Detection of Inflammatory Lesions by F-18 Fluorodeoxyglucose Positron Emission Tomography in Patients with Polymyositis and Dermatomyositis
The Journal of Rheumatology, 07/02/2012
Owada T et al. – FDG–PET imaging has limited usefulness for the evaluation of myositis in patients with polymyositis (PM)/dermatomyositis (DM) because of its low sensitivity, although it might be useful for detection of malignancy in these patients.Methods
- FDG–PET imaging was performed in 24 patients with active inflammatory myopathy (PM, 11; DM, 13).
- The images were read by radiologists in a blinded manner. FDG uptake into muscles was judged positive when the intensity of muscles was higher than or equal to that of the liver.
- As controls, FDG imaging findings of patients with a lung mass and without muscle diseases were used.
- To investigate associations between FDG–PET findings and clinical/laboratory findings, the patients’ medical records were reviewed retrospectively.
- Increased FDG uptake in muscles was found in 8 of 24 (33%) patients.
- In 67 of 69 (97%) controls without muscle diseases, no muscle FDG uptake was detected.
- The sensitivity of FDG–PET to detect myositis was lower than that of electromyogram (EMG), magnetic resonance imaging, and muscle biopsy.
- There were no significant differences in clinical manifestations between patients with and without increased FDG uptake in muscles, although patients with FDG muscle uptake had a tendency to have extended myositis with endomysial cell infiltration.
- FDG–PET detected neoplasms in patients with associated malignancy.
- FDG uptake in lungs was found in 7 of 18 patients with interstitial lung disease.