In vivo quantification of delayed gadolinium enhancement in the nucleus pulposus of human intervertebral disc.

PURPOSE: To quantify the delayed contrast agent enhancement in the nucleus pulposus of the intervertebral disc by means by T1 relaxation time measurements, and to correlate the enhancement with visual grading of disc degeneration. Diffusion of nutrients through the endplate is a key factor in tissue viability in the intervertebral disc. It can be simulated in vivo using magnetic resonance imaging (MRI) by measuring delayed gadolinium (Gd) enhancement of the disc. MATERIALS AND METHODS: Twenty male volunteers underwent a lumbar spine examination at 1.5T. T2-weighted sagittal images were used to score disc degeneration. T1 relaxation times were measured before and 90 minutes after intravenous administration of Gd-DTPA-BMA by applying a series of sagittal single-slice inversion-recovery fast spin-echo (IR-FSE) scans. RESULTS: A total of 93 discs were analyzed. A statistically significant decrease in the T1 relaxation time of the nucleus pulposus was observed as a result of contrast-agent intake. The percentage change in the T1 relaxation rate for individual discs was up to 126%. A positive trend was observed between the change in the T1 relaxation rate and the grading of disc degeneration. CONCLUSION: Quantification of delayed enhancement of the intervertebral disc may provide a new means of studying alterations in degenerative disc disease (DDD) that explain the variation in diffusion into the intervertebral disc.

A three-year follow-up of lumbar spine endplate (Modic) changes.

STUDY DESIGN: A longitudinal follow-up of Modic changes on magnetic resonance imaging (MRI). OBJECTIVES: To assess the prevalence and natural course Modic changes over a 3-year follow-up period. SUMMARY OF BACKGROUND DATA: Modic changes are bone marrow and endplate lesions visible on MRI. To the authors' knowledge, no follow-up studies on their natural course have been published. METHODS: The study population consisted of 60 unoperated sciatica patients 23 to 76 years of age. Baseline and 3-year lumbar MR images from L1-L2 through L5-S1 were analyzed independently by 2 radiologists and a consensus reading was performed. RESULTS: At baseline, the prevalence of Modic changes was 23%. Seven discs had mixed Type I/II, and 63 Type II change. Changes typically occurred at L4-L5 and L5-S1, and associated positively with age (P = 0.009). Ten of 70 discs (14%) with Modic changes at baseline displayed another type at 3 years. Furthermore, the nonconverted changes increased significantly in size. The incidence of new Modic changes during the follow-up was 6% (13 of 230). CONCLUSIONS: Modic changes are common MRI findings in patients with degenerative lumbar disc disease. We found evidence that Modic Type II changes may be less stable than previously assumed.

Determinants of spontaneous resorption of intervertebral disc herniations.

STUDY DESIGN: A follow-up of disc herniation (herniated nucleus pulposus [HNP]) resorption on magnetic resonance imaging (MRI). OBJECTIVE: To assess the determinants of resorption of HNP. SUMMARY OF BACKGROUND DATA: Neovascularization in the outermost areas of HNP, presenting as an enhancing rim in gadolinium diethylenetriamine pentaacetic acid MR images, is thought to be a major determinant of spontaneous resorption of HNP. METHODS: Patients with HNP-induced sciatica at baseline were rescanned at 2 months (N = 74) and after 12 months (N = 53). The volume of HNP (mm), thickness (mm) and extent (%) of enhancement, and the degree of HNP migration (Komori classification) were analyzed. Repeated measures analysis of covariance was used in statistical analysis. RESULTS: Significant resorption of HNP occurred from baseline to 2 months, although the resorption rate was more pronounced over the whole 1-year follow-up. Higher baseline scores of rim enhancement thickness, higher degree of HNP displacement in the Komori classification, and age category 41-50 years were associated with a higher resorption rate. Thickness of rim enhancement was a stronger determinant of spontaneous resorption than extent of rim enhancement. Clinical symptom alleviation occurs concordantly with a faster resorption rate. CONCLUSIONS: MRI is a useful prognostic tool for identifying patients with HNP-induced sciatica with a benign natural course.

Determinants of lumbar artery occlusion among patients with sciatica: a three-year follow-up with magnetic resonance angiography.

We showed previously that chronic Chlamydia pneumoniae infection increases the risk of lumbar artery occlusion. We did not evaluate, however, the effect of other risk factors for cardiovascular diseases in combination with this chronic infection. The purpose of this study was to investigate the combined effect of chronic C. pneumoniae infection and other known determinants of artery occlusion in a population of sciatica patients. Two-dimensional time-of-flight magnetic resonance angiography (MRA) was used to evaluate lumbar arteries at baseline and three years. The arteries on both sides (L1-L4) were evaluated visually and scored as normal, narrowed or occluded. Logistic regression analysis was performed separately for baseline total arterial stenosis and each L1-L4 segmental artery pair, and for incident new stenosis during the follow-up period. The determinants analyzed included age, body mass index (BMI, kg/m(2)), education, gender, and smoking, in addition to presence of chronic C. pneumoniae infection. MRA was obtained at baseline for 147 patients and at 3 years for 134 patients. Sixty-four (47.8%) of 134 patients had new arterial stenosis. Total incidence of new arterial stenosis was distributed quite evenly between the individual segmental levels, varying from 12.7 to 18.6%. BMI was the only predictor of new arterial stenosis (odds ratio (OR) 1.13). A reasonable logistic model could be established only for baseline L4 and total arterial scores. At L4, education was a protective factor (OR 0.07), whereas age (OR for the oldest age group 6.7) and BMI (OR 1.17) were associated with increased risk of occlusion. For total arterial score, chronic C. pneumoniae infection was an independent determinant of arterial occlusion, increasing the risk to almost eightfold. Additionally, BMI (OR 1.16), and age (for the oldest age group OR 11.4) were significant determinants for stenosis. Smoking was not statistically significant. As chronic C. pneumoniae infection was an independent determinant of lumbar artery occlusion, treatments of this chronic infection may have an impact on lumbar diseases. The importance of BMI for new arterial stenosis suggests that weight reduction may also have a beneficial effect in lumbar artery disease.

Three-year follow-up of lumbar artery occlusion with magnetic resonance angiography in patients with sciatica: associations between occlusion and patient-reported symptoms.

STUDY DESIGN: Comparison of occlusion of lumbar arteries in magnetic resonance angiography (MRA) with patient-reported sciatica symptoms during a 3-year follow-up. OBJECTIVES: To evaluate whether occlusion of lumbar arteries is associated with subjective pain symptoms and physical ability among sciatica patients. SUMMARY OF BACKGROUND DATA: Cadaveric studies indicate that atherosclerotic manifestations of the abdominal aorta are associated with low back pain (LBP). Impaired blood flow may disturb diffusion of nutrients into the disc, causing degeneration and possibly back pain. METHODS: Two-dimensional time-of-flight MRA was used to evaluate lumbar arteries at baseline and 3 years. The arteries on both sides (L1-L4) were evaluated visually and scored as normal, narrowed, or occluded. Incidence of new stenosis was estimated. The associations of stenosis with self-reported previous medical consultations, pain duration through the first year, and number of pain episodes through the last 2 years of follow-up were calculated. Additionally, leg and back pain (10-cm VAS), disability (Oswestry), and self-reported physical ability (self-efficacy) were inquired at 1, 2, and 3 years. In the statistical analysis, bivariate correlation, and the chi or Fisher's test were used. RESULTS: MRA was obtained at baseline for 147 patients and at 3 years for 134 patients. Baseline stenosis associated with intensity of back pain at 1 year, leg pain at 2 years, and self-efficacy at every follow-up assessment, but not with disability, previous LBP history, or future pain episodes. The associations of stenosis at 3 years were similar but weaker. Newly formed stenosis was associated with the preceding year's medical consultations due to LBP and prolonged LBP during the first follow-up year. CONCLUSIONS: Arterial stenosis is associated strongly and consistently with patient-estimated physical ability,but only slightly with subjective pain symptoms. Interestingly, new stenosis is preceded by pain symptoms. The evaluation of lumbar blood flow may thus be useful in clinical practice.

Effect of periradicular methylprednisolone on spontaneous resorption of intervertebral disc herniations.

STUDY DESIGN: Prospective comparison of periradicular infiltration with steroid versus saline on the spontaneous resorption of herniated nucleus pulposus in a randomized controlled trial. OBJECTIVES: To evaluate whether periradicular steroid retards the resorption of herniated nucleus pulposus. SUMMARY OF BACKGROUND DATA: Rim enhancement around herniated nucleus pulposus is associated with spontaneous resorption of disc herniations. As rim enhancement consists of a macrophage infiltrate, periradicular steroid could theoretically interfere with the resorption process. METHODS.: Patients with disc herniation-induced sciatica were randomized to receive either periradicular methylprednisolone (in combination with bupivacaine) or saline. Lumbar magnetic resonance imaging (MRI) was performed at baseline, at 2 months, and at 12 months. Disc herniation volume (mm3), coverage of rim enhancement (%), and rim enhancement thickness (mm) were evaluated by a radiologist blinded to the allocation. Operated patients were excluded from the 1-year imaging. Changes in the parameters from baseline to 2 months, and from 2 to 12 months, were evaluated with the Mann-Whitney U test. RESULTS: Change in herniation volume from baseline to 2 months was measurable in 34 patients of both groups, and from 2 to 12 months in 26 patients of the steroid group and 24 patients of the saline group. Significant spontaneous resorption of disc herniations occurred in both groups during the 1-year follow-up. In the subgroup analysis, there tended to be even faster resorption in the steroid group from baseline to 2 months for extrusions, and from 2 months to 12 months for contained herniations. No significant differences were observed in the enhancement parameters (coverage and thickness) between the two treatments. CONCLUSIONS: Periradicular corticosteroid does not have a negative effect on the spontaneous resorption of the herniated nucleus pulposus.

Chronic Chlamydia pneumoniae infection increases the risk of occlusion of lumbar segmental arteries of patients with sciatica: a 3-year follow-up study.

STUDY DESIGN: A magnetic resonance imaging follow-up study of lumbar arteries among patients with sciatica with chronic Chlamydia pneumoniae infection. OBJECTIVE: To determine whether chronic infection causes occlusion of lumbar arteries. SUMMARY OF BACKGROUND DATA: C. pneumoniae infection is associated with coronary heart disease, and the infectious pathogen has also been detected in abdominal aortic aneurysms and in atherosclerotic plaques. No studies are available on the effect of this infectious agent on lumbar arteries. METHODS: Chronic infection was defined as persistent high positive immunoglobulin G and/or immunoglobulin A antibodies and/or the presence of immune complexes. The lumbar arteries, evaluated with two-dimensional time-of-flight magnetic resonance angiography, were scored as normal, narrowed, or occluded. The differences in the segmental and whole lumbar spine (segments L1-L4) sum of arterial occlusion at baseline and at 3 years, and the incidence of new arterial stenosis were compared in patients with and without chronic infection using the Kolmogorov-Smirnov test. RESULTS: Patients with chronic infection were more likely to be persistent smokers (P = 0.006), male (P = 0.04), and more obese (P = 0.02) compared to patients with normal antibody levels. They had significantly higher degree of arterial stenosis at L4 segment at baseline and at 3 years (P = 0.001 and 0.002, respectively), in the whole lumbar spine at baseline and at 3 years (P < 0.001 for both), and at L1 and L3 segments at 3 years (P = 0.013 for both). The incidence of new arterial stenosis was similar in both patient groups. Patients with chronic infection also had significantly higher grade of endplate degeneration at L4-L5 (P = 0.008). CONCLUSIONS: The results of this study suggest that chronic C. pneumoniae infection may induce stenosis of lumbar arteries.

Radiologic phenotypes in lumbar MR imaging for a gene defect in the COL9A3 gene of type IX collagen.

PURPOSE: To evaluate whether the COL9A3 tryptophan allele (Trp3 allele) is associated with a specific radiologic phenotype among patients with sciatica. MATERIALS AND METHODS: One hundred fifty-three patients with sciatica were evaluated for the presence of Trp3 allele, Scheuermann disease, intervertebral disk degeneration, Schmorl nodules, dorsal anular tears, hyperintense lesions, and endplate degeneration on sagittal T2-weighted lumbar magnetic resonance images. The Trp3 genotype was determined by means of sequencing the COL9A3 gene. Radiologic phenotypes were evaluated while blinded to the genotype. Scheuermann disease was diagnosed if either endplate irregularities or Schmorl nodules and two of the other three criteria (disk space narrowing, disk dehydration, and wedging of anterior vertebral body margins) were present at three or more adjacent disk levels from T10-11 to L3-4. Disk degeneration was evaluated separately for each disk (T11-12 to L5-S1) and for all disks combined. Frequencies of radiologic phenotypes between individuals with or without Trp3 allele were compared. RESULTS: Thirty-four patients had at least one Trp3 allele. When compared with the matched control subjects, they had an increased likelihood of Scheuermann disease (P =.035) and an increased number of degenerated disks from T11 to S1 (P =.021). Comparisons at individual disks showed a statistically significant increase in disk degeneration at T11-12 (analysis of all grades of degeneration [graded], P =.018; analysis of any degeneration vs none [dichotomous], P =.039) and L4-5 (graded, P =.011; dichotomous, P =.016). Prevalences of anular tears, endplate degeneration, Schmorl nodules, and hyperintense lesions were comparable. CONCLUSION: The results of this study indicate that the presence of Trp3 allele is associated with Scheuermann disease and intervertebral disk degeneration. No associations were found for other radiologic phenotypes.

Endplate degeneration observed on magnetic resonance imaging of the lumbar spine: correlation with pain provocation and disc changes observed on computed tomography diskography.

STUDY DESIGN: One hundred and three lumbar intervertebral discs (L3/4-L5/S1) of 36 patients with low back pain were examined with computed tomography (CT) diskography and magnetic resonance imaging (MRI). OBJECTIVES: To determine whether lumbar endplate degeneration correlates with the degree of disc degeneration or disc rupture and to determine if there is an association between pain provocation during diskography and lumbar endplate degeneration. SUMMARY OF BACKGROUND DATA: There have been numerous attempts to explain the pathogenesis of pain provocation during diskography, but the possibility of endplate degeneration as a source of pain has not been widely assessed. METHODS: One hundred and three lumbar intervertebral discs (36 L3/4, 36 L4/5, and 31 L5/S1 intervertebral discs) of 36 patients were examined. On the basis of MRI, the intervertebral discs were divided into four categories based on the degree of endplate degeneration. Based on pain provocation on diskography, the intervertebral discs were divided into three categories: no pain, indifferent/untypical pain, and familiar/typical pain. Based on disc degeneration and disc rupture, the intervertebral discs were divided into four categories in accordance with the Dallas Discogram Description: Grades 0-3 of both degeneration and rupture. RESULTS: There was a positive correlation between endplate degeneration and disc degeneration and a positive correlation between disc rupture and pain provocation, but there was no association between endplate degeneration and disc rupture and no correlation between endplate degeneration and pain provocation on diskography. CONCLUSIONS: This study showed a stronger association between endplate degeneration and disc degeneration than between endplate degeneration and disc rupture. The results indicate that the contrast injection during diskography reflects mainly pain of discogenic origin, whereas the possible pain associated with endplate damage cannot be depicted by CT diskography.

Gadolinium diethylenetriaminepentaacetic acid enhancement in magnetic resonance imaging in relation to symptoms and signs among sciatic patients: a cross-sectional study.

STUDY DESIGN: A cross-sectional descriptive study. OBJECTIVES: Gadolinium enhancement in lumbar magnetic resonance imaging is not used routinely. The current study explored the possible intercorrelations of enhancement patterns with clinical symptoms and signs. SUMMARY OF BACKGROUND DATA: Rim enhancement has been reported to occur in the periphery of disc herniations, and it is thought to represent neovascularization. To the authors' knowledge, the significance of the enhancement in relation to clinical symptoms has not been studied. METHODS: Magnetic resonance imaging of the lumbar spine with intravenous gadolinium diethylenetriaminepentaacetic acid was performed in each patient. Various contrast enhancement parameters and volume of herniation were evaluated, and their correlations with clinical signs and symptoms (straight leg raising, motor defect, Achilles reflex, leg and back pain, disability) were analyzed. RESULTS: The extent of rim enhancement correlated highly significantly with the degree of disc displacement, being most pronounced in the case of sequesters. The duration of sciatic symptoms correlated negatively with enhancement. The clinical symptoms did not correlate significantly with the different enhancement parameters or disc herniation volume. Straight leg raising correlated only slightly with the extent of rim enhancement (P = 0.04) when bulges were excluded. Achilles reflex abnormality correlated significantly with all enhancement parameters for lesions at L5-S1. In the final stepwise logistic regression model, contrast enhancement extent correlated most significantly with abnormal Achilles reflex (P = 0.0002). CONCLUSIONS: Although rim enhancement of disc herniation is thought to represent a beneficial phagocytotic phenomenon, it may also have a harmful effect on the adjacent nerve root.

Magnetic resonance imaging findings in relation to the COL9A2 tryptophan allele among patients with sciatica.

STUDY DESIGN: The phenotype of patients with sciatica who have the Trp2 allele is characterized cross-sectionally. OBJECTIVE: To determine whether it is possible to differentiate patients with the Trp2 allele clinically or by magnetic resonance imaging. SUMMARY OF BACKGROUND DATA: Several studies have indicated a positive family history for intervertebral disc disease. Previously, a dominantly inherited defect was identified in the COL9A2 gene that changed a codon for glutamine to that for tryptophan in the alpha2 chain of collagen IX (Trp2 allele). This change may render intervertebral discs more fragile. METHODS: Clinical findings, clinical symptoms, and magnetic resonance imaging (1.5-T) findings from 159 patients with sciatica were evaluated according to the presence of the Trp2 allele. Additionally, the magnetic resonance imaging scans of 22 family members from three families were evaluated. These scans were analyzed intervertebral disc and endplate degeneration, Schmorl's nodes, transverse tears (hyperintensity in the region of Sharpey's fibers), high-intensity zone lesions (bright spots in the dorsal anulus), and radial tears (hyperintense linear area from the nucleus to the outer part of the anulus on T2 sequences). RESULTS: Six patients with sciatica and 11 family members had the Trp2 allele. No homozygotes were found. Clinical symptoms of patients with and those without the Trp2 allele were similar. Patients with sciatica who had the Trp2 allele were significantly more flexible (P < 0.05), according to the modified Schober measure. The disc and endplate degeneration in 6 patients with the Trp2 allele and their 18 controls (matched for age, occupation, gender) without the allele did not differ significantly, whereas family members with the Trp2 allele had a greater degree of disc and endplate degeneration at L5-S1. The overall prevalence of endplate degeneration was high in this study. The prevalences of dorsal transverse tears, high-intensity zone lesions, and Schmorl's nodes did not differ among patients with sciatica or family members according to the presence of the Trp2 allele. There was, however, a trend for increased prevalence of radial tears in nonherniated discs among the Trp2 allele-positive subjects (3 of 6 patients with sciatica and 3 of 11 family members), as compared with the Trp2-negatives subjects (none of 18 "matched" patients or 11 family members). CONCLUSION: The patients with the Trp2 allele were more flexible, and more often tended to have a radial tear in a nonherniated disc than their control counterparts.