6 research outputs found
Correlation between the elastic modulus of anterior cruciate ligament (ACL) and quantitative ultrashort echo time (UTE) magnetic resonance imaging.
Conventional magnetic resonance imaging (MRI) often acquires no signal in anterior cruciate ligament (ACL) due to the short apparent transverse relaxation time of ACL. Ultrashort echo time (UTE) MRI is capable of imaging ACL with high signal which enables quantitative ACL assessment. This study aimed to investigate the correlations of the mechanical and microstructural properties of human ACL specimens with quantitative three-dimensional UTE Cones (3D-UTE-Cones) MRI measures. ACL specimens were harvested from cadaveric knee joints of 13 (50.9 ± 21.1 years old, 11 males and 2 female) donors. Specimens were scanned using a series of quantitative 3D-UTE-Cones T2 * (UTE-T2 *), T1 (UTE-T1 ), Adiabatic T1ρ (UTE-Adiab-T1ρ ), and magnetization transfer (UTE-MT) sequences in a wrist coil on a clinical 3T scanner. ACL elastic modulus was measured using a uniaxial tensile mechanical test. Histomorphometry analysis was performed to measure the average fascicle specific surface, fascicle size, and number of cells per unit area. Spearmans rank correlations of UTE-MRI biomarkers with mechanical and histomorphometry measures were investigated. The elastic modulus of ACL showed significant moderate correlations with UTE-Adiab-T1ρ (R = -0.59, p = 0.01), macromolecular fraction from MT modeling (R = 0.54, p = 0.01), magnetization transfer ratio (R = 0.53, p = 0.01), UTE-T2* (R = -0.53, p = 0.01), and average fascicle specific surface (R = 0.54, p = 0.01). UTE-MRI showed nonsignificant correlations with histomorphometry measures. UTE-MRI biomarkers may be useful noninvasive tools for the ACL mechanical assessment
Recommended from our members
Ultrashort Echo Time (UTE) MRI porosity index (PI) and suppression ratio (SR) correlate with the cortical bone microstructural and mechanical properties: Ex vivo study
Ultrashort echo time (UTE) MRI can image and consequently enable quantitative assessment of cortical bone. UTE-MRI-based evaluation of bone is largely underutilized due to the high cost and time demands of MRI in general. The signal ratio in dual-echo UTE imaging, known as porosity index (PI), as well as the signal ratio between UTE and inversion recovery UTE (IR-UTE) imaging, known as the suppression ratio (SR), are two rapid UTE-based bone evaluation techniques (∼ 5 mins scan time each), which can potentially reduce the time demand and cost in future clinical studies. This study aimed to investigate the correlations of PI and SR measures with cortical bone microstructural and mechanical properties. Cortical bone strips (n = 135) from tibial and femoral midshafts of 37 donors (61 ± 24 years old) were scanned using a dual-echo 3D Cones UTE sequence and a 3D Cones IR-UTE sequence for PI and SR calculations, respectively. Average bone mineral density, porosity, and pore size were measured using microcomputed tomography (μCT). Bone mechanical properties were measured using 4-point bending tests. The μCT measures showed significant correlations with PI (moderate to strong, R = 0.68-0.71) and SR (moderate, R = 0.58-0.68). Young's modulus, yield stress, and ultimate stress demonstrated significant moderate correlations with PI and SR (R = 0.52-0.62) while significant strong correlations with μCT measures (R > 0.7). PI and SR can potentially serve as fast and noninvasive (non-ionizing radiation) biomarkers for evaluating cortical bone in various bone diseases
Recommended from our members
Correlations between elastic modulus and ultrashort echo time (UTE) adiabatic T1ρ relaxation time (UTE-Adiab-T1ρ) in Achilles tendons and entheses
Patients with psoriatic arthritis commonly have abnormalities of their entheses, which are the connections between tendons and bone. There are shortcomings with the use of conventional magnetic resonance imaging (MRI) sequences for the evaluation of entheses and tendons, whereas ultrashort echo time (UTE) sequences are superior for the detection of high signals, and can also be used for non-invasive quantitative assessments of these structures. The combination of UTE-MRI with an adiabatic-T1ρ preparation (UTE-Adiab-T1ρ) allows for reliable assessment of entheses and tendons with decreased susceptibility to detrimental magic angle effects. This study aimed to investigate the relationship between quantitative UTE-MRI measures and the biomechanical properties of Achilles tendons and entheses. In total, 28 tendon-enthesis sections were harvested from 11 fresh-frozen human cadaveric foot-ankle specimens (52 ± years old). Tendon-enthesis sections were scanned using the UTE-Adiab-T1ρ and UTE-T1 sequences on a clinical 3 T scanner. MRI-based measures and indentation tests were performed on the enthesis, transitional, and tensile tendon zones of the specimens. Hayes' elastic modulus showed significant inverse correlations (Spearman's) with UTE-Adiab-T1ρ in all zones (R= - 0.46, - 0.54, and - 0.61 in enthesis, transition, and tensile tendon zones, respectively). Oliver-Pharr's elastic modulus showed significant inverse correlations with UTE-Adiab-T1ρ in transition (R= - 0.52) and tensile tendon zone (R=- 0.60). UTE-T1 did not show significant correlations with the elastic modulus. UTE-MRI and elastic modulus were significantly lower in the tensile tendon compared with the enthesis regions This study highlights the potential of the UTE-Adiab-T1ρ technique for the non-invasive evaluation of tendons and enthuses
Recommended from our members
Ultrasound attenuation of cortical bone correlates with biomechanical, microstructural, and compositional properties
BackgroundWe investigated the relationship of two commonly used quantitative ultrasound (QUS) parameters, speed of sound (SoS) and attenuation coefficient (α), with water and macromolecular contents of bovine cortical bone strips as measured with ultrashort echo time (UTE) magnetic resonance imaging (MRI).MethodsSoS and α were measured in 36 bovine cortical bone strips utilizing a single-element transducer with nominal 5 MHz center frequency based on the time of flight principles after accommodating for reflection losses. Specimens were then scanned using UTE MRI to measure total, bound, and pore water proton density (TWPD, BWPD, and PWPD) as well as macromolecular proton fraction and macromolecular transverse relaxation time (T2-MM). Specimens were also scanned using microcomputed tomography (μCT) at 9-μm isometric voxel size to measure bone mineral density (BMD), porosity, and pore size. The elastic modulus (E) of each specimen was measured using a 4-point bending test.Resultsα demonstrated significant positive Spearman correlations with E (R = 0.69) and BMD (R = 0.44) while showing significant negative correlations with porosity (R = -0.41), T2-MM (R = -0.47), TWPD (R = -0.68), BWPD (R = -0.67), and PWPD (R = -0.45).ConclusionsThe negative correlation between α and T2-MM is likely indicating the relationship between QUS and collagen matrix organization. The higher correlations of α with BWPD than with PWPD may indicate that water organized in finer structure (bound to matrix) provides lower acoustic impedance than water in larger pores, which is yet to be investigated thoroughly.Relevance statementThis study highlights the importance of future investigations exploring the relationship between QUS measures and all major components of the bone, including the collagenous matrix and water. Investigating the full potential of QUS and its validation facilitates a more affordable and accessible tool for bone health monitoring in clinics.Key points• Ultrasound attenuation demonstrated significant positive correlations with bone mechanics and mineral density. • Ultrasound attenuation demonstrated significant negative correlations with porosity and bone water contents. • This study highlights the importance of future investigations exploring the relationship between QUS measures and all major components of the bone
Ultrasound attenuation of cortical bone correlates with biomechanical, microstructural, and compositional properties
Abstract Background We investigated the relationship of two commonly used quantitative ultrasound (QUS) parameters, speed of sound (SoS) and attenuation coefficient (α), with water and macromolecular contents of bovine cortical bone strips as measured with ultrashort echo time (UTE) magnetic resonance imaging (MRI). Methods SoS and α were measured in 36 bovine cortical bone strips utilizing a single-element transducer with nominal 5 MHz center frequency based on the time of flight principles after accommodating for reflection losses. Specimens were then scanned using UTE MRI to measure total, bound, and pore water proton density (TWPD, BWPD, and PWPD) as well as macromolecular proton fraction and macromolecular transverse relaxation time (T2-MM). Specimens were also scanned using microcomputed tomography (μCT) at 9-μm isometric voxel size to measure bone mineral density (BMD), porosity, and pore size. The elastic modulus (E) of each specimen was measured using a 4-point bending test. Results α demonstrated significant positive Spearman correlations with E (R = 0.69) and BMD (R = 0.44) while showing significant negative correlations with porosity (R = -0.41), T2-MM (R = -0.47), TWPD (R = -0.68), BWPD (R = -0.67), and PWPD (R = -0.45). Conclusions The negative correlation between α and T2-MM is likely indicating the relationship between QUS and collagen matrix organization. The higher correlations of α with BWPD than with PWPD may indicate that water organized in finer structure (bound to matrix) provides lower acoustic impedance than water in larger pores, which is yet to be investigated thoroughly. Relevance statement This study highlights the importance of future investigations exploring the relationship between QUS measures and all major components of the bone, including the collagenous matrix and water. Investigating the full potential of QUS and its validation facilitates a more affordable and accessible tool for bone health monitoring in clinics. Key points • Ultrasound attenuation demonstrated significant positive correlations with bone mechanics and mineral density. • Ultrasound attenuation demonstrated significant negative correlations with porosity and bone water contents. • This study highlights the importance of future investigations exploring the relationship between QUS measures and all major components of the bone. Graphical Abstrac