The importance of level stratification for quantitative MR studies of lumbar intervertebral discs: a cross-sectional analysis in 101 healthy adults

Abstract

Purpose To investigate whether quantitative T2-times depend on lumbar intervertebral disc (IVD) level. Methods The lumbar spine (Th12/L1-L5/S1) of 101 participants (53.5% female, 30.0[± 3.6]years, 173.5[± 9.6]cm and 69.9[± 13.4]kg), without history of back pain, was examined on a 3T scanner with sagittal T2-mapping. All IVDs were stratified according to Pfirrmann grade and lumbar level, with mean T2-time determined for the entire IVD volume and in five subregions of interests. Results Significant level-dependent T2-time differences were detected, both for the entire IVD volume and its subregions. For the entire IVD volume, Pfirrmann grade 2 IVDs displayed 9-18% higher T2-times in Th12/L1 IVDs compared to L2/ L3-L5/S1 IVDs (0.001 > p < 0.004) and significantly different T2-times in L1/L2-L2/L3 IVDs compared to most of the IVDs in the lower lumbar spine. In Pfirrmann grades 1, 3 and 4 IVDs, no significant level-dependent T2-time differences were observed for the entire IVD. More pronounced results were observed when comparing IVD subregions, with significant level-dependent differences also within Pfirrmann grade 1 and grade 3 IVDs. For example, in posterior IVD subregions mean T2-time was 80-82% higher in Th12/L1 compared to L3/L4-L4/L5 Pfirrmann grade 1 IVDs (p < 0.05) and 10-14% higher in L5/S1 compared to L3/L4-L4/L5 Pfirrmann grade 3 IVDs (0.02 > p < 0.001). Discussion Significant level-dependent T2-time differences within several Pfirrmann grades, both for the entire IVD volume and for multiple IVD subregions, were shown in this large cohort study. The T2-time differences between levels existed in both non-degenerated and degenerated IVDs. These findings show the importance of stratifying for lumbar level when quantitative IVD studies are performed using T2-mapping.

Mechanical loading influences the lumbar intervertebral disc. A cross‐sectional study in 308 athletes and 71 controls

“…Furthermore, the use of level stratification accounted for potential variance in individual IVDs outcomes. 28 The limitations, however, should also be considered when interpreting these data. First, the cross-sectional design precludes the inference of causality between sport exposure and IVD characteristics.…”

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

“…A recent study highlighted the role of level stratification in MR imaging-quantification studies using T2 data. 13 Our analysis of the same data demonstrated that while the level of stratification might be important when cohorts of IVDs are being compared, T2 times of healthy IVDs at other levels in the same individual are likely to provide a better measure of the health of a given IVD a Variability parameters represent the difference between T2 times of the central aspect of the index IVD from the mean T2 times of the other healthy IVDs from same individual (I), the mean of T2 times of all other healthy lumbar IVDs (X), the mean T2 times of all other healthy lumbar IVDs at the same segmental level as the index IVD (Xs), T2 time of a randomly selected healthy IVD from a different individual but at the same segmental level as the index IVD (Xcs), the mean T2 times of 6 randomly selected healthy discs from different individuals (Xc), each representing a particular segmental level between the T12 through S1 levels. than T2 times of a healthy IVD at the same segmental level from any other given individual or even an average T2 time of a large number of the same segmental-level IVDs from many other healthy controls.…”

“…Certain methodologic details of our experiment merit explanation of the rationale. As opposed to measuring the T2 time of the entire IVD, as in a previous study, 13 we chose to investigate that of a central aspect of the IVD, deliberately trying to exclude the outer annulus. While the central portion of the IVD is known to undergo loss of T2 signal in the presence of pathology, the T2 time of the abnormal annulus (annular fissures) may be expected to increase.…”

“…The existing literature not only lacks a normative definition, but it also fails to establish whether such a definition should be based on other IVDs from the same individual or from a pool of extraneous controls. While it has been shown that the segmental level influences the T2 times of the IVDs, 13 it remains unclear whether these intersegmental variations between cohorts of IVDs from different subjects are larger or smaller than the intrasubject variation in T2 times between lumbar IVDs at different segmental levels.…”

Diagnostic accuracy of contrast and non-contrast 1.5 tesla magnetic resonance imaging for lumbar herniated nucleus pulposus based on surgical findings

“…Its widespread use has a good intraobserver agreement on reproducibility test statistically, especially in the assessment of spondylolisthesis, disc degeneration, infection process, Modic changes, fracture, and facet arthropathy (Kusmiati T, Narendrani HP., 2019). Reports of a high prevalence of lumbar spine abnormalities seen on MRI in asymptomatic subjects are also available (Hebelka H et al, 2019;Jiang X, Chen D et al, 2018;Kim JH et al, 2018). In addition, a false positive imaging on MRI can lead to inappropriate therapy, increase the cost of treatment and result in suboptimal treatment (Bajamal AH et al, 2021).…”