Clinical features of PM/DM patients with increased FDG uptake in muscles. Data are number (%) unless otherwise indicated.
| Increased FDG Uptake in Muscles | + | – | p |
|---|---|---|---|
| Patients, n | 8 | 16 | |
| PM:DM | 5:3 | 6:10 | 0.39 |
| Age, mean ± SD yrs | 56.6 ± 18.7 | 56.9 ± 14.4 | 0.21 |
| Sex, M:F | 3:5 | 5:11 | 1.00 |
| Myalgia | 4/8 (50.0) | 9/16 (56.3) | 1.00 |
| Muscle weakness | 6/8 (75.0) | 12/16 (75.0) | 1.00 |
| CK, IU/ml | 3574 ± 4318 | 3707 ± 4453 | 0.31 |
| Anti-Jo-1 AB-positive | 0/8 (0.0) | 4/16 (25.0) | 0.26 |
| Myopathic change on EMG | 8/8 (100) | 8/14 (57.1) | 0.051 |
| Abnormal findings on muscle MRI | 5/7 (71.4) | 7/14 (50) | 0.83 |
| Abnormal findings in biopsy samples | 6/6 (100) | 11/11 (100) | 1.00 |
| Necrotic/regenerating fiber | 6/6 (100) | 10/11 (90.9) | 1.00 |
| Inflammatory cell infiltration | 4/6 (66.7) | 9/11 (81.8) | 0.72 |
| Perimysium | 4/6 (66.7) | 9/11 (81.8) | 0.72 |
| Endomysium | 4/6 (66.7) | 2/11 (18.2) | 0.109 |
| Interstitial lung disease | 6/8 (75.0) | 12/16 (75.0) | 1.00 |
| Malignancy | 1/8 (12.5) | 0/16 (0.0) | 0.33 |
CK: creatine kinase; DM: dermatomyositis; PM: polymyositis; EMG: electromyography; MRI: magnetic resonance imaging; Ab: antibody; FDG: fluorodeoxyglucose.