Uncertainties in the measurement of lumbar spinal stenosis at MR imaging: are they clinically relevant?

Relationship Between Magnetic Resonance Imaging Findings and Clinical Symptoms in Patients with Suspected Lumbar Spinal Canal Stenosis: a Case-control Study

Introduction:

Despite the availability of many imaging and clinical criteria for diagnosis of lumbar spinal stenosis (LSS), its correct diagnosis is a challenge for clinicians and radiologists.

Aim:

The aim of this study was to examine the relationship between magnetic resonance imaging (MRI) findings and clinical symptoms in symptomatic and asymptomatic patients with suspected LSS in MRI.

Methods:

This study is a case-control study. Two groups of 100 symptomatic and asymptomatic individuals (aged 20 to 84 years) with suspected lumbar spinal canal stenosis who referred to the imaging unit for lumbosacral MRI were included. The clinical symptoms and radiological parameters in MRI for all patients were recorded and relationship between them were evaluated.

Results:

Among the quantitative imaging findings, only the anterior-posterior diameter of the canal at the level of the intervertebral disc, the central spinal canal cross-section area and lateral recesses cross-sectional area were valuable. Coefficient of stenosis was calculated for the case and control groups which had statistically significant difference (p<0.001). The difference between qualitative findings such as disc protrusion, extrusion, sequestration and Cauda Equine serpain or redundant was significant between the two groups.

Conclusion:

According to the results, among the quantitative criteria of MRI imaging findings, central spinal canal cross-section (less than 77.5 mm2 for central stenosis) and lateral recesses cross-section (less than 22.5 mm2 for lateral stenosis) had the highest sensitivity and specificity for LSS diagnosis in symptomatic and asymptomatic patients with suspected LSS. Strongest observed correlation was between neurogenic claudication and LSS diagnostic radiological markers.

Preoperative MRI in Patients With Intermittent Neurogenic Claudication: Relevance for Diagnosis and Prognosis

STUDY DESIGN

We studied baseline magnetic resonance images of 155 patients with intermittent neurogenic claudication and lumbar spinal stenosis (LSS). Magnetic resonance imaging (MRI) and patient data were gathered from participants of a randomized trial.

OBJECTIVE

It is believed that the narrowness of the lumbar spinal canal correlates to the severity of complaints and that it may be a good predictor of clinical outcome if treated. However, this hypothesis has never been (prospectively) tested.

SUMMARY OF BACKGROUND DATA

MRI is an important tool to confirm the diagnosis of LSS as a cause for intermittent neurogenic claudication.

METHODS

Three raters were asked to evaluate the magnetic resonance images (Schizas scale). Symptom severities at baseline and 1-year follow-up were quantified. The radiological scores were correlated with clinical baseline and outcome scores to assess diagnostic and prognostic value of MRI findings at baseline.

RESULTS

There was good agreement on the clinically relevant level of LSS (kappa range 0.57-0.64). MRI assessment of grading of compression (kappa 0.33-0.46) did not correlate with baseline MRDQ nor with outcome based on postoperative change in MRDQ (P = 0.61). However, both absence of epidural fat and presence of tortuous caudal nerves on magnetic resonance images (kappa 0.53-0.72 and 0.67-0.70) in patients with LSS were relatively good predictors for satisfactory recovery after surgery (P = 0.03 and P < 0.01).

CONCLUSION

The grading of compression on the preoperative MRI is neither ambiguous nor correlating to severity of clinical condition. It does, furthermore, not have the ability to predict the outcome after 1 year if surgically treated.

LEVEL OF EVIDENCE

2.

Using Magnetic Resonance Myelography to Improve Interobserver Agreement in the Evaluation of Lumbar Spinal Canal Stenosis and Root Compression

STUDY DESIGN

Cross-sectional retrospective study designed to assess interobserver agreement.

PURPOSE

To investigate if interobserver agreement using magnetic resonance imaging (MRI) in the evaluation of lumbar spinal canal stenosis and root compression can be improved upon combination with magnetic resonance myelography (MRM).

OVERVIEW OF LITERATURE

The interpretation of lumbar spinal MRI, which is the imaging modality of choice, often has a significant influence on the diagnosis and treatment of low back pain. However, using MRI alone, substantial interobserver variability has been reported in the evaluation of lumbar spinal canal stenosis and nerve root compression.

METHODS

Hardcopies of 30 lumbar spinal MRI (containing a total of 150 disk levels) as well as MRM films were separately reviewed by two radiologists and a neurosurgeon. At each intervertebral disk, the observers were asked to evaluate the thecal sac for the presence and degree of spinal stenoses (mild, moderate, or severe) and presence of root canal compression. Interobserver agreement was measured using weighted kappa statistics.

RESULTS

Regarding lumbar spinal canal stenosis, interobserver agreement between the two radiologists was moderate (kappa, 0.4) for MRI and good (kappa, 0.6) for combination with MRM. However, the agreement between the radiologist and neurosurgeon remained fair for MRI alone or in combination with MRM (kappa, 0.38 and 033, respectively). In the evaluation of nerve root compression, interobserver agreement between the radiologists improved from moderate (kappa, 0.57) for MRI to good (kappa, 0.73) after combination with MRM; moderate agreement between the radiologist and neurosurgeon was noted for both MRI alone and after combination with MRM (kappa, 0.58 and 0.56, respectively).

CONCLUSIONS

Interobserver agreement in the evaluation of lumbar spinal canal stenosis and root compression between the radiologists improved when MRM was combined with MRI, relative to MRI alone.