Significant Association between the T2 Values of Vertebral Cartilage Endplates and Pfirrmann Grading

Objective: The T2 value of lumbar cartilage endplates was measured using the T2 mapping imaging technique, aiming to explore the correlation between the T2 value and Pfirrmann grading of intervertebral discs.

Methods: A total of 130 patients with lumbar spine MR examination due to persistent low back pain were enrolled, including 71 men and 59 women (age: 21-63 years). Lumbar Modic changes and Schmorl nodules were recognized by conventional T1WI and T2WI images in 49 patients, and these patients were excluded from the study. A total of 81 patients were enrolled in this study, including 45 men (45.16 ± 12.20 years) and 36 women (43.33 ± 11.27 years). Pfirrmann (Pm) grading of each lumbar disc was performed based on conventional T2WI median sagittal images and the position of cartilage endplates (CEP) was determined by IDEAL-SPGR images. Meanwhile, the T2 mapping technique was used to obtain T2 values of cartilage endplates. The T2 values of CEP corresponding to different Pm grade discs were compared, and the correlation between the T2 value and the Pm grade of intervertebral discs was analyzed.

Results: The T2 values of cephalic and caudal CEP of L_1-2 in Pm grades I-II, Pm grades III, and Pm grades IV-V were 61.96 ± 5.89 ms, 54.45 ± 3.29 ms, 42.47 ± 3.69 ms and 64.35 ± 5.93 ms, 55.28 ± 3.97 ms, 44.75 ± 2.12 ms, respectively. For cephalic and caudal CEP of L_2-3 , the T2 values in Pm grades I-II, Pm grades III, and Pm grades IV-V were 62.96 ± 6.93 ms, 55.19 ± 4.02 ms, 48.67 ± 4.56 ms and 65.51 ± 6.49 ms, 57.16 ± 5.55 ms, 52.05 ± 4.20 ms, respectively. The T2 values of cephalic and caudal CEP from L_3-4 to L₅ -S₁ in Pm grades I-II, Pm grades III, and Pm grades IV-V were (63.72 ± 5.76 ms, 53.96 ± 6.52 ms, 48.05 ± 5.00 ms), (65.46 ± 6.37 ms, 55.70 ± 7.50 ms, 48.10 ± 3.27 ms); (66.34 ± 7.68 ms, 56.76 ± 9.48 ms, 47.80 ± 4.33 ms), (64.44 ± 4.65 ms, 59.30 ± 8.80 ms, 47.30 ± 5.78 ms), (65.32 ± 5.11 ms, 55.33 ± 6.65 ms, 48.18 ± 5.37 ms), and (63.47 ± 4.92 ms, 50.32 ± 8.86 ms, 44.77 ± 4.69 ms), respectively. There were significant differences in T2 values of cartilage endplates between the Pm grades I-II, III, and IV-V of intervertebral discs (P = 0.000). T2 values corresponding to Pm I-II grades were higher than those in Pm III grade, while T2 values in Pm grades IV-V were lowest. The T2 value of the L_4-5 , L₅ -S₁ segment endplates was highly correlated with the Pm grades (r = -0.711, -0.721, -0.796, -0.745; P = 0.000) and that of L_1-2 , L_2-3 endplates were moderately correlated (r = -0.542, -0.562, -0.637, -0.612; P = 0.000).

Conclusion: The T2 values of cartilage endplates revealed varying degrees of degeneration of intervertebral discs, and more severe degeneration corresponded to lower T2 values. Measurement of changes in the T2 value through cartilage endplates can be useful for the diagnosis of early intervertebral disc degeneration and the prevention of disc degeneration.