Correlation between diffusion in lumbar intervertebral disks and lumbar artery status: evaluation with fresh blood imaging technique

Diffusion properties of asymptomatic lumbar intervertebral discs in a pediatric cohort: a preliminary study of apparent diffusion coefficient

PURPOSE

To explore the apparent diffusion coefficients of intervertebral discs in an asymptomatic pediatric cohort.

METHODS

We conducted a prospective MRI study of the lumbar spine from below the thoracolumbar junction to the lumbosacral junction on 12 subjects (mean age 13 y.o.) with no spinal pathology or spinal posture disorder. MRI was carried out using a 1.5 T machine with acquisitions realized both in sagittal and coronal planes. First, disc hydration was determined, and then, diffusion-weighted images were obtained using an SE single-shot echo-planar sequence. Apparent diffusion coefficients (ADC) of anterior annulus fibrosus (AAF), nucleus pulposus (NP) and posterior annulus fibrosus (PAF) were measured in the sagittal plane.

RESULTS

Averaged hydration of 0.27 SD 0.03 confirmed the asymptomatic nature of discs. Average scaled values of ADC were 0.46 SD 0.01, 0.22 SD 0.09 and 0.18 SD 0.03 for NP, AAF and PAF, respectively. ADC of NP were almost constant along the spine; PAF values show a slight increase in the thorax-sacrum direction, while AAF values showed a pronounced decrease. Locally, ADC of AAF was higher compared to ADC PAF values below the thoracolumbar junction and it reversed for subjacent discs.

CONCLUSIONS

In our knowledge, our study provided the first diffusive properties of asymptomatic intervertebral discs in an adolescent cohort. ADC of NP was slightly higher than adults'. ADC evolutions of AAF were correlated with lordosis concavity which pointed out the role of compressive strain on fluid transport properties. This study could furnish information about segment homeostasis for exploration of pediatric spinal pathologies.

A Simple Scale for Screening Lower-Extremity Arterial Disease as a Possible Cause of Low Back Pain: a Cross-sectional Study Among 542 Subjects

BACKGROUND

Epidemiological, imaging, and anatomical studies suggest an association between proximal arterial atherosclerosis and development of low back pain (LBP).

OBJECTIVES

We aimed to define (1) the frequency and (2) factors associated with exercise-induced proximal ischemia (EIPI) in individuals with LBP and (3) develop a clinical screening scale.

DESIGN

Monocentric cross-sectional study.

PARTICIPANTS

All patients with history of ongoing LBP referred to our exercise investigation laboratory for exercise transcutaneous oximetry (ex-tcPO₂) between January 2011 and December 2017 (n = 542; mean age, 65.4 ± 10.9; 83.9% men).

MAIN MEASURES

EIPI was defined as a decrease from rest of oxygen pressure (DROP) below - 15 mmHg on the lumbar and/or buttock probes. Ex-tcPO₂ is a reliable validated tool for diagnosing EIPI in comparison with arteriography and computed tomography angiography. Ex-tcPO₂ was performed on a treadmill until symptom manifestation or exhaustion. Clinical data were collected using interview questionnaires, medical file review, and clinical examination.

KEY RESULTS

EIPI was diagnosed in 282 patients (52%). Age ≤ 70 years (OR, 2.22; 95% CI, 1.35-3.57; p = 0.002), a history of proximal revascularization (OR, 2.64; 95% CI, 1.50-4.65; p = 0.001), use of antiplatelet medication (OR, 1.71; 95% CI, 0.96-3.06; p = 0.069), a relationship between exercise and LBP (OR, 2.61; 95% CI, 1.49-4.57; p = 0.001), and an abnormal ankle to brachial index (OR, 2.87; 95% CI, 1.77-4.66; p < 0.0001) were identified as EIPI predictors. Using these items, we developed a screening scale that showed an area under the receiver operating characteristics curve of .756. At a score of ≥ 3, the sensitivity, specificity, and accuracy for EIPI were 84%, 55%, and 71%, respectively.

CONCLUSIONS

EIPI was common among our patients with LBP undergoing ex-TcPO₂. Our screening scale could help better select the patients who require angiography.

Contribution of the endplates to disc degeneration

Purpose of review

The endplates form the interface between the rigid vertebral bodies and compliant intervertebral discs. Proper endplate function involves a balance between conflicting biomechanical and nutritional demands. This review summarizes recent data that highlight the importance of proper endplate function and the relationships between endplate dysfunction, adjacent disc degeneration, and axial low back pain.

Recent findings

Changes to endplate morphology and composition that impair its permeability associate with disc degeneration. Endplate damage also associates with disc degeneration, and the progression of degeneration may be accelerated and the chronicity of symptoms heightened when damage coincides with evidence of adjacent bone marrow lesions.

Summary

The endplate plays a key role in the development of disc degeneration and low back pain. Clarification of the mechanisms governing endplate degeneration and developments in clinical imaging that enable precise evaluation of endplate function and dysfunction will distinguish the correlative vs. causative nature of endplate damage and motivate new treatments that target pathologic endplate function.

Short-term increase in discs' apparent diffusion is associated with pain and mobility improvements after spinal mobilization for low back pain

Pain perception, trunk mobility and apparent diffusion coefficient (ADC) within all lumbar intervertebral discs (IVDs) were collected before and shortly after posterior-to-anterior (PA) mobilizations in 16 adults with acute low back pain. Using a pragmatic approach, a trained orthopaedic manual physical therapist applied PA mobilizations to the participants' spine, in accordance with his examination findings. ADC _all was computed from diffusion maps as the mean of anterior (ADC _ant ), middle (ADC _mid ), and posterior (ADC _post ) portions of the IVD. After mobilization, pain ratings and trunk mobility were significantly improved and a significant increase in ADC _all values was observed. The greatest ADC _all changes were observed at the L₃-L₄ and L₄-L₅ levels and were mainly explained by changes in ADC _ant and ADC _post , respectively. No significant changes in ADC were observed at L₅-S₁ level. The reduction in pain and largest changes in ADC observed at the periphery of the hyperintense IVD region suggest that increased peripheral random motion of water molecules is implicated in the IVD nociceptive response modulation. Additionally, ADC changes were observed at remote IVD anatomical levels that did not coincide with the PA spinal mobilization application level.

Infrarenal aortic diameter, aortoiliac bifurcation level and lumbar disc degenerative changes: a cross-sectional MR study

PURPOSE

To examine a possible correlation of infrarenal aortic diameter and aortoiliac bifurcation level with lumbar disc degenerative changes.

METHODS

This was a cross-sectional, single-center retrospective study on lumbar magnetic resonance images of patients with low back pain (n = 496). Lumbar disc degenerative changes were reported on the basis of the Pfirrmann grading system and accordingly, patients were grouped as with grade I-II findings (n = 192), with grade III findings (n = 64) and with grade IV-V findings (n = 240). The groups were matched for sex, body mass index and the history of diabetes mellitus, hypertension, hyperlipidemia and smoking. Infrarenal aortic diameter and aortoiliac bifurcation level were compared between the three groups.

RESULTS

Pairwise comparisons between the three groups of patients with Pfirrmann grades of I-II, III and IV-V revealed significant differences (p < 0.05) in terms of the median infrarenal aortic diameter (17 mm [interquartile range 4], 18 mm [4] and 19 mm [4], respectively) and the median aortoiliac bifurcation level (3 [2], 4 [2] and 5 [3], respectively; the higher the value, the more the caudal displacement). These associations were independent of conventional risk factors of atherosclerosis (including age) and from each other.

CONCLUSIONS

This study showed a significant, direct correlation of the infrarenal aortic diameter and the level of aortoiliac bifurcation with lumbar intervertebral degenerative changes according to the Pfirrmann grading system. The associations were independent of well-known risk factors of atherosclerosis and from each other.

Atherosclerotic Disease and its Relationship to Lumbar Degenerative Disk Disease, Facet Arthritis, and Stenosis With Computed Tomography Angiography

BACKGROUND

The intervertebral disk is the largest avascular structure in the body. It relies on passive diffusion from arteries at the periphery of the disk for nutrition. Previous studies have suggested a correlation between vascular disease and lumbar degenerative disk disease (DDD), but the association with facet arthritis and stenosis has not been evaluated.

OBJECTIVE

To evaluate the degree of lumbar artery stenosis, aortic atherosclerosis on computed tomography angiography, and its relationship to lumbar DDD, facet arthritis, and spinal canal stenosis.

DESIGN

Retrospective case review.

SETTING

Academic tertiary care hospital.

PARTICIPANTS

Not applicable.

METHODS

A total of 300 lumbar arteries (150 lumbar artery pairs of the first to fifth lumbar arteries) were evaluated on consecutive computed tomography angiography scans. Severity of vascular disease of lumbar arteries was documented as normal, mild, moderate, severe, or occluded. Aortic vascular disease was documented along the posterior wall where the lumbar arteries originate.

MAIN OUTCOME MEASUREMENTS

The relationship between vascular disease with DDD, facet arthritis, and spinal canal stenosis was examined and further evaluated controlling for age.

RESULTS

Lumbar artery and aortic atherosclerosis had a positive relationship with DDD, facet arthritis, and spinal stenosis that was statistically significant (P < .05) even after controlling for age. The correlation coefficient was greatest in the younger age group when looking at lumbar artery vascular disease with DDD (0.73, confidence interval 0.50-0.96, P < .0001) and aortic vascular disease with DDD (0.72, confidence interval 0.49-0.94, P < .0001). The correlation of vascular disease with facet arthritis and stenosis was not strong in the older age group.

CONCLUSION

Atherosclerotic disease of the lumbar arteries and aorta correlated with lumbar DDD, facet arthritis, and spinal canal stenosis after we adjusted for age, although the correlation with facet arthritis and spinal canal stenosis was not as strong in the older age group.

LEVEL OF EVIDENCE

IV.

Is there a relationship between blood lipids and lumbar disc herniation in young Turkish adults?

INTRODUCTION

Atherosclerosis might diminish the nutrient supply to intervertebral discs (IVD), leading to disc herniation. Therefore, there is interest in determining the possible association between the blood lipid profile and lumbar disc herniation (LDH). We aimed to evaluate the association between blood lipids and LDH in a homogeneous group of patients, controlling for age- and sex-specific effects.

MATERIAL AND METHODS

This is a case-control study which consisted of 100 individuals (mean age: 41.25 ±9.09; 50 men and 50 women), classified into two groups, as follows. Group I (G-I) consisted of 50 patients who underwent surgery for symptomatic LDH, while group II (G-II) consisted of 50 patients with nonspecific complaints of a headache, but with no previous history of back and/or leg pain, recruited among patients admitted to the outpatient clinic at the time of the study, and whose age and sex were matched to the study group. Total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), fasting blood glucose, and hemoglobin A_1c levels were measured. The TC/HDL-C ratio was calculated. Blood pressure, waist circumference, body mass index, and the history of smoking were included in the analysis.

RESULTS

The mean values of the TC, TG, LDL-C, HDL-C levels and TC/HDL-C ratio were 198.38, 132.76, 131.9, 40.38 mg/dl and 5.09, respectively. No statistically significant relationship between the blood lipid profile and LDH was identified in this population.

CONCLUSIONS

Blood lipid levels in this young adult Turkish population did not predict LDH, and may not be a leading cause of IVD ischemia and IVD degeneration.

Do abnormal serum lipid levels increase the risk of chronic low back pain? The Nord-Trøndelag Health Study

Background

Cross-sectional studies suggest associations between abnormal lipid levels and prevalence of low back pain (LBP), but it is not known if there is any causal relationship.

Objective

The objective was to determine, in a population-based prospective cohort study, whether there is any relation between levels of total cholesterol, high density lipoprotein (HDL) cholesterol and triglycerides and the probability of experiencing subsequent chronic (LBP), both among individuals with and without LBP at baseline.

Methods

Information was collected in the community-based HUNT 2 (1995–1997) and HUNT 3 (2006–2008) surveys of an entire Norwegian county. Participants were 10,151 women and 8731 men aged 30–69 years, not affected by chronic LBP at baseline, and 3902 women and 2666 men with LBP at baseline. Eleven years later the participants indicated whether they currently suffered from chronic LBP.

Results

Among women without LBP at baseline, HDL cholesterol levels were inversely associated and triglyceride levels positively associated with the risk of chronic LBP at end of follow-up in analyses adjusted for age only. Adjustment for the baseline factors education, work status, physical activity, smoking, blood pressure and in particular BMI largely removed these associations (RR: 0.96, 95% CI: 0.85–1.07 per mmol/l of HDL cholesterol; RR: 1.16, 95% CI: 0.94–1.42 per unit of lg(triglycerides)). Total cholesterol levels showed no associations. In women with LBP at baseline and men without LBP at baseline weaker relationships were observed. In men with LBP at baseline, an inverse association with HDL cholesterol remained after complete adjustment (RR: 0.83, 95% CI: 0.72–0.95 per mmol/l).

Conclusion

Crude associations between lipid levels and risk of subsequent LBP in individuals without current LBP are mainly caused by confounding with body mass. However, an association with low HDL levels may still remain in men who are already affected and possibly experience a higher pain intensity.

Intervertebral disc regeneration: do nutrients lead the way?

Strategies for the biological repair of intervertebral discs derive from the premise that disc degeneration results from impaired cellular activity and, therefore, that these structures can be induced to regenerate by implanting active cells or providing factors that restore normal cellular activity. In vitro and animal studies using this approach have had some success, but whether this success can be reproduced in degenerate human lumbar discs is unknown. Successful repair requires that the disc cells remain viable and active; they therefore need an adequate supply of nutrients. However, as the disc degenerates, the nutrient supply decreases, thereby limiting cell activity and viability. Current biologic approaches might place additional demands on an already precarious nutrient supply. Here, we discuss whether the loss of nutrients associated with disc degeneration limits the effectiveness of biologic approaches, and indicate that this neglected problem requires investigation if clinical application of such therapies is to succeed.

The association between the history of cardiovascular diseases and chronic low back pain in South Koreans: a cross-sectional study

Background

Cardiovascular disease and related risk factors have been suggested as a mechanism leading to atherosclerosis of the lumbar vessels and consequent lumbar pain or sciatica. But there is continued controversy concerning its generalization. This study examined whether cardiovascular disease or its risk factors were associated with chronic low back pain (cLBP) in Koreans.

Methods

Health surveys and examinations were conducted on a nationally representative sample (n = 23,632) of Koreans. A total of 13,841 eligible participants (aged 20 to 89 years) were examined to determine the association between cardiovascular disease, the Framingham risk score, major cardiovascular risk factors (blood pressure, diabetes, cholesterol, and smoking habits) and chronic LBP.

Results

The total prevalence of cLBP was 16.6% (men: 10.8%, women: 21.1%) and that in patients with a history of cardiovascular diseases was 36.6% (men: 26.5%, women: 47.1%). The results showed that patients’ medical history of cardiovascular disease was significantly associated with cLBP in both men and women when adjusted for covariates (men: OR 2.16; 95%CI 1.34∼3.49; women: OR 2.26; 95%CI 1.51∼3.38). No association was observed between cLBP and the Framingham risk score, medication for hyperlipemia, hypertension, diabetes, and major cardiovascular risk factors (systolic blood pressure, total cholesterol, high density lipoprotein cholesterol, triglycerides, glucose and smoking habits) in either men or women.

Conclusions

The prevalence of cLBP is correlated to a history of cardiovascular disease, but not to the major cardiovascular risk factors from the Framingham study. Further studies on whether these results were affected by psychological factors in patients with a history of cardiovascular diseases or whether new potential risk factors from the artery atherosclerosis hypothesis applying to Koreans exist are needed.

Quantitative assessment of abdominal aortic calcification and associations with lumbar intervertebral disc height loss: the Framingham Study

BACKGROUND CONTEXT

Vascular disease has been proposed as a risk factor for disc height loss (DHL).

PURPOSE

To examine the relationship between quantitative measures of abdominal aortic calcifications (AACs) as a marker of vascular disease, and DHL, on computed tomography (CT).

STUDY DESIGN

Cross-sectional study in a community-based population.

PATIENT SAMPLE

Four hundred thirty-five participants from the Framingham Heart Study.

OUTCOME MEASURES

Quantitative AAC scores assessed by CT were grouped as tertiles of "no" (reference), "low," and "high" calcification. Disc height loss was evaluated on CT reformations using a four-grade scale. For analytic purposes, DHL was dichotomized as moderate DHL of at least one level at L2-S1 versus less than moderate or no DHL.

METHODS

We examined the association of AAC and DHL using logistic regression before and after adjusting for cardiovascular risk factors and before and after adjusting for age, sex, and body mass index (BMI).

RESULTS

In crude analyses, low AAC (odds ratio [OR], 2.05 [1.27-3.30]; p=.003) and high AAC (OR, 2.24 [1.38-3.62]; p=.001) were strongly associated with DHL, when compared with the reference group of no AAC. Diabetes, hypercholesterolemia, hypertension, and smoking were not associated with DHL and did not attenuate the observed relationship between AAC and DHL. Adjustment for age, sex, and BMI markedly attenuated the associations between DHL and low AAC (OR, 1.20 [0.69-2.09]; p=.51) and high AAC (OR, 0.74 [0.36-1.53]; p=.42).

CONCLUSIONS

Abdominal aortic calcification was associated with DHL in this community-based population. This relationship was independent of cardiovascular risk factors. However, the association of AAC with DHL was explained by the effects of age, sex, and BMI.

Diffusion-weighted magnetic resonance imaging of the musculoskeletal system: an emerging technology with potential to impact clinical decision making

Diffusion-weighted imaging (DWI) is an application of magnetic resonance imaging that allows the measurement of water movement within and between tissues. Originally developed as a way of detecting early signs of stroke or brain disease, DWI is now being used to study physiologic events within the musculoskeletal system. The accurate measurement of water diffusion can provide important information regarding tissue responses associated with trauma and disease, as well as offer insight toward the mechanism by which physical therapy interventions affect tissues. The purpose of this paper is to discuss the rationale for DWI and its potential clinical and research applications for patients with musculoskeletal disorders. Specific examples of the use of DWI for patients with painful spinal disorders are used as illustrations.

Assessment of the Correlation between Apparent Diffusion Coefficient and Intervertebral Disk Degeneration Using 3 Tesla MRI

The objective is to use DW-MR imaging using 3 Tesla MRI to assess the correlation between the mean ADC with degenerative disk disease (DDD). We recruited 34 subjects and used DWI-MR to image lumbar intervertebral disks. We acquired a T2W scan and DWIs. The disks were graded for DDD. Assessment of correlation between mean ADC was made. 170 disks were evaluated. The observed sample correlation between mean ADC and disk degeneration was r = 0.65 [0.55-0.73]. The observed sample correlation between mid-sagittal ADC and disk degeneration was r = 0.61 [0.51-0.70]. The differences between mean ADC of each grade were significant, except between grades 4 and 5. There is a correlation of 0.65 between the mean ADC and disk degeneration. This correlation is not strong enough to use the ADC to determine DDD in clinical settings. There was no evident difference in ADC between the studied anatomic lumbar levels.

Triggered non-contrast enhanced MR angiography of peripheral arteries: optimization of systolic and diastolic time delays for electrocardiographic triggering

The purpose of this study was to determine the optimal systolic and diastolic time delays for electrocardiographic triggering of a non-contrast media enhanced MR angiography using a 3-dimensional fast spin echo sequence in patients suffering from peripheral arterial disease. 12 patients with suspected peripheral arterial disease were examined on a 1.5 T Philips Achieva MR scanner. A cardiac-triggered Volumetric Isotropic T2-weighted fast spin echo sequence was performed using variable trigger delays for systolic and diastolic phase. The signal in the popliteal arteries and anterior tibial arteries of the systolic and diastolic images was measured and optimal delay times for systolic and diastolic phase were determined. Minimum signal to noise ratio (SNR) appears at the time difference ΔT=-21 ms on systolic images of the popliteal arteries. In the anterior tibial arteries the minimum SNR is significantly higher and appears at the time difference ΔT=-14 ms. Diastolic delay times must be chosen as long or as short as possible depending on heart rate. In peripheral vessels triggered non-contrast MR angiography can yield results which are comparable with contrast enhanced MRA techniques. It is crucial to optimize timing parameters.

Diffusion-weighted MR imaging in musculoskeletal radiology: applications in trauma, tumors, and inflammation

Diffusion-weighted imaging is a noninvasive magnetic resonance technique that is capable of measuring icroscopic movement of water molecules (ie, random or Brownian motion) within biologic tissues. Diffusion weighting is achieved with a pulsed-field gradient that leaves "static" spins unaffected but causes dephasing of spin ensembles that experience different motion histories according to their diffusion paths, with respect to the direction of the gradient. This article focuses on the interesting opportunities of the use of diffusion weighted imaging in the diagnosis of musculoskeletal diseases, including trauma, tumor, and inflammation.

Association of lumbar artery narrowing, degenerative changes in disc and endplate and apparent diffusion in disc on postcontrast enhancement of lumbar intervertebral disc

OBJECTIVE

A decreased supply of nutrition to the intervertebral disc can lead to disc degeneration. Nutrient supply can be simulated in vivo by measuring gadolinium enhancement of the disc. We aimed to study the changes associated with disc degeneration that may have effect on the nutrition of the disc, i.e. lumbar artery narrowing, Modic changes, endplate defects, and apparent diffusion coefficient (ADC) in nucleus pulposus.

PATIENTS AND METHODS

Twenty male volunteers underwent a lumbar spine examination at 1.5 T for anatomical imaging, diffusion weighted imaging, magnetic resonance angiography, and for T1 relaxation time quantification of contrast enhancement of intervertebral disc.

RESULTS

Enhancement of the disc increased with degeneration. Disc space narrowing associated strongly with the enhancement (Pearson's correlation coefficient 0.46, P < 0.001). The enhancement rate in discs adjacent to Modic type 2 changes was 24%, adjacent to type 1/2 changes 58%, and 13% in the absence of Modic changes. Discs adjacent to endplate defects enhanced 32% compared to 10% of normal endplates. Lumbar artery narrowing or ADC in the disc were not associated with the enhancement.

CONCLUSION

Increased enhancement of a degenerated disc is associated mostly with disc space narrowing and with the presence of degenerative endplate changes and endplate defects.

Current understanding of lumbar intervertebral disc degeneration: a review with emphasis upon etiology, pathophysiology, and lumbar magnetic resonance imaging findings

Degeneration of the lumbar intervertebral discs (IVDs) is highly prevalent in adults and is nearly universal in the elderly population. Degenerative changes within, and adjacent to, the IVDs are likely to contribute to a variety of pain syndromes; however, the exact association between these findings and symptoms remains speculative. Recent research has provided new information regarding the etiology, pathophysiology, and clinical relevance of degeneration of the IVD. This information will assist clinicians and researchers in understanding the development and clinical course of lumbar disc degeneration, as well as its potential impact upon patients seeking physical therapy care for back pain. The purposes of this clinical commentary are to review the structure and metabolic capacity of the normal and degenerative lumbar IVD, and to discuss factors that influence the onset and progression of disc degeneration. Lumbar magnetic resonance images will be used to illustrate the common findings associated with this condition.