Apparent diffusion coefficients and T2 relaxation time measurements to evaluate disc degeneration: A quantitative MR study of young patients with previous vertebral fracture

Purpose: To assess the suitability of apparent diffusion coefficient (ADC) measurements to evaluate degeneration processes of the vertebral disc and to compare the results with T2 relaxation time measurements in both degenerated and normal intervertebral discs.

Material and Methods: Fourteen young patients (8.8-20.8 years old) who had had a vertebral compression fracture at least 1 year earlier, underwent MR studies with diffusion imaging in three orthogonal directions and T2 relaxation time measurements. ADC values and T2 relaxation times of both degenerated and normal intervertebral discs were compared to the values of 20 healthy young asymptomatic control subjects.

Results: In the degenerated discs of patients, the ADCx and ADCy values were decreased compared to earlier determined values of healthy controls. ADC values in the z-direction in degenerated discs did not differ significantly from the values of controls. T2 relaxation times were shorter in the degenerated discs of patients compared to the values of controls. The greatest changes in both these values were observed in degenerated discs followed by discs with normal signal intensity adjacent to primary trauma area and secondary trauma area.

Conclusion: We suggest that decreased ADC values reflect the lost integrity of the intervertebral disc. ADC measurements at MR may prove sensitive depicting of early degenerative changes in vertebral discs.

MR imaging of pituitary adenomas treated with the prolactin inhibitor quinagolide

Purpose: To evaluate the volume of micro- and macroadenomas in quinagolide-treated patients with resistance to or intolerance of bromocriptine.

Material and Methods: The effect of the prolactin inhibitor quinagolide on the volume of pituitary adenoma was evaluated retrospectively in 11 female patients. Prolactin levels before and after the treatment were also recorded. The indications for quinagolide therapy were side-effects of bromocriptine in 5 cases, a poor response to bromocriptine in 5 cases and both in 1 case. MR imaging with a 1.0-T magnet was performed to determine the volume reduction of the adenomas.

Results: The average volume reduction of macroadenomas was 324 mm3 (46%) and that of microadenomas 73 mm3 (57%). The level of prolactin secreted by macroadenomas was reduced by an average of 163 μg/l (65%) and that by microadenomas of 113 μg (73%). In 2 microadenomas and in 1 macroadenoma, signal intensity changed during the treatment in T1-weighted images. In follow-up no changes in signal intensity were seen in 8 adenomas in non-contrast T1-weighted images. A haemorrhagic lesion was seen in 1 macroadenoma before treatment, but it disappeared during treatment.

Conclusion: Quinagolide was found to be an effective alternative to bromocriptine in cases with drug intolerance or resistance, and MR imaging a suitable method for the follow-up of macro- and microadenomas.

MRI FINDINGS AFTER AN EXPERIMENTAL DISC LESION

Purpose: A minipig model was used to demonstrate MRI findings in the first three months after an annular disruption. Methods: An incision was made into one of the lumbar discs in each of eight minipigs in the outer and middle parts of the annulus. The remaining intact discs in the lumbar and thoracolumbar regions were used as controls. MR imaging was performed one month and three months after trauma using both a 1.0 T and a 1.5 T MR unit. The histologic analysis was also carried out to demonstrate morphological changes in disc. Results: Eighty-eight percent of the injured discs had a diminished area of bright signal in the nucleus pulposus, also in cases where no signs of trauma in the annulus could be detected in MRI. The degeneration process of the nucleus pulposus was shown to progress during follow-up. High intensity zones were detected in 50% of the injured discs and they tended to appear already after one month follow-up. Histological examination showed that the high-intensity zone contained clusters of nuclear cells originating in the nucleus pulposus. Conclusion: It is concluded that lesions producing high-intensity zones can be induced in an experimental animal model and it can already be detected one month after the trauma. Degeneration process of the nucleus is generally initiated after a peripheral annular lesion.

Cost effectiveness of periradicular infiltration for sciatica: subgroup analysis of a randomized controlled trial

STUDY DESIGN

A subgroup analysis of a prospective, randomized controlled trial was performed.

OBJECTIVE

To describe the cost effectiveness of periradicular infiltration with steroid in subgroups of patients with sciatica.

SUMMARY OF BACKGROUND DATA

A recent trial on periradicular infiltration indicated that a methylprednisolone-bupivacaine combination had a short-term effect, as compared with that of saline. This report describes the efficacy and cost effectiveness of steroid in subgroups of patients with sciatic.

METHODS

This study involved 160 patients with unilateral sciatica. Outcome assessments were leg pain (100-mm visual analog scale), disability on the Oswestry Low Back Disability Questionnaire, and the Nottingham Health Profile. Data on medical costs and sick leaves also were gathered. Patients were randomized for periradicular infiltration with either methylprednisolone-bupivacaine or saline. The adjusted between-group treatment differences at each follow-up assessment, the number of patients free of leg pain (responders, cutoff 75%), and efficacy by the area-under-the-curve method were calculated. For the cost-effectiveness estimate, the total costs were divided by the number of responders. The rate of operations in different subgroups was evaluated by Kaplan-Meier analysis.

RESULTS

In the case of contained herniations, the steroid injection produced significant treatment effects and short-term efficacy in leg pain and in Nottingham Health Profile emotional reactions. For symptomatic lesions at L3-L4-L5, steroid was superior to saline for leg pain, disability, and straight leg raising in the short term. By 1 year, steroid seemed to have prevented operations for contained herniations, costing $12,666 less per responder in the steroid group (P < 0.01). For extrusions, steroid seemed to increase the operation rate, and the steroid infiltration was more expensive, costing $4445 per responder (P < 0.01).

CONCLUSIONS

In addition to short-term effectiveness for contained herniations and lesions at L3-L4-L5, steroid treatment also prevented surgery for contained herniations. However, steroid was countereffective for extrusions. The results of the subgroup analyses call for a verification study.

Correlation of diffusion in lumbar intervertebral disks with occlusion of lumbar arteries: a study in adult volunteers

PURPOSE

To evaluate the correlation of the diffusion values in lumbar intervertebral disks with lumbar artery status and the degree of disk degeneration.

MATERIALS AND METHODS

Sagittal T2-weighted images of the lumbar spine were obtained in 37 asymptomatic volunteers aged 22-68 years. The apparent diffusion coefficient (ADC) of 98 lumbar intervertebral disks was determined, and two-dimensional time-of-flight magnetic resonance angiography was performed on the corresponding 98 lumbar artery pairs (total arteries = 196). The degree of disk degeneration and the status of lumbar arteries were evaluated independently by two radiologists. ADC calculations were performed on the basis of the average signal intensities of the selected region of interest in lumbar disks. The association between ADC values of disks, the disk degeneration, and the status of lumbar arteries of the same level were analyzed with analysis of covariance, and pairwise analysis between groups (Scheffé post hoc multiple comparison) was performed with statistical software. P values less than .01 were considered significant.

RESULTS

The lumbar arterial status correlated strongly with the diffusion values of intervertebral disks, and the ADC values decreased with higher degrees of arterial narrowing. The correlation between disk degeneration and diffusion was not significant. Eight severely degenerated disks with normal lumbar artery status and diffusion values were found.

CONCLUSION

Impaired flow in lumbar arteries is significantly associated with decreased diffusion in lumbar disks and may play an important role in disk degeneration.

Periradicular infiltration for sciatica: a randomized controlled trial

STUDY DESIGN

A randomized, double-blind trial was conducted.

OBJECTIVES

To test the efficacy of periradicular corticosteroid injection for sciatica.

SUMMARY OF BACKGROUND DATA

The efficacy of epidural corticosteroids for sciatica is controversial. Periradicular infiltration is a targeted technique, but there are no randomized controlled trials of its efficacy.

METHODS

In this study 160 consecutive, eligible patients with sciatica who had unilateral symptoms of 1 to 6 months duration, and who never underwent surgery were randomized for double-blind injection with methylprednisolone bupivacaine combination or saline. Objective and self-reported outcome parameters and costs were recorded at baseline, at 2 and 4 weeks, at 3 and 6 months, and at 1 year.

RESULTS

Recovery was better in the steroid group at 2 weeks for leg pain (P = 0.02), straight leg raising (P = 0.03), lumbar flexion (P = 0.05), and patient satisfaction (P = 0.03). Back pain was significantly lower in the saline group at 3 and 6 months (P = 0.03 and 0.002, respectively), and leg pain at 6 months (13.5, P = 0.02). Sick leaves and medical costs were similar for both treatments, except for cost of therapy visits and drugs at 4 weeks, which were in favor of the steroid injection (P = 0.05 and 0.005, respectively). By 1 year, 18 patients in the steroid group and 15 in the saline group underwent surgery.

CONCLUSIONS

Improvement during the follow-up period was found in both the methylprednisolone and saline groups. The combination of methylprednisolone and bupivacaine seems to have a short-term effect, but at 3 and 6 months, the steroid group seems to experience a "rebound" phenomenon.

Severity of symptoms and signs in relation to magnetic resonance imaging findings among sciatic patients

STUDY DESIGN

A cross-sectional study in sciatic population.

OBJECTIVES

To evaluate the separate roles of nerve root entrapment-based on magnetic resonance imaging-and other discogenic pain mechanisms on disability and physical signs among symptomatic sciatic patients.

SUMMARY OF BACKGROUND DATA

Data symptoms of sciatica are generally understood to be generated by nerve root compression, but other pain mechanisms of sciatica have been suggested.

METHODS

The authors obtained magnetic resonance scans from 160 patients with unilateral sciatic pain. The patients reported the intensity of their back and leg pain and their back-specific disability. Clinical examination and magnetic resonance imaging (1.5 T) was performed on every patient. The degree of disc displacement, neural enhancement, and nerve root compression was evaluated from magnetic resonance scans. The correlations of symptoms and signs with magnetic resonance imaging findings were calculated.

RESULTS

The degree of disc displacement in magnetic resonance imaging did not correlate with any subjective symptoms, nor did nerve root enhancement or nerve compression. Magnetic resonance imaging classification was associated, however, with straight leg raising restriction. In regression analysis, straight leg raising restriction was best explained with a simple classification of nonherniations versus herniations.

CONCLUSIONS

The results suggest that a discogenic pain mechanism other than the nerve root entrapment generates the subjective symptoms among sciatic patients. The findings of this study thus indicate that magnetic resonance imaging is unable to distinguish sciatic patients in terms of the severity of their symptoms.

Association of atherosclerosis with low back pain and the degree of disc degeneration

STUDY DESIGN

This was a cross-sectional observational study in which the abdominal aorta was evaluated for atheromatous lesions visible in computed tomographic scans in patients with and without low back pain.

OBJECTIVES

To evaluate whether patients with low back pain have more atherosclerosis in the abdominal aorta than patients without low back pain and whether the severity of atherosclerosis in the abdominal aorta correlates with the grade of disc damage.

SUMMARY OF BACKGROUND DATA

There are studies in which results indicate that insufficient blood supply may be a significant causative factor in disc degeneration. There are also studies in which smoking, one of the risk factors for arterial disease, has been correlated with low back pain. Calf pain has also been shown to correlate with low back pain. Results in a long-term follow-up study have further indicated an association between disc diseases and fatal ischemic heart disease. However, there seems to be only one postmortem study in which results show an association between atherosclerosis in the arteries of the lumbar area and disc diseases.

METHODS

Computed tomographic images of 29 patients with low back pain, who had been evaluated with computed tomographic discography for diagnostic purposes, were evaluated for the quantity of atherosclerotic calcifications visible on computed tomographic scans of the abdominal aorta. A similar evaluation was performed in an age- and sex-matched control group of 52 patients without low back pain selected from among the patients referred for abdominal computed tomography.

RESULTS

Sixteen (55%) of the 29 patients with low back pain had atherosclerotic calcifications visible on computed tomographic scans, whereas 11 (21%) of the 52 age-matched patients without low back pain were found to have aortic calcifications. Eleven (48%) patients with low back pain who were 50 years of age or less (n = 23) had aortic calcifications, whereas only 3 (8%) of the 36 control patients aged less than 50 years had aortic calcifications. There was no correlation between the amount of calcifications and the degree of disc degeneration assessed by computed tomographic discography.

CONCLUSIONS

A significant association is indicated between atheromatous lesions in the abdominal aorta and low back pain.

Bony vibration stimulation test combined with magnetic resonance imaging. Can discography be replaced?

STUDY DESIGN

The results of two noninvasive methods, magnetic resonance imaging and a bony vibration test, were compared with discographic pain provocation findings.

OBJECTIVES

To evaluate whether the combination of magnetic resonance imaging and vibration pain provocation tests could be used to replace discography in low back pain diagnostics.

SUMMARY OF BACKGROUND DATA

Magnetic resonance imaging gives a wealth of visual information on anatomic changes of the spine with often unknown clinical significance. Discographic examination of the spine is still the only widely accepted diagnostic method that can relate the pathoanatomic changes to the patient's clinical pain. Internal anular rupture has been shown to be one of the sources of back pain. The bony vibration test of the spinal processes has been shown correlate well with discographic pain provocation tests in cases of internal anular rupture.

METHODS

The three lowest lumbar discs of 33 patients with back pain were examined by means of magnetic resonance imaging and a bony vibration stimulation test, and the results were compared with those from computed tomography-discography.

RESULTS

In cases of intradiscal magnetic resonance imaging findings, the vibration provocation test showed a sensitivity of 0.88 and a specificity of 0.50 compared with the discographic pain provocation test. If the patients with previous back surgery were excluded, the specificity was 0.75. In the cases of total anular rupture, the sensitivity was 0.50, and the specificity was 0.33.

CONCLUSION

The combination of the two noninvasive methods, vibration stimulation and magnetic resonance imaging, gives more information on the origin of the back pain than magnetic resonance imaging alone. The pathoanatomic changes seen in magnetic resonance imaging can be correlated with the patient's disorder more reliably using the vibration provocation test in the cases of partial anular ruptures. The use of discography can be limited mostly to cases with total anular ruptures detected by magnetic resonance imaging.