Publication Date:
2014-12-23
Description:
Purpose Develop an MRI method to estimate skeletal muscle oxygen consumption (VO 2 ) with dynamic exercise using simultaneous measurement of venous blood flow (VBF) and venous oxygen saturation (SvO 2 ). Methods Real-time imaging of femoral VBF using a complex-difference method was interleaved with imaging of venous hemoglobin oxygen saturation (SvO 2 ) using magnetic susceptometry to estimate muscle VO 2 (Fick principle). Nine healthy subjects performed repeated 5-watt knee-extension (quadriceps) exercise within the bore of a 1.5 Tesla MRI scanner, for test/re-test comparison. VBF, SvO 2 , and derived VO 2 were estimated at baseline and immediately (〈1 s) postexercise and every 2.4 s for 4 min. Results Quadriceps muscle mass was 2.43 ± 0.31 kg. Mean baseline values were VBF = 0.13 ± 0.06 L/min/kg, SvO 2 = 69.4 ± 10.1%, and VO 2 = 6.8 ± 4.1 mL/min/kg. VBF, SvO 2 , and VO 2 values from peak exercise had good agreement between trials (VBF = 0.9 ± 0.1 versus 1.0 ± 0.1 L/min/kg, R 2 = 0.83, CV = 7.6%; SvO 2 = 43.2 ± 13.5 versus 40.9 ± 13.1%, R 2 = 0.88, CV = 15.6%; VO 2 = 95.7 ± 18.0 versus 108.9 ± 17.3 mL/min/kg, R 2 = 0.88, CV = 12.3%), as did the VO 2 recovery time constant (26.1 ± 3.5 versus 26.0 ± 4.0 s, R 2 = 0.85, CV = 6.0%). CV = coefficient of variation. Conclusion Rapid imaging of VBF and SvO 2 for the estimation of whole muscle VO 2 is compatible with dynamic exercise for the estimation of peak values and recovery dynamics following exercise with good reproducibility. Magn Reson Med, 2014. © 2014 Wiley Periodicals, Inc.
Print ISSN:
0740-3194
Electronic ISSN:
1522-2594
Topics:
Medicine
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