Variability of T2-Relaxation Times of Healthy Lumbar Intervertebral Discs is More Homogeneous within an Individual Than across Healthy Individuals

Abstract

BACKGROUND AND PURPOSE: When one uses T2 relaxometry to classify lumbar intervertebral discs as degenerated, it is unclear whether the normative data should be based on other intervertebral discs from the same individual or from a pool of extraneous controls. This study aimed to explore the extent of intra-versus intersubject variation in the T2 times of healthy intervertebral discs. MATERIALS AND METHODS:Using prospectively acquired T2-relaxometry data from 606 intervertebral discs in 101 volunteers without back pain (47 men, 54 women) in a narrow age range (25-35 years), we calculated intra-and intersubject variation in T2 times of intervertebral discs graded by 2 neuroradiologists on the Pfirrmann scale. Intrasubject variation of intervertebral discs was assessed relative to other healthy intervertebral discs (Pfirrmann grade, #2) in the same individual. Multiple intersubject variability measures were calculated using healthy extraneous references ranging from a single randomly selected intervertebral disc to all healthy extraneous intervertebral discs, without and with segmental stratification. These variability measures were compared for healthy and degenerated (Pfirrmann grade $3) intervertebral discs. RESULTS:The mean T2 values of healthy (493/606, 81.3%) and degenerated intervertebral discs were 121.1 6 22.5 ms and 91.5 6 18.6 ms, respectively (P , .001). The mean intrasubject variability for healthy intervertebral discs was 9.8 6 10.7 ms, lower than all intersubject variability measures (P , .001), and provided the most pronounced separation for healthy and degenerated intervertebral discs. Among intersubject variability measures, using all segment-matched healthy discs as references provided the lowest variability (P , .001). CONCLUSIONS:Normative measures based on the T2 times of healthy intervertebral discs from the same individual are likely to provide the most discriminating means of identifying degenerated intervertebral discs on the basis of T2 relaxometry. ABBREVIATIONS: I, X, Xs, Xc, Xcs ¼ various measures of variability in T2 times of intervertebral discs; IVD ¼ intervertebral disc; np ¼ used as a suffix to indicate measures assumed to represent nucleus pulposus L oss of signal intensity of the central part of intervertebral discs (IVDs) on T2-weighted MR images is a well-established indicator of underlying degenerative changes. [1][2][3][4] Visual recognition of the extent of this loss of signal intensity also forms the basis of grading the extent of disc degeneration on frequently used grading schemes such as one proposed by Pfirrmann et al. 5 To overcome the subjectivity of visual assessment, T2 relaxometry provides a reliable, objective, and

Associations between high‐intensity zones, endplate, and Modic changes and their effect on T2‐mapping with and without spinal load

“…T2-mapping is known to be sensitive to stimulated echoes that may result in large variabilities across individuals. 33 In this study, low variability between T2-measurements was ensuredwith the chosen scanner and protocol before patient examinations were initiated.…”

LncRNA NEAT1 promotes nucleus pulposus cell matrix degradation through regulating Nrf2/ARE axis

“…Pfirrmann grades according to T2-weighted section images were used to assess the degree of IVD. According to Pfirrmann grading, grades I and II indicate normal discs, whereas grades III, IV, and V indicate degenerated discs [ 23 ].…”

Interpretation of Morphological Details of Nondegenerated Lumbar Intervertebral Discs on Magnetic Resonance Imaging: Insights From a Comparison Between Computed Tomography Discograms and Magnetic Resonance Imaging

“…Understanding how the MRI image correlates with detailed anatomy, such as the extent of the nucleus pulposus (NP) and details regarding the annulus fibrosus appearance, [2][3][4][5][6][7][8] is valuable to adequately interpret MRI data, especially since quantitative MRI markers are increasingly used within spinal research. [9][10][11][12][13] On T2weighted imaging (T2WI), the outer annulus fibrosus (OA) is readily apparent as a hypointense structure surrounding a central hyperintense zone. 14 The latter represents a combination of two structures that cannot be individually identified on MRI-namely the inner annulus fibrosus (IA) and the NP.…”