Purpose: To assess absolute perfusion in the skeletal muscle of mice in vivo with spin labeling magnetic resonance imaging (MRI) under normal and stress conditions.
Materials and methods: Absolute perfusion in the skeletal muscle of 27 C57BL/6 mice was assessed in vivo non-invasively by spin labeling MRI at 7.05 T. This technique was based on the acquisition of T1 maps with global and slice-selective spin inversion in separate acquisitions. T1 mapping was performed by inversion recovery snapshot fast low angle shot imaging. To guarantee proper spin inversion within the whole mouse, a dedicated radiofrequency (RF) coil combination was constructed. A birdcage resonator was used for transmission, while detection of the MRI signal was achieved by a surface coil.
Results: Basal perfusion in the hindlimbs was determined to be 94 +/- 10 mL (100 g x minute)(-1) (mean +/- standard error of the mean [SEM], N = 27). This value is in good agreement with perfusion values determined by invasive techniques such as microspheres. A subgroup of six animals received a constant dose of 4 mg (kg x minute)(-1) of the vasodilator adenosine by an intraperitoneal catheter. In this case, perfusion was significantly increased to 179 +/- 56 mL (100 g x minute)(-1) (mean +/- SEM, N = 6, P < 0.02). Mean basal perfusion in this subgroup was 96 +/- 26 mL (100 g x minute)(-1).
Conclusion: Spin labeling MRI is a well-suited technique for the in vivo assessment of absolute perfusion in the murine skeletal muscle.
Copyright 2002 Wiley-Liss, Inc.