Utility of FDG PET/CT in patients with Myofascial Pain Syndrome

Mittra E, Marx E, Biswal S, Mackey S. Utility of FDG PET/CT in patients with Myofascial Pain Syndrome. J. Nucl. Med. 2015;56(supplement 3):1694-1694.
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1694Objectives The mechanism of uptake of 18F-FDG suggests a role in the evaluation of pain. Areas of FDG uptake in muscle are often seen in oncology PET scans but of unknown etiology. To understand this better, we examined a group of patients with significant focal muscle pain with FDG PET/CT.Methods Patients with a diagnosis of Myofascial Pain Syndrome (MPS) and active trigger points were prospectively recruited from the Stanford University Pain Management Center and scanned with a whole-body 18F-FDG PET/CT. Patients with a history of cancer, recent surgery, or recent trigger point injections were excluded. Medications that may decrease FDG uptake were temporarily stopped. The location of the patients pain were identified by a physician, as well as the by the patient, and recorded on a standard whole-body diagram. The PET/CT scans were reviewed without knowledge of the location of the patient s pain, then correlated.Results Eight subjects included 5 women and 3 men, with an average age of 49 years. The average pain score was 7.5/10. The sites of pain primarily included the neck and back. The physician and patient reported sites of pain agreed in all cases. Only 1 out of the 8 patients studied had any abnormal 18F-FDG uptake seen on their PET/CT scan; all other scans were negative, both qualitatively and qualitatively. That one patient (see figure) had abnormal focal FDG uptake in the right T9/10 intervertebral space, which correlated with the radicular distribution of his pain along the right mid-back. Ultimately, an osteid osteoma was removed from this site with subsequent pain resolution.Conclusions Our hypothesis that FDG would show focal areas of muscle activity in patients with MPS was not borne out. These results suggest that increased glucose utilization is either not associated with muscle pain, or the degree of uptake is below the sensitivity for PET. As such, this study does not support the use of FDG PET for MPS. Other types of painful conditions may have different findings and should be studied.
Last updated on 03/02/2021