Purpose: To investigate the origin of skeletal muscle BOLD MRI alterations in patients with systemic sclerosis (SSc) by correlating BOLD MRI T2* signal of calf muscles with microcirculatory blood flow of calf skin measured by laser Doppler flowmetry (LDF).
Materials and methods: BOLD MRI (3T) and LDF measurements were performed in 12 consecutive SSc patients (6 women, 6 men; mean age 54.0 ± 10.0 years) and 12 healthy volunteers (4 men, 8 women; mean age 44.7 ± 13.1 years). For both modalities, the same cuff compression paradigm at mid-thigh level was used. LDF datasets were acquired using a PeriScan PIM II Imager (Perimed AB, Stockholm, Sweden) at the upper calf corresponding to the level of MR imaging. Cross-correlations of BOLD and LDF signal intensity changes depending on time lags between both time series were calculated.
Results: Maximal cross-correlations of BOLD T2* and LDF measurements were calculated as 0.93 (healthy volunteers) and 0.94 (SSc patients) for a BOLD time lag of approximately 10 s. Key parameter analysis suggested that in contrast to hyperemic BOLD signal loss at maximum value in SSc patients, ischemic T2* decrease cannot be explained by differences of tissue perfusion.
Conclusion: Skeletal muscle BOLD T2* signal in SSc patients is closely correlated with changes of microperfusion as detected by LDF.
Keywords: blood oxygenation level dependent (BOLD) MRI; laser Doppler flowmetry (LDF); microcirculation; systemic sclerosis (scleroderma).
© 2013 Wiley Periodicals, Inc.