%

“…The relationship between the locally induced fields and architecture (density and orientation of the trabeculae), begs the question whether R Ã 2 or R 0 2 can serve as a surrogate for the bone's mechanical competence. Several studies have investigated this aspect by comparing the elastic modulus or ultimate strength measured by mechanical testing, with R 0 2 or R Ã 2 (40,47,48). As pointed out previously, the TB structure is highly anisotropic and, as expressed by eqn (6), R 0 2 has a strong angular dependence.…”

Section: Nature Of the Susceptibility-induced Fieldmentioning

confidence: 99%

“…those orthogonal to the field) are primarily polarized and therefore are expected to be the principal cause of the susceptibility-induced line broadening. In cadaver studies of the human vertebrae, Chung et al (40) provided compelling evidence for the critical role of the horizontal trabeculae in conferring strength from measurements of R 0 2 when the polarizing field was oriented parallel to the body axis. Specimens representing subjects of widely varying age were, after marrow removal, immersed in water and R 0 2 measured at 1.5 T. They found R 0 2 to be highly correlated with Young's modulus of elasticity for compressive loading (r ¼ 0.91; P < 0.0001).…”

Section: Nature Of the Susceptibility-induced Fieldmentioning

confidence: 99%

See 2 more Smart Citations

Quantitative MRI for the assessment of bone structure and function

et al. 2006

View full text Add to dashboard Cite

Osteoporosis is the most common degenerative disease in the elderly. It is characterized by low bone mass and structural deterioration of bone tissue, leading to morbidity and increased fracture risk in the hip, spine and wrist-all sites of predominantly trabecular bone. Bone densitometry, currently the standard methodology for diagnosis and treatment monitoring, has significant limitations in that it cannot provide information on the structural manifestations of the disease. Recent advances in imaging, in particular MRI, can now provide detailed insight into the architectural consequences of disease progression and regression in response to treatment. The focus of this review is on the emerging methodology of quantitative MRI for the assessment of structure and function of trabecular bone. During the past 10 years, various approaches have been explored for obtaining image-based quantitative information on trabecular architecture. Indirect methods that do not require resolution on the scale of individual trabeculae and therefore can be practiced at any skeletal location, make use of the induced magnetic fields in the intertrabecular space. These fields, which have their origin in the greater diamagnetism of bone relative to surrounding marrow, can be measured in various ways, most typically in the form of R 0 2 , the recoverable component of the total transverse relaxation rate. Alternatively, the trabecular network can be quantified by high-resolution MRI (m-MRI), which requires resolution adequate to at least partially resolve individual trabeculae. Micro-MRI-based structure analysis is therefore technically demanding in terms of image acquisition and algorithms needed to extract the structural information under conditions of limited signal-to-noise ratio and resolution. Other requirements that must be met include motion correction and image registration, both critical for achieving the reproducibility needed in repeat studies. Key clinical applications targeted involve fracture risk prediction and evaluation of the effect of therapeutic intervention.

show abstract

Section: Nature Of the Susceptibility-induced Fieldsupporting

confidence: 76%

Section: Nature Of the Susceptibility-induced Fieldmentioning

confidence: 99%

Section: Nature Of the Susceptibility-induced Fieldmentioning

confidence: 99%

See 1 more Smart Citation

Quantitative MRI for the assessment of bone structure and function

et al. 2006

View full text Add to dashboard Cite

show abstract

“…While both NMR and magnetic resonance imaging (MRI) have been used to characterize bone in a number of studies [40,45,[48][49][50][51][52][53][54][55][56], the present work is the first to quantify water distribution in bone for two age groups. A previous study had actually characterized water distribution in dentin samples from a 20 year, 35 year, and 50 year old donor [50].…”

Section: Discussionmentioning

confidence: 99%

Measurements of mobile and bound water by nuclear magnetic resonance correlate with mechanical properties of bone

Nyman

Nicolella

et al. 2008

Bone

179

189

View full text Add to dashboard Cite

Since clinical measures of bone mineral density do not necessarily predict whether a person will fracture a bone without an intervention, there is a need to find supplementary tools for assessing bone quality. Presently, we hypothesized that measures of mobile and bound water by a Nuclear Magnetic Resonance (NMR) technique are correlated with bone strength and toughness, respectively. To test this, bending specimens from the mid-diaphysis of 18 human femurs were collected from 18 male donors and divided into middle aged and elderly groups. After NMR measurements of each hydrated specimen, an inversion technique was used to convert the free induction decay data into a distribution of spin-spin (T2) relaxation rates. Then, the distribution resolved into three distinct components that likely represent solid hydrogen, water bound to bone tissue, and mobile water that occupy microscopic pores within the bone specimen. The integrated signal intensities of the bound and mobile components were normalized by the wet mass of the specimen. Following NMR measurements, three point bending tests were conducted to determine the modulus of elasticity, flexure strength, and work to fracture of each specimen. Next, the porosity, mineral-to-collagen ratio, and pentosidine concentration were measured. In this sample of human cortical bone, there was no age-related difference in the amount of mobile water, but the decrease in the amount of bound water with increasing age was statistically significant. Moreover, bound water was associated with both strength and work to fracture of bone, while mobile water was correlated with modulus of elasticity and appeared to quantify the level of microscopic pores within bone. On the other hand, bound water was correlated with the concentration of non-enzymatic collagen crosslinks. The results of this study indicate that quantifying mobile and bound water with magnetic resonance techniques could potentially serve as indicators of bone quality.

show abstract

“…However, it is well known that BMD is not the sole determinant of bone strength and that architecture plays a significant role in conferring strength to the trabecular network (6)(7)(8). Unlike bone mineral densitometry, which affords a measure of global or regional bone density, we and others have shown that magnetic resonance microimaging ( -MRI) can quantify trabecular bone microarchitecture in vitro in specimens and biopsies (9)(10)(11)(12)(13) and in vivo in laboratory animals and humans (14)(15)(16). Whereas microcomputed tomography ( -CT) can generate high-resolution images of trabecular bone architecture (17), magnetic resonance (MR) is unique in that it is also able to provide detailed information on structure and function of soft tissues and bone marrow, which are also affected by steroid treatment.…”

mentioning

confidence: 99%

In vivo NMR microscopy allows short-term serial assessment of multiple skeletal implications of corticosteroid exposure

Takahashi¹,

Wehrli²,

Hilaire³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Corticosteroids are in widespread clinical use but are known to have adverse skeletal side effects. Moreover, it is not known how soon these effects become apparent. Here, we describe a longitudinal approach to evaluate the short-term implications of excess corticosteroid exposure by quantitative in vivo magnetic resonance imaging and spectroscopy in conjunction with digital image processing and analysis in a rabbit model. Two-week treatment with dexamethasone induced a significant reduction in trabecular bone volume, which occurred at the expense of uniform trabecular thinning without affecting network architecture. Paralleling the loss in bone volume was conversion of hematopoietic to yellow marrow in the femoral metaphysis and atrophy of the femoral epiphyseal growth plate. This work demonstrates that detailed quantitative morphometric and physiological information can be obtained noninvasively at multiple skeletal locations. The method is likely to eventually replace invasive histomorphometry in that it obviates the need to sacrifice groups of animals at multiple time points. Finally, this work, which was performed on a clinical scanner, has implications for evaluating patients on high-dose steroid treatment.B one loss and concomitant fractures of the vertebrae and hip are common clinical consequences of corticosteroid (CS) treatment for inflammatory conditions (1). The overall incidence of osteopenia induced by treatment with CS for a period of less than 6 months is approximately 50% (2). Further, excess CS causes conversion of hematopoietic to fatty bone marrow (3). Besides bone loss, CS treatment is known to have multiple other skeletal implications and thus represents a major public health problem. Of particular concern are pediatric patients treated with high doses of CS (4, 5). Little, however, is known about the early response to supraphysiologic CS levels on the musculoskeletal system.Clinically, fracture risk is most commonly assessed on the basis of bone mineral density (BMD) measured with dual-energy x-ray bone absorptiometry (DEXA) or peripheral quantitative computed tomography (p-QCT). However, it is well known that BMD is not the sole determinant of bone strength and that architecture plays a significant role in conferring strength to the trabecular network (6-8). Unlike bone mineral densitometry, which affords a measure of global or regional bone density, we and others have shown that magnetic resonance microimaging ( -MRI) can quantify trabecular bone microarchitecture in vitro in specimens and biopsies (9-13) and in vivo in laboratory animals and humans (14-16). Whereas microcomputed tomography ( -CT) can generate high-resolution images of trabecular bone architecture (17), magnetic resonance (MR) is unique in that it is also able to provide detailed information on structure and function of soft tissues and bone marrow, which are also affected by steroid treatment.One of the difficulties of imaging microarchitecture in vivo is achievement of sufficient resolution and signal-to-noise ratio to...

show abstract

Relationship between NMR transverse relaxation, trabecular bone architecture, and strength.

Cited by 137 publications

References 18 publications

Quantitative MRI for the assessment of bone structure and function

Quantitative MRI for the assessment of bone structure and function

Measurements of mobile and bound water by nuclear magnetic resonance correlate with mechanical properties of bone

In vivo NMR microscopy allows short-term serial assessment of multiple skeletal implications of corticosteroid exposure

Contact Info

Product

Resources

About