CT remains gold standard for identifying facet arthrosis in the cervical spine

[Harrison]

CT remains gold standard for identifying facet arthrosis in the cervical spine

By Robert Trace
June 2008

GENEVA — Some orthopedic spine surgeons rely on magnetic resonance imaging to identify cervical facet arthrosis, but computed tomography should remain the diagnostic standard, according to a recent study presented at Spine Week 2008, here.

"With cervical disc arthroplasty, the presence of facet arthrosis remains a contraindication," said Melvin Helgeson, MD, of the Walter Reed Army Medical Center in Washington.

Three spine surgeons retrospectively evaluated CT scans and MRIs of the same patients, which were obtained within 30 days of each other and sent to the cervical spine clinic at the center in a blinded, random fashion, according to the abstract. Reviewers graded both the MRI and CT scans three times, and if the facet was considered abnormal, each reviewer graded the degree of arthrosis. "We then compared the radiologist's findings with what we found," he said.

According to Helgeson, 43.1% of 594 facets were categorized as normal on CT scan; of those, MRI concordance was only 63.7%, with moderate/substantial intermethod agreement. Meanwhile, MRI was concordant only 15.9% of the time in patients with ankylosed facet joints identified on CT.

Also, CT interrater reliability showed substantial agreement for diagnoses of both normal and ankylosis, as well as fair agreement for lesser degrees of facet arthrosis. MRI interrater reliability showed fair/moderate agreement in normal and ankylosed segments and only slight agreement with lesser degrees of facet arthrosis.

CT intrarater reliability showed substantial agreement in normal or ankylosed joints, but only fair agreement for all other categories; MRI showed only fair agreement in all categories, according to Helgeson.

"MRI was not as accurate as CT in detecting facet arthrosis and it was not as reliable in determining the degree of arthrosis," he said. "As a result, we think CT should remain the gold standard."

For more information:

Lehman R, Helgeson M Keeler K, et al. Comparison of magnetic resonance imaging and computed tomography in predicting facet arthrosis in the cervical spine. Paper C47. Presented at Spine Week 2008. May 26-31, 2008. Geneva.

Courtesy of Slack Inc.