Age-Dependent Changes in Knee Cartilage T1 , T2 , and T1p Simultaneously Measured Using MRI Fingerprinting

Abstract

Background: Magnetic resonance fingerprinting (MRF) techniques have been recently described for simultaneous multiparameter cartilage mapping of the knee although investigation of their ability to detect early cartilage degeneration remains limited.

Purpose: To investigate age-dependent changes in knee cartilage T₁ , T₂ , and T_1p relaxation times measured using a three-dimensional (3D) MRF sequence in healthy volunteers.

Study type: Prospective.

Subjects: The study group consisted of 24 healthy asymptomatic human volunteers (15 males with mean age 34.9 ± 14.4 years and 9 females with mean age 44.5 ± 13.1 years).

Field strength/sequence: A 3.0 T gradient-echo-based 3D-MRF sequence was used to simultaneously create proton density-weighted images and T₁ , T₂ , and T_1p maps of knee cartilage.

Assessment: Mean global cartilage and regional cartilage (lateral femur, lateral tibia, medial femur, medial tibia, and patella) T₁ , T₂ , and T_1ρ relaxation times of the knee were measured.

Statistical tests: Kruskal-Wallis tests were used to compared cartilage T₁ , T₂ , and T_1ρ relaxation times between different age groups, while Spearman correlation coefficients was used to determine the association between age and cartilage T₁ , T₂ , and T_1ρ relaxation times. The value of P < 0.05 was considered statistically significant.

Results: Higher age groups showed higher global and regional cartilage T₁ , T₂ , and T_1ρ . There was a significant difference between age groups in global cartilage T₂ and T_1ρ but no significant difference (P = 0.13) in global cartilage T_1. Significant difference was also present between age groups in cartilage T₂ and T_1ρ for medial femur cartilage and medial tibia cartilage. There were significant moderate correlations between age and T₂ and T_1ρ for global cartilage (R² = 0.63-0.64), medial femur cartilage (R² = 0.50-0.56), and medial tibia cartilage (R² = 0.54-0.66).

Conclusion: Cartilage T₂ and T_1p relaxation times simultaneously measured using a 3D-MRF sequence in healthy volunteers showed age-dependent changes in knee cartilage, primarily within the medial compartment.

Keywords: MRI fingerprinting; T1 relaxation time; T1ρ relaxation time; T2 relaxation time; cartilage; knee.