Analysis of the masseter muscle in patients with systemic sclerosis: a study by magnetic resonance imaging.

Objectives: The aim of this study was to investigate the relationship between mandibular osteolysis and the T1 and T2 tissue signal strength and morphology of the masseter muscle in patients with systemic sclerosis (SS).
Methods: All patients with SS underwent panoramic radiography to detect mandibular osteolysis. MRI of the masseter was performed on 15 patients with SS and 10 healthy control subjects.
Results: All patients presented mean T1 values that were statistically equal. The patients with osteolysis presented mean T2 values that were the same as those of patients without osteolysis and normal individuals. The patients without osteolysis showed stronger T2 signals than did the normal individuals. The morphological analysis showed more atrophy, fatty replacement and rectified morphology in relation to the healthy subjects.
Conclusions: The patients with SS presented more atrophy, fat replacement and rectification than did the normal individuals. The T2 signal was significantly stronger among the patients with SS without osteolysis than among normal individuals and among patients with SS and osteolysis.