Table 2.

Spearman correlation coefficients of QUS-based measures with mechanical, microstructural, and UTE-MRI-based properties of the cortical bone strips

	E	BMD	Porosity	Pore size	T1	MMF	T2-MM	TWPD	BWPD	PWPD	MTR-800	MTR-600	MTR-400
SoS	0.01 (p = 0.989)	0.23 (p = 0.177)	-0.18 (p = 0.295)	0.23 (p = 0.190)	0.07 (p = 0.671)	-0.19 (p = 0.278)	-0.23 (p = 0.193)	-0.14 (p = 0.419)	-0.34 (p = 0.046)	-0.03 (p = 0.862)	0.02 (p = 0.927)	0.09 (p = 0.602)	0.01 (p = 0.965)
α	0.69 (p < 0.001)	0.44 (p = 0.008)	-0.41 (p = 0.010)	-0.24 (p = 0.165)	-0.03 (p = 0.868)	0.20 (p = 0.258)	-0.47 (p = 0.005)	-0.68 (p < 0.001)	-0.67 (p < 0.001)	-0.45 (p = 0.006)	0.31 (p = 0.073)	0.28 (p = 0.109)	0.30 (p = 0.085)

α Attenuation coefficient, BMD Bone mineral density, BWPD Bound water proton density, E Elastic modulus, μCT Microcomputed tomography, MMF Macromolecular fraction, MRI Magnetic resonance imaging, MTR Magnetization transfer ratio (MTR-800, MTR-600, and MTR-400 refer to MTR at 2 kHz for 800°, 600°, and 400° pulse power level), PWPD Pore water proton density, QUS Quantitative ultrasound, SoS Speed of sound, T2-MM Macromolecular T2, TWPD Total water proton density, UTE Ultrashort echo time