Characterization of Age-Related and Sex-Related Differences of Relaxation Parameters in the Intervertebral Disc Using MR-Fingerprinting

Abstract

Background: Multiparameter characterization using MR fingerprinting (MRF) can quantify multiple relaxation parameters of intervertebral disc (IVD) simultaneously. These parameters may vary by age and sex.

Purpose: To investigate age- and sex-related differences in the relaxation parameters of the IVD of the lumbar spine using a multiparameter MRF technique.

Study type: Prospective.

Subjects: 17 healthy subjects (8 male; mean age = 34 ± 10 years, range 20-60 years).

Field strength/sequence: 3D-MRF sequence for simultaneous acquisition of proton density, T₁ , T₂ , and T_1ρ maps at 3.0T.

Assessment: Global mean T₁ , T₂ , and T_1ρ of all lumbar IVDs and mean T₁ , T₂ , and T_1ρ of each individual IVD (L1-L5) were measured. Gray level co-occurrence matrix was used to quantify textural features (median, contrast, correlation, energy, and homogeneity) from T₁ , T₂ , and T_1ρ maps.

Statistical tests: Spearman rank correlations (R) evaluated the association between age and T₁ , T₂ , and T_1ρ of IVD. Mann-Whitney U-tests evaluated differences between males and females in T₁ , T₂ , and T_1ρ of IVD. Statistical significance was defined as P-value <0.05.

Results: There was a significant negative correlation between age and global mean values of all IVDs for T₁ (R = -0.637), T₂ (R = -0.509), and T_1ρ (R = -0.726). For individual IVDs, there was a significant negative correlation between age and mean T₁ at all IVD segments (R range = -0.530 to -0.708), between age and mean T₂ at L2-L3, L3-L4, and L4-L5 (R range = -0.493 to 0.640), and between age and mean T_1ρ at all segments except L1-L2 (R range = -0.632 to -0.763). There were no significant differences between sexes in global mean T₁ , T_2, and T_1ρ (P-value = 0.23-0.76) The texture features with the highest significant correlations with age for all IVDs were global T_1ρ mean (R = -0.726), T₁ energy (R = -0.681), and T₁ contrast (R = 0.709).

Conclusion: This study showed that the 3D-MRF technique has potential to characterize age-related differences in T₁ , T_2, or T_1ρ of IVD in healthy subjects.

Level of evidence: 2 TECHNICAL EFFICACY: Stage 1.

Keywords: MR fingerprinting; degenerative; intervertebral disc; musculoskeletal; osteoarthritis; tissue characterization.