Impaired skeletal muscle microcirculation in systemic sclerosis.

Area of Science:

• Medical Imaging
• Cardiovascular System
• Rheumatology

Background:

• Systemic sclerosis (SSc) can affect skeletal muscles through microcirculation abnormalities.
• Blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) is a potential tool to investigate these changes.

Purpose of the Study:

• To investigate skeletal muscle microcirculation in SSc patients using BOLD MRI.
• To compare muscle oxygenation dynamics during ischemia and hyperemia between SSc patients and healthy controls.

Main Methods:

• BOLD MRI was performed on calf muscles of 11 SSc patients and 12 healthy volunteers.
• Measurements included oxygen desaturation during ischemia and re-oxygenation during reactive hyperemia.
• Key parameters analyzed were T2*min, T2*max, time to T2* peak (TTP), and slopes of oxygen normalization.

Main Results:

• SSc patients exhibited more intense oxygen desaturation during ischemia (-15.0% vs. -9.1%) and impaired oxygenation during hyperemia (9.2% vs. 20.1%) compared to controls.
• Muscle oxygen normalization was significantly slower and prolonged in SSc patients.
• These microcirculatory impairments were most pronounced in the gastrocnemius muscle.

Conclusions:

• BOLD MRI effectively demonstrates significant impairment of skeletal muscle microcirculation in systemic sclerosis.
• These findings suggest microvascular dysfunction contributes to muscle symptoms in SSc.