To compare and assess subregional, compartmental, and whole T1rho values of menisci in patients with doubtful-minimal (Kellgren-Lawrence [KL] grade 1-2) as compared to moderate-severe (KL3-4) osteoarthritis (OA) and healthy controls at 3 Tesla (T).
Forty-six subjects were included in the study and subdivided into three subgroups: 16 healthy controls (4 females, 12 males; mean age = 34.4 ± 10.2 years; age range, 24-63 years), 20 patients with doubtful-minimal (KL1-2) OA (9 females, 11 males; mean age = 61.9 ± 10.8 years; age range, 40-80 years), and 10 patients with moderate-severe (KL3-4) OA (4 females, 6 males; mean age = 71.1 ± 9.6 years; age range, 58-89 years). All subjects were evaluated on a 3T MR scanner using a spin-lock-based three-dimensional GRE sequence for T1rho mapping. Clinical proton density (PD)-weighted fast spin echoes (FSE) images in the sagittal (without fat saturation), axial, and coronal (fat-saturated) planes were acquired for cartilage Whole-Organ MR Imaging Score (WORMS) grading. Analysis of covariance was performed to determine whether there were any statistically significant differences between subregional, compartmental, and whole T1rho values of meniscus among healthy controls, OA patients with KL1-2 and with KL3-4.
Lateral anterior (median ± interquartile range: 26 ± 3 ms) and medial posterior (29 ± 6 ms) meniscus subregions in healthy controls had significantly lower T1rho values (P < 0.05) than the corresponding meniscus subregions in both KL1-2 (29 ± 7 ms and 35 ± 8 ms, respectively) and KL3-4 (30 ± 12 ms and 40 ± 13 ms, respectively) OA subjects. Significantly lower meniscus T1rho values (P < 0.05) were also identified in the medial compartment in healthy controls (28 ± 5 ms) relative to both KL1-2 OA subjects and KL3-4 OA subjects (32 ± 7 ms and 37 ± 7 ms, respectively). The entire meniscus T1rho values in healthy controls (28 ± 4 ms) were significantly lower than those of both KL1-2 and KL3-4 OA subjects (33 ± 6 ms and 34 ± 6 ms, respectively).
Significant elevations of T1rho values in specific regions of menisci in both KL1-2 and KL3-4 OA patients indicate that T1rho mapping may be sensitive to meniscus degeneration. The preliminary results suggest that damage in the medial posterior subregion and medial compartment of menisci may possibly be associated with osteoarthritis.