The lumbar high-intensity zone: 20 years on

Texture Analysis of Magnetic Resonance Images Enables Phenotyping of Potentially Painful Annular Fissures

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVE

To investigate whether intervertebral disc (IVD) image features, extracted from magnetic resonance (MR) images, can depict the extension and width of annular fissures and associate them to pain.

SUMMARY OF BACKGROUND DATA

Annular fissures are suggested to be associated with low back pain (LBP). Magnetic resonance imaging (MRI) is a sensitive method, yet fissures are sometimes unobservable in T2-weighted MR-images, even though fissure information is present in the image. Image features can mathematically be calculated from MR-images and might reveal fissure characteristics.

METHODS

Forty four LBP patients who underwent MRI, low-pressure discography (<50 psi), and computed tomography (CT) sequentially in 1 day, were reviewed. After semi-automated segmentation of 126 discs, image features were extracted from the T2-weighted images. The number of image features was reduced with principle component analysis (PCA). CT-discograms were graded and dichotomized regarding extension and width of fissures. IVDs were divided into fissures extending to outer annulus versus short/no fissures. Fissure width was dichotomized into narrow (<10%) versus broad fissures (>10%), and into moderately broad (10%-50%) versus very broad fissures (>50%). Logistic regression was performed to investigate if image features could depict fissure extension to outer annulus and fissure width. As a sub-analysis, the association between image features used to depict fissure characteristics and discography-provoked pain-response were investigated.

RESULTS

Fissure extension could be depicted with sensitivity/specificity = 0.97/0.77 and area under curve (AUC) = 0.97. Corresponding results for width depiction were sensitivity/specificity = 0.94/0.39 and 0.85/0.62, and AUC = 0.86 and 0.81 for narrow versus broad and moderately broad versus very broad fissures respectively. Pain prediction with image features used for depicting fissure characteristics showed sensitivity/specificity = 0.90/0.36, 0.88/0.4, 0.93/0.33; AUC = 0.69, 0.75, and 0.73 respectively.

CONCLUSION

Standard MR-images contains fissure information associated to pain that can be depicted with image features, enabling non-invasive phenotyping of potentially painful annular fissures.Level of Evidence: 2.

Quantitative MRI to Characterize the Nucleus Pulposus Morphological and Biomechanical Variation According to Sagittal Bending Load and Radial Fissure, an ex vivo Ovine Specimen Proof-of-Concept Study

Background and context: Low back pain is a dramatic burden worldwide. Discography studies have shown that 39% of chronic low back pain patients suffer from discogenic pain due to a radial fissure of intervertebral disc. This can have major implications in clinical therapeutic choices. The use of discography is restricted because of its invasiveness and interest in it remains low as it represents a static condition of the disc morphology. Magnetic Resonance Imaging (MRI) appears to be less invasive but does not describe the biomechanical dynamic behavior of the fissure. Purpose: We aimed to seek a quantitative MRI protocol combined with ex vivo sagittal loading to analyze the morphological and biomechanical changes of the intervertebral disc structure and stress distribution. Study design: Proof of concept. Methods: We designed a proof-of-concept ovine study including 3 different 3.0 T-MRI sequences (T₂-weighted, T₁ and T₂ mapping). We analyzed 3 different mechanical states (neutral, flexion and extension) on a fresh ovine spine specimen to characterize an intervertebral disc before and after puncturing the anterior part of the annulus fibrosus. We used a mark tracking method to calculate the bending angles and the axial displacements of the discal structures. In parallel, we created a finite element model to calculate the variation of the axial stress and the maximal intensity shear stress, extrapolated from our experimental boundary conditions. Results: Thanks to an original combination of specific nuclear relaxation time quantifications (T₁, T₂) of the discal tissue, we characterized the nucleus movement/deformation into the fissure according to the synchronous mechanical load. This revealed a link between disc abnormality and spine segment range of motion capability. Our finite element model highlighted significant variations within the stress distribution between intact and damaged disc. Conclusion: Quantitative MRI appears to provide a new opportunity to characterize intra-discal structural morphology, lesions and stress changes under the influence of mechanical load. This preliminary work could have substantial implications for non-invasive disc exploration and could help to validate novel therapies for disc treatment.

Comparison of lumbar degenerative disc disease using conventional fast spin echo T2W MRI and T2 fast spin echo dixon sequences

OBJECTIVES

To compare the grading of lumbar degenerative disc disease (DDD), Modic end-plate changes (MEPC) and identification of high intensity zones (HIZ) on a combination of sagittal T₁weighted turbo spin echo (T₁W TSE), T₂weighted fast spin echo (T₂W FSE) and short tau inversion recovery (STIR) sequences (routine protocol) with a single sagittal T₂W FSE Dixon MRI sequence which provides in-phase, opposed-phase, water only and fat only images in a single acquisition (Dixon protocol).

METHODS

50 patients underwent lumbar spine MRI using the routine protocol with the addition of a T₂W FSE Dixon sequence. DDD grade, MEPC and HIZ for each disc level were assessed on the routine and Dixon protocols. Each protocol was reviewed independently by three readers (consultant musculoskeletal radiologists with 26-, 8- and 4 years' experience), allowing assessment of inter-reader agreement and inter protocol agreement for each assessed variable.

RESULTS

The study included 17 males and 33 females (mean age 51 years; range 8-82 years). Inter-reader agreement for DDD grade on the routine protocol was 0.57 and for the Dixon protocol was 0.63 (p = 0.08). Inter-reader agreement for MEPC on the routine protocol was 0.45 and for the Dixon protocol was 0.53 (p = 0.02), and inter-reader agreement for identification of the HIZ on the routine protocol was 0.52 and for the Dixon protocol was 0.46 (p = 0.27). Intersequence agreement for DDD grade ranged from 0.61 to 0.97, for MEPC 0.46-0.62 and for HIZ 0.39-0.5.

CONCLUSION

A single sagittal T₂W FSE Dixon MRI sequence could potentially replace the routine three sagittal sequence protocol for assessment of lumbar DDD, MEPC and HIZ resulting in ~60% time saving.

ADVANCES IN KNOWLEDGE

Grading of lumbar DDD, presence of Modic changes and high intensity zones were compared on sagittal T₁W TSE, T₂W FSE and STIR sequences with a T₂W FSE Dixon sequence, with fair-to-good correlation suggesting that three conventional sequences could be replaced by a single Dixon sequence.

MRI During Spinal Loading Reveals Intervertebral Disc Behavior Corresponding to Discogram Findings of Annular Fissures and Pain Provocation

STUDY DESIGN

Retrospective analysis of prospectively collected data.

OBJECTIVE

The aim of this study was to investigate whether spinal loading, depicted with magnetic resonance imaging (MRI), induces regional intervertebral disc (IVD) differences associated with presence and width of annular fissure and induced pain at discography.

SUMMARY OF BACKGROUND DATA

Annular fissures play a role in low back pain (LBP) but cannot be accurately characterized with conventional MRI. Recently, annular fissures were suggested to influence different load-induced IVD behavior during MRI when comparing LBP-patients and controls. Thus, the loading effect could characterize behavior related to annular fissures noninvasively with MRI.

METHODS

Lumbar spines of 30 LBP-patients were investigated with MRI with and without loading, discography and CT. Five IVD regions were outlined on sagittal MRI images. Difference in normalized signal intensity (SI) with and without loading was calculated for each region. Eighty-three CT-discograms were graded regarding presence and width of fissures. Discograms were classified as pain-positive if a concordant pain response was obtained at a pressure <50 psi.

RESULTS

Comparing IVDs with outer fissures with IVDs without fissures, loading induced different behavior in the two ventral regions and in the posterior region. Higher SI increase in the central region was induced in IVDs with narrower fissures compared to IVDs with wider fissures. In the group of pain-negative discograms, a SI decrease was induced in the dorsal region whereas lack of such in the pain-positive group.

CONCLUSION

The spinal loading-effect, depicted with MRI, reveals different regional behaviors between IVDs with outer fissures compared to those without, and between IVDs with narrow and broad fissures, as well as within posterior annulus between pain-positive and pain-negative discograms. Findings are of importance for future attempts to uncover phenotypes of painful IVDs.

LEVEL OF EVIDENCE

2.

Abnormal Conditions of the Diskovertebral Segment: MRI With Anatomic-Pathologic Correlation

OBJECTIVE. The purpose of this article is to review the appearance of various abnormalities that affect the lumbar intervertebral disk and diskovertebral segment through anatomic-pathologic correlation in cadavers. CONCLUSION. Familiarity with the pathologic conditions in and around the intervertebral disk is important in recognizing such conditions as a potential source of symptoms. We revisit the principal role of MRI in evaluating these abnormalities and excluding other sources of significant clinical manifestations.

Does the performance of five back-associated exercises relate to the presence of low back pain? A cross-sectional observational investigation in regional Australian council workers

OBJECTIVES

Investigate the relationships between the ability/inability to perform five physical test exercises and the presence or absence of low back pain (LBP).

SETTING

Regional Australian council training facility.

PARTICIPANTS

Consecutive participants recruited during 39 back education classes (8-26 participants per class) for workers in general office/administration, parks/gardens maintenance, roads maintenance, library, child care and management. Total sample (n=539) was reduced through non-consent and insufficient demographic data to n=422. Age 38.6±15.3 years, range 18-64 years, 67.1% male.

METHODS

Cross-sectional, exploratory, observational investigation. LBP presence was ascertained from a three-response option questionnaire: 0=none/rarely (no) 1=sometimes (some), 2=mostly/always (most). Statistical correlation was performed with the number of the five test exercises the individual successfully performed: (1) extension in lying: 3 s; (2) 'toilet squat'; feet flat, feet touched: 3 s; (3) full squat then stand up: 5 times; (4) supine sit-up, knees flexed: 10 times; and (5) leg extension, supine bilateral: 10 times.

INTERVENTIONS

Nil.

RESULTS

For the group 'no-some', 94.3% completed 4-5 test exercises, while for group 'With', 95.7% completed 0-1 test exercises. The relationship between LBP presence and number of exercises performed was highly significant (χ²₍₁₀₎=300.61, p<0.001). Furthermore, multinomial logistic regression predicting LBP (0=no, 1=some, 2=most) from the number of exercises completed, substantially improved the model fit (initial-2LL=348.246, final-2LL=73.620, χ²₍₂₎=274.626, p<0.001). As the number of exercises performed increased, the odds of reporting 'some LBP' or 'most LBP' dropped substantially (ORs of 0.34 and 0.17, respectively).

CONCLUSION

The ability to complete/not complete five test exercises correlated statistically and significantly with a higher LBP absence/presence in a general working population. Training individuals to complete such exercises could facilitate reductions in LBP incidence; however, causality cannot be inferred. Randomised trials are recommended to establish the potential efficacy of exercise-based approaches, considering these five selected exercises, for predicting and managing LBP.

Correlation between high-intensity zone on MRI and discography in patients with low back pain

The aim of this study was to analyze the correlation between high-intensity zone (HIZ) on magnetic resonance imaging (MRI) of a lumbar disc and positive pain response assessed by discography for the diagnosis and treatment of discogenic low back pain (LBP). Thirty-seven patients aged 21 to 59 years with chronic LBP but without any neurological symptoms or lumbar disc herniation who underwent MRI and subsequent discography were included in this study. During discography, concordant pain was regarded as positive, whereas discordant pain and no pain were regarded as negative. X-ray and computed tomography (CT) after discography with positive pain response were analyzed to correlate with HIZ on MRI. A total of 98 discs underwent discography in 37 patients; 21 discs presented positive pain response, including 10 with HIZ (47.6%). Seventy-seven discs presented negative pain response, including 29 with HIZ (37.6%). The high grade of annular disruption group shows a high proportion of HIZ on MRI. A positive correlation between HIZ and degree of annular disruption was observed. However, no correlation between HIZ and positive pain response was established on discography. The findings confirm that the presence of HIZ on MRI is only a suggestive and screening iconography indication for the diagnosis of discogenic LBP and cannot replace the gold standard of the discography. MRI should be closely integrated with those of discography, and thus, they play a crucial role in selecting operative segments of multilevel lumbar degenerative disk disease.

The value of radiographic indexes in the diagnosis of discogenic low back pain: a retrospective analysis of imaging results

To explore value of different radiographic indexes in the diagnosis of discogenic low back pain (LBP). A total number of 120 cases (60 patients diagnosed with discogenic LBP and 60 healthy people) were retrospectively analysed to identify factors in the diagnosis of discogenic LBP by using univariate and multivariate analyses. A receiver operating characteristic (ROC) curve was drew to show the predictive accuracy of the finally enrolled factors. Among all the included patients, 60 were strictly admitted in the discogenic LBP group while the other 60 were enrolled in the control group. Five results shows significant differences between discogenic LBP and control groups, including Cobb angle, lumbar stability, height of the disc, Modic change and High intense zone (HIZ) based on the results of univariate analysis; lumbar stability, Modic change and HIZ show high value in the diagnosis of lumbar discogenic pain based on the multivariate logistic analysis. The ROC curve shows that good diagnostic accuracy was obtained from the enrolled diagnostic factors including lumbar stability (Angular motion, more than 14.35°), Modic change and HIZ.

Factors for Predicting Favorable Outcome of Percutaneous Epidural Adhesiolysis for Lumbar Disc Herniation

Background. Lower back pain is a common reason for disability and the most common cause is lumbar disc herniation. Percutaneous epidural adhesiolysis has been applied to relieve pain and increase the functional capacity of patients who present this condition. Objectives. In this study, we retrospectively evaluated the factors which predict the outcome of percutaneous epidural adhesiolysis in patients who were diagnosed with lumbar disc herniation. Methods. Electronic medical records of patients diagnosed with lumbar disc herniation who have received percutaneous epidural adhesiolysis treatment were reviewed. The primary outcome was the factors that were associated with substantial response of ≥4 points or ≥50% of pain relief in the numerical rating scale pain score 12 months after the treatment. Results. Multivariate logistic regression analysis demonstrated that the presence of high-intensity zone (HIZ) at magnetic resonance imaging was a predictor of substantial response to percutaneous epidural adhesiolysis for 12 months (P = 0.007). The presence of a condition involving the vertebral foramen was a predictor for unsuccessful response after 12 months (P = 0.02). Discussion and Conclusion. The presence of HIZ was a predictor of favorable long-term outcome after percutaneous epidural adhesiolysis for the treatment of lower back pain with radicular pain caused by lumbar disc herniation.

An update on the management of chronic lumbar discogenic pain

Lumbar degenerative disc disease without disc herniation, also known as discogenic pain, is an elusive diagnosis of chronic low back pain. Lumbar provocation discography and fusion surgery have been frequently utilized for several decades as the gold standards for the diagnosis and treatment of symptomatic lumbar discogenic pain, though controversial, based on conjecture, rather than evidence. In addition to lumbar fusion, various other operative and nonoperative modalities of treatments are available in managing chronic lumbar discogenic pain. This review provides an updated assessment of the management of chronic lumbar discogenic pain with a critical look at the many modalities of treatments that are currently available.