Early intervertebral disc degeneration changes in asymptomatic weightlifters assessed by t1ρ-magnetic resonance imaging

Abstract

Study design: Case-control study.

Objective: To evaluate early intervertebral disc degeneration quantified by T1ρ- and T2-weighted magnetic resonance imaging (MRI) in asymptomatic weightlifters compared with a healthy control group matched for sex and age.

Summary of background data: Athletes consistently recruit or transfer high levels of repetitive forces through the spine, and MRI has documented a higher rate of intervertebral disc degeneration in athletes compared with matched controls. This study aims to analyze the potential role of T1ρ-MRI in the assessment of early degenerative changes occurring in intervertebral discs of young asymptomatic weightlifters compared with healthy controls.

Methods: Twenty-six asymptomatic young male weightlifters versus a sedentary control group matched for age and sex, both having no lower back pain nor any spinal symptoms, underwent MRI (1.5 T). Degenerative grade was assessed using T2-weighted images, according to the Pfirrmann scale. T1ρ mapping and values in the nucleus pulposus (n=130) were obtained. Differences in T1ρ value between among the groups and linear regression analyses with degenerative grade were determined.

Results: Pfirrmann degenerative grade did not show significant differences among groups. Instead, T1ρ values were significantly lower in the lumbar spine of weightlifters compared with controls (P<0.05). T1ρ values decreased linearly with degenerative grade.

Conclusion: T1ρ values were significantly lower in athletes compared with a sedentary matched control group showing differences in intervertebral disc degeneration onset among individuals with lifestyle and environmental factors leading to back pain. T1ρ can be potentially used as a valid clinical tool to identify early changes in intervertebral disc on the verge of new emerging intervertebral discs regenerative strategies and treatments.

Level of evidence: 4.

Figure 1

Flowchart of processing data. Normal spine of a volunteer (23-yr-old-male control).

Figure 2

Representative T2-weighted images (A and C) and T1ρ map overlaid on T1ρ image (B and D) of a 23-year-old male with sedentary lifestyle (A and B) and a 19-year-old weightlifter (C and D). Both subjects show nondegenerated disc on T2-weighted images assessed as grade 1 of Pfirrmann. T1ρ mapping analysis shows lower values of T1ρ in athlete’s IVDs compared with the matched control, due to an increased proteoglycan loss.

Figure 3

Representative T2-weighted images (A and C) and T1ρ map overlaid on T1ρ image (B and D) from a 23-year-old male with sedentary lifestyle (A and B) and a 21-year-old weightlifter (C and D). Both subjects show degenerated disc on T2-weighted images, in particular al level L5–S1 graded as 3 (A) and 4 (C), and grade 2 the rest of discs. T1ρ mapping analysis showed a lower values of T1ρ in the athlete’s discs than those of the control.

Figure 4

Box plots of T1ρ value of nucleus pulposus according to the anatomic level of each disc. Gray denotes athletes; white, sedentary. The boxes represent the median and the interquartile range, with the vertical lines showing the range. The graph shows a significant lower T1ρ value in the weightlifter discs at all levels than that in the sedentary discs. *P < 0.05.

Figure 5

Scatter plot for the bivariate linear regression on the T1ρ value of the NP and Pfirrmann grade, showing differences in the T1ρ values in the discs of the 2 groups. NP indicates nucleus pulposus.