Appropriate Normal Range of Lumbar Disc T1rho of Men and Women with Respect to Physiological Aging

Dear Editor,

I read the article by Gübitz et al. [1] with great interest. The data provided by the authors are highly valuable, since even though numerous publications on T2 / T2*/T1rho relaxometry of lumbar intervertebral discs have been published, most of those studies were based on a small sample of selected volunteers or on patients with non-specific low back pain (LBP) who may or may not have disc pathologies associated with LBP. T2 / T2*/T1rho relaxometry data sampled from a general population remain scare [2]. T1rho demonstrates a number of advantages over conventional T2 for disc degeneration evaluation [3] [4], particularly for annulus fibrosis. Knowledge of the normal range of T1rho values in the healthy spine is important for further investigation of disc degeneration and other pathologies [5].

Disc T1rho may be region-specific, age-specific, as well as gender-specific. The fact that disc T1rho is region-specific has been reported and also demonstrated in the study by Gübitz et al. [1]. Disc T1rho is age-specific due to the physiological aging process even in the absence of pathological disc degeneration [6]. It is noteworthy that the study by Gübitz et al. demonstrated that body mass index (BMI) shows a negative correlation with T1rho of the lumbar disc [1]. This may additionally suggest the sensitivity of the T1rho technique for disc pathologies. The study by Gübitz et al. also examined whether disc T1rho might be gender-specific. Gender specificity was not observed.

For a population under the age of fifty, previous studies showed that lumbar disc injury and disc degeneration are more common in men than in women [7] [8]. However, women tend to have accelerated disc degeneration after menopause [9] [10] [11] [12]. It has also been shown that lumbar disc narrowing is more common and more severe in elderly women than in elderly men, and this disparity increases as age advances [13]. With respect to gender specificity of lumbar disc T1rho, it would be interesting for Gübitz et al. to examine pre-menopausal female participants and post-menopausal female participants separately and compare them with their age-matched male counterparts.

Even though the study participants in the study by Gübitz et al. did not have clinical symptoms associated with lumbar disc degeneration, it is still probable that a portion of them had disc degeneration in addition to physiological aging. Providing pooled data of normal subjects by excluding subjects with pathological disc degeneration will help to establish the appropriate normal range of discs at specific regions with respect to physiological aging. In one study composed of healthy volunteers and patients with mild nonspecific LBP, it was shown that on average women had an initially higher T2 value before the age of 50. This trend was reversed in elderly persons, with an intersection at 52.4 years [10]. However, it is still unclear whether menopause is associated with accelerated overall disc aging (as seen by a lowered T2 or T1rho value) or with a higher incidence of disc degeneration, or maybe both. Perhaps a re-analysis of the study by Gübitz et al. can shed some light on this question. A bigger population-based study will offer a more definitive answer.

• References

• 1 Gübitz R, Lange T, Gosheger G. et al. Influence of Age, BMI, Gender and Lumbar Level on T1ρ Magnetic Resonance Imaging of Lumbar Discs in Healthy Asymptomatic Adults. Rofo 2017; [Epub ahead of print] DOI: 10.1055/s-0043–115898.
• 2 Menezes-Reis R, Salmon CE, Bonugli GP. et al. Lumbar intervertebral discs T2 relaxometry and T1ρ relaxometry correlation with age in asymptomatic young adults. Quant Imaging Med Surg 2016; 6: 402-412
• 3 Yoo YH, Yoon CS, Eun NL. et al. Interobserver and Test-Retest Reproducibility of T1ρ and T2 Measurements of Lumbar Intervertebral Discs by 3T Magnetic Resonance Imaging. Korean J Radiol 2016; 17: 903-911
• 4 Wang YX, Zhao F, Griffith JF. et al. T1rho and T2 relaxation times for lumbar disc degeneration: an in vivo comparative study at 3.0-Tesla MRI. Eur Radiol 2013; 23: 228-234
• 5 Wáng YX. Towards consistency for magnetic resonance (MR) relaxometry of lumbar intervertebral discs. Quant Imaging Med Surg 2016; 6: 474-477
• 6 Adams MA, Lama P, Zehra U. et al. Why do some intervertebral discs degenerate, when others (in the same spine) do not?. Clin Anat 2015; 28: 195-204
• 7 Miller JA, Schmatz C, Schultz AB. Lumbar disc degeneration: correlation with age, sex, and spine level in 600 autopsy specimens. Spine 1988; 13: 173-178
• 8 Lebkowski WJ. Autopsy evaluation of the extent of degeneration of the lumbar intervertebral discs. (In Polish). Pol Merkur Lekarski 2002; 13: 188-190
• 9 Wang YX, Griffith JF. Effect of menopause on lumbar disc degeneration: potential etiology. Radiology 2010; 257: 318-320
• 10 Wang YX. Postmenopausal Chinese women show accelerated lumbar disc degeneration compared with Chinese men. J Orthop Translat 2015; 3: 205-211
• 11 Gambacciani M, Pepe A, Cappagli B. et al. The relative contributions of menopause and aging to postmenopausal reduction in intervertebral disk height. Climacteric 2007; 10: 298-305
• 12 Lou C, Chen HL, Feng XZ. et al. Menopause is associated with lumbar disc degeneration: a review of 4230 intervertebral discs. Climacteric 2014; 17: 700-704
• 13 Wang YX, Griffith JF, Zeng XJ. et al. Prevalence and sex difference of lumbar disc space narrowing in elderly Chinese men and women: osteoporotic fractures in men (Hong Kong) and osteoporotic fractures in women (Hong Kong) studies. Arthritis Rheum 2013; 65: 1004-1010