Abstract
Purpose: Macrophagic myofasciitis (MMF) is an emerging condition with specific muscle lesions characterized by an abnormal long-term persistence of aluminum hydroxide particles within macrophages at the site of previous immunization. Patients present with diffuse arthromyalgias, chronic fatigue, and cognitive dysfunction. The aim of this study was to characterize brain FDG-PET metabolic abnormalities in MMF patients, and the relation with cognitive dysfunction. Methods: FDG-PET brain imaging and a comprehensive battery of neuropsychological tests were performed in 100 consecutive MMF patients (mean age, 45.9 ± 11.8 y; women, 74%) followed in our Reference Center for Rare Neuromuscular Diseases. Images were analyzed using statistical parametric mapping (SPM12). Using ANCOVA analysis, all FDG-PET brain images of MMF patients were compared to a reference population of 44 healthy subjects matched for age (mean age, 45.4 ± 16 y; P = 0.87) and gender (women, 73%; P = 0.88). All results were collected at a P-value < 0.005 at the voxel level, for clusters k ≥ 200 voxels (corrected for cluster volume) with adjustment for age and gender. The neuropsychological assessment identified four categories of patients with: (i) no significant cognitive impairment (n = 42); (ii) frontal sub-cortical (FSC) dysfunction (n = 29); (iii) papezian dysfunction (n = 22); and (iv) callosal disconnection (n = 7). Results: In comparison with healthy subjects, ANCOVA analysis of the whole population of patients with MMF exhibited a pattern of hypometabolism (p<0.001) involving occipital lobes, temporal lobes, limbic system, cerebellum and frontoparietal cortices. The subgroup of patients with FSC dysfunction exhibited larger extents of involved area (35223 voxels vs. 13680 voxels in the subgroup with papezian dysfunction and 5453 voxels in patients without cognitive impairment). Not significant result was obtained in the last subgroup due to its small population size. Conclusion: Our study identified in MMF patients a peculiar patterm of a cerebral glucose hypometabolism mostly marked in MMF patients with FSC dysfunction. This characteristic pattern could reprensent a diagnostic biomarker of MMF in patients with chronic fatigue syndrome and cognitive dysfunction.
- Neurology
- PET
- PET/CT
- Statistical Analysis
- Aluminum hydroxide
- Brain FDG-PET
- Dysexecutive syndrome
- Macrophagic myofasciitis
- Statistical parametric mapping
- Copyright © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.