Forecasting Outcomes Using PET Imaging for Cervical Spinal Cord Compression Patients

For patients with degenerative cervical myelopathy, imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) could act as a marker for a potentially reversible phase of the disease in which considerable clinical improvement can be accomplished.

According to research published in the September 2013 issue of the Journal of Nuclear Medicine, patients who exhibited hypermetabolism at the point of compression in their spine experienced improved outcomes after undergoing decompressive surgery.

Cervical spinal stenosis is a disorder in which the spinal canal tapers in the neck. While many patients do not have symptoms, once symptoms appear, it typically is a sign of the presence of myelopathy. This compression can lead to progressive neurologic deficits, such as weakness, numbness, or tingling in a leg, foot, hand, or arm.

The investigators’ goal was to evaluate the regional alterations of glucose metabolism of the cervical spinal cord using 18F-FDG PET imaging. “To date, experiences with 18F-FDG PET in symptomatic patients with degenerative cervical spine stenosis and consecutive compressive myelopathy are very limited,” said Norbert Galldiks, MD, from Institute of Neuroscience and Medicine, Research Center Jülich (Jülich, Germany), and department of neurology, University of Cologne (Germany); one of the lead researchers of the study. “In the present study, we present the results of preoperative magnetic resonance imaging [MRI] and 18F-FDG PET imaging and postoperative follow-up imaging 12 months after decompressive surgery. Imaging findings were correlated with the clinical outcome.”

Researchers saw two substantially different patterns of 18F-FDG uptake among the 20 study participants prior to surgery: about half of the patients had increased 18F-FDG uptake at the site of spinal cord compression and were categorized as myelopathy type 1, whereas the other half had inconspicuous 18F-FDG uptake and were classified as myelopathy type 2. Postoperatively, those with myelopathy type 1 had a marked decrease in 18F-FDG uptake, whereas myelopathy type 2 patients had only a moderate decline in uptake.

The overall outcome in myelopathy type 1 patients was encouraging, and the patients showed significant improvement on their functional status assessment. In contrast, there was no significant clinical change in patients with inconspicuous 18F-FDG uptake.

“A hypermetabolism of the cervical spinal cord at the level of cervical spine stenosis as indicated by a locally increased 18F-FDG uptake seems to be a marker for a potentially reversible phase of a compression-induced cervical myelopathy,” explained Dr. Galldiks. “The lesion of the spinal cord seems to be predominantly functional. Presence of this metabolic pattern reflects the time frame when decompressive surgery can lead to substantial clinical improvement. To stratify eligible patients for decompressive surgery, our findings may help to implement 18F-FDG PET investigations of the cervical spine in clinical routine.”

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