Modic Type 1 Changes: Detection Performance of Fat-Suppressed Fluid-Sensitive MRI Sequences

The advancement of MRI in differentiating Modic type I degenerative changes from early spinal infections

MRI is the most sensitive and specific imaging method for the detection of advanced spinal infections. However, the differential diagnosis of early spinal infection and Modic Type I degenerative changes based on conventional MRI is difficult clinically, as they both may mimic each other by showing hypointensity on T1 weighted images and hyperintensity on T2 weighted spine MRI images. This review summarizes recent advancements in MRI, which may be useful in discriminating degenerative Modic Type I endplate changes from early spinal infection, and evaluates the diagnostic accuracy and limitations of MRI. We aim to provide indications for early differential diagnosis to help initiate appropriate treatment in a timely manner so that associated complications can be avoided.

Can T2-weighted Dixon fat-only images replace T1-weighted images in degenerative disc disease with Modic changes on lumbar spine MRI?

OBJECTIVES

To evaluate the diagnostic performance and interobserver agreement of a magnetic resonance imaging (MRI) protocol that only includes sagittal T2-weighted Dixon fat and water images as an alternative to a standard protocol that includes both sagittal T1-weighted sequence and T2-weighted Dixon water images as reference standard in lumbar degenerative disc disease with Modic changes.

METHODS

From February 2017 to March 2019, 114 patients who underwent lumbar spine MRI for low back pain were included in this retrospective study. All MRI showed Modic changes at least at one vertebral level. Two radiologists read the standard protocol and 1 month later the alternative protocol. All MRI were assessed for Modic changes (types, location, extension) as well as structural changes (endplate defects, facet arthropathy, spinal stenosis, foraminal stenosis, Schmorl nodes, spondylolisthesis, disc bulges, and degeneration). Interobserver agreement was assessed, as well as diagnostic performance using the standard protocol as reference standard.

RESULTS

Interobserver agreement was moderate to excellent (kappa ranging from 0.51 to 0.92). Diagnostic performance of the alternative protocol was good for detection of any Modic change (sensitivity = 100.00% [95% CI, 99.03-100.00]; specificity = 98.89% [95% CI, 98.02-99.44]), as well as for detection of each Modic subtype and structural variables (sensitivity respectively 100% and ranging from 88.43 to 99.75% ; specificity ranging respectively from 97.62 to 100% and 99.58 to 99.91% ).

CONCLUSIONS

Combined with T2-weighted Dixon water images, T2-weighted Dixon fat images provide good diagnostic performance compared to T1-weighted images in lumbar degenerative disc disease with Modic changes, and could therefore allow for a shortened protocol.

KEY POINTS

• Combined with T2-weighted Dixon water images, T2-weighted Dixon fat images (in comparison to T1-weighted sequence) can provide good diagnostic performance in lumbar degenerative disc disease with Modic changes. • Interobserver agreement of the alternative protocol including sagittal T2-weighted Dixon fat and water images was substantial to excellent for every studied variable except for facet arthropathy. • A shortened MRI protocol including T2-weighted Dixon sequence without T1-weighted sequence could be proposed in this clinical setting.

Oedema on STIR modified the effect of amoxicillin as treatment for chronic low back pain with Modic changes-subgroup analysis of a randomized trial

Objective

To evaluate potential MRI-defined effect modifiers of amoxicillin treatment in patients with chronic low back pain and type 1 or 2 Modic changes (MCs) at the level of a previous lumbar disc herniation (index level).

Methods

In a prospective trial (AIM), 180 patients (25–64 years; mean age 45; 105 women) were randomised to receive amoxicillin or placebo for 3 months. Primary outcome was the Roland-Morris Disability Questionnaire (RMDQ) score (0–24 scale) at 1 year. Mean RMDQ score difference between the groups at 1 year defined the treatment effect; 4 RMDQ points defined the minimal clinically important effect. Predefined baseline MRI features of MCs at the index level(s) were investigated as potential effect modifiers. The predefined primary hypothesis was a better effect of amoxicillin when short tau inversion recovery (STIR) shows more MC-related high signal. To evaluate this hypothesis, we pre-constructed a composite variable with three categories (STIR1/2/3). STIR3 implied MC-related STIR signal increases with volume ≥ 25% and height > 50% of vertebral body and maximum intensity increase ≥ 25% and presence on both sides of the disc. As pre-planned, interaction with treatment was analysed using ANCOVA in the per protocol population (n = 155).

Results

The STIR3 composite group (n = 41) and STIR signal volume ≥ 25% alone (n = 45) modified the treatment effect of amoxicillin. As hypothesised, STIR3 patients reported the largest effect (− 5.1 RMDQ points; 95% CI − 8.2 to − 1.9; p for interaction = 0.008).

Conclusions

Predefined subgroups with abundant MC-related index-level oedema on STIR modified the effect of amoxicillin. This finding needs replication and further support.

Key Points

• In the primary analysis of the AIM trial, the effect of amoxicillin in patients with chronic low back pain and type 1 or 2 MCs did not reach the predefined cut-off for clinical importance.

• In the present MRI subgroup analysis of AIM, predefined subgroups with abundant MC-related oedema on STIR reported an effect of amoxicillin.

• This finding requires replication and further support.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-020-07542-w.

Association of Modic change types and their short tau inversion recovery signals with clinical characteristics- a cross sectional study of chronic low back pain patients in the AIM-study

BACKGROUND

Modic Changes (MCs, magnetic resonance imaging (MRI) signal changes in the vertebral bone marrow extending from the vertebral endplate) may represent a subgroup of nonspecific chronic low back pain that could benefit from a specific management. The primary aim was to compare clinical characteristics between patients with type 1 versus type 2 MCs. The secondary aim was to explore associations between clinical characteristics and MC related short tau inversion recovery (STIR) signals.

METHODS

This cross-sectional study used baseline data prospectively collected between 2015 and 2017 on the 180 patients included in the AIM-study (Antibiotics In Modic changes), a randomized controlled trial in a Norwegian hospital out-patient setting of patients with chronic low back pain, a lumbar disc herniation within the last 2 years, low back pain intensity score ≥ 5 (on a 0-10 scale) and current type 1 or type 2 MCs at the previously herniated lumbar disc level. We used prespecified clinical characteristics including self-report measures, physiologic measures and functional measures from clinical history and examination. The diagnostic accuracy of various clinical characteristics to discriminate between patients with type 1 MCs (with or without additional type 2 MCs) and patents with type 2 MCs only (not type 1) were assessed by calculating the area under the receiver-operating curve. We assessed the correlations of clinical characteristics with details of MC related STIR signal increase.

RESULTS

No clinical characteristic differed between patients with type 1 (n = 118) versus type 2 (but not type 1) (n = 62) MCs. The clinical characteristics showed no/minor differences or no/weak correlations with MC related STIR signal increase. Patients with a positive Springing test (at any lumbar level) had slightly less volume of STIR signal increase than those with a negative test (mean difference 1.3 on a 0-48 scale, 95% CI 0.3 to 2.3).

CONCLUSION

Clinical characteristics were similar for patients with type 1 MCs and patients with type 2 MCs, and showed no clinically relevant correlations with MC related STIR signal increase.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02323412, First registered 23 December 2014.

Vertebral Bone Marrow and Endplate Assessment on MR Imaging for the Differentiation of Modic Type 1 Endplate Changes and Infectious Spondylodiscitis

On magnetic resonance (MR) imaging, Modic type 1 (MT1) endplate changes and infectious spondylodiscitis share similar findings. Therefore, this study investigated vertebral bone marrow and endplate changes to enable their differentiation. The lumbar spine MR examinations of 91 adult patients were retrospectively included: 39 with MT1; 19 with early spondylodiscitis without abscess; and 33 with advanced spondylodiscitis with abscess. The assessment included percentage of bone marrow edema on sagittal short tau inversion recovery images, and the signal ratio of edema to unaffected bone and endplate contour (normal; irregular, yet intact; blurred; destructive) on sagittal unenhanced T1-weighted images. Differences were tested for statistical significance by Chi-square test and mixed model analysis of variance. The MR diagnostic accuracy in differentiating MT1 and spondylodiscitis was assessed by cross-tabulation and receiver-operating characteristic analysis. The endplate contours, edema extents, and T1-signal ratios of MT1 (extent, 31.96%; ratio, 0.83) were significantly different (p < 0.001) from early spondylodiscitis (56.42%; 0.60), and advanced spondylodiscitis (91.84%; 0.61). The highest diagnostic accuracy (sensitivity, 94.87%; specificity, 94.23%; accuracy, 94.51%) in identifying MT1 was provided by an irregular, yet intact endplate contour. This may be a useful MR feature for the differentiation between MT1 and spondylodiscitis, particularly in its early stage.

Short tau inversion recovery MRI of Modic changes: a reliability study

Background

Limited reliability data exist for evaluation of spinal edema changes on magnetic resonance imaging (MRI) with short tau inversion recovery (STIR) sequences.

Purpose

To assess the inter-observer reliability for evaluation of STIR signal increase related to Modic changes (MCs) on MRI of the lumbar spine.

Material and Methods

We prospectively included 120 patients imaged to confirm their eligibility for the AIM (Antibiotics In Modic changes) trial. Three experienced radiologists independently evaluated MCs on T1-/T2-weighted fast spin-echo images and subsequently MC-related STIR signal increases. Inter-observer reliability was analyzed at four endplates (L4-S1) by calculating kappa values and means of differences with 95% limits of agreement.

Results

Overall agreement (mean Fleiss' kappa for all endplates and observers) was very good for presence of STIR signal increase (0.86), and moderate for its categorized height (0.51), anteroposterior extent (0.48), and volume (0.56). For height of region with STIR signal increase measured in % points of vertebral body height, the largest mean of differences was 6.9 and widest range for limits of agreement was ±22.3 for all endplates combined. The corresponding numbers were 11.2 ± 34.5 for anteroposterior extent of the STIR signal increase measured in % points of anteroposterior endplate diameter and 0.9 ± 7.6 for its maximum measured intensity on a % point scale (0% = normal vertebral marrow intensity, 100% = cerebrospinal fluid intensity).

Conclusion

Inter-observer reliability was very good for the presence and intensity of MC-related STIR signal increases, and moderate for their size.