title: Evaluation of exercised or cooled skeletal muscle on the basis of diffusion-weighted magnetic resonance imaging.
abstract: In this study, we assessed the physiological changes after exercising or cooling skeletal muscles on the basis of the apparent diffusion coefficient (ADC) values in magnetic resonance (MR) diffusion-weighted images (DWIs). DWIs of the ankle dorsiflexors were acquired with a 1.5-T MR device before and after exercising (22 subjects) or cooling (19 subjects). The exercise comprised a 5-min walk with the ankles dorsiflexed and a 30-time ankle dorsiflexion. Cooling (0 degrees C) of the ankle dorsiflexors was performed for 30 min. ADC values were calculated as ADC1-reflecting diffusion and perfusion and ADC2-approximating the true diffusion coefficient of the ankle dorsiflexors before and after exercising or cooling. ADC1 and ADC2 significantly increased with exercise and decreased with cooling (P < 0.05). Considering both diffusion and perfusion, ADC values allowed us to evaluate the intramuscular changes induced by exercising or cooling in terms of the motion of water molecules and microcirculation.
authors.affiliation: Faculty of Sport Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama, 359-1192, Japan, o.yanagisawa@aoni.waseda.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Yanagisawa
authors.forename: Daisuke
authors.initials: D
authors.lastname: Shimao
authors.forename: Katsuya
authors.initials: K
authors.lastname: Maruyama
authors.forename: Matthew
authors.initials: M
authors.lastname: Nielsen
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000033:anatomy & histology / Q000502:physiology; D003080:Cold Temperature; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology*