Quantitative 1H Magnetic Resonance Imaging on Normal and Pathologic Rat Bones by Solid-State 1H ZTE Sequence with Water and Fat Suppression

Víctor B Kassey; Matthias Walle; Jonathan Egan; Diana Yeritsyan; Indeevar Beeram; Sharon P Kassey; Yaotang Wu; Brian D Snyder; Edward K Rodriguez; Jerome L Ackerman; Ara Nazarian

doi:10.1002/jmri.29361

Quantitative ¹H Magnetic Resonance Imaging on Normal and Pathologic Rat Bones by Solid-State ¹H ZTE Sequence with Water and Fat Suppression

J Magn Reson Imaging. 2024 Mar 25. doi: 10.1002/jmri.29361. Online ahead of print.

Authors

Víctor B Kassey^{1

2

3

4}, Matthias Walle¹, Jonathan Egan¹, Diana Yeritsyan¹, Indeevar Beeram¹, Sharon P Kassey³, Yaotang Wu^{2

3

4}, Brian D Snyder^{2

4}, Edward K Rodriguez^{1

4}, Jerome L Ackerman^{3

4

5}, Ara Nazarian^{1

2

3

4}

Affiliations

¹ Musculoskeletal Translational Innovation Initiative, Carl J. Shapiro Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
² Department of Orthopaedic Surgery, Children's Hospital, Boston, Massachusetts, USA.
³ Athinoula Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.
⁴ Harvard Medical School, Boston, Massachusetts, USA.
⁵ Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, USA.

PMID: 38526032
DOI: 10.1002/jmri.29361

Abstract

Background: Osteoporosis (OP) and osteomalacia (OM) are metabolic bone diseases characterized by mineral and matrix density changes. Quantitative bone matrix density differentiates OM from OP. MRI is a noninvasive and nonionizing imaging technique that can measure bone matrix density quantitatively in ex vivo and in vivo.

Purpose: To demonstrate water + fat suppressed ¹H MRI to compute bone matrix density in ex vivo rat femurs in the preclinical model.

Study type: Prospective.

Animal model: Fifteen skeletally mature female Sprague-Dawley rats, five per group (normal, ovariectomized (OVX), partially nephrectomized/vitamin D (Vit-D) deficient), 250-275 g, ∼15 weeks old.

Field strength/sequence: 7T, zero echo time sequence with water + fat (VAPOR) suppression capability, μCT imaging, and gravimetric measurements.

Assessment: Cortical and trabecular bone segments from normal and disease models were scanned in the same coil along with a dual calibration phantom for quantitative assessment of bone matrix density.

Statistical tests: ANOVA and linear regression were used for data analysis, with P-values <0.05 statistically significant.

Results: The MRI-derived three-density PEG pellet densities have a strong linear relationship with physical density measures (r² = 0.99). The Vit-D group had the lowest bone matrix density for cortical bone (0.47 ± 0.16 g cm^-3), whereas the OVX had the lowest bone matrix density for trabecular bone (0.26 ± 0.04 g cm^-3). Gravimetry results confirmed these MRI-based observations for Vit-D cortical (0.51 ± 0.07 g cm^-3) and OVX trabecular (0.26 ± 0.03 g cm^-3) bone groups.

Data conclusion: Rat femur images were obtained using a modified pulse sequence and a custom-designed double-tuned (¹H/³¹P) transmit-receive solenoid-coil on a 7T preclinical MRI scanner. Phantom experiments confirmed a strong linear relation between MRI-derived and physical density measures and quantitative bone matrix densities in rat femurs from normal, OVX, and Vit-D deficient/partially nephrectomized animals were computed.

Level of evidence: 2 TECHNICAL EFFICACY: Stage 2.

Keywords: bone matrix density; bone mineral density; osteomalacia; osteoporosis; short‐T2 solid‐state MRI.

Abstract

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