Comparison of regional skeletal muscle tissue oxygenation in college athletes and sedentary control subjects using quantitative BOLD MR imaging

Abstract

Blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging permits noninvasive assessment of tissue oxygenation. We hypothesized that BOLD imaging would allow for regional evaluation of differences in skeletal muscle oxygenation between athletes and sedentary control subjects, and dynamic BOLD responses to ischemia (i.e., proximal cuff occlusion) and reactive hyperemia (i.e., rapid cuff deflation) would relate to lower extremity function, as assessed by jumping ability. College football athletes (linemen, defensive backs/wide receivers) were compared to sedentary healthy controls. BOLD signal of the gastrocnemius, soleus, anterior tibialis, and peroneus longus was assessed for peak hyperemic value (PHV), time to peak (TTP), minimum ischemic value (MIV), and time to recovery (TTR). Significantly higher PHVs were identified in athletes versus controls for the gastrocnemius (linemen, 15.8 ± 9.1%; defensive backs/wide receivers, 17.9 ± 5.1%; controls, 7.4 ± 3.5%), soleus (linemen, 25.9 ± 11.5%; backs/receivers, 22.0 ± 9.4%; controls, 12.9 ± 5.8%), and anterior tibialis (linemen, 12.8 ± 5.3%; backs/receivers, 12.6 ± 3.9%; controls, 7.7 ± 4.0%), whereas no differences in PHV were found for the peroneus longus (linemen, 14.1 ± 6.9%; backs/receivers, 11.7 ± 4.6%; controls, 9.0 ± 4.9%). In all subject groups, the gastrocnemius and soleus muscles exhibited the lowest MIVs during cuff occlusion. No differences in TTR were found between muscles for any subject group. PHV of the gastrocnemius muscle was significantly and positively related to maximal vertical (r = 0.56, P = 0.002) and broad jump (r = 0.47, P = 0.01). These results suggest that BOLD MR imaging is a useful noninvasive tool for evaluating differences in tissue oxygenation of specific muscles between active and sedentary individuals, and peak BOLD responses may relate to functional capacity.

Keywords: Blood oxygen level dependent; exercise training; magnetic resonance imaging; tissue oxygenation; vascular function.

Figure 1

Regional assessment of dynamic changes in skeletal muscle tissue oxygenation during cuff occlusion and reactive hyperemia. (A) Anatomical T1‐FLASH images were used to identify and guide segmentation of lower extremity calf muscles. (B) Muscle groups of interest were segmented on T2*‐weighted BOLD images to generate (C) averaged dynamic time‐course data in each muscle group for each of the three subject groups. Arrows indicate time of cuff inflation (initialization of ischemia) and deflation (start of reactive hyperemia phase). Plotted data represents average values for all subjects within each group.

Figure 2

Evaluation of peak hyperemic value between‐subject groups. All values are means ± SD. *significantly different from linemen. ^†significantly different from backs/receivers (P < 0.05).

Figure 3

Regional evaluation and comparison of quantitative BOLD indices between calf muscles of interest. All values are means ± SD. *significantly different from gastrocnemius. ^†significantly different from soleus. ^‡significantly different from peroneus longus (P < 0.05).

Figure 4

Relationship between peak hyperemic value of the gastrocnemius muscle and maximal vertical and broad jump. Peak hyperemic BOLD response in the gastrocnemius was significantly and positively related to both (A) vertical and (B) broad jumping ability. N = 28 subjects.