Determination of skeletal muscle perfusion using arterial spin labeling NMRI: Validation by comparison with venous occlusion plethysmography

Tl-based determination of perfusion was performed with the high temporal an d spatial resolution that monitoring of exercise physiology requires. As no data were available on the validation of this approach in human muscles, T -1-based NMRI of perfusion was compared to standard strain-gauge venous occ lusion plethysmography performed simultaneously within a 4 T magnet. Two di fferent situations were investigated in 21 healthy young volunteers: 1) a 5 -min ischemia of the leg, or 2) a 2-3 min ischemic exercise consisting of a plantar flexion on an amagnetic ergometer. Leg perfusion was monitored ove r 5-15 min of the recovery phase, after the air-cuff arterial occlusion had been released. The interesting features of the sequence were the use of a saturation-recovery module for the introduction of a T, modulation and of s ingle-shot spin echo for imaging. Spatial resolution was 1.7 x 2.0 mm and t emporal resolution was 2 s. For data analysis, ROIs were traced on differen t muscles and perfusion was calculated from the differences in muscle signa l intensity in successive images. To allow comparison with the global measu rement of perfusion by plethysmography, the T-1-based NMR measurements in e xercising muscles were rescaled to the leg cross-section. The perfusion mea surements obtained by plethysmography and NMRI were in close agreement with a correlation coefficient between 0.87 and 0.92. This indicates that pulse d arterial techniques provide determination of muscle perfusion not only wi th superior spatial and temporal resolution but also with exactitude. (C) 2 001 Wiley-Liss, Inc.