Emerging Role of Muscle Imaging in Diagnosis and Evaluation of Pompe Disease Patients.

The adult form of type II glycogenosis (GSDII) is a slowly progressive disease, with a few notable exceptions of patients who remain remarkably stable for decades and others who quite suddenly start to decline very quickly. A number of GSDII patients with nontypical presentation are misdiagnosed or diagnosed late. Whole-body muscle NMR imaging has proven useful in identifying as yet unrecognised GSDII patients by detecting muscle fatty infi ltration patterns that are highly suggestive of the disease. In particular, Pompe patients show early fatty infi ltration of tongue and subscapularis. Quantitative NMR imaging has interesting diagnostic applications but its primary role is to provide non-invasive biomarkers and assess disease progression and/or response to intervention. Studies have reported the effect of enzyme substitution therapy on muscle mass using NMRI. Imaging biomarkers may be of particular importance for adultform GSDII therapeutic trials, where obvious clinical benefi t has been diffi cult to document. Muscle water T2 increase is a non-specifi c process but it closely relates to “disease activity”, whatever the underlying mechanisms: infl ammation, necrosis, oedema. In FSHD patients, it has been suggested that abnormal T2 is predictive of fatty degenerative changes in subsequent years. We analysed the imaging data collected Emerging Role of Muscle Imaging in Diagnosis and Evaluation of Pompe Disease Patients