Trends and patterns of thoracic intervertebral disc degeneration in symptomatic subjects: a magnetic resonance imaging analysis

T2 mapping and q-Dixon for assessment of intervertebral disc degeneration in lower back pain

BACKGROUND

Low back pain(LBP) is very common among the population, and intervertebral disc(IVD) degeneration is considered to be the most common cause of LBP, but the pathophysiological process between IVD degeneration and LBP is not very clear. We conducted this study to clarify the interplay between quantitative magnetic resonance imaging (MRI) parameters, including q-Dixon and T2 mapping, and clinical symptomatology in patients with LBP.

METHODS

All LBP patients underwent lumbar spine MRI, encompassing q-Dixon and T2 mapping. The severity of pain was classified based on Oswestry Disability Index (ODI) scores. Midsagittal T2 and T2* mapping were used to assess anterior annulus fibrosus (AAF), nucleus pulposus (NP), and posterior annulus fibrosus (PAF), as well as vertebral bone marrow fat fraction (BMFF). ANOVA and Pearson's correlation analyses facilitated the comparative evaluation of MRI parameters with respect to Pfirrmann grades and ODI scores.

RESULTS

95 LBP patients were included (41 males, 54 females), with an average age of 44.39 ± 17.44. The T2 values of AAF and PAF were different and weakly correlated between most Pfirrmann grades (r = 0.435, 0.414). T2 and T2* values of NP were different and negatively correlated between all Pfirrmann grades (r=-0.844, -0.704), except for grade IV vs. V, revealing decreasing values for grades I-V. BMFF was different and moderately correlated (r = 0.646) between most Pfirrmann grades, except for grade V vs. grade III and IV. The T2 values of AAF, NP, and PAF, the T2* values of the NP, and the BMFF of the vertebrae could distinguish low pain from moderate and severe pain.

CONCLUSION

The T2 and T2* values of AAF, NP, PAF, as well as the BMFF of the vertebrae, can reflect intervertebral disc (IVD) degeneration and may be potentially used to quantitatively detect causes behind LBP.

Association of Thoracic MRI Findings With Specialty and Training

STUDY DESIGN

Retrospective.

OBJECTIVE

To compare the rate of positive pathology on thoracic MRI ordered by surgical spine specialists to those ordered by nonsurgical spine specialists.

METHODS

Outpatient thoracic MRIs from January-March 2019 were evaluated from a single academic health care system. Studies without a known ordering provider, imaging report, or patients with known presence of malignancy, multiple sclerosis, recent trauma, or surgery were excluded (n = 320). Imaging studies were categorized by type of provider placing the order (resident, attending, or advanced practice practitioner) and department. MRIs were deemed positive if they showed relevant pathology that correlated with indication for exam as determined by a radiologist. One-sided chi-squared analysis was performed to determine statistical significance.

RESULTS

Overall, our data demonstrated 17.2% of studies with positive pathology. Compared to nonspecialty clinicians, subspecialists showed 35/184 (19.0%) positivity rate versus the non-specialist with 20/136 (14.7%) positivity rate (P = .156). Posthoc analysis demonstrated that surgical specialists who order thoracic MRIs yield significantly higher positivity rates at 19/79 (24.0%) compared to nonsurgical specialists at 36/241 (14.9%) (P < .05). Overall, neurosurgery demonstrated the highest rate of positive thoracic MRIs at 14/40 (35.0%). Comparison between the rate of positivity between physicians and advanced practitioners was insignificant (P > .05).

CONCLUSIONS

Clinical diagnosis of symptomatic thoracic spine degenerative disease requires an expert physical exam combined with careful attention to radiology findings. Although the percent of relevant pathology on thoracic MRI is low, our data suggests evaluation by a surgical specialist should precede ordering a thoracic spine MRI.

Male spondyloarthritis patients and those with longer disease duration have less severe disc degeneration: propensity score-matched comparison

Objective

Using whole spine sagittal T2 MRI, we aimed to compare the severity and prevalence of disc degeneration (DD) in axial SpA patients vs the general population and to determine any association between spinal inflammation, structural changes, mobility and DD among SpA patients.

Methods

Two prospectively collected cohorts of SpA patients (n = 411) and the general population (n = 2007) were recruited. Eventually, 967 participants from the populational cohort and 304 participants from the SpA cohort were analysed. Two hundred and nineteen matched pairs were generated by propensity score matching. Imaging parameters, including Pfirrmann grading, disc herniation, high-intensity zone, Schmorl's node, Modic change and anterior marrow change were studied and compared from C2/3 to L5/S1. DD was defined as Pfirrmann grade 4 or 5. Demographic factors, including age, sex and BMI, were collected. Multivariable linear regression was used to determine the association between spinal inflammation [Spondyloarthritis Research Consortium of Canada (SPARCC) spine MRI index], structural changes [modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS)] and mobility (BASMI) with lumbar Pfirrmann score.

Results

SpA patients had lower prevalence of DD (P < 0.001). The disease stage-stratified regression model showed that SPARCC spinal MRI index was associated with higher lumbar Pfirrmann scores in early disease (β = 0.196, P = 0.044), whereas mSASSS was associated with lower lumbar Pfirrmann scores in later disease (β = -0.138, P = 0.038). Males had higher mSASSS (P < 0.001) and lower odds of whole spine DD (odds ratio = 0.622, P = 0.028).

Conclusion

SpA patients had lower DD severity than the general population. Males had higher mSASSSs, and increased mSASSS at later disease was associated with less severe DD.

Morphological alterations of lumbar intervertebral discs in patients with adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Etiology of adolescent idiopathic scoliosis (AIS) is still unknown. Prior in vitro research suggests intervertebral disc pathomorphology as a cause for the initiation and progression of the spinal deformity, however, this has not been well characterized in vivo.

PURPOSE

To quantify and compare lumbar disc health and morphology in AIS to controls.

STUDY DESIGN/SETTING

Cross-sectional study.

METHODS

All lumbar discs were imaged using a 3T MRI scanner. T2-weighted and quantitative T2* maps were acquired. Axial slices of each disc were reconstructed, and customized scripts were used to extract outcome measurements: Nucleus pulposus (NP) signal intensity and location, disc signal volume, transition zone slope, and asymmetry index. Pearson's correlation analysis was performed between the NP location and disc wedge angle for AIS patients. ANOVAs were utilized to elucidate differences in disc health and morphology metrics between AIS patients and healthy controls. α=0.05.

RESULTS

There were no significant differences in disc health metrics between controls and scoliotic discs. There was a significant shift in the NP location towards the convex side of the disc in AIS patients compared to healthy controls, with an associated increase of the transition zone slope on the convex side. Additionally, with increasing disc wedge angle, the NP center migrated towards the convex side of the disc.

CONCLUSIONS

The present study elucidates morphological distinctions of intervertebral discs between healthy adolescents and those diagnosed with AIS. Discs in patients diagnosed with AIS are asymmetric, with the NP shifted towards the convex side, which was exacerbated by an increased disc wedge angle.

CLINICAL SIGNIFICANCE

Investigation of the MRI signal distribution (T2w and T2* maps) within the disc suggests an asymmetric pressure gradient shifting the NP laterally towards the convexity. Quantifying the progression of these morphological alterations during maturation and in response to treatment will provide further insight into the mechanisms of curve progression and correction, respectively.

Why Are Some Intervertebral Discs More Prone to Degeneration?: Insights Into Isolated Thoracic "Dysgeneration"

STUDY DESIGN

Prospective observational study.

OBJECTIVE

To determine the prevalence of isolated thoracic degeneration on magnetic resonance imaging (MRI), demographic factors and imaging features, as well as the patient-reported quality of life outcomes associated with this condition.

SUMMARY OF BACKGROUND DATA

Thoracic intervertebral discs are least susceptible to disc degeneration (DD) and may represent a manifestation of "dysgeneration." These discs may never be hydrated from the beginning and seem hypointense on MRI.

PATIENTS AND METHODS

A population-based MRI study of 2007 volunteers was conducted. Each disc from C2/3 to L5/S1 was measured by Pfirrmann and Schneiderman grading. Disc herniation, Schmorl node (SN), high-intensity zones (HIZ), and Modic changes were studied. DD was defined by Pfirrmann 4 or 5. patient-reported quality of life scores, including a 36-item short-form questionnaire and visual analog scale for low back pain, were recorded. Subjects were divided into "isolated thoracic degeneration" (only thoracic segment) and "tandem thoracic degeneration" (thoracic with other segments). The association between imaging findings and isolated thoracic degeneration was determined using multivariate logistic regression.

RESULTS

The mean age of the subjects was 50.0 ± 0.5 and 61.4% were females (n = 1232). Isolated thoracic degeneration was identified in 2.3% of the cohort. Factors associated with isolated thoracic degeneration included lower age, C6/7 HIZ, T8/9 HIZ, and T8/9 SN. Factors associated with tandem thoracic degeneration included L4/5 posterior bulging. The thoracic and lumbar tandem degeneration group demonstrated higher bodily pain, despite a lower visual analog scale, and a higher physical component score of the 36-item short form.

CONCLUSIONS

Isolated thoracic degeneration demonstrated an earlier age of onset, mostly involving the mid-thoracic region (T5/6-T8/9), and in association with findings such as SN. Subjects with tandem thoracolumbar degeneration had less severe lumbar DD and low back pain as compared with those with isolated lumbar degeneration. This paints the picture of "dysgeneration" occurring in the thoracic and lumbar spine.

LEVEL OF EVIDENCE

1.